Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Comprehensive Income [Abstract]
Shareholders' comprehensive income (loss)	$ 781	$ 535
Net income (loss) attributable to redeemable noncontrolling interests	(1)	0
Net income (loss) attributable to other noncontrolling interests	(4)	(2)
Other comprehensive income (loss) attributable to redeemable noncontrolling interests	3	(9)
Total comprehensive income	$ 779	$ 524