Loans - Schedule of Debtor Troubled Debt Restructuring, Subsequent Periods (Details) - Entity Loan Modification Program $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	$ 265
Interest rate reduction
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	91
Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	70
Interest Rate Reduction and Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	104
Credit Card:
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	92
Credit Card: | Interest rate reduction
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	91
Credit Card: | Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Credit Card: | Interest Rate Reduction and Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	1
Credit Card: | Domestic credit card:
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	75
Credit Card: | Domestic credit card: | Interest rate reduction
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	74
Credit Card: | Domestic credit card: | Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Credit Card: | Domestic credit card: | Interest Rate Reduction and Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	1
Credit Card: | International card businesses:
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	17
Credit Card: | International card businesses: | Interest rate reduction
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	17
Credit Card: | International card businesses: | Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Credit Card: | International card businesses: | Interest Rate Reduction and Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Consumer Banking:
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	106
Consumer Banking: | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	106
Consumer Banking: | Interest rate reduction
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Consumer Banking: | Interest rate reduction | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Consumer Banking: | Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	3
Consumer Banking: | Term Extension | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	3
Consumer Banking: | Interest Rate Reduction and Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	103
Consumer Banking: | Interest Rate Reduction and Term Extension | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	103
Commercial Banking:
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	67
Commercial Banking: | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	67
Commercial Banking: | Interest rate reduction
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Interest rate reduction | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Interest rate reduction | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	67
Commercial Banking: | Term Extension | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Term Extension | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	67
Commercial Banking: | Interest Rate Reduction and Term Extension
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Interest Rate Reduction and Term Extension | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	0
Commercial Banking: | Interest Rate Reduction and Term Extension | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Amount	$ 0