Employee Retirement Plans - Pension Plans Assets (Details) - Pension Benefits - U.S.	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	100.00%	100.00%
Target Asset Allocation	100.00%	100.00%
Target allocation range	5.00%
Equity investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	61.40%	61.20%
Target Asset Allocation	61.60%	58.70%
U.S. equities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	25.80%	26.50%
Target Asset Allocation	27.60%	24.70%
Non-U.S. equities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	21.70%	20.90%
Target Asset Allocation	23.30%	20.90%
Global equities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	13.90%	13.80%
Target Asset Allocation	10.70%	13.10%
Fixed income funds & cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	35.50%	35.50%
Target Asset Allocation	35.00%	35.00%
Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	3.10%	3.30%
Target Asset Allocation	3.40%	6.30%

Defined Benefit Plan, Plan Assets, Target Allocation Range, Percentage

No definition available.

Name:	ugi_DefinedBenefitPlanPlanAssetsTargetAllocationRangePercentage
Namespace Prefix:	ugi_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ugi_DefinedBenefitPlanEquitySecuritiesUSNonUSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ugi_FixedIncomeFundsAndCashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ugi_AlternativeInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: