Utility Regulatory Assets and Liabilities and Regulatory Matters - Regulatory Assets and Liabilities Associated with Gas Utility and Electric Utility (Details) - UGI Utilities - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018
Regulatory Assets
Regulatory assets	$ 299.3	$ 301.0	$ 361.6
Regulatory Liabilities
Regulatory liabilities	379.5	390.2	380.7
Postretirement benefits
Regulatory Liabilities
Regulatory liabilities	16.9	17.8	17.1
Deferred fuel and power refunds
Regulatory Liabilities
Regulatory liabilities	17.7	36.7	35.3
State tax benefits — distribution system repairs
Regulatory Liabilities
Regulatory liabilities	24.3	22.6	19.9
PAPUC temporary rates order
Regulatory Liabilities
Regulatory liabilities	25.1	24.4	0.0
Excess federal deferred income taxes
Regulatory Liabilities
Regulatory liabilities	276.7	285.2	301.2
Other
Regulatory Liabilities
Regulatory liabilities	18.8	3.5	7.2
Income taxes recoverable
Regulatory Assets
Regulatory assets	120.3	110.1	128.3
Underfunded pension and postretirement plans
Regulatory Assets
Regulatory assets	83.6	87.1	135.3
Environmental costs
Regulatory Assets
Regulatory assets	58.8	58.8	59.8
Removal costs, net
Regulatory Assets
Regulatory assets	30.1	32.0	30.5
Other
Regulatory Assets
Regulatory assets	$ 6.5	$ 13.0	$ 7.7