Loans and Related Allowance for Credit Losses (Modified, Amortized Cost Basis) (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 869	$ 1,275
% of Loan Class	0.27%	0.40%
Unfunded lending related commitments	$ 100	$ 100
Principal Forgiveness
Financing Receivable [Line Items]
Amortized cost basis, modified		1
Interest Rate Reduction
Financing Receivable [Line Items]
Amortized cost basis, modified	1
Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	595	927
Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	97	148
Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	19	31
Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	3	7
Other
Financing Receivable [Line Items]
Amortized cost basis, modified	154	160
Total commercial
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 800	$ 1,149
% of Loan Class	0.36%	0.52%
Total commercial | Principal Forgiveness
Financing Receivable [Line Items]
Amortized cost basis, modified		$ 1
Total commercial | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 594	925
Total commercial | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	59	72
Total commercial | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	147	151
Total commercial | Commercial and industrial
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 512	$ 596
% of Loan Class	0.29%	0.34%
Total commercial | Commercial and industrial | Principal Forgiveness
Financing Receivable [Line Items]
Amortized cost basis, modified		$ 1
Total commercial | Commercial and industrial | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 366	432
Total commercial | Commercial and industrial | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	59	72
Total commercial | Commercial and industrial | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	87	91
Total commercial | Commercial real estate
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 288	$ 553
% of Loan Class	0.80%	1.54%
Total commercial | Commercial real estate | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 228	$ 493
Total commercial | Commercial real estate | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	60	60
Total consumer
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 69	$ 126
% of Loan Class	0.07%	0.12%
Total consumer | Interest Rate Reduction
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1	$ 1
Total consumer | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	1	2
Total consumer | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	38	76
Total consumer | Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	19	31
Total consumer | Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	3	7
Total consumer | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	7	9
Total consumer | Residential real estate
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 39	$ 78
% of Loan Class	0.08%	0.17%
Total consumer | Residential real estate | Interest Rate Reduction
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1	$ 1
Total consumer | Residential real estate | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	35	72
Total consumer | Residential real estate | Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	1	2
Total consumer | Residential real estate | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	2	3
Total consumer | Home equity
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 10	$ 15
% of Loan Class	0.04%	0.06%
Total consumer | Home equity | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 3	$ 4
Total consumer | Home equity | Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	2	5
Total consumer | Home equity | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	5	6
Total consumer | Credit card
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 18	$ 30
% of Loan Class	0.25%	0.42%
Total consumer | Credit card | Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 18	$ 30
Total consumer | Education
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1	$ 2
% of Loan Class	0.05%	0.10%
Total consumer | Education | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1	$ 2
Total consumer | Other consumer
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1	$ 1
% of Loan Class	0.02%	0.02%
Total consumer | Other consumer | Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1	$ 1