Loans and Related Allowance for Credit Losses (Financial Impact and TDRs by Concession Type) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	3,040	1,397	5,947	3,512
Pre-TDR Amortized Cost Basis	$ 85	$ 127	$ 174	$ 252
Post-TDR Amortized Cost Basis	76	103	155	225
Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	40	12	66	28
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	27	$ 91	80	$ 197
Principal Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	$ 9		$ 9
Total commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	15	11	27	30
Pre-TDR Amortized Cost Basis	$ 35	$ 104	$ 88	$ 197
Post-TDR Amortized Cost Basis	31	82	77	176
Total commercial | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	22	$ 82	68	$ 176
Total commercial | Principal Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	$ 9		$ 9
Total consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	3,025	1,386	5,920	3,482
Pre-TDR Amortized Cost Basis	$ 50	$ 23	$ 86	$ 55
Post-TDR Amortized Cost Basis	45	21	78	49
Total consumer | Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	40	12	66	28
Total consumer | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	$ 5	$ 9	$ 12	$ 21