Derivative Financial Instruments - Fair Value of Derivatives and Balance Offsetting (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 16,050	$ 13,650
Derivative Liabilities	14,462	12,359
Gross amounts of receivable subject to enforceable master netting agreements	12,050	10,198
Gross amounts of payable subject to enforceable master netting agreements	12,050	10,198
Less: Gross amounts of cash collateral received subject to enforceable master netting agreements	2,757	1,911
Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements	1,099	1,143
Derivative asset	1,243	1,541
Derivative liability	1,313	1,018
Less: Gross amounts of financial instrument collateral received not offset	252	255
Less: Gross amounts of financial instrument collateral posted not offset	50	10
Net amount of derivative asset	991	1,286
Net amount of derivative liability	$ 1,263	$ 1,008
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Interest, taxes and other liabilities	Interest, taxes and other liabilities
Trading assets
Derivatives, Fair Value [Line Items]
Less: Gross amounts of cash collateral received subject to enforceable master netting agreements	$ 2,757	$ 1,600
Trading Liabilities
Derivatives, Fair Value [Line Items]
Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements	1,099	1,143
Designated as Hedging Instrument | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	177	153
Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	42	13
Interest rate contracts | Designated as Hedging Instrument | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	17	24
Interest rate contracts | Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	42	13
Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading assets
Derivatives, Fair Value [Line Items]
Derivative Assets	837	761
Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	439	430
Interest rate contracts | Not Designated as Hedging Instrument, Other | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	2	1
Interest rate contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	85	73
Foreign exchange contracts | Designated as Hedging Instrument | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	160	129
Foreign exchange contracts | Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	0
Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading assets
Derivatives, Fair Value [Line Items]
Derivative Assets	11,277	9,452
Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	11,123	8,924
Equity contracts | Not Designated as Hedging Instrument, Trading | Trading assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,317	525
Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	573	567
Equity contracts | Not Designated as Hedging Instrument, Other | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	545	734
Equity contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	210	68
Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,753	1,883
Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	1,796	2,050
Credit contracts | Not Designated as Hedging Instrument, Trading | Trading assets
Derivatives, Fair Value [Line Items]
Derivative Assets	124	119
Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	33	59
Credit contracts | Not Designated as Hedging Instrument, Other | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	15	18
Credit contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	152	158
Other Contracts | Not Designated as Hedging Instrument, Other | Other assets:
Derivatives, Fair Value [Line Items]
Derivative Assets	3	4
Other Contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 9	$ 17