Utility Regulatory Assets and Liabilities and Regulatory Matters - Schedule of Regulatory Assets and Liabilities (Details) - UGI Utilities - USD ($) $ in Millions	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020
Regulatory Assets
Regulatory assets	$ 396	$ 397	$ 399
Regulatory Liabilities
Regulatory liabilities	334	353	358
Postretirement benefit overcollections
Regulatory Liabilities
Regulatory liabilities	12	13	13
Deferred fuel and power refunds
Regulatory Liabilities
Regulatory liabilities	21	29	28
State tax benefits — distribution system repairs
Regulatory Liabilities
Regulatory liabilities	30	28	29
PAPUC temporary rates order
Regulatory Liabilities
Regulatory liabilities	0	7	10
Excess federal deferred income taxes
Regulatory Liabilities
Regulatory liabilities	269	274	275
Other
Regulatory Liabilities
Regulatory liabilities	2	2	3
Income taxes recoverable
Regulatory Assets
Regulatory assets	131	124	133
Underfunded pension and postretirement plans
Regulatory Assets
Regulatory assets	166	175	169
Environmental costs
Regulatory Assets
Regulatory assets	58	61	62
Removal costs, net
Regulatory Assets
Regulatory assets	24	26	22
Other
Regulatory Assets
Regulatory assets	$ 17	$ 11	$ 13