Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss)
AOCI - balance at beginning of period	$ (21.2)	$ 8.4
Other comprehensive income (loss) before reclassification adjustments (after-tax)	(22.8)	52.8
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	4.6	(15.5)
Reclassification From AOCI Current Period Tax	(1.9)	2.1
Reclassification adjustments (after-tax)	2.7	(13.4)
Other comprehensive (loss) income	(20.1)	39.4
Add comprehensive loss (deduct comprehensive income) attributable to noncontrolling interests, principally in AmeriGas Partners	1.2	(15.6)
Comprehensive (loss) income	(18.9)	23.8
AOCI - balance at end of period	(40.1)	32.2
Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss)
AOCI - balance at beginning of period	(20.6)	(16.4)
Other comprehensive income (loss) before reclassification adjustments (after-tax)	0	0
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	1.0	0.3
Reclassification From AOCI Current Period Tax	(0.4)	0.1
Reclassification adjustments (after-tax)	0.6	0.4
Other comprehensive (loss) income	0.6	0.4
Add comprehensive loss (deduct comprehensive income) attributable to noncontrolling interests, principally in AmeriGas Partners	0	0
Comprehensive (loss) income	0.6	0.4
AOCI - balance at end of period	(20.0)	(16.0)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss)
AOCI - balance at beginning of period	(9.3)	(26.9)
Other comprehensive income (loss) before reclassification adjustments (after-tax)	7.7	40.5
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	3.6	(15.8)
Reclassification From AOCI Current Period Tax	(1.5)	2.0
Reclassification adjustments (after-tax)	2.1	(13.8)
Other comprehensive (loss) income	9.8	26.7
Add comprehensive loss (deduct comprehensive income) attributable to noncontrolling interests, principally in AmeriGas Partners	1.2	(15.6)
Comprehensive (loss) income	11.0	11.1
AOCI - balance at end of period	1.7	(15.8)
Foreign Currency
Accumulated Other Comprehensive Income (Loss)
AOCI - balance at beginning of period	8.7	51.7
Other comprehensive income (loss) before reclassification adjustments (after-tax)	(30.5)	12.3
Amounts reclassified from AOCI and noncontrolling interests:
Reclassification adjustments (pre-tax)	0	0
Reclassification From AOCI Current Period Tax	0	0
Reclassification adjustments (after-tax)	0	0
Other comprehensive (loss) income	(30.5)	12.3
Add comprehensive loss (deduct comprehensive income) attributable to noncontrolling interests, principally in AmeriGas Partners	0	0
Comprehensive (loss) income	(30.5)	12.3
AOCI - balance at end of period	$ (21.8)	$ 64.0

Reclassification From AOCI Current Period Tax

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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

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

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Amount after tax of other comprehensive income (loss) attributable to noncontrolling interests.

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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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