Condensed Consolidated Statements Of Comprehensive Income (Unaudited) - 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	$ 650	$ 311	$ 1,765	$ 565
Other comprehensive income:
Change in gross unrealized investment gains/losses	88	111	126	159
Effect of income taxes	(33)	(41)	(47)	(58)
Total change in unrealized investment gains/losses, net of tax	55	70	79	101
Reclassification adjustment for net realized gains included in investment income	(2)	(19)	(28)	(39)
Effect of income taxes	0	7	10	14
Total reclassification adjustment, net of tax	(2)	(12)	(18)	(25)
Other comprehensive income, net of tax	53	58	61	76
Comprehensive income	$ 703	$ 369	$ 1,826	$ 641