Derivative Instruments and Hedging Activities (Tables)

12 Months Ended

Dec. 31, 2013

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Unsettled Derivative Instruments

As of December 31, 2013, we had entered into the following crude oil derivative instruments:

				Swaps		Collars
Settlement Period	Type of Contract	Index	Bbls Per Day	Weighted Average Fixed Price		Weighted Average  Short Put  Price		Weighted Average Floor Price		Weighted Average  Ceiling Price
Instruments Entered Into as of December 31, 2013
2014	Swaps	NYMEX WTI	37,000	$	92.67	$	—	$	—	$	—
2014	Swaps	Dated Brent	13,000	103.21		—		—		—
2014	Three-Way Collars	NYMEX WTI	12,000	—		75.67		90.67		100.88
2014	Three-Way Collars	Dated Brent	8,000	—		84.38		98.25		121.56
2015	Swaps	NYMEX WTI	16,000	87.66		—		—		—
2015	Swaps	Dated Brent	8,000	100.20		—		—		—
2015	Three-Way Collars	NYMEX WTI	15,000	—		70.67		88.00		94.78
2015	Three-Way Collars	Dated Brent	11,000	—		76.36		95.27		109.26

As of December 31, 2013, we had entered into the following natural gas derivative instruments:

				Swaps		Collars
Settlement Period	Type of Contract	Index	MMBtu Per Day	Weighted Average Fixed Price		Weighted Average Short Put  Price		Weighted Average Floor Price		Weighted Average Ceiling Price
Instruments Entered Into as of December 31, 2013
2014	Swaps	NYMEX HH	60,000	$	4.24	$	—	$	—	$	—
2014	Three-Way Collars	NYMEX HH	230,000	—		2.83		3.75		4.98
2015	Swaps	NYMEX HH	80,000	4.32		—		—		—
2015	Three-Way Collars	NYMEX HH	120,000	—		3.54		4.25		5.06

Fair Value of Derivative Instruments

The fair values of derivative instruments in our consolidated balance sheets were as follows: 

Fair Value of Derivative Instruments
	Asset Derivative Instruments						Liability Derivative Instruments
	December 31, 2013			December 31, 2012			December 31, 2013			December 31, 2012
	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair  Value		Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
(millions)
Commodity DerivativeInstruments	Current Assets	$	1	Current Assets	$	63	Current Liabilities	$	65	Current Liabilities	$	7
	Noncurrent Assets	16		Noncurrent Assets	21		Noncurrent Liabilities	10		Noncurrent Liabilities	3
Total		$	17		$	84		$	75		$	10

Effect of derivative instruments on consolidated statement of operations

The effect of derivative instruments on our consolidated statements of operations was as follows: 

	Year Ended December 31,
(millions)	2013			2012			2011
Realized Mark-to-Market (Gain) Loss (1)
Crude Oil	$	52		$	83		$	44
Natural Gas	(50		)	(49		)	(108		)
Total Realized Mark-to-Market (Gain) Loss	2			34			(64		)
Unrealized Mark-to-Market (Gain) Loss (1)
Crude Oil	87			(120		)	5
Natural Gas	44			11			17
Total Unrealized Mark-to-Market (Gain) Loss	131			(109		)	22
Total (Gain) Loss on Commodity Derivative Instruments	$	133		$	(75	)	$	(42	)

Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]

Derivative Instruments in Cash Flow Hedge Relationships
	Amount of (Gain) Loss on Derivative Instruments Recognized in Other Comprehensive (Income) Loss							Amount of (Gain) Loss on Derivative Instruments Reclassified from Accumulated Other Comprehensive (Income) Loss
(millions)	2013		2012		2011			2013		2012		2011
Interest Rate Derivative Instruments in Cash Flow Hedging Relationships	$	—	$	—	$	(23	)	$	1	$	1	$	1
Total	—		—		(23		)	1		1		1