Company Quick10K Filing
Quick10K
Comerica
Market
Closing Price ($) Shares Out (MM) Market Cap ($MM)
$76.22 154 $11,750
Financials
10-Q 2019-06-30 Quarter: 2019-06-30
10-Q 2019-03-31 Quarter: 2019-03-31
10-K 2018-12-31 Annual: 2018-12-31
10-Q 2018-09-30 Quarter: 2018-09-30
10-Q 2018-06-30 Quarter: 2018-06-30
10-Q 2018-03-31 Quarter: 2018-03-31
10-K 2017-12-31 Annual: 2017-12-31
10-Q 2017-09-30 Quarter: 2017-09-30
10-Q 2017-06-30 Quarter: 2017-06-30
10-Q 2017-03-31 Quarter: 2017-03-31
10-K 2016-12-31 Annual: 2016-12-31
10-Q 2016-09-30 Quarter: 2016-09-30
10-Q 2016-06-30 Quarter: 2016-06-30
10-Q 2016-03-31 Quarter: 2016-03-31
10-K 2015-12-31 Annual: 2015-12-31
10-Q 2015-09-30 Quarter: 2015-09-30
10-Q 2015-06-30 Quarter: 2015-06-30
10-Q 2015-03-31 Quarter: 2015-03-31
10-K 2014-12-31 Annual: 2014-12-31
10-Q 2014-09-30 Quarter: 2014-09-30
10-Q 2014-06-30 Quarter: 2014-06-30
10-Q 2014-03-31 Quarter: 2014-03-31
10-K 2013-12-31 Annual: 2013-12-31
Current Reports
8-K 2019-08-01 Other Events, Exhibits
8-K 2019-07-18 Other Events, Exhibits
8-K 2019-07-17 Exhibits
8-K 2019-06-10 Regulation FD, Exhibits
8-K 2019-04-23 Officers, Regulation FD, Exhibits
8-K 2019-04-23 Regulation FD, Exhibits
8-K 2019-04-23 Shareholder Vote
8-K 2019-04-16 Exhibits
8-K 2019-03-08 Regulation FD, Exhibits
8-K 2019-01-28 Other Events, Exhibits
8-K 2019-01-16 Exhibits
8-K 2019-01-08 Enter Agreement
8-K 2018-12-03 Regulation FD, Exhibits
8-K 2018-10-18 Other Events
8-K 2018-10-16 Exhibits
8-K 2018-09-11 Regulation FD, Exhibits
8-K 2018-07-26 Other Events, Exhibits
8-K 2018-07-24 Officers, Regulation FD, Exhibits
8-K 2018-07-17 Exhibits
8-K 2018-06-11 Regulation FD, Exhibits
8-K 2018-05-23 Regulation FD, Exhibits
8-K 2018-04-24 Officers, Shareholder Vote, Exhibits
8-K 2018-04-17 Exhibits
8-K 2018-03-02 Regulation FD, Exhibits
8-K 2018-02-05 Enter Agreement
8-K 2018-01-23 Officers
8-K 2018-01-16 Exhibits
Comparables
TEL TE Connectivity 30,620
TELL Tellurian 2,400
PBFX PBF Logistics 1,280
KIN Kindred Biosciences 350
DOGZ Dogness 87
VLRX Valeritas Holdings 37
PW Power REIT 11
BHNY Brighthouse Life Insurance Co of Ny 0
NSM Nationstar 0
CAT9 CAT9 0
CMA 2019-06-30
Content
Part I. Financial Information
Item 1. Financial Statements
Note 1 - Basis of Presentation and Accounting Policies
Note 2 - Fair Value Measurements
Note 3 - Investment Securities
Note 4 - Credit Quality and Allowance for Credit Losses
Note 5 - Derivative and Credit-Related Financial Instruments
Note 6 - Variable Interest Entities (Vies)
Note 7 - Medium- and Long-Term Debt
Note 8 - Accumulated Other Comprehensive Loss
Note 9 - Net Income per Share
Note 10 - Employee Benefit Plans
Note 11 - Income Taxes and Tax-Related Items
Note 12 - Contingent Liabilities
Note 13 - Business Segment Information
Note 14 - Revenue From Contracts with Customers
Note 15 - Leases
Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations
Item 3. Quantitative and Qualitative Disclosures About Market Risk
Item 4. Controls and Procedures
Part II. Other Information
Item 1. Legal Proceedings
Item 1A. Risk Factors
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds
Item 6. Exhibits
Exhibits
EX-31.1 cma-2019q210q_ex311.htm
EX-31.2 cma-2019q210q_ex312.htm
EX-32 cma-2019q210q_ex32.htm

Comerica Earnings 2019-06-30

CMA 10Q Quarterly Report

Balance SheetIncome StatementCash Flow
Document
P90DP90D202808000000060000000000false--12-31Q22019false0000028412false004701624466100.000.000.000.0095.2579.0195.2579.0195370000000000P3Y4M24D532500000032500000022816482422816482470000000.0370.0380.021250.040.078750.0250.0370.0400.0380.021250.040.078750.0252023-07-312026-07-222019-05-232025-07-272026-09-152020-06-022023-07-312029-02-012026-07-222019-05-232026-05-202026-03-042028-01-262025-07-272026-09-152020-06-0240000003000000P3Y10M24DP3Y1M6DP4Y8M12D000000000000030000000004000000P9Y0M0D330000000000.02410.026110000002028-12-312019-12-31680811767836753414000000700000070000000 0000028412 2019-01-01 2019-06-30 0000028412 2019-07-25 0000028412 2019-06-30 0000028412 2018-12-31 0000028412 2018-04-01 2018-06-30 0000028412 2018-01-01 2018-06-30 0000028412 2019-04-01 2019-06-30 0000028412 us-gaap:CommonStockMember 2018-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2019-06-30 0000028412 2018-06-30 0000028412 us-gaap:CommonStockMember 2019-04-01 2019-06-30 0000028412 us-gaap:RetainedEarningsMember 2018-06-30 0000028412 us-gaap:TreasuryStockMember 2018-06-30 0000028412 us-gaap:TreasuryStockMember 2019-06-30 0000028412 us-gaap:TreasuryStockMember 2019-03-31 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-06-30 0000028412 2017-12-31 0000028412 us-gaap:RetainedEarningsMember 2019-01-01 2019-06-30 0000028412 us-gaap:RetainedEarningsMember 2019-04-01 2019-06-30 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-04-01 2019-06-30 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-03-31 0000028412 us-gaap:RetainedEarningsMember 2019-06-30 0000028412 us-gaap:CommonStockMember 2019-06-30 0000028412 us-gaap:CommonStockMember 2018-01-01 2018-06-30 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2019-03-31 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-12-31 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2017-12-31 0000028412 us-gaap:TreasuryStockMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommonStockMember 2018-12-31 0000028412 us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000028412 us-gaap:RetainedEarningsMember 2019-03-31 0000028412 us-gaap:CommonStockMember 2018-04-01 2018-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommonStockMember 2019-03-31 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-04-01 2018-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2018-06-30 0000028412 us-gaap:RetainedEarningsMember 2018-04-01 2018-06-30 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-01-01 2018-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2018-01-01 2018-06-30 0000028412 us-gaap:RetainedEarningsMember 2018-01-01 2018-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2018-04-01 2018-06-30 0000028412 2018-03-31 0000028412 us-gaap:TreasuryStockMember 2019-01-01 2019-06-30 0000028412 us-gaap:TreasuryStockMember 2018-03-31 0000028412 us-gaap:TreasuryStockMember 2018-04-01 2018-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2017-12-31 0000028412 2019-03-31 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-03-31 0000028412 us-gaap:TreasuryStockMember 2018-12-31 0000028412 us-gaap:CommonStockMember 2018-03-31 0000028412 us-gaap:CommonStockMember 2017-12-31 0000028412 us-gaap:TreasuryStockMember 2017-12-31 0000028412 us-gaap:RetainedEarningsMember 2018-03-31 0000028412 us-gaap:RetainedEarningsMember 2017-12-31 0000028412 us-gaap:AdditionalPaidInCapitalMember 2018-03-31 0000028412 us-gaap:TreasuryStockMember 2019-04-01 2019-06-30 0000028412 us-gaap:RetainedEarningsMember 2018-12-31 0000028412 us-gaap:CommonStockMember 2019-01-01 2019-06-30 0000028412 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-06-30 0000028412 us-gaap:AdditionalPaidInCapitalMember 2019-04-01 2019-06-30 0000028412 us-gaap:AccountingStandardsUpdate201602Member 2019-01-01 0000028412 us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-06-30 0000028412 us-gaap:EquitySecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 0000028412 us-gaap:EquitySecuritiesMember us-gaap:EquitySecuritiesMember 2018-01-01 2018-06-30 0000028412 us-gaap:AvailableforsaleSecuritiesMember 2018-06-30 0000028412 us-gaap:EquitySecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000028412 us-gaap:InterestRateContractMember 2019-03-31 0000028412 us-gaap:MunicipalBondsMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-06-30 0000028412 us-gaap:EquitySecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-06-30 0000028412 us-gaap:InterestRateContractMember 2019-04-01 2019-06-30 0000028412 us-gaap:InterestRateContractMember 2019-01-01 2019-06-30 0000028412 us-gaap:InterestRateContractMember 2018-01-01 2018-06-30 0000028412 us-gaap:InterestRateContractMember 2018-04-01 2018-06-30 0000028412 us-gaap:InterestRateContractMember 2018-12-31 0000028412 us-gaap:InterestRateContractMember 2019-06-30 0000028412 us-gaap:EquitySecuritiesMember us-gaap:EquitySecuritiesMember 2017-12-31 0000028412 us-gaap:MunicipalBondsMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000028412 us-gaap:EquitySecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-06-30 0000028412 us-gaap:InterestRateContractMember 2018-06-30 0000028412 us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 0000028412 us-gaap:MunicipalBondsMember us-gaap:AvailableforsaleSecuritiesMember 2018-06-30 0000028412 us-gaap:EquitySecuritiesMember us-gaap:EquitySecuritiesMember 2018-01-01 0000028412 us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000028412 us-gaap:InterestRateContractMember 2018-03-31 0000028412 us-gaap:InterestRateContractMember 2017-12-31 0000028412 us-gaap:EquitySecuritiesMember us-gaap:EquitySecuritiesMember 2018-06-30 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2018-12-31 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2019-06-30 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2019-06-30 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2019-06-30 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2019-06-30 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2019-06-30 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2019-06-30 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2019-06-30 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000028412 us-gaap:ForeignExchangeContractMember us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2018-12-31 0000028412 us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2018-12-31 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:CommodityContractMember us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:EquitySecuritiesMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000028412 us-gaap:InterestRateContractMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember cma:DeferredCompensationPlanAssetsMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-06-30 0000028412 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2018-12-31 0000028412 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-06-30 0000028412 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-06-30 0000028412 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000028412 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsNonrecurringMember 2019-06-30 0000028412 us-gaap:FairValueMeasurementsNonrecurringMember 2018-12-31 0000028412 us-gaap:FairValueMeasurementsRecurringMember 2019-01-01 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember 2018-01-01 2018-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember 2019-04-01 2019-06-30 0000028412 us-gaap:FairValueMeasurementsRecurringMember 2018-04-01 2018-06-30 0000028412 us-gaap:DebtSecuritiesMember 2018-01-01 2018-06-30 0000028412 us-gaap:DebtSecuritiesMember 2019-01-01 2019-06-30 0000028412 us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000028412 us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000028412 us-gaap:MortgageBackedSecuritiesMember 2019-06-30 0000028412 us-gaap:USTreasuryAndGovernmentMember 2019-06-30 0000028412 us-gaap:MortgageBackedSecuritiesMember us-gaap:PrepaymentRiskMember 2019-06-30 0000028412 us-gaap:DebtSecuritiesMember 2019-06-30 0000028412 us-gaap:DebtSecuritiesMember 2018-04-01 2018-06-30 0000028412 us-gaap:DebtSecuritiesMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2019-01-01 2019-06-30 0000028412 us-gaap:PaymentDeferralMember 2018-04-01 2018-06-30 0000028412 us-gaap:PaymentDeferralMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-04-01 2019-06-30 0000028412 us-gaap:ContractualInterestRateReductionMember 2019-04-01 2019-06-30 0000028412 us-gaap:ContractualInterestRateReductionMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PaymentDeferralMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PaymentDeferralMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:ContractualInterestRateReductionMember 2018-01-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PaymentDeferralMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ContractualInterestRateReductionMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ContractualInterestRateReductionMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ContractualInterestRateReductionMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-04-01 2018-06-30 0000028412 us-gaap:PaymentDeferralMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember 2018-01-01 2018-06-30 0000028412 us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:ContractualInterestRateReductionMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PaymentDeferralMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2018-01-01 2018-06-30 0000028412 us-gaap:ContractualInterestRateReductionMember 2018-01-01 2018-06-30 0000028412 us-gaap:PaymentDeferralMember 2018-01-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PaymentDeferralMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2018-01-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:ContractualInterestRateReductionMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PaymentDeferralMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:ContractualInterestRateReductionMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PaymentDeferralMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PaymentDeferralMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-01-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2018-04-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2018-03-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember 2018-04-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2017-12-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember 2019-04-01 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember 2018-12-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2018-04-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000028412 us-gaap:FinanceReceivablesMember 2018-01-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2019-04-01 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2019-01-01 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2019-04-01 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2017-12-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember 2019-01-01 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000028412 us-gaap:FinanceReceivablesMember 2018-03-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2018-01-01 2018-06-30 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:ConsumerPortfolioSegmentMember 2018-03-31 0000028412 us-gaap:FinanceReceivablesMember us-gaap:CommercialPortfolioSegmentMember 2019-01-01 2019-06-30 0000028412 us-gaap:FinanceReceivablesMember 2019-03-31 0000028412 us-gaap:FinanceReceivablesMember 2017-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionForeignMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionForeignMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionForeignMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionForeignMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionForeignMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionForeignMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:FinancingReceivables60To89DaysPastDueMember us-gaap:GeographicDistributionDomesticMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-01-01 2018-06-30 0000028412 cma:BusinessLoansMember us-gaap:CommercialBorrowerMember us-gaap:FinanceLeasesPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-01-01 2018-06-30 0000028412 cma:BusinessLoansMember us-gaap:CommercialBorrowerMember us-gaap:FinanceLeasesPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2018-01-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-04-01 2018-06-30 0000028412 cma:BusinessLoansMember us-gaap:CommercialBorrowerMember us-gaap:FinanceLeasesPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember 2018-01-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember 2019-04-01 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember 2018-04-01 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember 2019-01-01 2019-06-30 0000028412 cma:BusinessLoansMember us-gaap:CommercialBorrowerMember us-gaap:FinanceLeasesPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2019-01-01 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember 2018-04-01 2018-06-30 0000028412 cma:AbNoteRestructuresMember 2019-06-30 0000028412 us-gaap:ContractualInterestRateReductionMember 2018-06-30 0000028412 us-gaap:ContractualInterestRateReductionMember 2019-06-30 0000028412 cma:BusinessLoansMember us-gaap:CommercialBorrowerMember us-gaap:FinanceLeasesPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:PassMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionForeignMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember cma:LeaseFinancingMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember cma:ConsumerFinancingReceivableMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:SpecialMentionMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:GeographicDistributionDomesticMember us-gaap:SpecialMentionMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2018-12-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:DoubtfulMember 2018-12-31 0000028412 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:SubstandardMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PassMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:SubstandardMember 2018-12-31 0000028412 us-gaap:PassMember 2019-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2019-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2018-01-01 2018-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2017-12-31 0000028412 us-gaap:LoanOriginationCommitmentsMember 2019-03-31 0000028412 us-gaap:LoanOriginationCommitmentsMember 2018-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2019-01-01 2019-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2019-04-01 2019-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2018-12-31 0000028412 us-gaap:LoanOriginationCommitmentsMember 2018-04-01 2018-06-30 0000028412 us-gaap:LoanOriginationCommitmentsMember 2018-03-31 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:PaymentDeferralMember 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PaymentDeferralMember 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:RealEstateSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialAndIndustrialSectorMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2018-06-30 0000028412 us-gaap:CommercialBorrowerMember us-gaap:CommercialPortfolioSegmentMember us-gaap:RealEstateLoanMember us-gaap:GeographicDistributionDomesticMember us-gaap:PaymentDeferralMember 2019-06-30 0000028412 us-gaap:ConsumerBorrowerMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PaymentDeferralMember 2018-06-30 0000028412 cma:AbNoteRestructuresMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialPortfolioSegmentMember 2019-06-30 0000028412 us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000028412 cma:AbNoteRestructuresMember 2019-01-01 2019-06-30 0000028412 cma:AbNoteRestructuresMember 2018-04-01 2018-06-30 0000028412 cma:AbNoteRestructuresMember 2019-04-01 2019-06-30 0000028412 us-gaap:ResidentialRealEstateMember 2019-06-30 0000028412 us-gaap:ResidentialRealEstateMember 2018-12-31 0000028412 cma:RiskManagementDerivativesMember us-gaap:LongTermDebtMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:LongTermDebtMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2018-12-31 0000028412 cma:RiskManagementDerivativesMember us-gaap:LoansMember us-gaap:SwapMember us-gaap:CashFlowHedgingMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateContractMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:EnergySwapsMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:InterestRateCapsAndFloorsWrittenMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateSwapMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:InterestRateCapsAndFloorsPurchasedMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:EnergyCapsAndFloorsPurchasedMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:CommodityContractMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:InterestRateCapsAndFloorsPurchasedMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:EnergyCapsAndFloorsWrittenMember 2018-12-31 0000028412 cma:RiskManagementDerivativesMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember cma:ForeignExchangeSpotForwardAndSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember cma:ForeignExchangeSpotForwardAndSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:CashFlowHedgingMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:CommodityContractMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateSwapMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:EnergySwapsMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:ForeignExchangeSpotForwardsOptionsAndSwapsMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:EnergyCapsAndFloorsWrittenMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:CashFlowHedgingMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:InterestRateCapsAndFloorsWrittenMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateContractMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:EnergyCapsAndFloorsPurchasedMember 2018-12-31 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember cma:ForeignExchangeSpotForwardsOptionsAndSwapsMember 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:ForeignExchangeContractMember us-gaap:ForeignCurrencyGainLossMember 2019-04-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:ForeignExchangeContractMember us-gaap:ForeignCurrencyGainLossMember 2018-04-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateContractMember us-gaap:OtherIncomeMember 2019-01-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember 2018-01-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:EnergyRelatedDerivativeMember us-gaap:OtherIncomeMember 2018-01-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:EnergyRelatedDerivativeMember us-gaap:OtherIncomeMember 2019-04-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateContractMember us-gaap:OtherIncomeMember 2019-04-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:ForeignExchangeContractMember us-gaap:ForeignCurrencyGainLossMember 2018-01-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember 2019-01-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember 2018-04-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:EnergyRelatedDerivativeMember us-gaap:OtherIncomeMember 2019-01-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateContractMember us-gaap:OtherIncomeMember 2018-01-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:EnergyRelatedDerivativeMember us-gaap:OtherIncomeMember 2018-04-01 2018-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:ForeignExchangeContractMember us-gaap:ForeignCurrencyGainLossMember 2019-01-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember 2019-04-01 2019-06-30 0000028412 cma:CustomerInitiatedAndOtherActivitiesDerivativesMember us-gaap:InterestRateContractMember us-gaap:OtherIncomeMember 2018-04-01 2018-06-30 0000028412 cma:BankcardHomeEquityAndOtherMember srt:MaximumMember us-gaap:CommitmentsToExtendCreditMember 2018-12-31 0000028412 us-gaap:StandbyLettersOfCreditMember srt:MaximumMember 2019-06-30 0000028412 srt:MaximumMember us-gaap:CommitmentsToExtendCreditMember 2019-06-30 0000028412 cma:CommercialAndOtherMember srt:MaximumMember us-gaap:CommitmentsToExtendCreditMember 2019-06-30 0000028412 us-gaap:StandbyLettersOfCreditMember srt:MaximumMember 2018-12-31 0000028412 us-gaap:LetterOfCreditMember srt:MaximumMember 2018-12-31 0000028412 us-gaap:LetterOfCreditMember srt:MaximumMember 2019-06-30 0000028412 cma:CommercialAndOtherMember srt:MaximumMember us-gaap:CommitmentsToExtendCreditMember 2018-12-31 0000028412 cma:BankcardHomeEquityAndOtherMember srt:MaximumMember us-gaap:CommitmentsToExtendCreditMember 2019-06-30 0000028412 srt:MaximumMember us-gaap:CommitmentsToExtendCreditMember 2018-12-31 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2018-04-01 2018-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2018-01-01 2018-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2019-04-01 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2019-01-01 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:LongTermDebtMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2019-01-01 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:LoansMember us-gaap:SwapMember us-gaap:CashFlowHedgingMember 2019-01-01 2019-06-30 0000028412 cma:RiskManagementDerivativesMember us-gaap:LongTermDebtMember us-gaap:InterestRateSwapMember us-gaap:FairValueHedgingMember 2018-01-01 2018-12-31 0000028412 cma:OtherTaxCreditEntitiesMember 2019-06-30 0000028412 cma:LowIncomeHousingTaxCreditEntitiesMember 2019-06-30 0000028412 cma:OtherTaxBenefitsRelatedToTaxCreditEntitiesMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-01-01 2018-06-30 0000028412 cma:OtherTaxBenefitsRelatedToTaxCreditEntitiesMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-04-01 2019-06-30 0000028412 cma:OtherTaxBenefitsRelatedToTaxCreditEntitiesMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-04-01 2018-06-30 0000028412 cma:LowIncomeHousingTaxCreditsMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-01-01 2019-06-30 0000028412 us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-01-01 2019-06-30 0000028412 cma:LowIncomeHousingTaxCreditsMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-01-01 2018-06-30 0000028412 cma:LowIncomeHousingTaxCreditsMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-04-01 2019-06-30 0000028412 cma:LowIncomeHousingTaxCreditsMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-04-01 2018-06-30 0000028412 us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-04-01 2019-06-30 0000028412 us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-04-01 2018-06-30 0000028412 us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-01-01 2018-06-30 0000028412 cma:OtherTaxBenefitsRelatedToTaxCreditEntitiesMember us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-01-01 2019-06-30 0000028412 srt:ParentCompanyMember cma:A3.70NotesDue2023Member 2019-06-30 0000028412 srt:ParentCompanyMember cma:ThreePointEightZeroPercentSubNotesDue2026Member 2019-06-30 0000028412 srt:SubsidiariesMember cma:FourPercentagesubordinatedNotesDue2025Member 2018-12-31 0000028412 srt:ParentCompanyMember 2019-06-30 0000028412 srt:ParentCompanyMember 2018-12-31 0000028412 srt:SubsidiariesMember cma:FloatingratebasedonFHLBauctionratedue2028Member 2018-12-31 0000028412 srt:SubsidiariesMember 2019-06-30 0000028412 srt:SubsidiariesMember cma:TwoPointFivePercentageNotesDue2020MemberDomainDomain 2019-06-30 0000028412 srt:ParentCompanyMember cma:A4.00NotesDue2029Member 2018-12-31 0000028412 srt:SubsidiariesMember 2018-12-31 0000028412 srt:ParentCompanyMember cma:TwoPointOneTwoFivePercentageNotesDue2019MemberDomain 2019-06-30 0000028412 srt:ParentCompanyMember cma:A3.70NotesDue2023Member 2018-12-31 0000028412 srt:ParentCompanyMember cma:ThreePointEightZeroPercentSubNotesDue2026Member 2018-12-31 0000028412 srt:SubsidiariesMember cma:FourPercentagesubordinatedNotesDue2025Member 2019-06-30 0000028412 srt:SubsidiariesMember cma:FloatingratebasedonFHLBauctionratedue2028Member 2019-06-30 0000028412 srt:ParentCompanyMember cma:TwoPointOneTwoFivePercentageNotesDue2019MemberDomain 2018-12-31 0000028412 srt:SubsidiariesMember cma:SevenPointEightSevenFivePercentageSubordinatedNoteDue2026Member 2018-12-31 0000028412 srt:SubsidiariesMember cma:SevenPointEightSevenFivePercentageSubordinatedNoteDue2026Member 2019-06-30 0000028412 srt:ParentCompanyMember cma:A4.00NotesDue2029Member 2019-06-30 0000028412 srt:SubsidiariesMember cma:FloatingRateBasedonFHLBAuctionDue2026Member 2019-06-30 0000028412 srt:SubsidiariesMember cma:TwoPointFivePercentageNotesDue2020MemberDomainDomain 2018-12-31 0000028412 srt:SubsidiariesMember cma:FloatingRateBasedonFHLBAuctionDue2026Member 2018-12-31 0000028412 srt:ParentCompanyMember cma:A4.00NotesDue2029Member 2019-02-01 0000028412 srt:SubsidiariesMember cma:SevenPointEightSevenFivePercentageSubordinatedNoteDue2026Member 2018-01-01 2018-12-31 0000028412 srt:ParentCompanyMember cma:TwoPointOneTwoFivePercentageNotesDue2019MemberDomain 2019-01-01 2019-06-30 0000028412 srt:SubsidiariesMember cma:FourPercentagesubordinatedNotesDue2025Member 2019-01-01 2019-06-30 0000028412 srt:ParentCompanyMember cma:ThreePointEightZeroPercentSubNotesDue2026Member 2019-01-01 2019-06-30 0000028412 srt:SubsidiariesMember cma:FourPercentagesubordinatedNotesDue2025Member 2018-01-01 2018-12-31 0000028412 srt:SubsidiariesMember srt:MaximumMember cma:FloatingRateBasedonFHLBAuctionDue2026Member 2019-01-01 2019-06-30 0000028412 srt:SubsidiariesMember cma:TwoPointFivePercentageNotesDue2020MemberDomainDomain 2018-01-01 2018-12-31 0000028412 srt:ParentCompanyMember cma:TwoPointOneTwoFivePercentageNotesDue2019MemberDomain 2018-01-01 2018-12-31 0000028412 srt:ParentCompanyMember cma:A3.70NotesDue2023Member 2019-01-01 2019-06-30 0000028412 srt:ParentCompanyMember cma:A3.70NotesDue2023Member 2018-01-01 2018-12-31 0000028412 srt:SubsidiariesMember cma:TwoPointFivePercentageNotesDue2020MemberDomainDomain 2019-01-01 2019-06-30 0000028412 srt:ParentCompanyMember cma:ThreePointEightZeroPercentSubNotesDue2026Member 2018-01-01 2018-12-31 0000028412 srt:ParentCompanyMember cma:A4.00NotesDue2029Member 2019-01-01 2019-06-30 0000028412 srt:SubsidiariesMember cma:FloatingratebasedonFHLBauctionratedue2028Member 2019-01-01 2019-06-30 0000028412 srt:SubsidiariesMember cma:SevenPointEightSevenFivePercentageSubordinatedNoteDue2026Member 2019-01-01 2019-06-30 0000028412 srt:SubsidiariesMember srt:MinimumMember cma:FloatingRateBasedonFHLBAuctionDue2026Member 2019-01-01 2019-06-30 0000028412 srt:MinimumMember us-gaap:EmployeeStockOptionMember 2019-01-01 2019-06-30 0000028412 us-gaap:EmployeeStockOptionMember 2019-01-01 2019-06-30 0000028412 srt:MinimumMember us-gaap:EmployeeStockOptionMember 2018-01-01 2018-06-30 0000028412 us-gaap:EmployeeStockOptionMember 2018-04-01 2018-06-30 0000028412 srt:MaximumMember us-gaap:EmployeeStockOptionMember 2018-01-01 2018-06-30 0000028412 srt:MaximumMember us-gaap:EmployeeStockOptionMember 2019-04-01 2019-06-30 0000028412 srt:MaximumMember us-gaap:EmployeeStockOptionMember 2018-04-01 2018-06-30 0000028412 us-gaap:EmployeeStockOptionMember 2019-04-01 2019-06-30 0000028412 srt:MinimumMember us-gaap:EmployeeStockOptionMember 2019-04-01 2019-06-30 0000028412 srt:MinimumMember us-gaap:EmployeeStockOptionMember 2018-04-01 2018-06-30 0000028412 srt:MaximumMember us-gaap:EmployeeStockOptionMember 2019-01-01 2019-06-30 0000028412 us-gaap:EmployeeStockOptionMember 2018-01-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 us-gaap:PensionPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 us-gaap:PensionPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 cma:SalariesandbenefitsexpenseMember us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000028412 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000028412 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000028412 cma:ComponentrecognizedinnoninterestexpenseMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000028412 srt:MinimumMember 2019-01-01 2019-06-30 0000028412 srt:MaximumMember 2019-01-01 2019-06-30 0000028412 cma:ButteLocalDevelopmentv.MastersGroupv.ComericaBankMember 2014-01-16 2014-01-17 0000028412 srt:MaximumMember us-gaap:PendingLitigationMember 2019-06-30 0000028412 srt:MinimumMember us-gaap:PendingLitigationMember 2019-06-30 0000028412 cma:Other1Member 2019-04-01 2019-06-30 0000028412 cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 cma:FinanceMember 2018-04-01 2018-06-30 0000028412 cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 cma:Other1Member 2018-04-01 2018-06-30 0000028412 cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 cma:FinanceMember 2019-04-01 2019-06-30 0000028412 cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 stpr:CA 2019-01-01 2019-06-30 0000028412 stpr:MI 2019-01-01 2019-06-30 0000028412 cma:OtherMarketsMember 2019-01-01 2019-06-30 0000028412 stpr:CA 2018-01-01 2018-06-30 0000028412 stpr:MI 2018-01-01 2018-06-30 0000028412 cma:FinanceOtherMember 2018-01-01 2018-06-30 0000028412 cma:OtherMarketsMember 2018-01-01 2018-06-30 0000028412 stpr:TX 2019-01-01 2019-06-30 0000028412 cma:FinanceOtherMember 2019-01-01 2019-06-30 0000028412 stpr:TX 2018-01-01 2018-06-30 0000028412 cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 cma:Other1Member 2018-01-01 2018-06-30 0000028412 cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 cma:FinanceMember 2018-01-01 2018-06-30 0000028412 cma:Other1Member 2019-01-01 2019-06-30 0000028412 cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 cma:RetailBankMember 2018-01-01 2018-06-30 0000028412 cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 cma:FinanceMember 2019-01-01 2019-06-30 0000028412 stpr:CA 2018-04-01 2018-06-30 0000028412 stpr:TX 2018-04-01 2018-06-30 0000028412 cma:FinanceOtherMember 2019-04-01 2019-06-30 0000028412 stpr:CA 2019-04-01 2019-06-30 0000028412 stpr:MI 2018-04-01 2018-06-30 0000028412 cma:OtherMarketsMember 2019-04-01 2019-06-30 0000028412 cma:OtherMarketsMember 2018-04-01 2018-06-30 0000028412 stpr:TX 2019-04-01 2019-06-30 0000028412 cma:FinanceOtherMember 2018-04-01 2018-06-30 0000028412 stpr:MI 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:RetailBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialLoanMember cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember 2018-04-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 cma:NoninterestDomain 2019-04-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember 2019-04-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember 2019-01-01 2019-06-30 0000028412 cma:NoninterestDomain cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:RetailBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialLoanMember 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 us-gaap:DepositAccountMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:RetailBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 cma:NoninterestDomain cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 cma:NoninterestDomain cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:DepositAccountMember 2019-01-01 2019-06-30 0000028412 cma:NoninterestDomain 2019-01-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:RetailBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember 2019-01-01 2019-06-30 0000028412 cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 cma:NoninterestDomain cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:RetailBankMember 2018-01-01 2018-06-30 0000028412 cma:NoninterestDomain cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:WealthManagementMember 2019-04-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 cma:NoninterestDomain 2018-01-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 cma:NoninterestDomain cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 us-gaap:DepositAccountMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 cma:NoninterestDomain cma:BusinessBankMember 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:WealthManagementMember 2019-01-01 2019-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:RetailBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 cma:NoninterestDomain cma:FinanceOther1MemberDomain 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember 2018-04-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember 2018-04-01 2018-06-30 0000028412 us-gaap:DepositAccountMember 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 us-gaap:CommercialLoanMember cma:RetailBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:BusinessBankMember 2018-01-01 2018-06-30 0000028412 us-gaap:CommercialLoanMember cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 cma:NoninterestDomain cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember cma:WealthManagementMember 2018-04-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember 2019-01-01 2019-06-30 0000028412 us-gaap:CommercialLoanMember cma:FinanceOther1MemberDomain 2018-04-01 2018-06-30 0000028412 cma:NoninterestDomain cma:BusinessBankMember 2019-04-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:FinanceOther1MemberDomain 2019-01-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember 2019-04-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:WealthManagementMember 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:RetailBankMember 2018-04-01 2018-06-30 0000028412 cma:BrokerageCommissionsRevenueMember cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 us-gaap:DepositAccountMember cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 cma:NoninterestDomain 2018-04-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:BusinessBankMember 2019-01-01 2019-06-30 0000028412 us-gaap:DepositAccountMember cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:FinanceOther1MemberDomain 2018-01-01 2018-06-30 0000028412 us-gaap:CreditAndDebitCardMember 2019-04-01 2019-06-30 0000028412 us-gaap:FiduciaryAndTrustMember cma:RetailBankMember 2018-01-01 2018-06-30 xbrli:shares iso4217:USD xbrli:shares iso4217:USD xbrli:pure cma:Security cma:segments cma:markets