Summary Of Significant Accounting Policies (Schedule Of Other Accruals And Current Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Regulatory Liabilities	$ 11,085	$ 20,013
Reserve for Gas Replacement	(3,176)	(51,484)
Other	25,236	22,833
Other Accruals and Current Liabilities	235,900	83,946
Accrued Capital Expenditures [Member]
Segment Reporting Information [Line Items]
Other	90,831	41,100
Reserve For Gas Replacement [Member]
Segment Reporting Information [Line Items]
Reserve for Gas Replacement	73,883	0
Federal [Member]
Segment Reporting Information [Line Items]
Income Taxes Payable	30,802	0
State [Member]
Segment Reporting Information [Line Items]
Income Taxes Payable	$ 4,063	$ 0