Deferred Policy Acquisition Costs and Value of Business Acquired - DAC and VOBA Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance	$ 2,155	$ 1,935	$ 2,077
Deferrals of commissions and expenses	102	97	126
Amortization:
Amortization, excluding unlocking	(303)	(241)	(235)
Unlocking	12	(62)	(71)
Interest accrued	122	125	129
Net amortization included in Consolidated Statements of Operations	(169)	(178)	(177)
Change in unrealized capital gains/losses on available-for-sale securities	(326)	301	(91)
Ending balance	1,762	2,155	1,935
Movement Analysis Of Value of Business Acquired VOBA [Roll Forward]
Beginning balance	818	556	811
Deferrals of commissions and expenses	8	9	8
Amortization, excluding unlocking	(134)	(103)	(152)
Unlocking	48	(10)	(89)
Interest accrued	56	58	65
Net amortization included in Consolidated Statements of Operations	(30)	(55)	(176)
Change in unrealized capital gains/losses on available-for-sale securities	(332)	308	(87)
Ending balance	464	818	556
Movement Analysis of Deferred Policy Acquisition Costs and Value of Business Acquired (VOBA) [Roll Forward]
Beginning balance	2,973	2,491	2,888
Deferrals of commissions and expenses	110	106	134
Amortization, excluding unlocking	(437)	(344)	(387)
Unlocking	60	(72)	(160)
Interest accrued	178	183	194
Net amortization included in Consolidated Statements of Operations	(199)	(233)	(353)
Change in unrealized capital gains/losses on available-for-sale securities	(658)	609	(178)
Ending balance	$ 2,226	$ 2,973	$ 2,491
Minimum
Movement Analysis of Deferred Policy Acquisition Costs and Value of Business Acquired (VOBA) [Roll Forward]
Rates at which interest accrued	3.50%	3.50%	4.00%
Maximum
Movement Analysis of Deferred Policy Acquisition Costs and Value of Business Acquired (VOBA) [Roll Forward]
Rates at which interest accrued	7.40%	7.40%	7.40%
Guaranteed Minimum Interest Rates
Amortization:
Unlocking		$ (25)	$ (80)
Movement Analysis Of Value of Business Acquired VOBA [Roll Forward]
Unlocking		$ (26)	$ (140)