Noninterest Income - Summary of Other Noninterest Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Trading Activity, Gains and Losses, Net [Line Items]
Revenue from contracts with customers	$ 315	$ 247	$ 948	$ 757
Net gains on revaluation of foreign currency instruments, net of foreign exchange forward contracts	(4)	(1)	1	(1)
Gains from conversion of convertible debt options	0	30	0	30
Other service revenue	14	10	45	21
Other	25	49	97	76
Fund management fees
Trading Activity, Gains and Losses, Net [Line Items]
Revenue from contracts with customers	$ 15	$ 10	$ 51	$ 26