CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS (USED IN) OPERATING ACTIVITIES
Net income	$ 60,206	$ 57,357
Adjustments to reconcile net income to cash flows from operating activities:
Unrealized (gain) on derivative instruments	(18,335)	(27,474)
Depreciation and amortization	11,303	9,600
Allowance for equity used during construction	(606)	(42)
Allowance for bad debt expense	562	966
Deferred income taxes	22,233	37,724
Manufactured gas plant remediation costs	(941)	(2,099)
Equity in earnings of affiliates, net of distributions received	1,699	2,711
Cost of removal - asset retirement obligations	(137)	(341)
Contributions to postemployment benefit plans	(21,487)	(21,538)
Changes in:
Components of working capital	(88,145)	(144,912)
Other noncurrent assets	(14,101)	5,992
Other noncurrent liabilities	2,782	4,591
Cash flows (used in) operating activities	(44,967)	(77,465)
CASH FLOWS (USED IN) INVESTING ACTIVITIES
Utility plant expenditures	(32,869)	(19,395)
Solar equipment expenditures	(15,320)	(47,611)
Real estate properties and other expenditures	(154)	(89)
Cost of removal expenditures	(1,276)	(2,323)
Distribution from equity investees	458	0
Withdrawal from restricted cash construction fund	5	28
Cash flows (used in) investing activities	(49,156)	(69,390)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of common stock	5,838	3,248
Tax benefit from stock options exercised	62	62
Proceeds from sale-leaseback transaction	7,076	6,522
Payments of long-term debt	(1,384)	(1,198)
Purchases of treasury stock	0	(3,717)
Payments of common stock dividends	(33,320)	(14,946)
Net proceeds from short-term debt	114,600	157,250
Cash flows from financing activities	92,872	147,221
Change in cash and cash equivalents	(1,251)	366
Cash and cash equivalents at beginning of period	4,509	7,440
Cash and cash equivalents at end of period	3,258	7,806
CHANGES IN COMPONENTS OF WORKING CAPITAL
Receivables	(142,852)	(74,161)
Inventories	(54,993)	1,808
Recovery of gas costs	371	26,444
Gas purchases payable	58,354	(26,728)
Prepaid and accrued taxes	21,993	(1,218)
Accounts payable and other	11,298	(6,740)
Restricted broker margin accounts	13,188	3,468
Customers' credit balances and deposits	(10,897)	(72,625)
Other current assets	15,393	4,840
Components of working capital	(88,145)	(144,912)
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION
Cash paid for Interest (net of amounts capitalized)	966	555
Cash paid for Income taxes	5	135
SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING ACTIVITIES
Accrued capital expenditures	$ (4,934)	$ 13,200