CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES
NET INCOME	$ 171.4	$ 132.0	$ 270.4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	1,016.0	905.3	765.6
Deferred income taxes	66.1	32.1	156.8
Asset Impairment Charges	93.0	133.0	218.2
Equity-based compensation	27.1	25.6	22.0
Amortization of debt issuance costs and discounts	6.4	5.3	4.1
Net gain from asset sales	(103.0)	(1.2)	(1.4)
Income from unconsolidated affiliates	(5.8)	(6.8)	(5.5)
Distributions from unconsolidated affiliates and other	7.9	7.9	8.1
Non-cash loss on early extinguishment of debt	0	0	0.7
Unrealized loss (gain) on derivative contracts	88.7	(63.2)	(117.7)
Changes in operating assets and liabilities
Accounts receivable	3.2	9.6	(144.6)
Inventories	2.6	28.7	(22.0)
Prepaid expenses	14.0	(16.8)	1.6
Accounts payable and accrued expenses	(179.7)	101.3	127.8
Federal income taxes	(27.4)	3.5	17.0
Other	11.2	(0.3)	(8.5)
Net Cash Provided by Operating Activities	1,191.7	1,296.0	1,292.6
INVESTING ACTIVITIES
Property acquisitions	(40.9)	(1,406.1)	(48.0)
Property, plant and equipment, including dry exploratory well expense	(1,561.7)	(1,393.6)	(1,383.1)
Proceeds from disposition of assets	211.1	5.2	8.2
Acquisition deposit held in escrow	(50.0)	0	0
Net Cash Used in Investing Activities	(1,441.5)	(2,794.5)	(1,422.9)
FINANCING ACTIVITIES
Checks outstanding in excess of cash balances	51.2	10.3	9.9
Long-term debt issued	0	1,450.0	0
Long-term debt issuance costs paid	(3.2)	(17.8)	(10.6)
Long-term debt repaid	0	(6.7)	(58.5)
Proceeds from credit facility	3,085.0	2,739.0	1,950.3
Repayments of credit facility	(3,295.0)	(2,655.5)	(1,743.8)
Treasury stock repurchased	(9.3)	0	0
Other capital contributions	7.0	(2.2)	0.7
Dividends paid	(14.3)	(14.2)	(14.1)
Excess tax benefit on equity-based compensation	0	2.2	1.6
Distribution from Questar	0	0	0.2
Proceeds from Issuance Initial Public Offering	449.6	0	0
Distribution to noncontrolling interest	(9.3)	(6.6)	(5.4)
Net Cash Provided by Financing Activities	261.7	1,498.5	130.3
Change in cash and cash equivalents	11.9	0	0
Beginning cash and cash equivalents	0	0	0
Ending cash and cash equivalents	$ 11.9	$ 0	$ 0