Commitments and Contingencies (Details Textual) (USD $) In Millions, unless otherwise specified		12 Months Ended						9 Months Ended
	Jun. 30, 2012 Customer	Sep. 30, 2008 Partnership [Member] lb	Jun. 30, 2012 UGI Utilities [Member] Claims	Apr. 11, 2012 SCE & G [Member]	Sep. 22, 2006 SCE & G [Member]	Jun. 06, 2006 Key Span [Member]	Jun. 24, 2004 Key Span [Member]	Jun. 30, 2012 Environmental matters [Member]	Jun. 30, 2012 Environmental matters [Member] CPG MGP [Member]	Jun. 30, 2012 Environmental matters [Member] PNG MGP [Member]	Jun. 30, 2011 Environmental matters [Member] PNG MGP [Member]
Commitments and Contingencies [Line Items]
Environmental expenditures cap during calendar year									$ 1.8	$ 1.1
Accrual for environmental loss contingencies									15.8		20.1
Base year for determination of investigation and remediation cost (in years)								5 years
Number of Sites Claimant Withdrew (in claims)			3
Percentage of costs associated with sites (as a percent)					25.00%		50.00%
Approximate remediation cost spent by claimant					22.0		2.3
Third party claim relating to the site					26
Environmental exit cost anticipated by claimant				14			11
Environmental exit cost based on third party estimate						10
Additional environment exit cost based on claimant estimate						$ 20
Amount of propane in cylinders before reduction (in pounds)		17
Amount of propane in cylinders after reduction (in pounds)		15
Commitments and Contingencies (Textual) [Abstract]
Alleged number of residential customers (in customers)	400