Schedule V (Details) - USD ($) $ in Millions		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020
Schedule V [Roll Forward]
Reinsurance recoverables, allowance for estimated uncollectible reinsurance	$ 92	$ 141	$ 146	$ 92
Accounting Standards Update [Extensible List]	Accounting Standards Update 2016-13 [Member]
Cumulative Effect, Period of Adoption, Adjustment [Member]
Schedule V [Roll Forward]
Reinsurance recoverables, allowance for estimated uncollectible reinsurance	$ 53			53	$ 53
Reinsurance recoverables [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period		146	92	110
Valuation and qualifying accounts, charged to costs and expenses		(5)	1	(18)
Valuation and qualifying accounts, charged to other accounts		0	53	0
Valuation and qualifying accounts, deductions		0	0	0
Valuation and qualifying accounts, balance at end of period	92	141	146	92
Allowance for uncollectible premiums receivable from underwriting activities [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period		105	55	54
Valuation and qualifying accounts, charged to costs and expenses		65	95	59
Valuation and qualifying accounts, charged to other accounts		0	2	0
Valuation and qualifying accounts, deductions		63	47	58
Valuation and qualifying accounts, balance at end of period	55	107	105	55
Allowance for uncollectible deductibles [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period		27	22	24
Valuation and qualifying accounts, charged to costs and expenses		2	7	(2)
Valuation and qualifying accounts, charged to other accounts		0	(2)	0
Valuation and qualifying accounts, deductions		0	0	0
Valuation and qualifying accounts, balance at end of period	$ 22	$ 29	$ 27	$ 22