Accumulated Other Comprehensive Income - Schedule of Accumulated Comprehensive Income (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI - Balance at beginning of the period		$ (21.2)	$ 8.4
Other comprehensive (loss) income before reclassification adjustments (after-tax)		(98.5)	5.8
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)		6.6	(45.6)
Reclassification adjustments tax (expense) benefit		(3.6)	1.4
Reclassification adjustments (after-tax)		3.0	(44.2)
Other comprehensive (loss) income		(95.5)	(38.4)	$ 106.4
Add comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners		2.1	8.8
Other comprehensive (loss) income attributable to UGI		(93.4)	(29.6)
AOCI - Balance at the end of the period		(114.6)	(21.2)	8.4
Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI - Balance at beginning of the period		(20.6)	(16.4)
Other comprehensive (loss) income before reclassification adjustments (after-tax)		(1.2)	(5.2)
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)		2.2	1.6
Reclassification adjustments tax (expense) benefit		(0.8)	(0.6)
Reclassification adjustments (after-tax)		1.4	1.0
Other comprehensive (loss) income		0.2	(4.2)
Add comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners		0.0	0.0
Other comprehensive (loss) income attributable to UGI		0.2	(4.2)
AOCI - Balance at the end of the period		(20.4)	(20.6)	(16.4)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI - Balance at beginning of the period		(9.3)	(26.9)
Other comprehensive (loss) income before reclassification adjustments (after-tax)		16.8	54.0
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)		4.4	(47.2)
Reclassification adjustments tax (expense) benefit		(2.8)	2.0
Reclassification adjustments (after-tax)		1.6	(45.2)
Other comprehensive (loss) income		18.4	8.8
Add comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners		2.1	8.8
Other comprehensive (loss) income attributable to UGI		20.5	17.6
AOCI - Balance at the end of the period		11.2	(9.3)	(26.9)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI - Balance at beginning of the period	[1]	8.7	51.7
Other comprehensive (loss) income before reclassification adjustments (after-tax)	[1]	(114.1)	(43.0)
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	[1]	0.0	0.0
Reclassification adjustments tax (expense) benefit	[1]	0.0	0.0
Reclassification adjustments (after-tax)	[1]	0.0	0.0
Other comprehensive (loss) income	[1]	(114.1)	(43.0)
Add comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners	[1]	0.0	0.0
Other comprehensive (loss) income attributable to UGI	[1]	(114.1)	(43.0)
AOCI - Balance at the end of the period	[1]	$ (105.4)	$ 8.7	$ 51.7

[1] See Note 2 relating to correction of prior period error in comprehensive income.