Derivative Financial Instruments - Impact of Derivatives on Consolidated Statement of Income (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	$ 282	$ 156	$ 744	$ 485
Foreign exchange contracts | Foreign exchange trading services
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	230	198	645	621
Foreign exchange contracts | Interest expense
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	82	(24)	195	(40)
Interest rate contracts
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	2	(3)	11	(2)
Other derivative contracts | Other fee revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	(10)	6	(13)	5
Other derivative contracts | Compensation and employee benefits
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	$ (22)	$ (21)	$ (94)	$ (99)