Derivative Financial Instruments - Fair Value Hedges Basis Adjusments (Details) - USD ($) $ in Millions		Jun. 30, 2025	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Liability, Statement of Financial Position [Extensible Enumeration]		Other Liabilities	Other Liabilities
Amortized Cost		$ 71,652	$ 73,833
Financial Asset, Closed Portfolio, Portfolio Layer Method, Amortized Cost		29,700	30,500
Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Financial Asset, Closed Portfolio, Portfolio Layer Method, Amortized Cost		17,400	18,000
Fair Value Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Liability, Long Term Debt, Fair Value Hedge	[1]	28,931	29,469
Fair Value Hedges | Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		122	(121)
Fair Value Hedges | Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		(452)	(533)
Fair Value Hedges | Available-for-sale Securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of the Hedged Assets and Liabilities(1)	[1],[2]	41,809	43,621
Fair Value Hedges | Available-for-sale Securities | Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		91	(503)
Fair Value Hedges | Available-for-sale Securities | Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		14	15
Fair Value Hedges | Loans and leases
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of the Hedged Assets and Liabilities(1)	[1]	209	297
Fair Value Hedges | Loans and leases | Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		0	0
Fair Value Hedges | Loans and leases | Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		$ 4	$ 5

[1] Carrying value shown represents amortized cost.

[2] As of June 30, 2025, closed portfolios of securities hedged under the portfolio layer method have an amortized cost of $29.7 billion, of which $17.4 billion was designated as hedged. As of December 31, 2024, closed portfolios of securities hedged under the portfolio layer method have an amortized cost of $30.5 billion, of which $18.0 billion was designated as hedged. The remaining amount of amortized cost is from securities with terminated hedges where the basis adjustment is being amortized into earnings using the effective interest method over the contractual life of the security and hedges not designated under the portfolio-layer method.