Fair Value - Level 3 Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Available-for-Sale Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 320	$ 399	$ 341	$ 427
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(11)	(39)	(29)	(75)
Net transfers	0	0	(1)	0
Total gains (losses) realized & unrealized	(8)	(9)	(10)	(1)
Ending Balance	301	351	301	351
Mortgage Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	367	376	388	399
Purchases	0	0	0	0
Sales	0	(1)	0	(1)
Issuances	0	0	0	0
Settlements	(20)	(12)	(47)	(41)
Net transfers	32	1	38	0
Total gains (losses) realized & unrealized	(5)	7	(5)	14
Ending Balance	374	371	374	371
Net Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	69	33	65	39
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	1	2	5	21
Net transfers	0	0	10	0
Total gains (losses) realized & unrealized	(35)	13	(45)	(12)
Ending Balance	35	48	35	48
Long-term Debt
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(346)	(350)	(347)	(353)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	6	4	15	10
Net transfers	0	0	0	0
Total gains (losses) realized & unrealized	26	(6)	18	(9)
Ending Balance	(314)	(352)	(314)	(352)
Mortgage-related securities | Trading Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	26	25	27	28
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Net transfers	0	0	0	(3)
Total gains (losses) realized & unrealized	(4)	1	(5)	1
Ending Balance	$ 22	$ 26	$ 22	$ 26