Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income (loss)	$ 146	$ (207)	$ 436	$ (5)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	13	(21)	21	(5)
Net change in unrealized gains and losses on derivative financial instruments	(21)	(84)	(76)	(153)
Net change in available-for-sale securities	2	0	2	0
Net change in unrealized costs associated with certain retirement plans	(1)	0	(1)	0
Total other comprehensive income (loss)	(7)	(105)	(54)	(158)
Total comprehensive income (loss)	$ 139	$ (312)	$ 382	$ (163)