Accumulated Other Comprehensive Income/(Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Balance at beginning of year	$ 176
Other comprehensive income/(loss) before reclassifications	(104)
Amounts reclassified from accumulated other comprehensive income/(loss)	1
Other comprehensive income/(loss)	(103)	107
Balance at end of period	73	224
Foreign currency translation
Balance at beginning of year	184
Other comprehensive income/(loss) before reclassifications	(104)
Amounts reclassified from accumulated other comprehensive income/(loss)	0
Other comprehensive income/(loss)	(104)
Balance at end of period	80	229
Derivative financial instruments
Balance at beginning of year	(8)
Other comprehensive income/(loss) before reclassifications	0
Amounts reclassified from accumulated other comprehensive income/(loss)	1
Other comprehensive income/(loss)	1
Balance at end of period	$ (7)	$ (5)