Deferred Policy Acquisition Costs and Value of Business Acquired - DAC and VOBA Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance			$ 1,762	$ 2,155	$ 2,155
Deferrals of commissions and expenses			51	62
Amortization:
Amortization, excluding unlocking			(136)	(162)
Unlocking			7	15
Interest accrued			62	64
Net amortization included in the Consolidated Statements of Operations			(67)	(83)
Change due to unrealized capital gains/losses on available-for-sale securities			(115)	(255)
Ending balance	$ 1,634	$ 1,879	1,634	1,879	1,762	$ 2,155
Movement Analysis Of Value of Business Acquired VOBA [Roll Forward]
Beginning balance			464	818	818
Deferrals of commissions and expenses			2	4
Amortization:
Amortization, excluding unlocking			(49)	(68)
Unlocking			(6)	23
Interest accrued			27	28
Net amortization included in Condensed Consolidated Statements of Operations			(28)	(17)
Change due to unrealized capital gains/losses on available-for-sale securities			(105)	(266)
Ending balance	333	539	333	539	464	$ 818
Movement Analysis of Deferred Policy Acquisition Costs and Value of Business Acquired (VOBA) [Roll Forward]
Beginning balance			$ 2,226	2,973	$ 2,973
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201613Member		us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201802Member
Deferrals of commissions and expenses			$ 53	66
Amortization:
Amortization, excluding unlocking			(185)	(230)
Unlocking			1	38
Interest accrued			89	92
Net amortization included in Condensed Consolidated Statements of Operations	(19)	(43)	(95)	(100)
Change due to unrealized capital gains/losses on available-for-sale securities			(220)	(521)
Ending balance	$ 1,967	$ 2,418	$ 1,967	$ 2,418	$ 2,226	$ 2,973
Minimum
Amortization:
Value of Business Acquired (VOBA), Interest accrued percentage			3.50%	2.70%
Maximum
Amortization:
Value of Business Acquired (VOBA), Interest accrued percentage			7.40%	7.40%
Accounting Standards Update 2016-13
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance			$ 3
Amortization:
Ending balance					3
Movement Analysis Of Value of Business Acquired VOBA [Roll Forward]
Beginning balance			0
Amortization:
Ending balance					0
Movement Analysis of Deferred Policy Acquisition Costs and Value of Business Acquired (VOBA) [Roll Forward]
Beginning balance			$ 3
Amortization:
Ending balance					$ 3