CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
OPERATING ACTIVITIES
Net income (loss)	$ (110.8)	$ 118.5
Net income attributable to noncontrolling interest	0.0	17.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	649.3	755.8
Deferred income taxes	22.7	91.5
Impairment	35.5	3.6
Share-based compensation	23.3	23.7
Pension curtailment loss	11.2	0.0
Amortization of debt issuance costs and discounts	4.7	5.1
Net (gain) loss from asset sales	(6.9)	210.3
Income from unconsolidated affiliates	0.0	(4.6)
Distributions from unconsolidated affiliates and other	0.0	5.1
Unrealized (gains) loss on derivative contracts	148.0	(65.9)
Changes in operating assets and liabilities	(503.1)	59.0
Net Cash Provided by Operating Activities	273.9	1,219.7
INVESTING ACTIVITIES
Property acquisitions	(23.5)	(949.7)
Property, plant and equipment, including dry exploratory well expense	(862.6)	(1,270.4)
Proceeds from disposition of assets	5.2	706.2
Acquisition deposit held in escrow	0.0	50.0
Other investing activities	0.0	3.2
Net Cash Used in Investing Activities	(880.9)	(1,460.7)
FINANCING ACTIVITIES
Checks outstanding in excess of cash balances	(41.9)	(81.1)
Long-term debt issued	0.0	300.0
Long-term debt issuance costs paid	0.0	(1.1)
Proceeds from credit facility	0.0	4,509.0
Repayments of credit facility	0.0	(4,461.5)
Treasury stock repurchases	(2.3)	(6.6)
Other capital contributions	(0.1)	5.1
Dividends paid	(10.6)	(10.8)
Excess tax (provision) benefit on equity-based compensation	(2.4)	(0.6)
Distribution to noncontrolling interest	0.0	(23.3)
Net Cash (Used In) Provided by Financing Activities	(57.3)	229.1
Change in cash and cash equivalents	(664.3)	(11.9)
Beginning cash and cash equivalents	1,160.1	11.9
Ending cash and cash equivalents	495.8	0.0
Supplemental Disclosures:
Cash paid for interest, net of capitalized interest	107.4	128.9
Cash paid for income taxes	492.3	(1.1)
Non-cash investing activities
Change in capital expenditure accrual balance	$ (68.9)	$ 66.5