Acquisitions and Dispositions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 30, 2012
Finite Lived Intangible Asset Useful Life
Estimated useful life (in years)	15 years
Heritage Propane [Member]
Assets acquired:
Current assets	301.4
Property, plant & equipment	890.2
Customer relationships (estimated useful life of 15 years)	418.9
Trademarks and tradenames	91.1
Goodwill	1,217.7
Other assets	9.9
Total assets acquired	2,929.2
Liabilities assumed:
Current liabilities	(238.1)
Long-term debt	(62.9)
Other noncurrent liabilities	(23.4)
Total liabilities assumed	(324.4)
Total	2,604.8
Customer Relationships [Member] \| Heritage Propane [Member]
Finite Lived Intangible Asset Useful Life
Estimated useful life (in years)	15 years

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The amount of acquisition cost of a business combination allocated to assets acquired.

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Amount of goodwill arising from a business combination, which is the excess of the cost of the acquired entity over the amounts assigned to assets acquired and liabilities assumed.

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