Derivative Financial Instruments - Impact of Derivatives on Consolidated Statement of Income (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	$ 250	$ 145	$ 462	$ 330
Foreign exchange contracts | Foreign exchange trading services
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	208	191	415	423
Foreign exchange contracts | Interest expense
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	64	(22)	113	(16)
Interest rate contracts
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	2	0	9	1
Other derivative contracts | Other fee revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	(1)	0	(3)	0
Other derivative contracts | Compensation and employee benefits
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	$ (23)	$ (24)	$ (72)	$ (78)