CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
ASSETS
Property, plant and equipment	$ 6,860,358	$ 6,607,552
Construction in progress	274,112	209,242
Total property, plant and equipment and construction in progress	7,134,470	6,816,794
Less accumulated depreciation and amortization	1,658,866	1,668,876
Net property, plant and equipment	5,475,604	5,147,918
Current assets
Cash and cash equivalents	64,239	131,419
Accounts receivable, net	234,526	273,303
Gas stored underground	256,415	289,760
Other current assets	272,782	316,471
Total current assets	827,962	1,010,953
Goodwill and intangible assets	740,847	740,207
Deferred charges and other assets	451,262	383,793
Total assets	7,495,675	7,282,871
Shareholders' equity
Common stock, no par value (stated at $.005 per share)	451	451
Additional paid-in capital	1,745,467	1,732,935
Retained earnings	660,932	570,495
Accumulated other comprehensive income (loss)	(47,607)	(48,460)
Shareholders' equity	2,359,243	2,255,421
Long-term debt	1,956,305	2,206,117
Total capitalization	4,315,548	4,461,538
Current liabilities
Accounts payable and accrued liabilities	215,229	291,205
Other current liabilities	489,665	367,563
Short-term debt	570,929	206,396
Current maturities of long-term debt	131	2,434
Total current liabilities	1,275,954	867,598
Deferred income taxes	1,015,083	960,093
Regulatory cost of removal obligation	381,164	428,947
Deferred credits and other liabilities	507,926	564,695
Total shareholders' equity and liabilities	$ 7,495,675	$ 7,282,871