Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

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Revenue from Contracts with Customers - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Contract liabilities	$ 104		$ 109	$ 161
Contract with customer, liability, revenue recognized	$ 137	$ 122
Midstream & Marketing
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation			2,000
UGI Utilities
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation			$ 200