Loans and Related Allowance for Credit Losses (Modified, Amortized Cost Basis) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 623
% of Loan Class	0.19%
Unfunded lending related commitments	$ 100
Principal Forgiveness
Financing Receivable [Line Items]
Amortized cost basis, modified	1
Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	529
Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	67
Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	14
Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	4
Other
Financing Receivable [Line Items]
Amortized cost basis, modified	8
Total commercial
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 497
% of Loan Class	0.22%
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	471
Total commercial | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	20
Total commercial | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	5
Total commercial | Commercial and industrial
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 224
% of Loan Class	0.12%
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	198
Total commercial | Commercial and industrial | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	20
Total commercial | Commercial and industrial | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	5
Total commercial | Commercial real estate
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 273
% of Loan Class	0.76%
Total commercial | Commercial real estate | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 273
Total consumer
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 126
% of Loan Class	0.12%
Total consumer | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 58
Total consumer | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	47
Total consumer | Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	14
Total consumer | Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	4
Total consumer | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	3
Total consumer | Residential real estate
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 49
% of Loan Class	0.11%
Total consumer | Residential real estate | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 46
Total consumer | Residential real estate | Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	2
Total consumer | Residential real estate | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	1
Total consumer | Home equity
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 5
% of Loan Class	0.02%
Total consumer | Home equity | Payment Delay
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1
Total consumer | Home equity | Interest Rate Reduction and Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	2
Total consumer | Home equity | Other
Financing Receivable [Line Items]
Amortized cost basis, modified	2
Total consumer | Credit card
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 13
% of Loan Class	0.19%
Total consumer | Credit card | Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 13
Total consumer | Education
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 58
% of Loan Class	2.72%
Total consumer | Education | Term Extension
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 58
Total consumer | Other consumer
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1
% of Loan Class	0.02%
Total consumer | Other consumer | Repayment Plan
Financing Receivable [Line Items]
Amortized cost basis, modified	$ 1