Derivative Financial Instruments (Schedule of Changes in Fair Value of Derivatives) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Derivative [Line Items]
Gain (loss) recognized in Other comprehensive income (loss)	$ (6)		$ (9)		$ (12)		$ (26)
Gain (loss) recognized in Earnings (loss)	(17)		3		(11)		(45)
Tax expense recognized in Other comprehensive income (loss)	5		4		16		15
Foreign Currency Forwards and Swaps [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) recognized in Other comprehensive income (loss)	0		0		0		0
Equity Method Investments' Derivative [Member]
Derivative [Line Items]
Gain (loss) associated with equity method investments' derivative			2				1
Interest Rate Swap [Member]
Derivative [Line Items]
Tax expense recognized in Other comprehensive income (loss)			(2)				(8)
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) recognized in Other comprehensive income (loss)	(6)		(9)	[1]	(12)		(26)	[2]
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) recognized in Other comprehensive income (loss)	0		0		0		0
Interest Expense [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) recognized in Earnings (loss)	(4)	[3]	(15)	[3]	(11)	[3]	(45)	[3]
Interest Expense [Member] | Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) recognized in Earnings (loss)	0	[4]	1	[4]	0	[4]	(2)	[4]
Foreign Currency Gain (Loss) [Member] | Foreign Currency Forwards and Swaps [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) recognized in Earnings (loss)	$ (13)	[5]	$ 17	[5]	$ 0	[5]	$ 2	[5]

[1] Amount excludes $2 million of gains associated with the Company's equity method investments' derivative activity and $2 million of tax expense recognized in Other comprehensive income (loss).

[2] Amount excludes $1 million of gains associated with the Company's equity method investments' derivative activity and $8 million of tax expense recognized in Other comprehensive income (loss).

[3] Amount represents reclassification from Accumulated other comprehensive income (loss), net and is included in Interest expense in the unaudited interim consolidated statements of operations.

[4] Included in Interest expense in the unaudited interim consolidated statements of operations.

[5] Included in Foreign exchange gain (loss), net for operating activity or Other income (expense), net for non-operating activity in the unaudited interim consolidated statements of operations.