Federal Income Taxes - Reconciliation of the Effective Tax Rate Differences (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income (loss) before taxes	$ 1,338	$ 4,022	$ (1,148)
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Federal income tax expense (benefit) at federal statutory rate	281	845	(241)
Effects of Tax credits:
Foreign tax credits	(48)	(36)	(36)
Other tax credits	(5)	(3)	(4)
Nontaxable or nondeductible items:
Tax-preferred investment income	(82)	(32)	(126)
Share-based compensation expense	1	3	4
Other nontaxable or nondeductible items	14	11	7
Changes in unrecognized tax benefits	0	(41)	0
Federal income tax expense (benefit)	$ 161	$ 747	$ (396)
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%
Tax Jurisdiction of Domicile [Extensible Enumeration]	UNITED STATES	UNITED STATES	UNITED STATES
Effects of Tax credits:
Foreign tax credits	(4.00%)	(1.00%)	3.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	0.00%	0.00%	0.00%
Nontaxable or nondeductible items:
Tax-preferred investment income	(6.00%)	0.00%	11.00%
Share-based compensation expense	0.00%	0.00%	0.00%
Other nontaxable or nondeductible items	1.00%	0.00%	(1.00%)
Changes in unrecognized tax benefits	0.00%	(1.00%)	0.00%
Effective income tax rate	12.00%	19.00%	34.00%