Condensed Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 1,115	$ 254
Other comprehensive income:
Change in gross unrealized investment gains/losses	38	48
Effect of income taxes	(14)	(17)
Total change in unrealized investment gains/losses, net of tax	24	31
Reclassification adjustment for net realized gains included in investment income	(26)	(20)
Effect of income taxes	10	7
Total reclassification adjustment, net of tax	(16)	(13)
Other comprehensive income, net of tax	8	18
Comprehensive income	$ 1,123	$ 272