Utility Regulatory Assets and Liabilities and Regulatory Matters - Regulatory Assets and Liabilities Associated with Utilities (Details) - UGI Utilities - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Regulatory Assets [Line Items]
Regulatory assets	$ 397	$ 397
Regulatory Liabilities [Line Items]
Regulatory liabilities	388	353
Postretirement benefit overcollections
Regulatory Liabilities [Line Items]
Regulatory liabilities	13	13
Deferred fuel and power refunds
Regulatory Liabilities [Line Items]
Regulatory liabilities	36	29
State income tax benefits — distribution system repairs
Regulatory Liabilities [Line Items]
Regulatory liabilities	32	28
PAPUC Temporary Rates Order
Regulatory Liabilities [Line Items]
Regulatory liabilities	0	7
Excess federal deferred income taxes
Regulatory Liabilities [Line Items]
Regulatory liabilities	287	274
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities	20	2
Income taxes recoverable
Regulatory Assets [Line Items]
Regulatory assets	143	124
Underfunded pension and postretirement plans
Regulatory Assets [Line Items]
Regulatory assets	108	175
Environmental costs
Regulatory Assets [Line Items]
Regulatory assets	58	61
Deferred fuel and power costs
Regulatory Assets [Line Items]
Regulatory assets	11	0
Removal costs, net
Regulatory Assets [Line Items]
Regulatory assets	24	26
Other
Regulatory Assets [Line Items]
Regulatory assets	$ 53	$ 11