Derivative Financial Instruments - Schedule of the Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 20,928	$ 15,187
Fair value of derivative liabilities	21,507	16,126
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	20,919	15,185
Fair value of derivative liabilities	21,208	15,825
Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	9	2
Fair value of derivative liabilities	0	0
Derivatives not designated as hedging instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	20,775	15,216
Derivatives not designated as hedging instruments | Other Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	21,453	16,091
Derivatives not designated as hedging instruments | Foreign exchange contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	20,775	15,216
Derivatives not designated as hedging instruments | Foreign exchange contracts | Other Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	21,154	15,790
Derivatives not designated as hedging instruments | Other derivative contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	0	0
Derivatives not designated as hedging instruments | Other derivative contracts | Other Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	299	301
Derivatives designated as hedging instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	153	61
Derivatives designated as hedging instruments | Other Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	54	35
Derivatives designated as hedging instruments | Foreign exchange contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	144	59
Derivatives designated as hedging instruments | Foreign exchange contracts | Other Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	54	35
Derivatives designated as hedging instruments | Interest rate contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	9	2
Derivatives designated as hedging instruments | Interest rate contracts | Other Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 0	$ 0