Risk Management and Financial Instruments (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Recognized in Other Comprehensive Income (Loss)	$ (143)	$ 124	$ (176)	$ (149)
Effective Portion Reclassified from Accumulated Other Comprehensive Loss to Earnings	37	(79)	149	(114)
Ineffective Portion Reclassified in Other (Expense) Income	0	12	(10)	(25)
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Recognized in Other Comprehensive Income (Loss)	(70)	165	(136)	(61)
Effective Portion Reclassified from Accumulated Other Comprehensive Loss to Earnings	68	(66)	202	(92)
Ineffective Portion Reclassified in Other (Expense) Income	0	12	(10)	(25)
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Recognized in Other Comprehensive Income (Loss)	(51)	(16)	(44)	(55)
Effective Portion Reclassified from Accumulated Other Comprehensive Loss to Earnings	0	(1)	0	(1)
Ineffective Portion Reclassified in Other (Expense) Income	0	0	0	0
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Recognized in Other Comprehensive Income (Loss)	(22)	(25)	4	(33)
Effective Portion Reclassified from Accumulated Other Comprehensive Loss to Earnings	(31)	(12)	(53)	(21)
Ineffective Portion Reclassified in Other (Expense) Income	$ 0	$ 0	$ 0	$ 0