Schedule V (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reinsurance recoverables [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period	$ 110	$ 111	$ 116
Valuation and qualifying accounts, charged to costs and expenses	0	0	0
Valuation and qualifying accounts, charged to other accounts	0	0	0
Valuation and qualifying accounts, deductions	18	1	5
Valuation and qualifying accounts, balance at end of period	92	110	111
Allowance for uncollectible premiums receivable from underwriting activities [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period	54	58	61
Valuation and qualifying accounts, charged to costs and expenses	59	50	38
Valuation and qualifying accounts, charged to other accounts	0	0	0
Valuation and qualifying accounts, deductions	58	54	41
Valuation and qualifying accounts, balance at end of period	55	54	58
Allowance for uncollectible deductibles [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period	24	26	34
Valuation and qualifying accounts, charged to costs and expenses	(2)	(1)	(2)
Valuation and qualifying accounts, charged to other accounts	0	0	0
Valuation and qualifying accounts, deductions	0	1	6
Valuation and qualifying accounts, balance at end of period	$ 22	$ 24	$ 26