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	$ 2,711	$ (1,434)	$ 857
Amounts recognized for:
Insurance reserves	(126)	315	(315)
DAC and DSI	(191)	163	(50)
Amounts recognized	(317)	478	(365)
Deferred income taxes	(505)	202	117
Increase (decrease) in unrealized net capital gains and losses, after-tax	1,889	(754)	609
Equity securities				$ 1,160
EMA limited partnerships
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	(4)	(1)	5
Fixed income securities
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	2,715	(1,431)	204
Equity securities
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	0	0	651
Derivatives
Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
Change in unrealized net capital gains and losses	$ 0	$ (2)	$ (3)