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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, 2022	Dec. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	$ 1,578	$ 1,151
Reported in Net investment gains (losses)	$ 1	$ (12)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment (losses) gains	Net investment (losses) gains
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other comprehensive (loss) income	Other comprehensive (loss) income
Reported in Other comprehensive income (loss)	$ (323)	$ (43)
Total realized and unrealized investment gains (losses)	(308)	(46)
Purchases	580	612
Sales	(10)	(32)
Settlements	(145)	(130)
Transfers into Level 3	85	150
Transfers out of Level 3	(104)	(127)
Balance, Ending, Assets	1,676	1,578
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	(4)	(2)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period	(321)	(44)
Corporate and other bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	937	770
Reported in Net investment gains (losses)	(2)	(10)
Reported in Other comprehensive income (loss)	(184)	(32)
Total realized and unrealized investment gains (losses)	(185)	(42)
Purchases	137	312
Sales	(5)	(3)
Settlements	(84)	(68)
Transfers into Level 3	10	20
Transfers out of Level 3	0	(52)
Balance, Ending, Assets	810	937
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	(183)	(32)
States, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	56	46
Reported in Net investment gains (losses)	0	0
Reported in Other comprehensive income (loss)	(13)	(1)
Total realized and unrealized investment gains (losses)	(13)	(1)
Purchases	0	12
Sales	0	0
Settlements	0	(1)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance, Ending, Assets	43	56
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	(13)	(1)
Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	556	308
Reported in Net investment gains (losses)	9	0
Reported in Other comprehensive income (loss)	(126)	(10)
Total realized and unrealized investment gains (losses)	(101)	(3)
Purchases	424	287
Sales	(2)	(9)
Settlements	(70)	(61)
Transfers into Level 3	75	109
Transfers out of Level 3	(94)	(75)
Balance, Ending, Assets	788	556
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	(125)	(11)
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	29	27
Reported in Net investment gains (losses)	(6)	(2)
Reported in Other comprehensive income (loss)	0	0
Total realized and unrealized investment gains (losses)	(9)	0
Purchases	19	1
Sales	(3)	(20)
Settlements	9	0
Transfers into Level 3	0	21
Transfers out of Level 3	(10)	0
Balance, Ending, Assets	35	29
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period	(4)	(2)
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	14	9
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
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	16	7
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	$ (3)	$ 2

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss), Included In Earnings And Other Comprehensive Income (Loss)

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Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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