Accumulated Other Comprehensive Income/(Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ 152	$ 13	$ 117	$ 176
Other comprehensive income/(loss) before reclassifications	(317)	115	(284)	(50)
Amounts reclassified from accumulated other comprehensive income/(loss)	1	1	3	3
Other comprehensive income/(loss)	(316)	116	(281)	(47)
Balance at end of period	(164)	129	(164)	129
Foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	159	17	122	184
Other comprehensive income/(loss) before reclassifications	(316)	117	(279)	(50)
Amounts reclassified from accumulated other comprehensive income/(loss)	0	0	0	0
Other comprehensive income/(loss)	(316)	117	(279)	(50)
Balance at end of period	(157)	134	(157)	134
Derivative financial instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(7)	(4)	(5)	(8)
Other comprehensive income/(loss) before reclassifications	(1)	(2)	(5)	0
Amounts reclassified from accumulated other comprehensive income/(loss)	1	1	3	3
Other comprehensive income/(loss)	0	(1)	(2)	3
Balance at end of period	$ (7)	$ (5)	$ (7)	$ (5)