Loans and Related Allowance for Credit Losses (Financial Impact and TDRs by Concession Type) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	2,247	1,353	8,194	4,865
Pre-TDR Amortized Cost Basis	$ 136	$ 154	$ 310	$ 406
Post-TDR Amortized Cost Basis	112	167	267	392
Principal Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis			9
Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	39	21	105	49
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	$ 73	$ 146	$ 153	$ 343
Total commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	15	13	42	43
Pre-TDR Amortized Cost Basis	$ 96	$ 123	$ 184	$ 320
Post-TDR Amortized Cost Basis	77	139	154	315
Total commercial | Principal Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis			9
Total commercial | Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	10		10
Total commercial | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	$ 67	$ 139	$ 135	$ 315
Total consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	2,232	1,340	8,152	4,822
Pre-TDR Amortized Cost Basis	$ 40	$ 31	$ 126	$ 86
Post-TDR Amortized Cost Basis	35	28	113	77
Total consumer | Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	29	21	95	49
Total consumer | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-TDR Amortized Cost Basis	$ 6	$ 7	$ 18	$ 28