Investments - Change in unrealized net capital gains and losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	$ 1,163	$ (917)	$ 373
Amounts recognized for:
Insurance reserves	(126)	315	(315)
DAC and DSI	(178)	154	(49)
Amounts recognized	(304)	469	(364)
Deferred income taxes	(180)	94	145
Increase (decrease) in unrealized net capital gains and losses, after-tax	679	(354)	154
EMA limited partnerships
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	(2)	(1)	3
Fixed income securities
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	1,165	(914)	147
Equity securities
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	0	0	226
Derivative instruments
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	$ 0	$ (2)	$ (3)
Accounting Standards Update 2016-01
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Equity securities				$ 308