Common Stock and Equity-Based Compensation - Schedule of Payment for UGI Performance Unit and UGI Stock Unit Awards in Shares and Cash (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
UGI Performance Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of original awards granted, net of forfeitures	121,948	144,521	136,621
Performance period beginning January 1:	2017	2016	2015
Payment of awards:
Shares of UGI Common Stock issued, net of shares withheld for taxes	0	116,950	69,680
Cash paid	$ 0	$ 10	$ 2
UGI Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of original awards granted, net of forfeitures	227,721	50,985	39,680
Payment of awards:
Shares of UGI Common Stock issued, net of shares withheld for taxes	148,477	43,479	29,095
Cash paid	$ 3	$ 1	$ 1

Number of company original awards granted.

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- Definition

Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of shares issued under share-based payment arrangement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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