Loans and ACL - Types of Modifications and Allowance at Period End (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	$ 1,897		$ 1,897		$ 1,542
Newly Designated TDRs | Commercial:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Related ALLL at Period End	0	$ 0	0	$ 13
Financing Receivable, Troubled Debt Restructuring, Premodification	1	6	11	153
Newly Designated TDRs | Consumer:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Related ALLL at Period End	14	10	29	23
Financing Receivable, Troubled Debt Restructuring, Premodification	293	137	622	370
Newly Designated TDRs | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Related ALLL at Period End	1	1	2	3
Financing Receivable, Troubled Debt Restructuring, Premodification	2	3	4	7
Newly Designated TDRs | Rate | Commercial:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	0	0	0	27
Newly Designated TDRs | Rate | Consumer:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	97	63	245	138
Newly Designated TDRs | Rate | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	2	2	4	6
Newly Designated TDRs | Structure | Commercial:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	1	6	9	109
Newly Designated TDRs | Structure | Consumer:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	197	71	388	226
Newly Designated TDRs | Structure | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	0	0	0	0
Re-Modification of Previously Designated TDRs | Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	9	14	30	28
Re-Modification of Previously Designated TDRs | Structure
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	29	$ 6	40	$ 20
Performing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	1,693		1,693		1,390
Performing | Commercial: | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	105		105		147
Performing | Commercial: | CRE
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	5		5		5
Performing | Commercial: | Commercial construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	1		1		0
Performing | Consumer: | Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	1,042		1,042		692
Performing | Consumer: | Residential home equity and direct
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	84		84		98
Performing | Consumer: | Indirect auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	401		401		389
Performing | Consumer: | Indirect other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	6		6		7
Performing | Consumer: | Student
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	27		27		25
Performing | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	$ 22		$ 22		$ 27