CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current Assets
Cash and cash equivalents	$ 11.9	$ 0
Accounts receivable, net	408.5	387.5
Fair value of derivative contracts	0.2	188.7
Gas, oil and NGL inventories, at lower of average cost or market	13.4	13.1
Deferred Tax Assets, Net	30.6	0
Prepaid expenses and other	54.4	68.0
Total Current Assets	519.0	657.3
Property, Plant and Equipment (successful efforts method for gas and oil properties)
Proved properties	11,571.4	10,234.3
Unproved properties, net	665.1	937.9
Midstream field services	1,698.1	1,634.9
Marketing and other	85.5	64.6
Materials and supplies	59.0	61.9
Total Property, Plant and Equipment	14,079.1	12,933.6
Less Accumulated Depreciation, Depletion and Amortization
Exploration and production	4,930.9	4,258.1
Midstream field services	409.7	357.9
Marketing and other	22.1	18.1
Total Accumulated Depreciation, Depletion and Amortization	5,362.7	4,634.1
Net Property, Plant and Equipment	8,716.4	8,299.5
Investment in unconsolidated affiliates	39.0	41.2
Goodwill	0	59.5
Fair value of derivative contracts	1.0	4.1
Restricted Cash, Noncurrent	50.0	0
Other noncurrent assets	51.4	46.9
TOTAL ASSETS	9,376.8	9,108.5
Current Liabilities
Checks outstanding in excess of cash balances	90.9	39.7
Accounts payable and accrued expenses	434.9	643.4
Production and property taxes	51.8	41.8
Interest payable	37.2	36.9
Fair value of derivative contracts	26.7	2.6
Deferred income taxes	0	5.0
Total Current Liabilities	641.5	769.4
Long-term debt	2,997.5	3,206.9
Deferred income taxes	1,560.6	1,493.5
Asset retirement obligations	191.8	191.4
Fair value of derivative contracts	0	3.6
Other long-term liabilities	108.6	130.0
Commitments and contingencies (Note 10)
EQUITY
Common stock - par value $0.01 per share; 500.0 million shares authorized; 179.3 million and 178.5 million shares issued, respectively	1.8	1.8
Treasury stock - 0.4 million and 0.1 million shares, respectively	(14.9)	(3.7)
Additional paid-in capital	498.4	462.1
Retained earnings	2,917.8	2,773.0
Accumulated other comprehensive (loss)income	(26.5)	32.8
Total Common Shareholders' Equity	3,376.6	3,266.0
Noncontrolling interest	500.2	47.7
Total Equity	3,876.8	3,313.7
TOTAL LIABILITIES AND EQUITY	$ 9,376.8	$ 9,108.5