Fair Value - Level 3 Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Available-for-Sale Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 399	$ 461	$ 427	$ 514
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(39)	(19)	(75)	(74)
Net transfers	0	0	0	(1)
Total gains (losses) realized & unrealized	(9)	6	(1)	9
Ending Balance	351	448	351	448
Mortgage Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	376	425	399	477
Purchases	0	0	0	0
Sales	(1)	0	(1)	(6)
Issuances	0	0	0	0
Settlements	(12)	(14)	(41)	(47)
Net transfers	1	1	0	(9)
Total gains (losses) realized & unrealized	7	18	14	15
Ending Balance	371	430	371	430
Net Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	33	94	39	77
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	2	5	21	34
Net transfers	0	0	0	0
Total gains (losses) realized & unrealized	13	(19)	(12)	(31)
Ending Balance	48	80	48	80
Long-term Debt
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(350)	(380)	(353)	(385)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	4	5	10	12
Net transfers	0	(1)	0	0
Total gains (losses) realized & unrealized	(6)	(18)	(9)	(21)
Ending Balance	(352)	(394)	(352)	(394)
Mortgage-related | Trading Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	25	32	28	26
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Net transfers	0	1	(3)	8
Total gains (losses) realized & unrealized	1	2	1	1
Ending Balance	$ 26	$ 35	$ 26	$ 35