Accumulated Other Elements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ (540)
Foreign currency translation gain (loss)	(469)	$ (526)	$ (70)
Gain (loss) on derivatives recognized in other comprehensive income, net of tax	(65)	(76)	14
Balance at end of period	(877)	(540)
Accumulated Foreign Currency Translation Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(428)	(49)	46
Foreign currency translation gain (loss)	(358)	(379)	(95)
Actuarial gains (losses) recognized in other comprehensive income, net of tax	0	0	0
Curtailment and settlement gains (losses) recognized in other comprehensive income, net of tax	0	0
Amortization of actuarial (gains) losses, net of tax	0	0	0
Gain (loss) on derivatives recognized in other comprehensive income, net of tax	0	0	0
(Gain) loss on derivatives reclassified from accumulated other comprehensive income, net of tax	0	0
Balance at end of period	(786)	(428)	(49)
Prior Service Credits and Net Actuarial Losses
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(78)	(45)	(87)
Foreign currency translation gain (loss)	0	0	0
Actuarial gains (losses) recognized in other comprehensive income, net of tax	12	(31)	40
Curtailment and settlement gains (losses) recognized in other comprehensive income, net of tax	1	(3)
Amortization of actuarial (gains) losses, net of tax	3	1	2
Gain (loss) on derivatives recognized in other comprehensive income, net of tax	0	0	0
(Gain) loss on derivatives reclassified from accumulated other comprehensive income, net of tax	0	0
Balance at end of period	(62)	(78)	(45)
Accumulated Gain (Loss) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(34)	14	11
Foreign currency translation gain (loss)	0	0	0
Actuarial gains (losses) recognized in other comprehensive income, net of tax	0	0	0
Curtailment and settlement gains (losses) recognized in other comprehensive income, net of tax	0	0
Amortization of actuarial (gains) losses, net of tax	0	0	0
Gain (loss) on derivatives recognized in other comprehensive income, net of tax	(54)	(52)	6
(Gain) loss on derivatives reclassified from accumulated other comprehensive income, net of tax	59	4	(3)
Balance at end of period	(29)	(34)	14
Accumulated Other Elements of Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(540)	(80)	(30)
Foreign currency translation gain (loss)	(358)	(379)	(95)
Actuarial gains (losses) recognized in other comprehensive income, net of tax	12	(31)	40
Curtailment and settlement gains (losses) recognized in other comprehensive income, net of tax	1	(3)
Amortization of actuarial (gains) losses, net of tax	3	1	2
Gain (loss) on derivatives recognized in other comprehensive income, net of tax	(54)	(52)	6
(Gain) loss on derivatives reclassified from accumulated other comprehensive income, net of tax	59	4	(3)
Balance at end of period	(877)	(540)	(80)
Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(460)	(50)
Foreign currency translation gain (loss)	(358)	(379)	(95)
Actuarial gains (losses) recognized in other comprehensive income, net of tax	12	(31)	40
Curtailment and settlement gains (losses) recognized in other comprehensive income, net of tax	1	(3)
Amortization of actuarial (gains) losses, net of tax	3	1	2
Gain (loss) on derivatives recognized in other comprehensive income, net of tax	(54)	(52)	6
(Gain) loss on derivatives reclassified from accumulated other comprehensive income, net of tax	59	4	(3)
Balance at end of period	$ (337)	$ (460)	$ (50)