Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2013		Mar. 31, 2012		Sep. 30, 2012
Segment information
Revenues	$ 2,537.1		$ 2,427.5		$ 4,560.3		$ 4,116.3
Cost of sales	1,500.6		1,526.6		2,719.4		2,628.4
Segment profit:
Operating income (loss)	486.2		380.8		782.3		569.1
Income (loss) from equity investees	0.1		0		0.1		(0.1)
Loss on extinguishment of debt	0		13.4		0		13.4
Interest expense	(60.1)		(65.3)		(120.4)		(101.3)
Income (loss) before income taxes	426.2		302.1		662.0		454.3
Noncontrolling interests' net income	154.3		93.6		222.4		116.7
Depreciation and amortization	(87.3)		(82.8)		(174.4)		(143.1)
Capital expenditures	93.6		65.3		184.9		154.0
Total assets (at period end)	10,236.3		10,129.4		10,236.3		10,129.4		9,709.7
Bank loans (at period end)	177.7		190.2		177.7		190.2		165.1
Goodwill (at period end)	2,813.8		2,795.2		2,813.8		2,795.2		2,818.3
Eliminations [Member]
Segment information
Revenues	(61.1)	[1]	(44.8)	[1]	(119.6)	[1]	(100.8)	[1]
Cost of sales	(58.8)	[1]	(43.6)	[1]	(116.1)	[1]	(98.6)	[1]
Segment profit:
Operating income (loss)	(0.9)	[1]			(0.9)	[1]	0
Income (loss) before income taxes	(0.9)		0		(0.9)		0
Capital expenditures	(1.0)				(1.0)
Total assets (at period end)	(110.8)		(84.4)		(110.8)		(84.4)
AmeriGas Propane [Member]
Segment information
Revenues	1,176.3		1,155.6		2,052.9		1,839.4
Cost of sales	612.4		670.0		1,064.5		1,113.8
Segment profit:
Operating income (loss)	257.4		195.0		397.3		255.1
Loss on extinguishment of debt	0		13.4		0		13.4
Interest expense	(41.8)		(45.1)		(83.0)		(61.6)
Income (loss) before income taxes	215.6		136.5		314.3		180.1
Partnership EBITDA	303.6	[2]	224.5	[2]	491.4	[3]	308.2	[3]
Noncontrolling interests' net income	154.0		93.2		222.0		116.2
Depreciation and amortization	(48.6)		(44.8)		(98.0)		(69.0)
Capital expenditures	27.9		23.5		54.4		45.1
Total assets (at period end)	4,682.8		4,823.8		4,682.8		4,823.8
Bank loans (at period end)	115.9		50.9		115.9		50.9
Goodwill (at period end)	1,919.2		1,881.3		1,919.2		1,881.3
Noncontrolling Interests Principally General Partners Interest in Related Parties	2.4	[4]	1.9	[4]	3.9	[4]	2.5	[4]
Gas Utility [Member]
Segment information
Revenues	368.6		319.5		616.9		574.5
Cost of sales	196.7		177.5		320.3		319.2
Segment profit:
Operating income (loss)	105.7		85.0		175.5		146.2
Interest expense	(9.3)		(10.1)		(18.9)		(20.2)
Income (loss) before income taxes	96.4		74.9		156.6		126.0
Depreciation and amortization	(12.7)		(12.2)		(25.3)		(24.3)
Capital expenditures	24.4		25.7		52.9		47.5
Total assets (at period end)	2,205.5		2,038.5		2,205.5		2,038.5
Bank loans (at period end)	0		0		0		0
Goodwill (at period end)	182.1		182.1		182.1		182.1
Midstream And Marketing, Energy Services [Member]
Segment information
Revenues	304.0		261.4		531.8		495.5
Cost of sales	247.0		216.4		434.9		413.1
Segment profit:
Operating income (loss)	43.5		33.1		70.8		60.5
Interest expense	(0.8)		(1.3)		(1.8)		(2.4)
Income (loss) before income taxes	42.7		31.8		69.0		58.1
Depreciation and amortization	(1.9)		(0.8)		(3.5)		(1.5)
Capital expenditures	19.3		4.3		32.8		22.9
Total assets (at period end)	450.4		387.7		450.4		387.7
Bank loans (at period end)	47.0		112.0		47.0		112.0
Goodwill (at period end)	2.8		2.8		2.8		2.8
Midstream & Marketing, Electric Generation [Member]
Segment information
Revenues	17.1		8.8		32.0		16.2
Cost of sales	10.6		6.4		20.2		11.2
Segment profit:
Operating income (loss)	0.5		(2.5)		0.7		(6.0)
Interest expense	0		0		0		0
Income (loss) before income taxes	0.5		(2.5)		0.7		(6.0)
Depreciation and amortization	(2.4)		(2.2)		(4.9)		(4.3)
Capital expenditures	4.2		1.6		11.0		11.1
Total assets (at period end)	261.7		255.4		261.7		255.4
Bank loans (at period end)	0		0		0		0
Goodwill (at period end)	0		0		0		0
International Propane, Antargaz [Member]
Segment information
Revenues	452.6		445.3		871.9		746.9
Cost of sales	285.8		288.6		565.7		464.3
Segment profit:
Operating income (loss)	67.8		60.2		115.3		97.5
Income (loss) from equity investees	0.1				0.1		(0.1)
Interest expense	(6.3)		(6.9)		(12.8)		(13.4)
Income (loss) before income taxes	61.6		53.3		102.6		84.0
Noncontrolling interests' net income	0.3		0.4		0.4		0.5
Depreciation and amortization	(14.2)		(15.0)		(28.3)		(29.1)
Capital expenditures	13.2		4.9		25.4		16.0
Total assets (at period end)	1,847.7		1,843.3		1,847.7		1,843.3
Goodwill (at period end)	610.0		638.5		610.0		638.5
International Propane, Flaga & Other [Member]
Segment information
Revenues	230.9		236.4		476.5		453.1
Cost of sales	177.4		185.2		372.3		353.3
Segment profit:
Operating income (loss)	13.8		10.0		24.1		14.4
Interest expense	(1.3)		(1.2)		(2.6)		(2.2)
Income (loss) before income taxes	12.5		8.8		21.5		12.2
Depreciation and amortization	(5.8)		(6.4)		(11.3)		(11.9)
Capital expenditures	4.1		3.9		6.3		8.7
Total assets (at period end)	551.3		548.4		551.3		548.4
Bank loans (at period end)	14.8		27.3		14.8		27.3
Goodwill (at period end)	92.7		83.5		92.7		83.5
Corporate & Other [Member]
Segment information
Revenues	48.7	[5]	45.3	[5]	97.9	[5]	91.5	[5]
Cost of sales	29.5	[5]	26.1	[5]	57.6	[5]	52.1	[5]
Segment profit:
Operating income (loss)	(1.6)	[5]	0	[5]	(0.5)	[5]	1.4	[5]
Interest expense	(0.6)	[5]	(0.7)	[5]	(1.3)	[5]	(1.5)	[5]
Income (loss) before income taxes	(2.2)	[5]	(0.7)	[5]	(1.8)	[5]	(0.1)	[5]
Depreciation and amortization	(1.7)	[5]	(1.4)	[5]	(3.1)	[5]	(3.0)	[5]
Capital expenditures	1.5	[5]	1.4	[5]	3.1	[5]	2.7	[5]
Total assets (at period end)	347.7	[5]	316.7	[5]	347.7	[5]	316.7	[5]
Goodwill (at period end)	$ 7.0	[5]	$ 7.0	[5]	$ 7.0	[5]	$ 7.0	[5]

[1] Principally represents the elimination of intersegment transactions among Midstream & Marketing, Gas Utility and AmeriGas Propane.

[2] The following table provides a reconciliation of Partnership EBITDA to AmeriGas Propane operating income:Three Months Ended March 31, 2013 2012Partnership EBITDA $303.6 224.5Depreciation and amortization (48.6) (44.8)Loss on extinguishments of debt — 13.4Noncontrolling interests (i) 2.4 1.9Operating income $257.4 $195.0(i)Principally represents the General Partner’s 1.01% interest in AmeriGas OLP.

[3] The following table provides a reconciliation of Partnership EBITDA to AmeriGas Propane operating income:Six Months Ended March 31, 2013 2012Partnership EBITDA $491.4 $308.2Depreciation and amortization (98.0) (69.0)Loss on extinguishments of debt — 13.4Noncontrolling interests (i) 3.9 2.5Operating income $397.3 $255.1(i)Principally represents the General Partner’s 1.01% interest in AmeriGas OLP.

[4] Principally represents the General Partner’s 1.01% interest in AmeriGas OLP.

[5] Corporate & Other results principally comprise Electric Utility, UGI Enterprises’ heating, ventilation, air-conditioning, refrigeration and electrical contracting businesses (”HVAC/R”), net expenses of UGI’s captive general liability insurance company and UGI Corporation’s unallocated corporate and general expenses and interest income. Corporate & Other assets principally comprise cash, short-term investments, the assets of Electric Utility and HVAC/R, and an intercompany loan. The intercompany loan and associated interest is removed in the segment presentation.