Fair Value Measurements (Details 3) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment charges - nonrecurring	$ 0	$ 0	$ 0	$ 0
Notional amount of foreign currency derivatives	0		0		355,000,000
Realized
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gain (loss) on foreign currency contracts		(1,000,000)		1,000,000
Unrealized
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gain (loss) on foreign currency contracts		$ 4,000,000		$ 3,000,000