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	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	$ 1,580	$ 1,375	$ 1,578	$ 1,151
Reported in Net investment gains (losses)	(1)	(2)	(1)	(11)
Reported in Other comprehensive income (loss)	(92)	2	(339)	(27)
Total realized and unrealized investment gains (losses)	(91)	2	(329)	(32)
Purchases	125	139	487	429
Sales	0	(20)	(10)	(27)
Settlements	(18)	(22)	(108)	(74)
Transfers into Level 3	47	52	76	92
Transfers out of Level 3	(53)	(90)	(104)	(103)
Balance, Ending, Assets	1,590	1,436	1,590	1,436
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	(7)	(3)	(8)	(1)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	(93)	2	(338)	(27)
Corporate and other bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	846	883	937	770
Reported in Net investment gains (losses)	0	1	(2)	(9)
Reported in Other comprehensive income (loss)	(50)	1	(203)	(23)
Total realized and unrealized investment gains (losses)	(49)	2	(204)	(32)
Purchases	9	55	127	219
Sales	0	0	(5)	(3)
Settlements	(4)	(11)	(63)	(35)
Transfers into Level 3	0	0	10	10
Transfers out of Level 3	0	(52)	0	(52)
Balance, Ending, Assets	802	877	802	877
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	0	0	0	0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	(51)	2	(203)	(22)
States, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	46	57	56	46
Reported in Net investment gains (losses)	0	0	0	0
Reported in Other comprehensive income (loss)	(4)	0	(14)	0
Total realized and unrealized investment gains (losses)	(4)	0	(14)	0
Purchases	0	0	0	12
Sales	0	0	0	0
Settlements	0	0	0	(1)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, Ending, Assets	42	57	42	57
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	0	0	0	0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	(4)	0	(14)	0
Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	641	410	556	308
Reported in Net investment gains (losses)	2	0	7	0
Reported in Other comprehensive income (loss)	(38)	1	(122)	(4)
Total realized and unrealized investment gains (losses)	(31)	2	(104)	0
Purchases	116	83	348	197
Sales	0	(9)	(2)	(9)
Settlements	(14)	(11)	(54)	(38)
Transfers into Level 3	47	41	66	71
Transfers out of Level 3	(43)	(38)	(94)	(51)
Balance, Ending, Assets	716	478	716	478
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	0	0	0	0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	(38)	0	(121)	(5)
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	47	25	29	27
Reported in Net investment gains (losses)	(3)	(3)	(6)	(2)
Reported in Other comprehensive income (loss)	0	0	0	0
Total realized and unrealized investment gains (losses)	(7)	(2)	(7)	0
Purchases	0	1	12	1
Sales	0	(11)	(3)	(15)
Settlements	0	0	9	0
Transfers into Level 3	0	11	0	11
Transfers out of Level 3	(10)	0	(10)	0
Balance, Ending, Assets	30	24	30	24
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	(7)	(3)	(8)	(1)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	0	0	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	2	2	11	6
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	1	0	1	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	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	5	1	11	4
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	$ (4)	$ 1	$ (1)	$ 2