CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 166,390	$ 134,830
Adjustments to reconcile net income to cash flows from operating activities:
Unrealized loss (gain) on derivative instruments	45,810	(23,683)
Depreciation and amortization	39,014	34,966
Allowance for equity used during construction	(1,154)	(1,926)
Allowance for bad debt expense	1,685	1,829
Deferred income taxes	21,226	23,406
Manufactured gas plant remediation costs	(3,391)	(5,326)
Equity in earnings of equity investees, net of distributions received	1,364	(1,050)
Cost of removal - asset retirement obligations	(257)	(926)
Contributions to postemployment benefit plans	(3,618)	(24,538)
Changes in:
Components of working capital	83,223	(22,092)
Other noncurrent assets	15,735	(2,607)
Other noncurrent liabilities	10,434	12,256
Cash flows from operating activities	376,461	125,139
CASH FLOWS (USED IN) INVESTING ACTIVITIES
Utility plant expenditures	(90,381)	(73,654)
Solar and wind equipment expenditures	(91,569)	(39,756)
Real estate properties and other expenditures	(636)	(532)
Cost of removal expenditures	(18,690)	(21,186)
Distribution from equity investees in excess of equity in earnings	1,344	2,107
Proceeds from sale of asset	6,010	0
Withdrawal from restricted cash construction fund	100	0
Proceeds from sale of available-for-sale securities	0	482
Cash flows (used in) investing activities	(193,822)	(132,539)
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES
Proceeds from issuance of common stock	12,161	10,581
Tax benefit from stock options exercised	348	110
Proceeds from sale-leaseback transaction	7,576	7,076
Proceeds from long-term debt	125,000	50,000
Payments of long-term debt	(78,964)	(5,808)
Purchases of treasury stock	(4,387)	(23,689)
Payments of common stock dividends	(52,922)	(50,619)
Net (payments) proceeds from short-term debt	(191,100)	17,100
Cash flows (used in) from financing activities	(182,288)	4,751
Change in cash and cash equivalents	351	(2,649)
Cash and cash equivalents at beginning of period	2,969	4,509
Cash and cash equivalents at end of period	3,320	1,860
CHANGES IN COMPONENTS OF WORKING CAPITAL
Receivables	(37,575)	(120,719)
Inventories	100,021	(24,792)
Recovery of gas costs	(5,725)	4,994
Gas purchases payable	3,367	86,932
Prepaid and accrued taxes	28,404	20,059
Accounts payable and other	8,439	(6,385)
Restricted broker margin accounts	(19,045)	26,760
Customers' credit balances and deposits	(4,738)	(30,899)
Other current assets	10,075	21,958
Components of working capital	83,223	(22,092)
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION
Cash paid for Interest (net of amounts capitalized)	12,419	11,121
Cash paid for Income taxes	12,782	9,539
SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING ACTIVITIES
Accrued capital expenditures	$ 14,317	$ (9,734)