Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commercial mortgage loans [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 0	$ 5	$ 15
Charged (Credited) to costs and expenses	0	1	0
Charged (Credited) to other accounts	0	0	0
Other deductions	0	(6)	(10)
Balance at end of period	0	0	5
Premiums, accounts and notes receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	207	200	75
Charged (Credited) to costs and expenses	18	19	134
Charged (Credited) to other accounts	(3)	(11)	(8)
Other deductions	(5)	(1)	(1)
Balance at end of period	217	207	200
Deferred tax asset valuation allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	72	87	71
Charged (Credited) to costs and expenses	(5)	11	21
Charged (Credited) to other accounts	132	(26)	(5)
Other deductions	0	0	0
Balance at end of period	199	72	87
Reinsurance recoverables [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	3	3	3
Charged (Credited) to costs and expenses	(1)	0	0
Charged (Credited) to other accounts	0	0	0
Other deductions	0	0	0
Balance at end of period	$ 2	$ 3	$ 3