Federal Income Taxes - Reconciliation of the Effective Tax Rate Differences (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income (loss) before taxes	$ 2,582	$ (2,461)	$ (2,112)
Federal statutory rate	21.00%	21.00%	21.00%
Federal income tax expense (benefit) at federal statutory rate	$ 542	$ (517)	$ (444)
Effect of:
Tax-preferred investment income	(32)	(126)	(90)
Tax credits	(39)	(40)	(42)
Excess tax expense (benefit) from stock-based compensation	3	3	(1)
Goodwill impairment	0	0	133
Release of uncertain tax positions	(34)	0	0
Other items	12	7	7
Federal income tax expense (benefit)	$ 452	$ (673)	$ (437)
Effective tax rate	18.00%	27.00%	21.00%