Fair Value Measurements (Details) (USD $) In Millions																		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011 Fair Value, Measurements, Recurring [Member] Estimate of Fair Value, Fair Value Disclosure [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Estimate of Fair Value, Fair Value Disclosure [Member]		Sep. 30, 2011 Fair Value, Measurements, Recurring [Member] Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Quoted Prices in Active Markets for Identical Assets, Level 1 [Member]		Sep. 30, 2011 Fair Value, Measurements, Recurring [Member] Significant Other Observable Inputs, Level 2 [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Significant Other Observable Inputs, Level 2 [Member]		Sep. 30, 2011 Fair Value, Measurements, Recurring [Member] Significant Unobservable Inputs, Level 3 [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Significant Unobservable Inputs, Level 3 [Member]		Sep. 30, 2011 Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 79	[1]	$ 29	[1]	$ 0	[1]	$ 0	[1]	$ 79	[1]	$ 29	[1]	$ 0	[1]	$ 0	[1]
Derivative liabilities		27	[1]	25	[1]	0	[1]	0	[1]	27	[1]	25	[1]	0	[1]	0	[1]
Time deposits inclded in cash and cash equivalents	$ 617
Deposits maturity period																		3 months

[1] (A) We calculate derivative asset and liability amounts using a variety of valuation techniques, depending on the specific characteristics of the hedging instrument, taking into account credit risk. Refer to Note 5.