Business Segment Information (Tables)

12 Months Ended

Sep. 30, 2012

Business Segment Information [Abstract]

Segment Information By Segment

	Year Ended September 30, 2012
	Utility	Pipeline and Storage	Exploration and   Production	Energy Marketing	Total Reportable Segments	All   Other	Corporate and Intersegment Eliminations	Total Consolidated
	(Thousands)
Revenue from External Customers(1)	$ 704,518	$ 172,312	$ 558,180	$ 186,579	$ 1,621,589	$ 4,307	$ 957	$ 1,626,853
Intersegment Revenues.....................	$ 14,604	$ 86,963	$              —	$ 1,425	$ 102,992	$ 16,771	$ (119,763)	$—
Interest Income......................................	$ 2,765	$ 199	$ 1,493	$ 188	$ 4,645	$ 175	$ (1,131)	$ 3,689
Interest Expense....................................	$ 33,181	$ 25,603	$ 29,243	$ 41	$ 88,068	$ 1,738	$ (3,566)	$ 86,240
Depreciation, Depletion and Amortization	$ 42,757	$ 38,182	$ 187,624	$ 90	$ 268,653	$ 2,091	$ 786	$ 271,530
Income Tax Expense (Benefit)........	$ 29,110	$ 37,655	$ 79,050	$ 1,933	$ 147,748	$ 4,335	$ (1,529)	$ 150,554
Segment Profit: Net Income (Loss)	$ 58,590	$ 60,527	$ 96,498	$ 4,169	$ 219,784	$ 6,868	$ (6,575)	$ 220,077
Expenditures for Additions to Long-Lived Assets	$ 58,284	$ 144,167	$ 693,810	$ 770	$ 897,031	$ 80,017	$ 346	$ 977,394

	At September 30, 2012
	(Thousands)
Segment Assets.........................	$ 2,070,413	$ 1,243,862	$ 2,367,485	$ 61,968	$ 5,743,728	$ 209,934	$ (18,520)	$ 5,935,142

	Year Ended September 30, 2011
	Utility	Pipeline and Storage	Exploration and   Production	Energy Marketing	Total Reportable Segments	All   Other	Corporate and Intersegment Eliminations	Total Consolidated
	(Thousands)
Revenue from External Customers(1)	$ 835,853	$ 134,071	$ 519,035	$ 284,546	$ 1,773,505	$ 4,401	$ 936	$ 1,778,842
Intersegment Revenues.....................	$ 16,642	$ 81,037	$—	$ 420	$ 98,099	$ 10,017	$ (108,116)	$—
Interest Income......................................	$ 2,049	$ 324	$ (27)	$ 104	$ 2,450	$ 247	$ 219	$ 2,916
Interest Expense....................................	$ 34,440	$ 25,737	$ 17,402	$ 20	$ 77,599	$ 2,173	$ (1,651)	$ 78,121
Depreciation, Depletion and Amortization	$ 40,808	$ 37,266	$ 146,806	$ 47	$ 224,927	$ 840	$ 760	$ 226,527
Income Tax Expense (Benefit)........	$ 33,325	$ 19,854	$ 89,034	$ 4,489	$ 146,702	$ 18,961	$ (1,282)	$ 164,381
Gain on Sale of Unconsolidated Subsidiaries	$—	$—	$—	$—	$—	$50,879(2)	$—	$ 50,879
Segment Profit: Net Income (Loss)	$ 63,228	$ 31,515	$ 124,189	$ 8,801	$ 227,733	$ 38,502	$ (7,833)	$ 258,402
Expenditures for Additions to Long-Lived Assets	$ 58,398	$ 129,206	$ 648,815	$ 460	$ 836,879	$ 17,022	$ 285	$ 854,186

	At September 30, 2011
	(Thousands)
Segment Assets.........................	$ 2,001,546	$ 1,112,494	$ 1,885,014	$ 71,138	$ 5,070,192	$ 166,730	$ (15,838)	$ 5,221,084

	Year Ended September 30, 2010
	Utility	Pipeline  and  Storage	Exploration and  Production	Energy Marketing	Total Reportable Segments	All Other	Corporate and Intersegment Eliminations	Total Consolidated
	(Thousands)
Revenue from External Customers(1)	$ 804,466	$ 138,905	$ 438,028	$ 344,802	$ 1,726,201	$ 33,428	$ 874	$ 1,760,503
Intersegment Revenues.....................	$ 15,324	$ 79,978	$             —	$—	$ 95,302	$ 2,315	$ (97,617)	$              —
Interest Income......................................	$ 2,144	$ 199	$ 980	$ 44	$ 3,367	$ 137	$ 225	$ 3,729
Interest Expense....................................	$ 35,831	$ 26,328	$ 30,853	$ 27	$ 93,039	$ 2,152	$ (1,245)	$ 93,946
Depreciation, Depletion and Amortization	$ 40,370	$ 35,930	$ 106,182	$ 42	$ 182,524	$ 7,907	$ 768	$ 191,199
Income Tax Expense (Benefit)........	$ 31,858	$ 22,634	$ 78,875	$ 4,806	$ 138,173	$ 464	$ (1,410)	$ 137,227
Segment Profit: Income (Loss) from Continuing Operations	$ 62,473	$ 36,703	$ 112,531	$ 8,816	$ 220,523	$ 3,396	$ (4,786)	$ 219,133
Expenditures for Additions to Long-Lived Assets from Continuing Operations	$ 57,973	$ 37,894	$ 398,174	$ 407	$ 494,448	$ 6,694	$ 210	$ 501,352

	At September 30, 2010
	(Thousands)
Segment Assets...........................	$ 2,027,101	$ 1,080,772	$ 1,539,705	$ 69,561	$ 4,717,139	$ 198,706	$ 131,209	$ 5,047,054

(1)	All Revenue from External Customers originated in the United States.
(2)	In February 2011, the Company sold its 50% equity method investments in Seneca Energy and Model City for $59.4 million, resulting in a gain of $50.9 million.

Schedule of Long-Lived Assets, By Geographical Areas

Geographic Information	At September 30
	2012	2011	2010
	(Thousands)
Long-Lived Assets:
United States.......................................................................................................................................................	$ 5,579,566	$ 4,809,183	$ 4,238,253