Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2011

Derivative Instruments

Schedule of commodity derivatives

	2011		2012		2013		2014
Oil Bbl/D:		20,020		19,000		13,000		2,000
Natural Gas MMBtu/D:		15,000		15,000		—		—

Schedule of crude oil three-way collars entered into during the period

Term	Average Barrels Per Day		Floor/Swap/Ceiling Prices
February 2011 - December 2013		1,000	$70.00 / $90.00 / $116.50
Full year 2012 and 2013		1,000	$70.00 / $90.00 / $120.00
Full year 2012 and 2013		1,000	$70.00 / $95.00 / $120.10
June 2011 - December 2014		1,000	$77.95 / $105.00 / $115.00
Full year 2012, 2013, and 2014		1,000	$80.00 / $107.00 / $119.60

Schedule of derivative assets and liabilities

		June 30, 2011
		Derivative Assets			Derivative Liabilities
(in millions)		Balance Sheet Classification	Fair Value		Balance Sheet Classification	Fair Value
Current:
	Commodity	Derivative assets	$	3.1	Derivative liabilities	$	60.4
Long term:
	Commodity	Derivative assets		1.4	Derivative liabilities		46.5
Total derivatives			$	4.5		$	106.9

		December 31, 2010
		Derivative Assets			Derivative Liabilities
(in millions)		Balance Sheet Classification	Fair Value		Balance Sheet Classification	Fair Value
Current:
	Commodity	Derivative assets	$	2.7	Derivative liabilities	$	84.9
Long term:
	Commodity	Derivative assets		2.1	Derivative liabilities		33.5
Total derivatives			$	4.8		$	118.4

Summary of gains (losses) before income taxes of derivative instruments recognized in the condensed statements of income (loss)

		Three months ended June 30,						Six months ended June 30,
	Location of (Gain) Loss Recognized in Earnings
Description of (Gain) Loss		2011			2010			2011		2010
Commodity
(Gain) loss reclassified from AOCL into earnings (amortization of frozen amounts)	Sales of oil and gas	$	14.9		$	4.1		$	29.5	$	6.9
(Gain) loss recognized in earnings (cash settlements and mark-to-market movements)	Realized and unrealized (gain) loss on derivatives, net		(91.8	)		(58.8	)		35.7		(63.7	)
Interest rate
(Gain) loss reclassified from AOCL into earnings (amortization of frozen amounts)	Interest	$	0.4		$	2.4		$	1.2	$	5.1
(Gain) loss recognized in earnings (cash settlements and mark-to-market movements)	Realized and unrealized (gain) loss on derivatives, net		—			2.7			—		6.0