Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 579	$ 271	$ 1,274	$ 517
Changes in:
Unrealized net capital gains and losses	270	424	473	1,004
Unrealized foreign currency translation adjustments	11	5	8	19
Unrecognized pension and other postretirement benefit cost	18	16	37	27
Other comprehensive income, after-tax	299	445	518	1,050
Comprehensive income	$ 878	$ 716	$ 1,792	$ 1,567