Stockholders' Equity and Statutory Accounting Practices (Schedule of Accumulated Other Comprehensive Income (Loss) by Component) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	$ 10,513	$ 9,893
Other comprehensive income (loss) before reclassifications	819	284	$ 827
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(74)	(397)	(99)
Other comprehensive income (loss) after tax (expense) benefit	893	681	926
Total stockholder's equity at end of period	11,621	10,513	9,893
Reclassification from AOCI, tax	18	106	26
Tax (expense) benefit on other comprehensive income (loss)	(201)	(210)	(235)
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(1,991)	(2,672)	(3,598)
Total stockholder's equity at end of period	(1,098)	(1,991)	(2,672)
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(13)	(12)	(7)
Other comprehensive income (loss) before reclassifications	(22)	(34)	(24)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(20)	(33)	(19)
Other comprehensive income (loss) after tax (expense) benefit	(2)	(1)	(5)
Total stockholder's equity at end of period	(15)	(13)	(12)
Reclassification from AOCI, tax	5	9	5
Tax (expense) benefit on other comprehensive income (loss)	0	0	1
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(1,876)	(1,613)	(2,738)
Other comprehensive income (loss) before reclassifications	842	(310)	1,072
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(46)	(47)	(53)
Other comprehensive income (loss) after tax (expense) benefit	888	(263)	1,125
Total stockholder's equity at end of period	(988)	(1,876)	(1,613)
Reclassification from AOCI, tax	12	13	14
Tax (expense) benefit on other comprehensive income (loss)	(238)	68	(304)
Pension and postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(191)	(525)	(591)
Other comprehensive income (loss) before reclassifications	17	17	39
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	(8)	(317)	(27)
Other comprehensive income (loss) after tax (expense) benefit	25	334	66
Total stockholder's equity at end of period	(166)	(191)	(525)
Reclassification from AOCI, tax	1	84	7
Tax (expense) benefit on other comprehensive income (loss)	(6)	(89)	(17)
Cumulative impact of changes in discount rates used to measure long duration contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	353	(359)	(41)
Other comprehensive income (loss) before reclassifications	(161)	712	(318)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	0	0	0
Other comprehensive income (loss) after tax (expense) benefit	(161)	712	(318)
Total stockholder's equity at end of period	192	353	(359)
Reclassification from AOCI, tax	0	0	0
Tax (expense) benefit on other comprehensive income (loss)	43	(189)	85
Cumulative foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total stockholder's equity at beginning of period	(264)	(163)	(221)
Other comprehensive income (loss) before reclassifications	143	(101)	58
Amounts reclassified from accumulated other comprehensive income (loss) net of tax	0	0	0
Other comprehensive income (loss) after tax (expense) benefit	143	(101)	58
Total stockholder's equity at end of period	(121)	(264)	(163)
Reclassification from AOCI, tax	0	0	0
Tax (expense) benefit on other comprehensive income (loss)	$ 0	$ 0	$ 0