XML 63 R41.htm IDEA: XBRL DOCUMENT
v3.25.3

Summary of Significant Accounting Policies - Schedule of Depreciable Plant by Segment (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Sep. 30, 2024
--- | --- | ---
Segment Reporting Information [Line Items] |  |
Depreciable plant | $ 14,973,440 | $ 13,998,897
Integrated Upstream and Gathering |  |
Segment Reporting Information [Line Items] |  |
Depreciable plant | 9,151,025 | 8,417,495
Pipeline and Storage |  |
Segment Reporting Information [Line Items] |  |
Depreciable plant | 3,003,944 | 2,919,506
Utility |  |
Segment Reporting Information [Line Items] |  |
Depreciable plant | 2,801,821 | 2,645,981
All Other and Corporate |  |
Segment Reporting Information [Line Items] |  |
Depreciable plant | $ 16,650 | $ 15,915

X
- Definition Carrying amount at the balance sheet date for depreciable plant assets used in the normal conduct of business and not intended for resale. Amount does not include depreciation. + References No definition available. + Details
Name: | nfg_DepreciablePlantAssets
Namespace Prefix: | nfg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=nfg_IntegratedUpstreamAndGatheringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=nfg_PipelineAndStorageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=nfg_UtilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=nfg_AllOtherAndCorporateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |