Derivatives (Details 1) In Millions, unless otherwise specified	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2011 Prepaid expenses and other assets [Member] USD ($)	Dec. 31, 2010 Prepaid expenses and other assets [Member] USD ($)	Dec. 31, 2011 Other Assets [Member] USD ($)	Dec. 31, 2010 Other Assets [Member] USD ($)	Dec. 31, 2011 Other Liabilities [Member] USD ($)	Dec. 31, 2010 Other Liabilities [Member] USD ($)	Dec. 31, 2011 Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2010 Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2011 Not Designated as Hedging Instrument [Member] USD ($) Gallons	Dec. 31, 2010 Not Designated as Hedging Instrument [Member] USD ($) Gallons	Dec. 31, 2011 Not Designated as Hedging Instrument [Member] Commodity Contract [Member]	Dec. 31, 2010 Not Designated as Hedging Instrument [Member] Commodity Contract [Member]	Dec. 31, 2011 Not Designated as Hedging Instrument [Member] Prepaid expenses and other assets [Member] USD ($)	Dec. 31, 2010 Not Designated as Hedging Instrument [Member] Prepaid expenses and other assets [Member] USD ($)	Dec. 31, 2011 Not Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2010 Not Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2011 Not Designated as Hedging Instrument [Member] Other Liabilities [Member] USD ($)	Dec. 31, 2010 Not Designated as Hedging Instrument [Member] Other Liabilities [Member] USD ($)	Dec. 31, 2011 Not Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2010 Not Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2011 Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2011 Designated as Hedging Instrument [Member] CAD	Dec. 31, 2011 Designated as Hedging Instrument [Member] JPY (¥)	Dec. 31, 2010 Designated as Hedging Instrument [Member] USD ($) Gallons	Dec. 31, 2010 Designated as Hedging Instrument [Member] CAD	Dec. 31, 2010 Designated as Hedging Instrument [Member] JPY (¥)	Dec. 31, 2011 Designated as Hedging Instrument [Member] InterestRateCashFlowHedgesContract [Member]	Dec. 31, 2010 Designated as Hedging Instrument [Member] InterestRateCashFlowHedgesContract [Member]	Dec. 31, 2011 Designated as Hedging Instrument [Member] InterestRateFairValueHedgesContract [Member]	Dec. 31, 2010 Designated as Hedging Instrument [Member] Commodity Contract [Member]	Dec. 31, 2011 Designated as Hedging Instrument [Member] Foreign Exchange Contract [Member]	Dec. 31, 2010 Designated as Hedging Instrument [Member] Foreign Exchange Contract [Member]	Dec. 31, 2011 Designated as Hedging Instrument [Member] Prepaid expenses and other assets [Member] USD ($)	Dec. 31, 2010 Designated as Hedging Instrument [Member] Prepaid expenses and other assets [Member] USD ($)	Dec. 31, 2011 Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2010 Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2011 Designated as Hedging Instrument [Member] Other Liabilities [Member] USD ($)	Dec. 31, 2010 Designated as Hedging Instrument [Member] Other Liabilities [Member] USD ($)	Dec. 31, 2011 Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2010 Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)
Derivatives, Fair Value [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives																							$ 989			$ 1,143
Notional Amount of Interest Rate Fair Value Hedge Derivatives																							500
Notional Amount of Foreign Currency Derivatives																								313	126,993		233	141,100
Nonmonetary Notional Amount of Price Risk Derivatives											1,225,000,000	192,000,000														1,500,000,000	1,500,000,000	1,500,000,000
Derivative, Higher Remaining Maturity Range													December 2012	June 2012															May 2019	May 2019	August 2022	February 2012	April 2014	November 2013
Interest Rate Cash Flow Hedge Asset at Fair Value																																			0	0	0	0
Interest Rate Cash Flow Hedge Liability at Fair Value																																							27	35	57	39
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net																							(84)			(74)
Interest Rate Fair Value Hedge Asset at Fair Value																																			0		0
Interest Rate Fair Value Hedge Liability at Fair Value																																							0		7
Interest Rate Fair Value Hedge Derivative at Fair Value, Net																							(7)
Foreign Currency Fair Value Hedge Asset at Fair Value																																			7	0	5	0
Foreign Currency Fair Value Hedge Liability at Fair Value																																							58	60	43	36
Foreign Currency Fair Value Hedge Derivative at Fair Value, Net																							(89)			(96)
Price Risk Derivative Assets, at Fair Value															570	27	0	14																		328		24
Price Risk Derivative Liabilities, at Fair Value																			500	19	0	8																		0		0
Price Risk Derivatives, at Fair Value, Net											70	14														352
Derivative Asset, Fair Value, Gross Asset			577	355	5	38
Derivative Liability, Fair Value, Gross Liability							(585)	(114)	(107)	(83)
Derivative, Fair Value, Net	$ 110	$ (196)