Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income	$ 1,145	$ 838
Other comprehensive income:
Change in accumulated other comprehensive income (loss) of equity method investees	1	(2)
Other comprehensive income (loss), net of tax	1	(2)
Total comprehensive income	$ 1,146	$ 836