Loans and ACL - Types of Modifications and Allowance at Period End (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	$ 2,060		$ 2,060		$ 1,542
Newly Designated TDRs | Commercial:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Related ALLL at Period End	9	$ 4	9	$ 17
Financing Receivable, Troubled Debt Restructuring, Premodification	66	30	77	183
Newly Designated TDRs | Consumer:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Related ALLL at Period End	12	7	41	30
Financing Receivable, Troubled Debt Restructuring, Premodification	236	126	858	496
Newly Designated TDRs | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Related ALLL at Period End	1	1	3	4
Financing Receivable, Troubled Debt Restructuring, Premodification	2	3	6	10
Newly Designated TDRs | Rate | Commercial:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	66	8	66	35
Newly Designated TDRs | Rate | Consumer:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	123	74	368	212
Newly Designated TDRs | Rate | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	2	3	6	9
Newly Designated TDRs | Structure | Commercial:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	0	20	9	129
Newly Designated TDRs | Structure | Consumer:
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	117	51	505	277
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	43	23	73	51
Re-Modification of Previously Designated TDRs | Structure
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs	50	$ 9	90	$ 37
Performing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	1,873		1,873		1,390
Performing | Commercial: | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	165		165		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	1,144		1,144		692
Performing | Consumer: | Residential home equity and direct
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	78		78		98
Performing | Consumer: | Indirect auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	425		425		389
Performing | Consumer: | Indirect other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	7		7		7
Performing | Consumer: | Student
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	29		29		25
Performing | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring	$ 19		$ 19		$ 27