CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
REVENUES
Oil sales	$ 218.0	$ 201.6	$ 655.7	$ 553.1
Gas sales	130.7	123.2	399.4	287.5
NGL sales	32.2	19.8	84.0	56.2
Other revenue	3.6	2.5	10.3	4.3
Purchased oil and gas sales	5.6	35.3	44.5	76.3
Total Revenues	390.1	382.4	1,193.9	977.4
OPERATING EXPENSES
Purchased oil and gas expense	6.9	37.1	45.4	80.8
Lease operating expense	76.2	50.7	215.4	163.3
Transportation and processing costs	60.2	75.8	202.6	218.9
Gathering and other expense	1.7	0.9	5.0	3.8
General and administrative	43.4	66.5	108.3	157.9
Production and property taxes	28.5	26.8	86.1	65.3
Depreciation, depletion and amortization	176.9	217.8	560.2	667.5
Exploration expenses	21.3	0.2	21.7	0.9
Impairment	28.3	5.0	28.4	1,188.2
Total operating expenses	443.4	480.8	1,273.1	2,546.6
Net gain (loss) from asset sales	185.4	5.3	205.2	5.0
OPERATING INCOME (LOSS)	132.1	(93.1)	126.0	(1,564.2)
Realized and unrealized gains (losses) on derivative contracts (Note 7)	(104.3)	44.5	163.3	(85.1)
Interest and other income (expense)	0.1	4.6	2.5	5.6
Interest expense	(34.4)	(35.9)	(103.1)	(109.2)
INCOME (LOSS) BEFORE INCOME TAXES	(6.5)	(79.9)	188.7	(1,752.9)
Income tax (provision) benefit	3.2	29.0	(69.7)	641.2
NET INCOME (LOSS)	$ (3.3)	$ (50.9)	$ 119.0	$ (1,111.7)
Earnings per common share
Earnings Per Share, Basic	$ (0.01)	$ (0.21)	$ 0.49	$ (5.15)
Earnings Per Share, Diluted	$ (0.01)	$ (0.21)	$ 0.49	$ (5.15)
Weighted-average common shares outstanding
Used in basic calculation (in shares)	240.7	239.6	240.5	215.7
Used in diluted calculation (in shares)	240.7	239.6	240.5	215.7
Dividends per common share (in dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00