Investments - Change in unrealized net capital gains and losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	$ (917)	$ 373	$ 312
Equity securities		308
Amounts recognized for:
Insurance reserves	315	(315)	0
DAC and DSI	154	(49)	(78)
Amounts recognized	469	(364)	(78)
Deferred income taxes	94	145	(81)
(Decrease) increase in unrealized net capital gains and losses, after-tax	(354)	154	153
EMA limited partnerships
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	(1)	3	0
Fixed income securities
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	(914)	147	251
Equity securities
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	0	226	66
Derivative instruments
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	(2)	(3)	$ (5)
Accounting Standards Update 2016-01
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Equity securities	$ 308	$ 308