Derivative Financial Instruments - Schedule of the Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 19,953	$ 19,707
Fair value of derivative liabilities	20,589	19,602
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	19,900	19,694
Fair value of derivative liabilities	20,431	19,416
Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	53	13
Fair value of derivative liabilities	1	4
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	19,893	19,498
Fair value of derivative liabilities	20,398	19,335
Derivatives not designated as hedging instruments | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	19,893	19,498
Fair value of derivative liabilities	20,241	19,153
Derivatives not designated as hedging instruments | Other derivative contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	0	0
Fair value of derivative liabilities	157	182
Derivatives designated as hedging instruments
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	60	209
Fair value of derivative liabilities	191	267
Derivatives designated as hedging instruments | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	7	196
Fair value of derivative liabilities	190	263
Derivatives designated as hedging instruments | Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	53	13
Fair value of derivative liabilities	$ 1	$ 4