Derivative Financial Instruments - Fair Value of Derivatives and Balance Offsetting (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 14,259	$ 17,169
Derivative Liabilities	14,253	17,263
Gross amounts of receivable subject to enforceable master netting agreements	11,660	14,110
Gross amounts of payable subject to enforceable master netting agreements	11,660	14,110
Less: Gross amounts of cash collateral received subject to enforceable master netting agreements	1,711	1,760
Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements	1,080	1,321
Derivative asset	888	1,299
Derivative liability	1,513	1,832
Less: Gross amounts of financial instrument collateral received not offset	88	63
Less: Gross amounts of financial instrument collateral posted not offset	35	273
Net amount of derivative asset	800	1,236
Net amount of derivative liability	$ 1,478	$ 1,559
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Interest, taxes and other liabilities (includes $661 million and $10 million designated under fair value option at March 31, 2024 and December 31, 2023, respectively)	Interest, taxes and other liabilities (includes $661 million and $10 million designated under fair value option at March 31, 2024 and December 31, 2023, respectively)
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets, net of allowance for credit losses of nil at both March 31, 2024 and December 31, 2023 (includes $661 million and $10 million designated under fair value option at March 31, 2024 and December 31, 2023, respectively)	Other assets, net of allowance for credit losses of nil at both March 31, 2024 and December 31, 2023 (includes $661 million and $10 million designated under fair value option at March 31, 2024 and December 31, 2023, respectively)
Trading Assets
Derivatives, Fair Value [Line Items]
Less: Gross amounts of cash collateral received subject to enforceable master netting agreements	$ 1,399	$ 1,416
Trading Liabilities
Derivatives, Fair Value [Line Items]
Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements	1,079	1,321
Designated as Hedging Instrument | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	32	0
Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	13	140
Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,330	1,255
Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	909	962
Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	10,476	13,606
Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	10,570	13,479
Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	435	420
Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	1,097	1,080
Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,222	1,153
Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	1,136	1,033
Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	138	95
Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	98	137
Credit contracts | Not Designated as Hedging Instrument, Other | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	9	14
Credit contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	131	123
Bilateral OTC | Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,289	1,178
Bilateral OTC | Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	905	946
Bilateral OTC | Interest rate contracts | Not Designated as Hedging Instrument, Other | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Bilateral OTC | Interest rate contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	101	76
Bilateral OTC | Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	10,420	13,606
Bilateral OTC | Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	10,570	13,479
Bilateral OTC | Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	435	413
Bilateral OTC | Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	1,097	1,080
Bilateral OTC | Equity contracts | Not Designated as Hedging Instrument, Other | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	613	621
Bilateral OTC | Equity contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	164	193
Bilateral OTC | Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,222	1,150
Bilateral OTC | Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	1,136	1,033
Bilateral OTC | Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	131	81
Bilateral OTC | Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	98	137
Bilateral OTC | Credit contracts | Not Designated as Hedging Instrument, Other | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	9	13
Bilateral OTC | Credit contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	131	122
Bilateral OTC | Other Contracts | Not Designated as Hedging Instrument, Other | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	4	5
Bilateral OTC | Other Contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	34	40
Bilateral OTC | Fair Value Hedging | Interest rate contracts | Designated as Hedging Instrument | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Bilateral OTC | Fair Value Hedging | Interest rate contracts | Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	13	83
Bilateral OTC | Cash Flow Hedging | Interest rate contracts | Designated as Hedging Instrument | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1	0
Bilateral OTC | Cash Flow Hedging | Interest rate contracts | Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	1
Bilateral OTC | Cash Flow Hedging | Foreign exchange contracts | Designated as Hedging Instrument | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	31	0
Bilateral OTC | Cash Flow Hedging | Foreign exchange contracts | Designated as Hedging Instrument | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	56
OTC Cleared | Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	36	70
OTC Cleared | Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	0
OTC Cleared | Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	56	0
OTC Cleared | Foreign exchange contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	0
OTC Cleared | Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	7	14
OTC Cleared | Credit contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	0
OTC Cleared | Credit contracts | Not Designated as Hedging Instrument, Other | Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	0	1
OTC Cleared | Credit contracts | Not Designated as Hedging Instrument, Other | Interest taxes and other liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	1
Exchange Traded | Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	5	7
Exchange Traded | Interest rate contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	4	16
Exchange Traded | Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	0	7
Exchange Traded | Equity contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	0
Exchange Traded | Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Assets
Derivatives, Fair Value [Line Items]
Derivative Assets	0	3
Exchange Traded | Precious metals contracts | Not Designated as Hedging Instrument, Trading | Trading Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 0	$ 0