Deferred Policy Acquisition Costs and Value of Business Acquired (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance	$ 385	$ 477	$ 520
Deferrals of commissions and expenses	55	75	74
Amortization, excluding unlocking	(75)	(76)	(72)
Unlocking (1)	(26)	(61)	(24)
Interest accrued	35	37	38
Amortization:
Net amortization included in the Consolidated Statements of Operations	(66)	(100)	(58)
Change in unrealized capital gains/losses on available-for-sale securities	162	(67)	(59)
Ending balance	536	385	477
Movement Analysis Of Value of Business Acquired VOBA [Roll Forward]
Beginning balance	367	537	709
Deferrals of commissions and expenses	6	5	5
Amortization, excluding unlocking	(72)	(83)	(87)
Unlocking (1)	13	(93)	(73)
Interest accrued	39	43	51
Net amortization included in the Consolidated Statements of Operations	(20)	(133)	(109)
Change in unrealized capital gains/losses on available-for-sale securities	198	(42)	(68)
Ending balance	551	367	537
Movement Analysis of Deferred Policy Acquisition Costs and Value of Business Acquired (VOBA) [Roll Forward]
Beginning balance	752	1,014	1,229
Deferrals of commissions and expenses	61	80	79
Amortization, excluding unlocking	(147)	(159)	(159)
Unlocking (1)	(13)	(154)	(97)
Interest accrued	74	80	89
Net amortization included in the Consolidated Statements of Operations	(86)	(233)	(167)
Change in unrealized capital gains/losses on available-for-sale securities	360	(109)	(127)
Ending balance	1,087	752	$ 1,014
Estimated amount of VOBA amortization expense, net of interest:
2019	18
2020	15
2021	14
2022	14
2023	14
Guaranteed Minimum Interest Rates
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Unlocking (1)	25	80
Movement Analysis Of Value of Business Acquired VOBA [Roll Forward]
Unlocking (1)	$ 26	$ 140
Minimum
Deferred Policy Acquisition Cost and Value of Business Acquired [Line Items]
Interest Accrual Rate Associated with Amortization Method of Present Value of Future Insurance Profits	5.50%	5.50%	5.50%
Maximum
Deferred Policy Acquisition Cost and Value of Business Acquired [Line Items]
Interest Accrual Rate Associated with Amortization Method of Present Value of Future Insurance Profits	7.00%	7.00%	7.00%