Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 1,027	$ 453	$ 725
Oil and Gas Cash Flow Hedges
Realized Losses Reclassified Into Earnings	0	0	20
Less Tax Benefit	0	0	(8)
Interest Rate Cash Flow Hedges [Abstract]
Unrealized Change in Fair Value	0	23	(63)
Less Tax Provision (Benefit)	0	(8)	22
Net Change in Pension and Other	(20)	(17)	0
Less Tax Benefit	7	6	0
Other Comprehensive Income	(13)	4	(29)
Comprehensive Income	$ 1,014	$ 457	$ 696