Segment Information (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Sep. 30, 2010
Segment Informations [Abstract]
Revenues	$ 1,105.4	$ 961.9	$ 5,052.0	$ 4,701.0
Cost of sales	731.0	615.5	3,317.5	3,009.2
Segment profit:
Operating income (loss)	17.2	31.2	626.5	640.4
Loss from equity investees	(0.2)	(1.9)	(0.8)	(1.9)
Loss on extinguishment of debt			(18.8)
Interest expense	(35.0)	(33.6)	(102.6)	(101.9)
(Loss) income before income taxes	(18.0)	(4.3)	504.3	536.6
Noncontrolling interests' net loss	(6.3)	(7.6)	101.8	115.2
Depreciation and amortization	57.8	51.7	168.6	157.3
Capital expenditures	78.5	83.1	246.1	229.4
Total assets (at period end)	6,673.7	5,831.6	6,673.7	5,831.6	6,374.3
Bank loans (at period end)	206.1	35.2	206.1	35.2	200.4
Goodwill (at period end)	1,612.0	1,475.9	1,612.0	1,475.9	1,562.7
Elims [Member]
Segment Informations [Abstract]
Revenues	(40.0)	(22.2)	(172.9)	(146.9)
Cost of sales	(39.1)	(20.7)	(170.3)	(142.3)
Segment profit:
Operating income (loss)		(0.4)	0.2	(0.7)
(Loss) income before income taxes		(0.4)	0.2	(0.7)
Noncontrolling interests' net loss		0.1		0.1
Depreciation and amortization				(0.1)
Total assets (at period end)	(81.0)	(69.3)	(81.0)	(69.3)
Goodwill (at period end)		(3.9)		(3.9)
AmeriGas Propane [Member]
Segment Informations [Abstract]
Revenues	470.8	396.6	2,077.8	1,939.3
Cost of sales	300.8	235.8	1,300.9	1,165.1
Segment profit:
Operating income (loss)	6.7	5.3	252.9	261.2
Loss on extinguishment of debt			(18.8)
Interest expense	(15.7)	(17.0)	(47.4)	(50.2)
(Loss) income before income taxes	(9.0)	(11.7)	186.7	211.0
Partnership EBITDA	31.1	27.2	301.9	323.7
Noncontrolling interests' net loss	(6.1)	(7.5)	101.2	114.5
Depreciation and amortization	24.5	21.8	70.4	65.0
Capital expenditures	18.6	14.4	59.2	59.8
Total assets (at period end)	1,772.1	1,658.4	1,772.1	1,658.4
Bank loans (at period end)	176.0	15.0	176.0	15.0
Goodwill (at period end)	695.8	674.8	695.8	674.8
Gas Utility [Member]
Segment Informations [Abstract]
Revenues	148.1	149.1	921.7	922.3
Cost of sales	78.8	83.0	562.3	584.2
Segment profit:
Operating income (loss)	17.2	13.8	193.2	168.6
Interest expense	(9.9)	(10.0)	(30.2)	(30.5)
(Loss) income before income taxes	7.3	3.8	163.0	138.1
Depreciation and amortization	11.6	12.5	36.1	37.0
Capital expenditures	20.9	16.1	54.5	40.6
Total assets (at period end)	2,002.0	1,829.4	2,002.0	1,829.4
Goodwill (at period end)	180.1	180.1	180.1	180.1
Electric Utility [Member]
Segment Informations [Abstract]
Revenues	24.1	25.3	84.7	90.9
Cost of sales	14.6	15.8	53.4	58.0
Segment profit:
Operating income (loss)	2.4	2.6	9.0	11.1
Interest expense	(0.7)	(0.4)	(1.8)	(1.3)
(Loss) income before income taxes	1.7	2.2	7.2	9.8
Depreciation and amortization	1.1	1.0	3.1	3.0
Capital expenditures	1.0	2.3	5.1	3.9
Total assets (at period end)	156.5	120.4	156.5	120.4
Energy Services [Member]
Segment Informations [Abstract]
Revenues	217.1	198.6	857.0	949.5
Cost of sales	193.1	177.3	738.6	830.9
Segment profit:
Operating income (loss)	8.4	6.9	76.7	75.4
Interest expense	(0.6)		(2.0)
(Loss) income before income taxes	7.8	6.9	74.7	75.4
Depreciation and amortization	1.8	2.0	5.4	6.0
Capital expenditures	18.7	34.3	81.5	84.7
Total assets (at period end)	572.2	463.3	572.2	463.3
Goodwill (at period end)	2.8	11.8	2.8	11.8
International Propane, Antargaz [Member]
Segment Informations [Abstract]
Revenues	161.0	150.8	889.7	755.3
Cost of sales	95.3	81.9	554.0	394.4
Segment profit:
Operating income (loss)	(11.4)	4.3	101.0	123.4
Loss from equity investees	(0.2)	(1.9)	(0.8)	(1.8)
Interest expense	(7.1)	(5.3)	(18.5)	(17.1)
(Loss) income before income taxes	(18.7)	(2.9)	81.7	104.5
Noncontrolling interests' net loss	(0.2)	(0.2)	0.6	0.6
Depreciation and amortization	13.5	11.5	38.4	37.2
Capital expenditures	12.0	12.8	31.8	32.1
Total assets (at period end)	1,678.2	1,446.4	1,678.2	1,446.4
Goodwill (at period end)	641.1	540.6	641.1	540.6
International Propane, Other [Member]
Segment Informations [Abstract]
Revenues	102.3	41.0	332.4	129.8
Cost of sales	74.6	30.0	243.8	86.8
Segment profit:
Operating income (loss)	(3.6)	(1.4)	(0.2)	4.2
Loss from equity investees				(0.1)
Interest expense	(0.8)	(0.7)	(2.1)	(2.3)
(Loss) income before income taxes	(4.4)	(2.1)	(2.3)	1.8
Depreciation and amortization	4.7	2.6	13.7	8.2
Capital expenditures	6.6	2.0	12.6	5.7
Total assets (at period end)	407.3	231.2	407.3	231.2
Bank loans (at period end)	30.1	20.2	30.1	20.2
Goodwill (at period end)	85.3	65.6	85.3	65.6
Corporate And Other [Member]
Segment Informations [Abstract]
Revenues	22.0	22.7	61.6	60.8
Cost of sales	12.9	12.4	34.8	32.1
Segment profit:
Operating income (loss)	(2.5)	0.1	(6.3)	(2.8)
Interest expense	(0.2)	(0.2)	(0.6)	(0.5)
(Loss) income before income taxes	(2.7)	(0.1)	(6.9)	(3.3)
Depreciation and amortization	0.6	0.3	1.5	1.0
Capital expenditures	0.7	1.2	1.4	2.6
Total assets (at period end)	166.4	151.8	166.4	151.8
Goodwill (at period end)	$ 6.9	$ 6.9	$ 6.9	$ 6.9