Fair Value - Schedule of Fair Value Measurements, Assets, Using Significant Unobservable Inputs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 2	$ 2,792	$ 16	$ 2,756
Total realized and unrealized gain (losses) recorded in revenue	0	(2)	(3)	(7)
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	61	0	27
Purchases	1	672	110	861
Sales	0	(34)	0	(95)
Settlements	(1)	(30)	(1)	(83)
Transfers into Level 3	0	50	15	50
Transfers out of Level 3	0	0	(135)	0
Fair value, end of period	2	3,509	2	3,509
Change in unrealized gains (losses) related to financial instruments held	0	(4)	(1)	(4)
Derivative instruments, assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	2	2	2	4
Total realized and unrealized gain (losses) recorded in revenue	0	(2)	(3)	(7)
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0	0	0
Purchases	1	9	4	10
Sales	0	0	0	0
Settlements	(1)	(3)	(1)	(1)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair value, end of period	2	6	2	6
Change in unrealized gains (losses) related to financial instruments held	0	(4)	(1)	(4)
Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	2	2	2	4
Total realized and unrealized gain (losses) recorded in revenue	0	(2)	(3)	(7)
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0	0	0
Purchases	1	9	4	10
Sales	0	0	0	0
Settlements	(1)	(3)	(1)	(1)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair value, end of period	2	6	2	6
Change in unrealized gains (losses) related to financial instruments held	0	(4)	(1)	(4)
Asset-backed securities, collateralized loan obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		1,869	14	1,820
Total realized and unrealized gain (losses) recorded in revenue		0	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income		14	0	(10)
Purchases		663	106	850
Sales		(34)	0	(95)
Settlements		(24)	0	(77)
Transfers into Level 3		50	0	50
Transfers out of Level 3		0	(120)	0
Fair value, end of period	0	2,538	0	2,538
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		1,869	14	1,820
Total realized and unrealized gain (losses) recorded in revenue		0	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income		14	0	(10)
Purchases		663	106	850
Sales		(34)	0	(95)
Settlements		(24)	0	(77)
Transfers into Level 3		50	0	50
Transfers out of Level 3		0	(120)	0
Fair value, end of period	0	2,538	0	2,538
Other U.S. debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period			0
Total realized and unrealized gain (losses) recorded in revenue			0
Total realized and unrealized gain (losses) recorded in other comprehensive income			0
Purchases			0
Sales			0
Settlements			0
Transfers into Level 3			15
Transfers out of Level 3			(15)
Fair value, end of period	0		0
Non-U.S. debt securities, asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		876		887
Total realized and unrealized gain (losses) recorded in revenue		0		0
Total realized and unrealized gain (losses) recorded in other comprehensive income		45		35
Purchases		0		1
Sales		0		0
Settlements		(3)		(5)
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair value, end of period		918		918
Non-U.S. debt securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		45		45
Total realized and unrealized gain (losses) recorded in revenue		0		0
Total realized and unrealized gain (losses) recorded in other comprehensive income		2		2
Purchases		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair value, end of period		47		47
Total non-U.S. debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		921		932
Total realized and unrealized gain (losses) recorded in revenue		0		0
Total realized and unrealized gain (losses) recorded in other comprehensive income		47		37
Purchases		0		1
Sales		0		0
Settlements		(3)		(5)
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair value, end of period		965		965
Investment securities available-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		2,790	14	2,752
Total realized and unrealized gain (losses) recorded in revenue		0	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income		61	0	27
Purchases		663	106	851
Sales		(34)	0	(95)
Settlements		(27)	0	(82)
Transfers into Level 3		50	15	50
Transfers out of Level 3		0	(135)	0
Fair value, end of period	$ 0	$ 3,503	$ 0	$ 3,503