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Estimated maximum period of capitalized and amortized costs to install partnership and subsidiary owned tanks.

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Foreign subsidiary customer deposits.

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Interest income expenses on tax deficiencies and penalties.

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Maturities Period of highly liquid investments.

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Maximum period of benefit for computer software amortization expense.

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Ownership interests in certain subsidiaries under equity method investment.

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Reclassification of benefit plans actuarial losses and prior service costs net of tax to regulatory assets.

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Significant Accounting Policies.

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Voting rights in investment businesses not traded publicly accounted for under the cost method.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Glossary Diluted Earnings Per Share

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The maximum useful life of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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Significant Accounting Policies (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Jan. 29, 2009
Significant Accounting Policies (Textual) [Abstract]
Ownership interests in certain subsidiaries under equity method investment	100% or Less
Voting rights in investment businesses not traded publicly accounted for under the cost method	20% or Less
Investments in other assets	$ 72.4	$ 68.8
Equity interest purchased by Flaga for ZLH				50.00%
Interest (income) expense on tax deficiencies and penalties	0.2	(0.2)	(0.4)
Reclassification of benefit plans actuarial losses and prior service costs net of tax to regulatory assets		83.3
Maturities Period of highly liquid investments	three months or less
Refundable customer deposit	$ 204.4	$ 211.8
Prudently incurred remediation cost	a five-year average
Estimated maximum period of capitalized and amortized costs to install partnership and antargaz-owned tanks	less than 10 years
Maximum period of benefit for computer software amortization expense	less than fifteen years
Antidilutive Outstanding stock option award (a)	3,700		2,800
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	15
Property, Plant and Equipment, Useful Life, Maximum	40
Storage and customer tanks and cylinders [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	7
Property, Plant and Equipment, Useful Life, Maximum	40
Electric Generation, Transmission and Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	25
Property, Plant and Equipment, Useful Life, Maximum	35
Vehicles, equipment and office furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	2
Property, Plant and Equipment, Useful Life, Maximum	12
Gas Utility [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense as percentage of related average depreciable base	2.30%	2.50%	2.40%
Electric Utility [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense as percentage of related average depreciable base	2.60%	2.60%	2.90%