Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 306	$ (4,101)
Other comprehensive (loss) income, net of taxes:
Unrealized gains on securities	1	0
Defined benefit plans:
Amortization of unrecognized amounts included in net periodic benefit costs	11	8
Foreign exchange losses	(1)	(9)
Other comprehensive income (loss)	11	(1)
Total comprehensive income (loss)	317	(4,102)
Total comprehensive income attributable to noncontrolling interests	(78)	(71)
Preferred dividends attributable to redeemable noncontrolling interest	0	(11)
Total comprehensive income (loss) attributable to common stockholders	$ 239	$ (4,184)