Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	$ 2,216	$ 2,014
Reported in Net investment gains (losses)	$ (6)	$ (13)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment losses	Net investment losses
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other comprehensive income	Other comprehensive income
Reported in Other comprehensive income (loss)	$ 57	$ (29)
Total realized and unrealized investment gains (losses)	72	(9)
Purchases	410	480
Sales	(7)	(43)
Settlements	(210)	(187)
Transfers into Level 3	58	11
Transfers out of Level 3	0	(50)
Balance, Ending, Assets	2,539	2,216
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	2	7
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	59	(35)
Corporate and other bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	1,278	1,045
Reported in Net investment gains (losses)	(6)	(1)
Reported in Other comprehensive income (loss)	57	(15)
Total realized and unrealized investment gains (losses)	51	(16)
Purchases	197	352
Sales	0	(10)
Settlements	(101)	(104)
Transfers into Level 3	58	11
Transfers out of Level 3	0	0
Balance, Ending, Assets	1,483	1,278
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	0	(1)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	57	(21)
States, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	42	44
Reported in Net investment gains (losses)	0	0
Reported in Other comprehensive income (loss)	3	(2)
Total realized and unrealized investment gains (losses)	3	(2)
Purchases	0	0
Sales	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance, Ending, Assets	45	42
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	0	0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	3	(2)
Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	876	901
Reported in Net investment gains (losses)	(2)	(12)
Reported in Other comprehensive income (loss)	(3)	(12)
Total realized and unrealized investment gains (losses)	14	(3)
Purchases	213	125
Sales	0	(14)
Settlements	(105)	(83)
Transfers into Level 3	0	0
Transfers out of Level 3	0	(50)
Balance, Ending, Assets	998	876
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	0	0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	(1)	(12)
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	20	24
Reported in Net investment gains (losses)	2	0
Reported in Other comprehensive income (loss)	0	0
Total realized and unrealized investment gains (losses)	4	12
Purchases	0	3
Sales	(7)	(19)
Settlements	(4)	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance, Ending, Assets	13	20
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	2	8
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	0	0
Reported in Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Reported in Net investment income	21	33
Reported in Net investment income | Corporate and other bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Reported in Net investment income	0	0
Reported in Net investment income | States, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Reported in Net investment income	0	0
Reported in Net investment income | Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Reported in Net investment income	19	21
Reported in Net investment income | Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Reported in Net investment income	$ 2	$ 12