Fair Value Measurements Unobservable Input Or Level 3 Table and Footnote (Details) (USD $) In Millions, unless otherwise specified		9 Months Ended										9 Months Ended
	Sep. 30, 2012 Interest rate contract	Sep. 30, 2013 Fair Value, Inputs, Level 3 [Member] Natural Gas, Oil and NGL sales	Sep. 30, 2012 Fair Value, Inputs, Level 3 [Member] Natural Gas, Oil and NGL sales	Sep. 30, 2013 Fair Value, Inputs, Level 3 [Member] Interest Expense	Sep. 30, 2012 Fair Value, Inputs, Level 3 [Member] Interest Expense	Sep. 29, 2013 Fair Value, Inputs, Level 3 [Member] Commodity contracts	Sep. 29, 2012 Fair Value, Inputs, Level 3 [Member] Commodity contracts	Sep. 30, 2013 Fair Value, Inputs, Level 3 [Member] Commodity contracts	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Commodity contracts	Sep. 30, 2012 Fair Value, Inputs, Level 3 [Member] Commodity contracts	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Commodity contracts	Sep. 29, 2013 Fair Value, Inputs, Level 3 [Member] Interest rate contract	Sep. 29, 2012 Fair Value, Inputs, Level 3 [Member] Interest rate contract	Sep. 30, 2013 Fair Value, Inputs, Level 3 [Member] Interest rate contract	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Interest rate contract	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Interest rate contract
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (2)							$ (585)	$ (1,016)	$ (1,073)	$ (1,654)			$ 0	$ 0	$ 0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings Or Change In Net Assets Unrealized		338	525	(1)	4	338	525					(1)	4
Sales						0	0					1	(6)
Settlements						93	56					0	0
Ending balance	(2)							(585)	(1,016)	(1,073)	(1,654)			0	0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		$ 327	$ 370	$ 0	$ (2)