Partnership Distributions (Details) - USD ($) $ / shares in Units, $ in Millions	11 Months Ended	12 Months Ended
	Aug. 21, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Distribution Made to Limited Partner
Partnership distributions to partners (days following quarter end)		45 days
Quarterly distribution (in dollars per share)	$ 0.55
First target distribution (in dollars per share)	0.055
Available cash for per common unit (more than) (in dollars per share)	0.605			$ 0.605
Threshold for increased distribution to General Partner (in dollars per share)	$ 0.605
Pre-Incentive distribution of available cash to General Partners (as a percentage)		2.00%	2.00%	2.00%
General Partners distribution based on ownership interest			$ 55	$ 55
Incentive distributions received by the General Partner			$ 45	$ 45
Limited Partner
Distribution Made to Limited Partner
Distribution of available cash, percent	98.00%
General Partner
Distribution Made to Limited Partner
Distribution of available cash, percent	2.00%
AmeriGas Partners
Distribution Made to Limited Partner
Distribution of available cash, percent	1.00%
AmeriGas OLP
Distribution Made to Limited Partner
Distribution of available cash, percent	1.01%