Derivative Instruments and Hedging Activities (Tables)

12 Months Ended

Dec. 31, 2012

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Unsettled Derivative Instruments

As of December 31, 2012, 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, 2012
2013	Swaps	NYMEX WTI	8,000	$	89.63	$	—	$	—	$	—
2013	Swaps	Dated Brent	3,000	98.03		—		—		—
2013	Two-Way Collars	NYMEX WTI	5,000	—		—		95.00		115.00
2013	Three-Way Collars	NYMEX WTI	7,000	—		63.57		83.57		109.04
2013	Three-Way Collars	Dated Brent	26,000	—		82.50		100.93		126.63
2014	Swaps	NYMEX WTI	11,000	90.26		—		—		—
2014	Swaps	Dated Brent	10,000	105.14		—		—		—
2014	Three-Way Collars	NYMEX WTI	4,000	—		77.00		92.00		106.13
2014	Three-Way Collars	Dated Brent	11,000	—		85.45		99.09		128.40

As of December 31, 2012, 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, 2012
2013	Swaps	NYMEX HH	60,000	$	4.58	$	—	$	—	$	—
2013	Two-Way Collars	NYMEX HH	40,000	—		—		3.25		5.14
2013	Three-Way Collars	NYMEX HH	100,000	—		3.88		4.75		5.63
2014	Swaps	NYMEX HH	60,000	4.24		—		—		—
2014	Three-Way Collars	NYMEX HH	130,000	—		2.56		3.56		5.21

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, 2012			December 31, 2011			December 31, 2012			December 31, 2011
	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	$	63	Current Assets	$	10	Current Liabilities	$	7	Current Liabilities	$	76
	Noncurrent Assets	21		Noncurrent Assets	37		Noncurrent Liabilities	3		Noncurrent Liabilities	7
Total		$	84		$	47		$	10		$	83

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,
	2012			2011			2010
(millions)
Realized Mark-to-Market (Gain) Loss	$	34		$	(64	)	$	(87	)
Unrealized Mark-to-Market (Gain) Loss	(109		)	22			(70		)
Total (Gain) Loss on Commodity Derivative Instruments	$	(75	)	$	(42	)	$	(157	)

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
	2012		2011			2010		2012		2011		2010
(millions)
Commodity Derivative Instruments in Previously Designated Cash Flow Hedging Relationships (1)
Crude Oil	$	—	$	—		$	—	$	—	$	—	$	19
Natural Gas	—		—			—		—		—		1
Interest Rate Derivative Instruments in Cash Flow Hedging Relationships	—		(23		)	63		1		1		1
Total	$	—	$	(23	)	$	63	$	1	$	1	$	21

⁽¹⁾  Includes effect of commodity derivative instruments previously accounted for as cash flow hedges. All net derivative gains and losses that were deferred in AOCL as a result of previous cash flow hedge accounting, had been reclassified to earnings by December 31, 2010.