XML 63 R43.htm IDEA: XBRL DOCUMENT
v3.8.0.1

REGULATION - REGULATORY FILINGS (Details) - USD ($) $ in Millions |  | 3 Months Ended
--- | --- | ---
Nov. 01, 2017 | Dec. 31, 2017
SAVEGREEN |  |
Schedule of Regulatory Filings [Line Items] |  |
Approved rate increase (decrease), amount | $ (3.9) |
RAC |  |
Schedule of Regulatory Filings [Line Items] |  |
Requested rate increase (decrease), amount |  | $ (2.4)
NJCEP |  |
Schedule of Regulatory Filings [Line Items] |  |
Requested rate increase (decrease), amount |  | 1.8
Natural Gas Distribution |  |
Schedule of Regulatory Filings [Line Items] |  |
Tax Cuts and Jobs Act of 2017, regulatory liability |  | 228.0
Tax Cuts and Jobs Act of 2017, revaluation of deferred income taxes, provisional liability |  | 164.3
Tax Cuts and Jobs Act of 2017, income tax effects on revaluation, provisional liability |  | $ 63.7

X
- Definition Schedule of Regulatory Filings [Line Items] + References No definition available. + Details
Name: | njr_ScheduleOfRegulatoryFilingsLineItems
Namespace Prefix: | njr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Income Tax Effects On Revaluation, Provisional Liability + References No definition available. + Details
Name: | njr_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateIncomeTaxEffectsOnRevaluationProvisionalLiability
Namespace Prefix: | njr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Liability + References No definition available. + Details
Name: | njr_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateProvisionalLiability
Namespace Prefix: | njr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Revaluation Of Deferred Income Taxes, Provisional Liability + References No definition available. + Details
Name: | njr_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateRevaluationOfDeferredIncomeTaxesProvisionalLiability
Namespace Prefix: | njr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of public utility's approved rate increase (decrease) by regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=njr_SAVEGREENMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=njr_RACMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=njr_NJCEPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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