Accumulated Other Comprehensive Income (Loss) - Components of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Derivatives	$ 145	$ 170	$ 127
DAC/VOBA adjustment on available-for-sale securities	(1,498)	(380)	(1,471)
Premium deficiency reserve	(249)	(57)	(190)
Sales inducements and other intangibles adjustment on available-for-sale securities	(185)	(64)	(278)
Other	0	0	(18)
Unrealized capital gains (losses), before tax	3,759	743	3,556
Deferred income tax asset (liability)	(435)	(143)	(840)
Net unrealized capital gains (losses)	3,324	600	2,716
Pension and other postretirement benefits liability, net of tax	7	7	15
AOCI	3,331	607	2,731
Fixed maturities
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Fixed maturities, net of OTTI	5,546	1,074	5,351
Equity securities
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Equity securities	0	$ 0	$ 35
Other Contract
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Portion of AOCI expected to be reclassified into earnings within the next 12 months	$ 25