CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 376.1	$ 1,160.1
Accounts receivable, net	278.2	441.9
Income Taxes Receivable, Current	87.3	0.0
Fair value of derivative contracts, current assets	146.8	339.0
Gas, oil and NGL inventories, at lower of average cost or market	13.3	13.7
Prepaid expenses and other	30.1	46.8
Total Current Assets	931.8	2,001.5
Property, Plant and Equipment (successful efforts method for gas and oil properties)
Proved properties	13,314.9	12,278.7
Unproved properties	691.0	825.2
Marketing and other	297.9	293.8
Materials and supplies	38.5	54.3
Total Property, Plant and Equipment	14,342.3	13,452.0
Less Accumulated Depreciation, Depletion and Amortization
Exploration and production	6,870.2	6,153.0
Marketing and other	87.5	67.8
Total Accumulated Depreciation, Depletion and Amortization	6,957.7	6,220.8
Net Property, Plant and Equipment	7,384.6	7,231.2
Fair value of derivative contracts, noncurrent assets	23.2	9.9
Other noncurrent assets	85.9	44.2
TOTAL ASSETS	8,425.5	9,286.8
Current Liabilities
Checks outstanding in excess of cash balances	29.8	54.7
Accounts payable and accrued expenses	351.7	575.4
Income taxes payable	0.0	532.1
Production and property taxes	46.1	61.7
Interest payable	36.4	36.4
Fair value of derivative contracts, current liability	0.8	0.0
Deferred income taxes	0.0	84.5
Long-term Debt, Current Maturities	176.8	0.0
Total Current Liabilities	641.6	1,344.8
Long-term debt	2,042.0	2,218.1
Long-term Debt, Gross	2,218.8	2,218.1
Deferred income taxes	1,479.8	1,362.7
Asset retirement obligations	204.9	193.8
Fair value of derivative contracts, noncurrent liability	4.0	0.0
Other long-term liabilities	$ 105.3	$ 92.1
Commitments and Contingencies (Note 10)
EQUITY
Common stock - par value $0.01 per share; 500.0 million shares authorized; 177.3 million and 176.2 million shares issued, respectively	$ 1.8	$ 1.8
Treasury stock - 0.5 million and 0.8 million shares, respectively	(14.6)	(25.4)
Additional paid-in capital	554.8	535.3
Retained earnings	3,418.3	3,587.9
Accumulated other comprehensive (loss) income	(12.4)	(24.3)
Total Common Shareholders' Equity	3,947.9	4,075.3
Total Equity	3,947.9	4,075.3
TOTAL LIABILITIES AND EQUITY	$ 8,425.5	$ 9,286.8

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.