Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement Of Comprehensive Income [Abstract]
Shareholders' comprehensive income (loss)	$ 654	$ 397	$ 1,435	$ 932
Net income (loss) attributable to redeemable noncontrolling interests	(2)	(1)	(3)	(1)
Net income (loss) attributable to other noncontrolling interests	(5)	(3)	(9)	(5)
Other comprehensive income (loss) attributable to redeemable noncontrolling interests	(1)	(3)	2	(12)
Total comprehensive income	$ 646	$ 390	$ 1,425	$ 914