Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income (loss)	$ 283	$ 228	$ 719	$ 223
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	25	2	46	(3)
Net change in unrealized gains and losses on derivative financial instruments	(24)	(31)	(100)	(184)
Net change in available-for-sale securities	1	0	3	0
Net change in unrealized costs associated with certain retirement plans	0	0	(1)	0
Total other comprehensive income (loss)	2	(29)	(52)	(187)
Total comprehensive income (loss)	$ 285	$ 199	$ 667	$ 36