Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Sales-Outside	$ 1,160,114	$ 1,084,041	$ 3,512,055	$ 3,584,805
Sales-Gas Royalty Interests	15,506	12,968	46,738	34,707
Sales-Purchased Gas	1,608	953	4,372	2,443
Freight-Outside	11,563	27,430	35,749	126,195
Other Income (including equity earnings)	42,627	34,697	138,824	293,196
Total Revenue and Other Income	1,231,418	1,160,089	3,737,738	4,041,346
Cost of Goods Sold and Other Operating Charges (exclusive of depreciation, depletion and amortization shown below)	851,088	827,530	2,639,929	2,588,460
Gas Royalty Interests Costs	12,864	10,543	38,204	27,916
Purchased Gas Costs	941	737	2,961	2,123
Freight Expense	11,563	27,430	35,749	126,195
Selling, General and Administrative Expenses	33,472	36,681	104,265	109,412
Depreciation, Depletion and Amortization	169,152	153,877	489,774	463,048
Interest Expense	56,301	54,075	164,197	168,788
Taxes Other Than Income	85,463	80,587	251,575	256,543
Total Costs	1,220,844	1,191,460	3,726,654	3,742,485
Earnings Before Income Taxes	10,574	(31,371)	11,084	298,861
Income Tax Expense (Benefit)	74,623	(19,898)	89,767	60,428
Net Income (Loss)	(64,049)	(11,473)	(78,683)	238,433
Add: Net Loss Attributable to Noncontrolling Interest	(398)	(105)	(942)	(134)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (63,651)	$ (11,368)	$ (77,741)	$ 238,567
Earnings Per Share:
Basic	$ (0.28)	$ (0.05)	$ (0.34)	$ 1.05
Dilutive	$ (0.28)	$ (0.05)	$ (0.34)	$ 1.04
Weighted Average Number of Common Shares Outstanding:
Basic	228,876,336	227,654,395	228,640,671	227,491,284
Dilutive	228,876,336	227,654,395	228,640,671	229,191,870
Dividends Paid Per Share	$ 0.125	$ 0.125	$ 0.250	$ 0.375