Stockholders' Equity - Changes in Each Component of Accumulated Other Comprehensive Income of the Parent (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		$ (1,284)
Other comprehensive income (loss):
Ending Balance		(1,342)	$ (1,284)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(646)	(608)	$ (427)
Other comprehensive income (loss):
Currency translation adjustments		(22)	(43)	(179)
Holding loss on net investment hedge		(2)		(2)
Elimination due to disposal group or sale of subsidiary			2
Tax (expense) benefit			3
Other comprehensive income (loss) attributable to the parent company		(24)	(38)	(181)
Ending Balance		(670)	(646)	(608)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(34)	(4)	(9)
Other comprehensive income (loss):
Holding gains and losses		(162)	(16)	(14)
Reclassification of amount to net income	[1]	128	(14)	20
Tax (expense) benefit		4		(1)
Other comprehensive income (loss) attributable to the parent company		(30)	(30)	5
Ending Balance		(64)	(34)	(4)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		0	2	5
Other comprehensive income (loss):
Holding gains and losses		1	3	(3)
Reclassification of amount to net income	[1]		(7)
Elimination due to disposal group or sale of subsidiary			2
Tax (expense) benefit		1
Other comprehensive income (loss) attributable to the parent company		2	(2)	(3)
Ending Balance		2	0	2
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(604)	(564)	(566)
Other comprehensive income (loss):
Net actuarial losses		(28)	(88)	(28)
Curtailment gain		1
Reclassification adjustment for net actuarial losses included in net periodic benefit cost	[2]	30	26	25
Elimination due to disposal group or sale of subsidiary			1	10
Tax (expense) benefit		(9)	21	(5)
Other comprehensive income (loss) attributable to the parent company		(6)	(40)	2
Ending Balance		(610)	(604)	(564)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(1,284)	(1,174)	(997)
Other comprehensive income (loss):
Currency translation adjustments		(22)	(43)	(179)
Holding loss on net investment hedge		(2)		(2)
Holding gains and losses		(161)	(13)	(17)
Reclassification of amount to net income	[1]	128	(21)	20
Net actuarial losses		(28)	(88)	(28)
Curtailment gain		1
Reclassification adjustment for net actuarial losses included in net periodic benefit cost	[2]	30	26	25
Elimination due to disposal group or sale of subsidiary			5	10
Tax (expense) benefit		(4)	24	(6)
Other comprehensive income (loss) attributable to the parent company		(58)	(110)	(177)
Ending Balance		$ (1,342)	$ (1,284)	$ (1,174)

[1] Foreign currency contract and investment reclassifications are included in other income (expense), net.

[2] See Note 12 for additional details.