Asset Quality - Schedule of Modifications for Borrowers Experiencing Financial Difficulty (Details) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 93
Amortized Cost Basis (as a percent)	0.08%
Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	83
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	1
Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	9
Total commercial real estate loans | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 84
Amortized Cost Basis (as a percent)	0.14%
Total commercial real estate loans | Commercial and Industrial | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total commercial real estate loans | Commercial and Industrial | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	79
Total commercial real estate loans | Commercial and Industrial | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	1
Total commercial real estate loans | Commercial and Industrial | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	4
Total commercial real estate loans | Commercial mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 4
Amortized Cost Basis (as a percent)	0.02%
Total commercial real estate loans | Commercial mortgage | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total commercial real estate loans | Commercial mortgage | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	4
Total commercial real estate loans | Commercial mortgage | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial real estate loans | Commercial mortgage | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial real estate loans | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Amortized Cost Basis (as a percent)	0.00%
Total commercial real estate loans | Construction | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total commercial real estate loans | Construction | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial real estate loans | Construction | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial real estate loans | Construction | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial real estate loans | Total commercial real estate loans
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 4
Amortized Cost Basis (as a percent)	0.02%
Total commercial real estate loans | Total commercial real estate loans | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total commercial real estate loans | Total commercial real estate loans | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	4
Total commercial real estate loans | Total commercial real estate loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial real estate loans | Total commercial real estate loans | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 88
Amortized Cost Basis (as a percent)	0.11%
Total commercial loans | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total commercial loans | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	83
Total commercial loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	1
Total commercial loans | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	4
Total commercial loans | Commercial lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Amortized Cost Basis (as a percent)	0.00%
Total commercial loans | Commercial lease financing | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total commercial loans | Commercial lease financing | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial loans | Commercial lease financing | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total commercial loans | Commercial lease financing | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 5
Amortized Cost Basis (as a percent)	0.01%
Total consumer loans | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total consumer loans | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	5
Total consumer loans | Real estate — residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 1
Amortized Cost Basis (as a percent)	0.00%
Total consumer loans | Real estate — residential mortgage | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total consumer loans | Real estate — residential mortgage | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Real estate — residential mortgage | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Real estate — residential mortgage | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	1
Total consumer loans | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 2
Amortized Cost Basis (as a percent)	0.03%
Total consumer loans | Home equity loans | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total consumer loans | Home equity loans | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Home equity loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Home equity loans | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	2
Total consumer loans | Consumer direct loans
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 1
Amortized Cost Basis (as a percent)	0.02%
Total consumer loans | Consumer direct loans | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total consumer loans | Consumer direct loans | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Consumer direct loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Consumer direct loans | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	1
Total consumer loans | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 1
Amortized Cost Basis (as a percent)	0.10%
Total consumer loans | Credit cards | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total consumer loans | Credit cards | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Credit cards | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Credit cards | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	1
Total consumer loans | Consumer indirect loans
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Amortized Cost Basis (as a percent)	0.00%
Total consumer loans | Consumer indirect loans | Interest Rate Reduction
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0
Total consumer loans | Consumer indirect loans | Term Extension
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Consumer indirect loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	0
Total consumer loans | Consumer indirect loans | Combination
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost Basis	$ 0