Segment Information - Reconciliation of Partnership Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information
Depreciation and amortization	$ (104.1)	$ (98.1)	$ (301.5)	$ (299.4)
Interest expense	(56.8)	(56.4)	(168.0)	(171.6)
Loss on extinguishments of debt	(4.4)	(37.1)	(59.7)	(37.1)
Income (loss) before income taxes	$ (79.3)	$ 62.2	$ 735.8	$ 867.8
Amerigas Propane | AmeriGas OLP
Segment Reporting Information
General Partnership interest (percentage)	1.01%	1.01%	1.01%	1.01%
Operating Segments | Amerigas Propane
Segment Reporting Information
Partnership Adjusted EBITDA	$ 58.4	$ 64.6	$ 514.7	$ 537.7
Depreciation and amortization	(46.2)	(46.4)	(135.8)	(143.0)
Interest expense	(40.6)	(40.9)	(120.6)	(122.7)
Loss on extinguishments of debt	(4.4)	(37.1)	(59.7)	(37.1)
MGP environmental remediation accrual	(7.5)	0.0	(7.5)	0.0
Noncontrolling interest	(0.1)	0.1	2.4	3.6
Income (loss) before income taxes	$ (40.4)	$ (59.7)	$ 193.5	$ 238.5