Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Comprehensive Income
Shareholders' comprehensive income (loss)	$ 582	$ 585	$ 2,229	$ 2,020
Comprehensive income (loss) attributable to noncontrolling interests:
Net income (loss) attributable to redeemable noncontrolling interests	2	(1)	(1)	(4)
Net income (loss) attributable to other noncontrolling interests	0	(3)	(5)	(12)
Other comprehensive income (loss) attributable to redeemable noncontrolling interests	0	(3)	0	(1)
Total comprehensive income (loss) attributable to noncontrolling interests	2	(7)	(6)	(17)
Total comprehensive income	$ 584	$ 578	$ 2,223	$ 2,003