Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period			$ 3,601.8
Other comprehensive (loss) income before reclassification adjustments (after-tax)	$ 17.3	$ 17.0	(41.3)	$ (6.4)
Amounts reclassified from AOCI:
Reclassification adjustments (pre-tax)	(7.2)	(6.6)	(12.2)	(14.4)
Reclassification adjustments tax (expense) benefit	2.2	2.6	3.7	5.5
Reclassification adjustments (after-tax)	(5.0)	(4.0)	(8.5)	(8.9)
Other comprehensive income (loss) attributable to UGI	12.3	13.0	(49.8)	(15.3)
Balance, end of period	3,937.4	3,925.0	3,937.4	3,925.0
Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(28.1)	(20.0)	(29.1)	(20.4)
Other comprehensive (loss) income before reclassification adjustments (after-tax)	0.0	0.0	0.0	0.0
Amounts reclassified from AOCI:
Reclassification adjustments (pre-tax)	0.7	0.4	2.3	1.1
Reclassification adjustments tax (expense) benefit	(0.3)	(0.1)	(0.9)	(0.4)
Reclassification adjustments (after-tax)	0.4	0.3	1.4	0.7
Other comprehensive income (loss) attributable to UGI	0.4	0.3	1.4	0.7
Balance, end of period	(27.7)	(19.7)	(27.7)	(19.7)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(5.6)	12.7	(13.4)	11.2
Other comprehensive (loss) income before reclassification adjustments (after-tax)	(0.5)	(29.7)	11.8	(22.9)
Amounts reclassified from AOCI:
Reclassification adjustments (pre-tax)	(7.9)	(7.0)	(14.5)	(15.5)
Reclassification adjustments tax (expense) benefit	2.5	2.7	4.6	5.9
Reclassification adjustments (after-tax)	(5.4)	(4.3)	(9.9)	(9.6)
Other comprehensive income (loss) attributable to UGI	(5.9)	(34.0)	1.9	(32.5)
Balance, end of period	(11.5)	(21.3)	(11.5)	(21.3)
Foreign Currency
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(183.1)	(135.6)	(112.2)	(105.4)
Other comprehensive (loss) income before reclassification adjustments (after-tax)	17.8	46.7	(53.1)	16.5
Amounts reclassified from AOCI:
Reclassification adjustments (pre-tax)	0.0	0.0	0.0	0.0
Reclassification adjustments tax (expense) benefit	0.0	0.0	0.0	0.0
Reclassification adjustments (after-tax)	0.0	0.0	0.0	0.0
Other comprehensive income (loss) attributable to UGI	17.8	46.7	(53.1)	16.5
Balance, end of period	(165.3)	(88.9)	(165.3)	(88.9)
Total
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(216.8)	(142.9)	(154.7)	(114.6)
Amounts reclassified from AOCI:
Balance, end of period	$ (204.5)	$ (129.9)	$ (204.5)	$ (129.9)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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