Common Stock and Equity Based Compensation - Stock Option Awards (Details) - UGI Stock Option Awards - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Shares
Shares under option - beginning balance (in shares)	8,957,290	10,193,952	12,086,658
Granted (in shares)	1,336,985	1,665,600	2,275,350
Canceled (in shares)	(85,365)	(86,707)	(134,754)
Exercised (in shares)	(953,533)	(2,815,555)	(4,033,302)
Shares under option - ending balance (in shares)	9,255,377	8,957,290	10,193,952	12,086,658
Weighted Average Option Price
Shares under option - beginning balance (in usd per share)	$ 21.44	$ 19.28	$ 17.75
Granted (in usd per share)	37.70	27.93	22.38
Canceled (in usd per share)	30.45	22.76	20.34
Exercised (in usd per share)	19.10	17.44	16.39
Shares under option - ending balance (in usd per share)	$ 23.97	$ 21.44	$ 19.28	$ 17.75
Total Intrinsic Value
Shares under option - beginning balance (in usd)	$ 113.3	$ 69.6	$ 41.4
Exercised (in usd)	15.4	37.4	35.4
Shares under option - beginning balance (in usd)	$ 104.5	$ 113.3	$ 69.6	$ 41.4
Weighted Average Contract Term
Weighted average contract term (in years)	6 years 7 months 18 days	7 years	6 years 9 months 18 days	6 years 1 month 6 days
Options Exercisable [Abstract]
Options exercisable (in shares)	6,050,946	5,073,347	5,871,091
Option exercisable (in usd per share)	$ 20.74	$ 19.45	$ 17.95
Option exercisable (in usd)	$ 85.4
Option exercisable (in years)	5 years 9 months 18 days
Options Not Exercisable [Abstract]
Options not exercisable (in shares)	3,204,431
Options not exercisable (in usd per share)	$ 30.05
Options not exercisable (in usd)	$ 19.1
Options not exercisable (in years)	8 years 3 months 18 days