Derivatives and Risk Management (Details 1) In Millions, unless otherwise specified																															12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2013 Prepaid Expenses and Other Assets [Member] USD ($)	Dec. 31, 2012 Prepaid Expenses and Other Assets [Member] USD ($)	Dec. 31, 2013 Other Assets [Member] USD ($)	Dec. 31, 2012 Other Assets [Member] USD ($)	Dec. 31, 2013 Other Accrued Liabilities [Member] USD ($)	Dec. 31, 2012 Other Accrued Liabilities [Member] USD ($)	Dec. 31, 2013 Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2012 Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2013 Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2012 Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2013 Designated as Hedging Instrument [Member] Prepaid Expenses and Other Assets [Member] USD ($)	Dec. 31, 2012 Designated as Hedging Instrument [Member] Prepaid Expenses and Other Assets [Member] USD ($)	Dec. 31, 2013 Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2012 Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2013 Designated as Hedging Instrument [Member] Other Accrued Liabilities [Member] USD ($)	Dec. 31, 2012 Designated as Hedging Instrument [Member] Other Accrued Liabilities [Member] USD ($)	Dec. 31, 2013 Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2012 Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2013 Not Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2012 Not Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2013 Not Designated as Hedging Instrument [Member] Prepaid Expenses and Other Assets [Member] USD ($)	Dec. 31, 2012 Not Designated as Hedging Instrument [Member] Prepaid Expenses and Other Assets [Member] USD ($)	Dec. 31, 2013 Not Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2012 Not Designated as Hedging Instrument [Member] Other Assets [Member] USD ($)	Dec. 31, 2013 Not Designated as Hedging Instrument [Member] Other Accrued Liabilities [Member] USD ($)	Dec. 31, 2012 Not Designated as Hedging Instrument [Member] Other Accrued Liabilities [Member] USD ($)	Dec. 31, 2013 Not Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2012 Not Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] USD ($)	Dec. 31, 2013 Fuel Contract [Member] Not Designated as Hedging Instrument [Member] gal	Dec. 31, 2012 Fuel Contract [Member] Not Designated as Hedging Instrument [Member] gal	Dec. 31, 2013 Cash Flow Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2012 Cash Flow Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2013 Cash Flow Hedging [Member] Foreign Exchange Contract [Member] Designated as Hedging Instrument [Member] CAD	Dec. 31, 2013 Cash Flow Hedging [Member] Foreign Exchange Contract [Member] Designated as Hedging Instrument [Member] JPY (¥)	Dec. 31, 2012 Cash Flow Hedging [Member] Foreign Exchange Contract [Member] Designated as Hedging Instrument [Member] CAD	Dec. 31, 2012 Cash Flow Hedging [Member] Foreign Exchange Contract [Member] Designated as Hedging Instrument [Member] JPY (¥)	Dec. 31, 2013 Fair Value Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2012 Fair Value Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member] USD ($)
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount																																	$ 477	$ 740	438	¥ 120,915	430	¥ 119,277	$ 445	$ 469
Derivative, Nonmonetary Notional Amount																															4,077,000,000	1,792,000,000
Derivative, Maturity Date																															Mar. 31, 2015	Dec. 31, 2013	May 31, 2019	May 31, 2019	Aug. 31, 2016	Aug. 31, 2016	Dec. 31, 2015	Dec. 31, 2015	Aug. 31, 2022	Aug. 31, 2022
Interest Rate Contracts (Cash Flow Hedges), Assets													0	0	0	0
Interest Rate Contracts (Cash Flow Hedges), Liabilities																	(17)	(22)	(26)	(48)
Interest Rate Contracts (Cash Flow Hedges), Hedge Derivatives, Net											(43)	(70)
Interest Rate Contracts (Fair Value Hedges), Assets													0	0	0	6
Interest Rate Contracts (Fair Value Hedges), Liabilities																	(2)	(2)	(22)	0
Interest Rate Contracts (Fair Value Hedges), Hedge Derivatives, Net											(24)	4
Foreign Currency Exchange Contracts, Assets													157	62	100	63
Foreign Currency Exchange Contracts, Liabilities																	0	(1)	0	(1)
Foreign Currency Exchange Contracts, Hedge Derivatives, Net	257	123									257	123
Fuel Contracts, Assets																							428	511	29	0
Fuel Contracts, Liabilities																											(127)	(262)	(16)	0
Fuel Contracts, Derivatives, Net	314	249																			314	249
Total Derivative Contracts, Assets			585	573	129	69
Total Derivative Contracts, Liabilities							(146)	(287)	(64)	(49)
Net Derivative Contracts, Hedge Derivatives, Net	504	306
Net Derivative Contracts, Assets			456	320	116	69
Net Derivative Contracts, Liabilities							$ (19)	$ (34)	$ (49)	$ (49)