Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax
AOCI - balance at beginning of period	$ (40.1)	$ 32.2	$ (21.2)	$ 8.4
Other comprehensive income (loss) before reclassification adjustments (after-tax)	(44.3)	5.7	(67.1)	58.5
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	(2.4)	(34.4)	2.2	(49.9)
Reclassification adjustments tax benefit	0.9	3.2	(1.0)	5.3
Reclassification adjustments (after-tax)	(1.5)	(31.2)	1.2	(44.6)
Other comprehensive (loss) income	(45.8)	(25.5)	(65.9)	13.9
Add other comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners	0.5	17.6	1.7	2.0
Other comprehensive income (loss) attributable to UGI	(45.3)	(7.9)	(64.2)	15.9
AOCI - balance at end of period	(85.4)	24.3	(85.4)	24.3
Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax
AOCI - balance at beginning of period	(20.0)	(16.0)	(20.6)	(16.4)
Other comprehensive income (loss) before reclassification adjustments (after-tax)	0	0	0	0
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	0.6	0.3	1.6	0.6
Reclassification adjustments tax benefit	(0.2)	(0.1)	(0.6)	0
Reclassification adjustments (after-tax)	0.4	0.2	1.0	0.6
Other comprehensive (loss) income	0.4	0.2	1.0	0.6
Add other comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners	0	0	0	0
Other comprehensive income (loss) attributable to UGI	0.4	0.2	1.0	0.6
AOCI - balance at end of period	(19.6)	(15.8)	(19.6)	(15.8)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax
AOCI - balance at beginning of period	1.7	(15.8)	(9.3)	(26.9)
Other comprehensive income (loss) before reclassification adjustments (after-tax)	20.2	6.3	27.9	46.8
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	(3.0)	(34.7)	0.6	(50.5)
Reclassification adjustments tax benefit	1.1	3.3	(0.4)	5.3
Reclassification adjustments (after-tax)	(1.9)	(31.4)	0.2	(45.2)
Other comprehensive (loss) income	18.3	(25.1)	28.1	1.6
Add other comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners	0.5	17.6	1.7	2.0
Other comprehensive income (loss) attributable to UGI	18.8	(7.5)	29.8	3.6
AOCI - balance at end of period	20.5	(23.3)	20.5	(23.3)
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax
AOCI - balance at beginning of period	(21.8)	64.0	8.7	51.7
Other comprehensive income (loss) before reclassification adjustments (after-tax)	(64.5)	(0.6)	(95.0)	11.7
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	0	0	0	0
Reclassification adjustments tax benefit	0	0	0	0
Reclassification adjustments (after-tax)	0	0	0	0
Other comprehensive (loss) income	(64.5)	(0.6)	(95.0)	11.7
Add other comprehensive loss attributable to noncontrolling interests, principally in AmeriGas Partners	0	0	0	0
Other comprehensive income (loss) attributable to UGI	(64.5)	(0.6)	(95.0)	11.7
AOCI - balance at end of period	$ (86.3)	$ 63.4	$ (86.3)	$ 63.4