Fair Value Measurement - Level 3 Recurring Fair Value Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Derivative, Fair Value, Net [Abstract]
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]			Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Derivative assets, gross amount	$ 2,456		$ 2,456		$ 2,675
Derivative liabilities, gross amount	2,773		2,773		2,932
Recurring | Level 3
Derivative, Fair Value, Net [Abstract]
Beginning balance			58
Ending balance	69		69
Net unrealized gains (losses) included in OCI related to assets and liabilities still held	(2)	$ (13)	(9)	$ (5)
Derivative assets, gross amount	909	1,200	909	1,200	886
Derivative liabilities, gross amount	840	1,100	840	1,100	$ 828
Total RMBS | Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	309	247	146	236
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income	2	3	4	4
Total Gains or (Losses) (Realized/Unrealized), Included in OCI	(3)	(2)	(3)	1
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(2)	(6)	(5)	(11)
Transfers Into Level 3	3	11	185	45
Transfers Out of Level 3	(5)	(47)	(23)	(69)
Ending balance	304	206	304	206
Derivative, Fair Value, Net [Abstract]
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held	2	2	4	4
CMBS | Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	129	145	132	142
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income	0	0	0	0
Total Gains or (Losses) (Realized/Unrealized), Included in OCI	(1)	(11)	(3)	(6)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(2)	(1)	(3)	(3)
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(124)	0	(124)	0
Ending balance	2	133	2	133
Derivative, Fair Value, Net [Abstract]
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held	0	0	0	0
Total securities available for sale | Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	438	392	278	378
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income	2	3	4	4
Total Gains or (Losses) (Realized/Unrealized), Included in OCI	(4)	(13)	(6)	(5)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(4)	(7)	(8)	(14)
Transfers Into Level 3	3	11	185	45
Transfers Out of Level 3	(129)	(47)	(147)	(69)
Ending balance	306	339	306	339
Derivative, Fair Value, Net [Abstract]
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held	2	2	4	4
Retained interests in securitizations | Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	35	36	35	36
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income	(1)	0	(1)	0
Total Gains or (Losses) (Realized/Unrealized), Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Ending balance	34	36	34	36
Derivative, Fair Value, Net [Abstract]
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held	(1)	0	(1)	0
Net derivative assets (liabilities) | Recurring | Level 3
Derivative, Fair Value, Net [Abstract]
Beginning balance	54	18	58	5
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income	(3)	(13)	3	(18)
Total Gains or (Losses) (Realized/Unrealized), Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	2	69	(3)	173
Settlements	16	45	11	57
Transfers Into Level 3	0	(55)	0	(152)
Transfers Out of Level 3	0	0	0	(1)
Ending balance	69	64	69	64
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held	$ 0	$ 6	$ 1	$ 51