Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Comprehensive Income
Shareholders' comprehensive income (loss)	$ 758	$ 582	$ 1,957	$ 2,229
Comprehensive income (loss) attributable to noncontrolling interests:
Net income (loss) attributable to redeemable noncontrolling interests	2	2	6	(1)
Net income (loss) attributable to other noncontrolling interests	0	0	0	(5)
Other comprehensive income (loss) attributable to redeemable noncontrolling interests	(9)	0	(19)	0
Total comprehensive income (loss) attributable to noncontrolling interests	(7)	2	(13)	(6)
Total comprehensive income	$ 751	$ 584	$ 1,944	$ 2,223