Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Comprehensive Income
Shareholders' comprehensive income (loss)	$ 2,537	$ 1,735	$ 1,780
Comprehensive income (loss) attributable to noncontrolling interests:
Net income (loss) attributable to redeemable noncontrolling interests	0	(7)	(6)
Net income (loss) attributable to other noncontrolling interests	(5)	(17)	(11)
Other comprehensive income (loss) attributable to redeemable noncontrolling interests	(3)	(10)	(17)
Other comprehensive income (loss) attributable to other noncontrolling interests	0	0	(1)
Total comprehensive income (loss) attributable to noncontrolling interests	(8)	(34)	(35)
Total comprehensive income	$ 2,529	$ 1,701	$ 1,745