Common Stock and Equity-Based Compensation - Weighted Average Assumptions Used to Determine the Fair Value of UGI Performance Unit Awards and Related Compensation Costs (Details) - UGI Performance Units	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Risk free rate	1.60%	2.50%	2.00%
Expected life	3 years	3 years	3 years
Expected volatility	18.60%	17.70%	18.90%
Dividend yield	2.90%	1.90%	2.10%