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	$ 4,022	$ (1,148)	$ 1,725
Federal statutory rate	21.00%	21.00%	21.00%
Federal income tax expense (benefit) at federal statutory rate	$ 845	$ (241)	$ 362
Effect of:
Tax-preferred investment income	(32)	(126)	(90)
Tax credits	(39)	(40)	(42)
Excess tax expense (benefit) from stock-based compensation	3	4	(1)
Goodwill impairment	0	0	133
Release of uncertain tax positions	(41)	0	0
Other items	11	7	5
Federal income tax expense (benefit)	$ 747	$ (396)	$ 367
Effective tax rate	19.00%	34.00%	21.00%