$NFG
NATIONAL FUEL GAS CO Stock $nfg

$nfg Overview Financials Valuation SEC Filings Company Website

2019 Form 10-K Financial Statement

#000007014519000030 Filed on November 15, 2019

Income Statement

Concept	2019	2018 Q3	2018 Q2
Revenue	$1.693B	$289.2M	$342.9M
YoY Change	6.32%	0.79%	-1.57%
Cost Of Revenue	$386.3M	$15.00M	$52.20M
YoY Change	14.34%	37.61%	13.23%
Gross Profit	$1.307B	$274.2M	$290.7M
YoY Change	4.16%	-0.65%	-3.84%
Gross Profit Margin	77.19%	94.81%	84.77%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$275.7M	$63.20M	$60.82M
YoY Change	14.4%	14.08%	9.35%
% of Gross Profit	21.09%	23.05%	20.92%
Operating Expenses	$1.182B	$189.5M	$228.9M
YoY Change	10.12%	28.3%	1.73%
Operating Profit	$511.8M	$84.66M	$114.0M
YoY Change	-1.52%	-3.13%	-7.58%
Interest Expense	$106.8M	-$29.40M	-$28.20M
YoY Change	-6.78%	-10.37%	-3.42%
% of Operating Profit	20.86%	-34.73%	-24.74%
Other Income/Expense, Net	-$15.54M	-$1.000M	-$3.612M
YoY Change	-26.6%	-97.1%	-358.0%
Pretax Income	$389.5M	$54.30M	$82.21M
YoY Change	1.43%	-11.13%	-13.92%
Income Tax	$85.22M	$12.80M	$19.18M
% Of Pretax Income	21.88%	23.57%	23.33%
Net Earnings	$304.3M	$38.00M	$63.03M
YoY Change	-22.28%	-16.64%	5.54%
Net Earnings / Revenue	17.97%	13.14%	18.38%
Basic Earnings Per Share	$3.53	$0.44	$0.73
Diluted Earnings Per Share	$3.51	$0.44	$0.73
COMMON SHARES
Basic Shares Outstanding	86.24M shares	85.95M shares	85.93M shares
Diluted Shares Outstanding	86.77M shares		86.50M shares

Balance Sheet

Concept	2019	2018 Q3	2018 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$20.40M	$229.6M	$313.3M
YoY Change	-91.11%	-58.67%	9.81%
Cash & Equivalents	$20.40M	$229.6M	$313.3M
Short-Term Investments
Other Short-Term Assets	$73.90M	$68.02M	$52.69M
YoY Change	7.73%	32.07%	3.61%
Inventory	$77.30M	$73.60M	$50.80M
Prepaid Expenses
Receivables	$140.0M	$141.5M	$151.0M
Other Receivables	$50.90M	$31.30M	$22.30M
Total Short-Term Assets	$362.6M	$544.6M	$589.0M
YoY Change	-33.42%	-33.45%	8.64%
LONG-TERM ASSETS
Property, Plant & Equipment	$5.510B	$4.977B	$4.843B
YoY Change	10.7%	6.48%	5.67%
Goodwill		$5.476M	$5.476M
YoY Change		0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments	$144.9M	$132.5M	$130.7M
YoY Change	9.36%	5.75%	3.32%
Other Assets	$439.6M	$102.0K	$108.0K
YoY Change	16.7%	-86.25%	-77.45%
Total Long-Term Assets	$6.100B	$514.8M	$541.9M
YoY Change	11.07%	-15.75%	-26.95%
TOTAL ASSETS
Total Short-Term Assets	$362.6M	$544.6M	$589.0M
Total Long-Term Assets	$6.100B	$514.8M	$541.9M
Total Assets	$6.462B	$6.036B	$5.974B
YoY Change	7.05%	-1.1%	1.82%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$132.2M	$160.0M	$111.8M
YoY Change	-17.38%	26.56%	13.12%
Accrued Expenses	$52.20M	$132.7M	$38.08M
YoY Change	-9.06%	18.59%	11.42%
Deferred Revenue
YoY Change
Short-Term Debt	$55.20M	$0.00	$0.00
YoY Change
Long-Term Debt Due	$0.00	$0.00	$250.0M
YoY Change		-100.0%	-16.67%
Total Short-Term Liabilities	$421.9M	$440.1M	$661.5M
YoY Change	-4.14%	-31.88%	9.85%
LONG-TERM LIABILITIES
Long-Term Debt	$2.134B	$2.131B	$1.836B
YoY Change	0.11%	2.29%	2.66%
Other Long-Term Liabilities	$1.114B	$1.015B	$1.058B
YoY Change	9.76%	30.36%	16.06%
Total Long-Term Liabilities	$3.248B	$1.528B	$1.550B
YoY Change	3.22%	-8.51%	-13.59%
TOTAL LIABILITIES
Total Short-Term Liabilities	$421.9M	$440.1M	$661.5M
Total Long-Term Liabilities	$3.248B	$1.528B	$1.550B
Total Liabilities	$4.323B	$1.968B	$2.211B
YoY Change	5.46%	-15.03%	-7.7%
SHAREHOLDERS EQUITY
Retained Earnings		$1.099B	$1.097B
YoY Change		29.03%	30.4%
Common Stock		$85.96M	$85.94M
YoY Change		0.48%	0.56%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$2.139B	$1.937B	$1.927B
YoY Change
Total Liabilities & Shareholders Equity	$6.462B	$6.036B	$5.974B
YoY Change	7.05%	-1.1%	1.82%

Cashflow Statement

Concept	2019	2018 Q3	2018 Q2
OPERATING ACTIVITIES
Net Income	$304.3M	$38.00M	$63.03M
YoY Change	-22.28%	-16.64%	5.54%
Depreciation, Depletion And Amortization	$275.7M	$63.20M	$60.82M
YoY Change	14.4%	14.08%	9.35%
Cash From Operating Activities	$694.5M	$97.20M	$229.4M
YoY Change	12.87%	-27.14%	15.16%
INVESTING ACTIVITIES
Capital Expenditures	$788.9M	-$180.0M	-$142.3M
YoY Change	35.09%	32.84%	33.49%
Acquisitions
YoY Change
Other Investing Activities	$10.24M	$1.400M	$31.00M
YoY Change	2531.62%	-87.72%	-549.28%
Cash From Investing Activities	-$799.2M	-$178.7M	-$111.1M
YoY Change	51.11%	43.88%	-2.11%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net	$0.00
YoY Change	-100.0%
Cash From Financing Activities	-$101.1M	-1.100M	-34.30M
YoY Change	-75.38%	-100.42%	8.54%
NET CHANGE
Cash From Operating Activities	$694.5M	97.20M	229.4M
Cash From Investing Activities	-$799.2M	-178.7M	-111.1M
Cash From Financing Activities	-$101.1M	-1.100M	-34.30M
Net Change In Cash	-$205.8M	-82.60M	84.00M
YoY Change	-36.53%	-130.54%	55.27%
FREE CASH FLOW
Cash From Operating Activities	$694.5M	$97.20M	$229.4M
Capital Expenditures	$788.9M	-$180.0M	-$142.3M
Free Cash Flow	-$94.46M	$277.2M	$371.7M
YoY Change	-401.78%	3.09%	21.55%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2019	dei	Amendment Flag AmendmentFlag	false
CY2019	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--09-30
CY2019	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2019	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
CY2019	dei	Entity Central Index Key EntityCentralIndexKey	0000070145
CY2017	nfg	Depreciation Depletion And Amortization Per Mcfe Of Production DepreciationDepletionAndAmortizationPerMcfeOfProduction	0.63	USD
CY2018	nfg	Depreciation Depletion And Amortization Per Mcfe Of Production DepreciationDepletionAndAmortizationPerMcfeOfProduction	0.67	USD
CY2019	nfg	Depreciation Depletion And Amortization Per Mcfe Of Production DepreciationDepletionAndAmortizationPerMcfeOfProduction	0.71	USD
CY2017	nfg	Results Of Operations Sales Revenue To Affiliated Enterprises ResultsOfOperationsSalesRevenueToAffiliatedEnterprises	0	USD
CY2018	nfg	Results Of Operations Sales Revenue To Affiliated Enterprises ResultsOfOperationsSalesRevenueToAffiliatedEnterprises	0	USD
CY2019	nfg	Results Of Operations Sales Revenue To Affiliated Enterprises ResultsOfOperationsSalesRevenueToAffiliatedEnterprises	0	USD
CY2018Q3	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	24537000	USD
CY2019Q3	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	25788000	USD
CY2018Q3	us-gaap	Commercial Paper At Carrying Value CommercialPaperAtCarryingValue	0	USD
CY2017	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.64
CY2018	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.68
CY2019	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.72
CY2018Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2019Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2018Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	200000000	shares
CY2019Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	200000000	shares
CY2018Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	85956814	shares
CY2019Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	86315287	shares
CY2018Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	85956814	shares
CY2019Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	86315287	shares
CY2019Q3	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Prior Service Cost Credit After Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditAfterTax	1000000	USD
CY2017Q3	us-gaap	Defined Benefit Plan Ultimate Health Care Cost Trend Rate1 DefinedBenefitPlanUltimateHealthCareCostTrendRate1	0.045
CY2018Q3	us-gaap	Defined Benefit Plan Ultimate Health Care Cost Trend Rate1 DefinedBenefitPlanUltimateHealthCareCostTrendRate1	0.045
CY2017	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	100000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	100000	USD
CY2018Q3	us-gaap	Fair Value Assets Level1 To Level2 Transfers Amount FairValueAssetsLevel1ToLevel2TransfersAmount	0	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Net FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet	0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	0	USD
CY2017	us-gaap	Results Of Operations Sales Or Transfers To Entitys Other Operations ResultsOfOperationsSalesOrTransfersToEntitysOtherOperations	2357000	USD
CY2018	us-gaap	Results Of Operations Sales Or Transfers To Entitys Other Operations ResultsOfOperationsSalesOrTransfersToEntitysOtherOperations	2134000	USD
CY2019	us-gaap	Results Of Operations Sales Or Transfers To Entitys Other Operations ResultsOfOperationsSalesOrTransfersToEntitysOtherOperations	2532000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1
CY2018Q3	us-gaap	Short Term Bank Loans And Notes Payable ShortTermBankLoansAndNotesPayable	0	USD
CY2019Q3	us-gaap	Short Term Bank Loans And Notes Payable ShortTermBankLoansAndNotesPayable	0	USD
CY2019	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	0	shares
CY2019	us-gaap	Stock Issued During Period Shares Employee Benefit Plan StockIssuedDuringPeriodSharesEmployeeBenefitPlan	0	shares
CY2019	dei	Document Type DocumentType	10-K
CY2019	dei	Document Annual Report DocumentAnnualReport	true
CY2019	dei	Document Period End Date DocumentPeriodEndDate	2019-09-30
CY2019	dei	Document Transition Report DocumentTransitionReport	false
CY2019	dei	Entity File Number EntityFileNumber	1-3880
CY2019	dei	Entity Registrant Name EntityRegistrantName	National Fuel Gas Company
CY2019	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	NJ
CY2019	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	13-1086010
CY2019	dei	Entity Address Address Line1 EntityAddressAddressLine1	6363 Main Street
CY2019	dei	Entity Address City Or Town EntityAddressCityOrTown	Williamsville,
CY2019	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
CY2019	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	14221
CY2019	dei	City Area Code CityAreaCode	716
CY2019	dei	Local Phone Number LocalPhoneNumber	857-7000
CY2019	dei	Security12b Title Security12bTitle	Common Stock, par value $1.00 per share
CY2019	dei	Trading Symbol TradingSymbol	NFG
CY2019	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2019	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2019	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2019	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2019	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2019	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2019	dei	Entity Small Business EntitySmallBusiness	false
CY2019	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2019	dei	Entity Shell Company EntityShellCompany	false
CY2019Q1	dei	Entity Public Float EntityPublicFloat	5152011000	USD
CY2019	dei	Entity Listing Par Value Per Share EntityListingParValuePerShare	1.00
CY2019Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	86324767	shares
CY2019	us-gaap	Revenues Revenues	1693332000	USD
CY2018	us-gaap	Revenues Revenues	1592668000	USD
CY2017	us-gaap	Revenues Revenues	1579881000	USD
CY2019	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	88886000	USD
CY2017	nfg	Beginning Retained Earnings Unappropriated And Current Period Net Income Loss BeginningRetainedEarningsUnappropriatedAndCurrentPeriodNetIncomeLoss	959843000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	148432000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	144290000	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	140090000	USD
CY2019Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1272601000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	85221000	USD
CY2018Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1098900000	USD
CY2017Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	851669000	USD
CY2018	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	84393000	USD
CY2017	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	84995000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	275660000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	240961000	USD
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	224195000	USD
CY2019	us-gaap	Operating Expenses OperatingExpenses	1181523000	USD
CY2018	us-gaap	Operating Expenses OperatingExpenses	1072945000	USD
CY2017	us-gaap	Operating Expenses OperatingExpenses	986103000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	511809000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	519723000	USD
CY2017	us-gaap	Operating Income Loss OperatingIncomeLoss	593778000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-15542000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-21174000	USD
CY2017	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-29777000	USD
CY2019	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	101614000	USD
CY2018	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	110946000	USD
CY2017	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	116471000	USD
CY2019	us-gaap	Interest Expense Other InterestExpenseOther	5142000	USD
CY2018	us-gaap	Interest Expense Other InterestExpenseOther	3576000	USD
CY2017	us-gaap	Interest Expense Other InterestExpenseOther	3366000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	389511000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	384027000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	444164000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-7494000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	160682000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	304290000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	391521000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	283482000	USD
CY2018Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1098900000	USD
CY2017Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	851669000	USD
CY2016Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	676361000	USD
CY2019	nfg	Beginning Retained Earnings Unappropriated And Current Period Net Income Loss BeginningRetainedEarningsUnappropriatedAndCurrentPeriodNetIncomeLoss	1403190000	USD
CY2018	nfg	Beginning Retained Earnings Unappropriated And Current Period Net Income Loss BeginningRetainedEarningsUnappropriatedAndCurrentPeriodNetIncomeLoss	1243190000	USD
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.53
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.56
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.32
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.51
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.53
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.30
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	86235550	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	85830597	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	85364929	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	86773259	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	86439698	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	86021386	shares
CY2019	us-gaap	Net Income Loss NetIncomeLoss	304290000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	391521000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	283482000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTax	44089000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTax	-6225000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTax	-15661000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	7332000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	9704000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	13433000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	132000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	4008000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	79301000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-74103000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	5347000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	430000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	1575000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-5464000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-1189000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	81605000	USD
CY2019	nfg	Other Comprehensive Income Loss Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilities	-11738000	USD
CY2018	nfg	Other Comprehensive Income Loss Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilities	0	USD
CY2017	nfg	Other Comprehensive Income Loss Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilities	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	36270000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-57283000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-44731000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBeforeReclassificationAdjustmentsTax	10473000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBeforeReclassificationAdjustmentsTax	-1582000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBeforeReclassificationAdjustmentsTax	-6175000	USD
CY2017	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	258999000	USD
CY2019Q3	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	11204838000	USD
CY2018Q3	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	10439839000	USD
CY2019Q3	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	5695328000	USD
CY2018Q3	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	5462696000	USD
CY2019Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	5509510000	USD
CY2018Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	4977143000	USD
CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	20428000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	20675000	USD
CY2018Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	229606000	USD
CY2019Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	6832000	USD
CY2018Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	3441000	USD
CY2019Q3	us-gaap	Receivables Net Current ReceivablesNetCurrent	139956000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	1698000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	2437000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	4929000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-15000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	1505000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	20619000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-22547000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	2009000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	158000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	580000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax	-2726000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax	955000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax	34286000	USD
CY2019	nfg	Other Comprehensive Income Loss Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilitiesTax	4301000	USD
CY2018	nfg	Other Comprehensive Income Loss Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilitiesTax	0	USD
CY2017	nfg	Other Comprehensive Income Loss Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilitiesTax	0	USD
CY2019	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	-10406000	USD
CY2018	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	0	USD
CY2017	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-19656000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-20248000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	15595000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-37627000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-24483000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	319885000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	353894000	USD
CY2018Q3	us-gaap	Receivables Net Current ReceivablesNetCurrent	141498000	USD
CY2019Q3	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	18758000	USD
CY2018Q3	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	24182000	USD
CY2019Q3	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	36632000	USD
CY2018Q3	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	37813000	USD
CY2019Q3	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	40717000	USD
CY2018Q3	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	35823000	USD
CY2019Q3	us-gaap	Unrecovered Costs For Purchased Gas Amount UnrecoveredCostsForPurchasedGasAmount	2246000	USD
CY2018Q3	us-gaap	Unrecovered Costs For Purchased Gas Amount UnrecoveredCostsForPurchasedGasAmount	4204000	USD
CY2019Q3	us-gaap	Other Assets Current OtherAssetsCurrent	97054000	USD
CY2018Q3	us-gaap	Other Assets Current OtherAssetsCurrent	68024000	USD
CY2019Q3	us-gaap	Assets Current AssetsCurrent	362623000	USD
CY2018Q3	us-gaap	Assets Current AssetsCurrent	544591000	USD
CY2019Q3	nfg	Recoverable Future Taxes RecoverableFutureTaxes	115197000	USD
CY2018Q3	nfg	Recoverable Future Taxes RecoverableFutureTaxes	115460000	USD
CY2019Q3	us-gaap	Unamortized Loss Reacquired Debt Noncurrent UnamortizedLossReacquiredDebtNoncurrent	14005000	USD
CY2018Q3	us-gaap	Unamortized Loss Reacquired Debt Noncurrent UnamortizedLossReacquiredDebtNoncurrent	15975000	USD
CY2019Q3	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	167320000	USD
CY2018Q3	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	112918000	USD
CY2019Q3	us-gaap	Deferred Costs DeferredCosts	33843000	USD
CY2018Q3	us-gaap	Deferred Costs DeferredCosts	40025000	USD
CY2019Q3	us-gaap	Other Investments OtherInvestments	144917000	USD
CY2018Q3	us-gaap	Other Investments OtherInvestments	132545000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	5476000	USD
CY2018Q3	us-gaap	Goodwill Goodwill	5476000	USD
CY2019Q3	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	60517000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	82733000	USD
CY2019Q3	us-gaap	Derivative Instruments And Hedges Noncurrent DerivativeInstrumentsAndHedgesNoncurrent	48669000	USD
CY2018Q3	us-gaap	Derivative Instruments And Hedges Noncurrent DerivativeInstrumentsAndHedgesNoncurrent	9518000	USD
CY2019Q3	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	80000	USD
CY2018Q3	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	102000	USD
CY2019Q3	us-gaap	Assets Noncurrent AssetsNoncurrent	590024000	USD
CY2018Q3	us-gaap	Assets Noncurrent AssetsNoncurrent	514752000	USD
CY2019Q3	us-gaap	Assets Assets	6462157000	USD
CY2018Q3	us-gaap	Assets Assets	6036486000	USD
CY2019Q3	us-gaap	Common Stock Value CommonStockValue	86315000	USD
CY2018Q3	us-gaap	Common Stock Value CommonStockValue	85957000	USD
CY2019Q3	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	832264000	USD
CY2018Q3	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	820223000	USD
CY2019Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1272601000	USD
CY2018Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1098900000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-52155000	USD
CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-67750000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2139025000	USD
CY2018Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1937330000	USD
CY2019Q3	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	2133718000	USD
CY2018Q3	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	2131365000	USD
CY2019Q3	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	4272743000	USD
CY2018Q3	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	4068695000	USD
CY2019Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	55200000	USD
CY2018Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2019Q3	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	USD
CY2018Q3	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	USD
CY2019Q3	us-gaap	Accounts Payable Current AccountsPayableCurrent	132208000	USD
CY2018Q3	us-gaap	Accounts Payable Current AccountsPayableCurrent	160031000	USD
CY2019Q3	us-gaap	Refundable Gas Costs RefundableGasCosts	4017000	USD
CY2018Q3	us-gaap	Refundable Gas Costs RefundableGasCosts	3394000	USD
CY2019Q3	us-gaap	Dividends Payable Current DividendsPayableCurrent	37547000	USD
CY2018Q3	us-gaap	Dividends Payable Current DividendsPayableCurrent	36532000	USD
CY2019Q3	nfg	Interest Payable On Long Term Debt InterestPayableOnLongTermDebt	18508000	USD
CY2018Q3	nfg	Interest Payable On Long Term Debt InterestPayableOnLongTermDebt	19062000	USD
CY2019Q3	nfg	Customer Advances CustomerAdvances	13044000	USD
CY2018Q3	nfg	Customer Advances CustomerAdvances	13609000	USD
CY2019Q3	us-gaap	Security Deposit Liability SecurityDepositLiability	16210000	USD
CY2018Q3	us-gaap	Security Deposit Liability SecurityDepositLiability	25703000	USD
CY2019Q3	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	139600000	USD
CY2018Q3	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	132693000	USD
CY2019Q3	us-gaap	Derivative Instruments And Hedges Liabilities DerivativeInstrumentsAndHedgesLiabilities	5574000	USD
CY2018Q3	us-gaap	Derivative Instruments And Hedges Liabilities DerivativeInstrumentsAndHedgesLiabilities	49036000	USD
CY2019Q3	us-gaap	Liabilities Current LiabilitiesCurrent	421908000	USD
CY2018Q3	us-gaap	Liabilities Current LiabilitiesCurrent	440060000	USD
CY2019Q3	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	653382000	USD
CY2018Q3	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	512686000	USD
CY2019Q3	nfg	Taxes Refundable To Customers TaxesRefundableToCustomers	366503000	USD
CY2018Q3	nfg	Taxes Refundable To Customers TaxesRefundableToCustomers	370628000	USD
CY2019Q3	nfg	Cost Of Removal Regulatory Liability CostOfRemovalRegulatoryLiability	221699000	USD
CY2018Q3	nfg	Cost Of Removal Regulatory Liability CostOfRemovalRegulatoryLiability	212311000	USD
CY2019Q3	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	142367000	USD
CY2018Q3	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	146743000	USD
CY2019Q3	us-gaap	Pension And Other Postretirement And Postemployment Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent	133729000	USD
CY2018Q3	us-gaap	Pension And Other Postretirement And Postemployment Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent	66103000	USD
CY2019Q3	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	127458000	USD
CY2018Q3	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	108235000	USD
CY2019Q3	us-gaap	Deferred Credits And Other Liabilities Noncurrent DeferredCreditsAndOtherLiabilitiesNoncurrent	122368000	USD
CY2018Q3	us-gaap	Deferred Credits And Other Liabilities Noncurrent DeferredCreditsAndOtherLiabilitiesNoncurrent	111025000	USD
CY2019Q3	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	1767506000	USD
CY2018Q3	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	1527731000	USD
CY2019Q3	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	USD
CY2018Q3	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	USD
CY2019Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	6462157000	USD
CY2018Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	6036486000	USD
CY2018	us-gaap	Increase Decrease In Deferred Gas Cost IncreaseDecreaseInDeferredGasCost	-419000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	304290000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	391521000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	283482000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	275660000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	240961000	USD
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	224195000	USD
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	122265000	USD
CY2018	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-18153000	USD
CY2017	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	117975000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	21186000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	15762000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	12262000	USD
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-8608000	USD
CY2018	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-16133000	USD
CY2017	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-16476000	USD
CY2019	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-6379000	USD
CY2018	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	30882000	USD
CY2017	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	3380000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	3713000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	4021000	USD
CY2017	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	1417000	USD
CY2019	us-gaap	Increase Decrease In Deferred Gas Cost IncreaseDecreaseInDeferredGasCost	-1958000	USD
CY2017	us-gaap	Increase Decrease In Deferred Gas Cost IncreaseDecreaseInDeferredGasCost	2183000	USD
CY2019	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	29030000	USD
CY2018	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	16519000	USD
CY2017	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-7849000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	-24770000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	17962000	USD
CY2017	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	17192000	USD
CY2019	us-gaap	Increase Decrease In Regulatory Clause Revenue IncreaseDecreaseInRegulatoryClauseRevenue	623000	USD
CY2018	us-gaap	Increase Decrease In Regulatory Clause Revenue IncreaseDecreaseInRegulatoryClauseRevenue	3394000	USD
CY2017	us-gaap	Increase Decrease In Regulatory Clause Revenue IncreaseDecreaseInRegulatoryClauseRevenue	-19537000	USD
CY2019	nfg	Increase Decrease In Customer Advances Current IncreaseDecreaseInCustomerAdvancesCurrent	-565000	USD
CY2018	nfg	Increase Decrease In Customer Advances Current IncreaseDecreaseInCustomerAdvancesCurrent	-2092000	USD
CY2017	nfg	Increase Decrease In Customer Advances Current IncreaseDecreaseInCustomerAdvancesCurrent	939000	USD
CY2019	us-gaap	Increase Decrease In Security Deposits IncreaseDecreaseInSecurityDeposits	-9493000	USD
CY2018	us-gaap	Increase Decrease In Security Deposits IncreaseDecreaseInSecurityDeposits	5331000	USD
CY2017	us-gaap	Increase Decrease In Security Deposits IncreaseDecreaseInSecurityDeposits	4353000	USD
CY2019	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	10992000	USD
CY2018	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	3865000	USD
CY2017	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	27004000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-5115000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	9556000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	1178000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	2885000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	4978000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	2183000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	694483000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	615303000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	684508000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	788938000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	584004000	USD
CY2017	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	450335000	USD
CY2019	us-gaap	Proceeds From Sale Of Oil And Gas Property And Equipment ProceedsFromSaleOfOilAndGasPropertyAndEquipment	0	USD
CY2018	us-gaap	Proceeds From Sale Of Oil And Gas Property And Equipment ProceedsFromSaleOfOilAndGasPropertyAndEquipment	55506000	USD
CY2017	us-gaap	Proceeds From Sale Of Oil And Gas Property And Equipment ProceedsFromSaleOfOilAndGasPropertyAndEquipment	26554000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	10237000	USD
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	389000	USD
CY2017	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-1216000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-799175000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-528887000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-422565000	USD
CY2019	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	55200000	USD
CY2018	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	0	USD
CY2017	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	0	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	295020000	USD
CY2017	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	295151000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	566512000	USD
CY2017	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2019	us-gaap	Payments For Repurchase Of Equity PaymentsForRepurchaseOfEquity	8877000	USD
CY2018	us-gaap	Proceeds From Issuance Or Sale Of Equity ProceedsFromIssuanceOrSaleOfEquity	4110000	USD
CY2017	us-gaap	Proceeds From Issuance Or Sale Of Equity ProceedsFromIssuanceOrSaleOfEquity	7784000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	147418000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	143258000	USD
CY2017	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	139063000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-101095000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-410640000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	163872000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-205787000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-324224000	USD
CY2017	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	425815000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	233047000	USD
CY2017Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	557271000	USD
CY2016Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	131456000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	27260000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	233047000	USD
CY2017Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	557271000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	102920000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	126079000	USD
CY2017	us-gaap	Interest Paid Net InterestPaidNet	116894000	USD
CY2019	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	17342000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	31771000	USD
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	34826000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	81121000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	88813000	USD
CY2017	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	72216000	USD
CY2019	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="line-height:120%;padding-top:8px;text-indent:16px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Reclassifications</span></div><div style="line-height:120%;padding-top:6px;text-align:justify;text-indent:32px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">In November 2016, the FASB issued authoritative guidance related to the presentation of restricted cash on the statement of cash flows. The new guidance requires restricted cash and cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows, and requires disclosure of how cash and cash equivalents on the statement of cash flows reconciles to the balance sheet. The Company considers Hedging Collateral Deposits to be restricted cash. The Company adopted this guidance effective October 1, 2018 on a retrospective basis. As a result, prior periods have been reclassified to conform to the current year presentation. Additional discussion is provided below at Consolidated Statement of Cash Flows.</span></div><div style="line-height:120%;padding-top:6px;text-align:justify;text-indent:32px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">In March 2017, the FASB issued authoritative guidance related to the presentation of net periodic pension cost and net periodic postretirement benefit cost. The new guidance requires segregation of the service cost component from the other components of net periodic pension cost and net periodic postretirement benefit cost for financial reporting purposes. The service cost component is to be presented on the income statement in the same line items as other compensation costs included within Operating Expenses and the other components of net periodic pension cost and net periodic postretirement benefit cost are to be presented on the income statement below the subtotal labeled Operating Income (Loss). Under this guidance, the service cost component is eligible to be capitalized as part of the cost of inventory or property, plant and equipment while the other components of net periodic pension cost and net periodic postretirement benefit cost are generally not eligible for capitalization, unless allowed by a regulator. The Company adopted this guidance effective October 1, 2018. The Company applied the guidance retrospectively for the pension and postretirement benefit costs using amounts disclosed in prior period financial statement notes as estimates for the reclassifications in accordance with a practical expedient allowed under the guidance. For the years ended September 30, 2018 and September 30, 2017, Operating Income increased </span><span style="font-family:inherit;font-size:10pt;"><span>$32.6 million</span></span><span style="font-family:inherit;font-size:10pt;"> and </span><span style="font-family:inherit;font-size:10pt;"><span>$40.9 million</span></span><span style="font-family:inherit;font-size:10pt;">, respectively, and Other Income (Deductions) decreased by the same amounts as a result of the reclassifications. For the year ended September 30, 2019, Other Income (Deductions) includes </span><span style="font-family:inherit;font-size:10pt;"><span>$27.3 million</span></span><span style="font-family:inherit;font-size:10pt;"> of pension and postretirement benefit costs.</span></div>
CY2018	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	32600000	USD
CY2017	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	40900000	USD
CY2019	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	27300000	USD
CY2018Q3	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	1300000000	USD
CY2019Q3	nfg	Full Cost Ceiling Test Discount Factor FullCostCeilingTestDiscountFactor	0.10
CY2019Q3	nfg	Full Cost Ceiling Exceeds Book Value Of Oil And Gas Properties FullCostCeilingExceedsBookValueOfOilAndGasProperties	381200000	USD
CY2019	us-gaap	Effect On Future Cash Flows Amount EffectOnFutureCashFlowsAmount	-17700000	USD
CY2018	us-gaap	Effect On Future Cash Flows Amount EffectOnFutureCashFlowsAmount	-25100000	USD
CY2017	us-gaap	Effect On Future Cash Flows Amount EffectOnFutureCashFlowsAmount	30500000	USD
CY2019Q3	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	1700000000	USD
CY2019	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	149900000	USD
CY2018	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	119900000	USD
CY2017	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	108500000	USD
CY2019Q3	nfg	Depreciable Plant Assets DepreciablePlantAssets	10788616000	USD
CY2018Q3	nfg	Depreciable Plant Assets DepreciablePlantAssets	10076671000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	5500000	USD
CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-67750000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	25066000	USD
CY2019	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-8372000	USD
CY2019	nfg	Reclassification Adjustmentfrom Aoc Ifor Cumulative Effectof Adoptionof Authoritative Guidancefor Financial Assetsand Liabilities ReclassificationAdjustmentfromAOCIforCumulativeEffectofAdoptionofAuthoritativeGuidanceforFinancialAssetsandLiabilities	7437000	USD
CY2019	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	-10406000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-52155000	USD
CY2017Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-30123000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-46766000	USD
CY2018	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-9139000	USD
CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-67750000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Prior Service Cost Credit After Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditAfterTax	1000000.0	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	27260000	USD
CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	20428000	USD
CY2018Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	229606000	USD
CY2017Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	555530000	USD
CY2016Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	129972000	USD
CY2019Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	6832000	USD
CY2018Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	3441000	USD
CY2017Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	1741000	USD
CY2016Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	1484000	USD
CY2017Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	557271000	USD
CY2019Q3	us-gaap	Prepaid Taxes PrepaidTaxes	14361000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	233047000	USD
CY2016Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	131456000	USD
CY2019Q3	us-gaap	Other Prepaid Expense Current OtherPrepaidExpenseCurrent	12728000	USD
CY2018Q3	us-gaap	Other Prepaid Expense Current OtherPrepaidExpenseCurrent	11126000	USD
CY2018Q3	us-gaap	Prepaid Taxes PrepaidTaxes	14088000	USD
CY2019Q3	nfg	Other Current Assets Fair Values Of Firm Commitments OtherCurrentAssetsFairValuesOfFirmCommitments	7538000	USD
CY2018Q3	nfg	Other Current Assets Fair Values Of Firm Commitments OtherCurrentAssetsFairValuesOfFirmCommitments	1739000	USD
CY2019Q3	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	11460000	USD
CY2018Q3	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	9792000	USD
CY2019Q3	us-gaap	Other Assets Current OtherAssetsCurrent	97054000	USD
CY2018Q3	us-gaap	Other Assets Current OtherAssetsCurrent	68024000	USD
CY2017	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	157649	shares
CY2019Q3	nfg	Liabilityfor Royaltyand Working Interest Current LiabilityforRoyaltyandWorkingInterestCurrent	18057000	USD
CY2018Q3	nfg	Liabilityfor Royaltyand Working Interest Current LiabilityforRoyaltyandWorkingInterestCurrent	12062000	USD
CY2019Q3	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	139600000	USD
CY2018Q3	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	132693000	USD
CY2019Q3	nfg	Customer Advances CustomerAdvances	13000000.0	USD
CY2018Q3	nfg	Customer Advances CustomerAdvances	13600000	USD
CY2019Q3	us-gaap	Security Deposit Liability SecurityDepositLiability	16200000	USD
CY2018Q3	us-gaap	Security Deposit Liability SecurityDepositLiability	25700000	USD
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	242302	shares
CY2018	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	317899	shares
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	162000000.0	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	138400000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	115100000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	82300000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	72900000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	297600000	USD
CY2018Q3	us-gaap	Asset Retirement Obligation AssetRetirementObligation	108235000	USD
CY2017Q3	us-gaap	Asset Retirement Obligation AssetRetirementObligation	106395000	USD
CY2016Q3	us-gaap	Asset Retirement Obligation AssetRetirementObligation	112330000	USD
CY2019	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	4122000	USD
CY2018	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	5597000	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	2963000	USD
CY2019	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	16693000	USD
CY2018	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-419000	USD
CY2017	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-10578000	USD
CY2019	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	7670000	USD
CY2018	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	12858000	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	4967000	USD
CY2019	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	6078000	USD
CY2018	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	9520000	USD
CY2017	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	6647000	USD
CY2019Q3	us-gaap	Asset Retirement Obligation AssetRetirementObligation	127458000	USD
CY2018Q3	us-gaap	Asset Retirement Obligation AssetRetirementObligation	108235000	USD
CY2017Q3	us-gaap	Asset Retirement Obligation AssetRetirementObligation	106395000	USD
CY2019Q3	us-gaap	Regulatory Assets RegulatoryAssets	307982000	USD
CY2018Q3	us-gaap	Regulatory Assets RegulatoryAssets	254145000	USD
CY2019Q3	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	11460000	USD
CY2018Q3	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	9792000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-38927000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	103046000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	23751000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	20774000	USD
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	14929000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	160682000	USD
CY2019Q3	us-gaap	Regulatory Liabilities RegulatoryLiabilities	784918000	USD
CY2018Q3	us-gaap	Regulatory Liabilities RegulatoryLiabilities	790501000	USD
CY2019Q3	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	54349000	USD
CY2018Q3	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	60819000	USD
CY2019	us-gaap	Public Utilities Approved Return On Equity Percentage PublicUtilitiesApprovedReturnOnEquityPercentage	0.087
CY2017	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.245
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2018	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	-103500000	USD
CY2018	nfg	Reduction In Deferred Taxes Rate Regulated Activities Impact Of Change In Corporate Tax Rate ReductionInDeferredTaxesRateRegulatedActivitiesImpactOfChangeInCorporateTaxRate	336700000	USD
CY2018	nfg	Decrease To Recoverable Future Taxes Impactof Change In Corporate Tax Rate DecreaseToRecoverableFutureTaxesImpactofChangeInCorporateTaxRate	65700000	USD
CY2018	nfg	Increase To Taxes Refundable To Customers Impact Of Changes In Corporate Tax Rate IncreaseToTaxesRefundableToCustomersImpactOfChangesInCorporateTaxRate	271000000.0	USD
CY2019	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	-5000000.0	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-41645000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	2025000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	32034000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	4601000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	8634000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	10673000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	98514000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	85221000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-7494000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	160682000	USD
CY2019	us-gaap	Investment Tax Credit InvestmentTaxCredit	91000	USD
CY2018	us-gaap	Investment Tax Credit InvestmentTaxCredit	105000	USD
CY2017	us-gaap	Investment Tax Credit InvestmentTaxCredit	173000	USD
CY2019	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	85130000	USD
CY2018	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	-7599000	USD
CY2017	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	160509000	USD
CY2019	us-gaap	Investment Tax Credit InvestmentTaxCredit	91000	USD
CY2018	us-gaap	Investment Tax Credit InvestmentTaxCredit	105000	USD
CY2017	us-gaap	Investment Tax Credit InvestmentTaxCredit	173000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	85221000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-7494000	USD
CY2017	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	160509000	USD
CY2019	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	85130000	USD
CY2018	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	-7599000	USD
CY2019	nfg	Income From Continuing Operations Before Income Taxes IncomeFromContinuingOperationsBeforeIncomeTaxes	389420000	USD
CY2018	nfg	Income From Continuing Operations Before Income Taxes IncomeFromContinuingOperationsBeforeIncomeTaxes	383922000	USD
CY2017	nfg	Income From Continuing Operations Before Income Taxes IncomeFromContinuingOperationsBeforeIncomeTaxes	443991000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	81778000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	94061000	USD
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	155397000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	22397000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	22203000	USD
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	16641000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	7361000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	6576000	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	6679000	USD
CY2019	nfg	Nfg Effective Income Tax Rate Reconciliation Deductible Expense Amortizationof Excess Deferred Income Taxes Nfg_EffectiveIncomeTaxRateReconciliationDeductibleExpenseAmortizationofExcessDeferredIncomeTaxes	-5036000	USD
CY2018	nfg	Nfg Effective Income Tax Rate Reconciliation Deductible Expense Amortizationof Excess Deferred Income Taxes Nfg_EffectiveIncomeTaxRateReconciliationDeductibleExpenseAmortizationofExcessDeferredIncomeTaxes	-3236000	USD
CY2017	nfg	Nfg Effective Income Tax Rate Reconciliation Deductible Expense Amortizationof Excess Deferred Income Taxes Nfg_EffectiveIncomeTaxRateReconciliationDeductibleExpenseAmortizationofExcessDeferredIncomeTaxes	0	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-5000000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-112598000	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2019	us-gaap	Income Tax Reconciliation Deductions Other IncomeTaxReconciliationDeductionsOther	1648000	USD
CY2018	us-gaap	Income Tax Reconciliation Deductions Other IncomeTaxReconciliationDeductionsOther	1453000	USD
CY2017	us-gaap	Income Tax Reconciliation Deductions Other IncomeTaxReconciliationDeductionsOther	4850000	USD
CY2019	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	85130000	USD
CY2018	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	-7599000	USD
CY2017	nfg	Income Tax Expense Benefit Including Deferred Investment Tax Credit IncomeTaxExpenseBenefitIncludingDeferredInvestmentTaxCredit	160509000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.245
CY2017	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2017	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2019	nfg	Reversalof Estimate For Potential Sequestrationof Amt Credit Refunds Under2017 Tax Reform Ac ReversalofEstimateForPotentialSequestrationofAMTCreditRefundsUnder2017TaxReformAc	5000000.0	USD
CY2018	nfg	Estimate For Potential Sequestrationof Amt Credit Refunds Under2017 Tax Reform Act EstimateForPotentialSequestrationofAMTCreditRefundsUnder2017TaxReformAct	5000000.0	USD
CY2018	nfg	Income Tax Benefitfrom Blended Tax Rateunder2017 Tax Reform Act IncomeTaxBenefitfromBlendedTaxRateunder2017TaxReformAct	9100000	USD
CY2019Q3	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	861278000	USD
CY2018Q3	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	770794000	USD
CY2019Q3	nfg	Deferred Tax Liabilities Pension And Other Post Retirement Costs DeferredTaxLiabilitiesPensionAndOtherPostRetirementCosts	55795000	USD
CY2018Q3	nfg	Deferred Tax Liabilities Pension And Other Post Retirement Costs DeferredTaxLiabilitiesPensionAndOtherPostRetirementCosts	39541000	USD
CY2019Q3	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	54486000	USD
CY2018Q3	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	49734000	USD
CY2019Q3	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	971559000	USD
CY2018Q3	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	860069000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	175542000	USD
CY2018Q3	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	214128000	USD
CY2019Q3	nfg	Deferred Tax Assets Pension And Other Post Retirement Costs DeferredTaxAssetsPensionAndOtherPostRetirementCosts	87280000	USD
CY2018Q3	nfg	Deferred Tax Assets Pension And Other Post Retirement Costs DeferredTaxAssetsPensionAndOtherPostRetirementCosts	62969000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	55355000	USD
CY2018Q3	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	75286000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	318177000	USD
CY2018Q3	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	352383000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	USD
CY2018Q3	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	5000000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	318177000	USD
CY2018Q3	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	347383000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	653382000	USD
CY2018Q3	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	512686000	USD
CY2018Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	USD
CY2017Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1251000	USD
CY2016Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	396000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1251000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	788000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	396000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	463000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2019Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	USD
CY2018Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	USD
CY2017Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1251000	USD
CY2019Q3	us-gaap	Deferred Tax Assets Charitable Contribution Carryforwards DeferredTaxAssetsCharitableContributionCarryforwards	2097000	USD
CY2019Q3	nfg	Earnings Reinvested In Business Available For Dividends EarningsReinvestedInBusinessAvailableForDividends	1100000000	USD
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	126879	shares
CY2019	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	159413	shares
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	19500000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	14200000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10800000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3800000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3400000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4400000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	100000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	3200000	USD
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	1225831	shares
CY2019Q3	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	2133718000	USD
CY2018Q3	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	2131365000	USD
CY2019Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	10000000	shares
CY2019Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	1
CY2019Q3	us-gaap	Unsecured Debt UnsecuredDebt	2149000000	USD
CY2018Q3	us-gaap	Unsecured Debt UnsecuredDebt	2149000000	USD
CY2019Q3	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	15282000	USD
CY2018Q3	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	17635000	USD
CY2019Q3	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	USD
CY2018Q3	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	USD
CY2019	us-gaap	Debt Instrument Interest Rate Increase Decrease DebtInstrumentInterestRateIncreaseDecrease	0.0200
CY2018	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	1000000.0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	500000000.0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	549000000.0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	0	USD
CY2019Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	1100000000.0	USD
CY2019Q3	us-gaap	Commercial Paper At Carrying Value CommercialPaperAtCarryingValue	55200000	USD
CY2019Q3	nfg	Committed Credit Facility Debtto Capitalization Ratio Ceiling Test Impairment Adjustment CommittedCreditFacilityDebttoCapitalizationRatioCeilingTestImpairmentAdjustment	0.50
CY2019Q3	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0250
CY2019	nfg	Committed Credit Facility Debt To Capitalization Ratio CommittedCreditFacilityDebtToCapitalizationRatio	0.65
CY2019Q3	nfg	Committed Credit Facility Debtto Capitalization Ratio Ceiling Test Impairment Maximum Adjustment CommittedCreditFacilityDebttoCapitalizationRatioCeilingTestImpairmentMaximumAdjustment	250000000	USD
CY2019	nfg	Debt To Capitalization Ratio DebtToCapitalizationRatio	0.51
CY2019Q3	us-gaap	Debt Instrument Unused Borrowing Capacity Amount DebtInstrumentUnusedBorrowingCapacityAmount	1780000000	USD
CY2019	nfg	Committed Credit Facility Debt To Capitalization Ratio CommittedCreditFacilityDebtToCapitalizationRatio	0.65
CY2019	nfg	Amount Which Could Trigger Repayment Obligation Under Committed Credit Facility AmountWhichCouldTriggerRepaymentObligationUnderCommittedCreditFacility	40000000.0	USD
CY2018Q3	us-gaap	Other Investments OtherInvestments	132545000	USD
CY2019	us-gaap	Maximum Remaining Maturity Of Foreign Currency Derivatives1 MaximumRemainingMaturityOfForeignCurrencyDerivatives1	P7Y
CY2019	nfg	Amount Which Could Trigger Repayment Obligation Under Committed Credit Facility AmountWhichCouldTriggerRepaymentObligationUnderCommittedCreditFacility	40000000.0	USD
CY2019Q3	nfg	Maximum Debt Increase Under Existing Indenture Covenants MaximumDebtIncreaseUnderExistingIndentureCovenants	1020000000.00	USD
CY2019	nfg	Debt Instrument Principal Outstanding Portion Of Long Term Debt DebtInstrumentPrincipalOutstandingPortionOfLongTermDebt	0.046
CY2019Q3	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	10521000	USD
CY2019Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	6832000	USD
CY2019Q3	nfg	Fair Value Assets Measured On Recurring Basis Total FairValueAssetsMeasuredOnRecurringBasisTotal	169742000	USD
CY2019Q3	nfg	Fair Value Liabilities Measured On Recurring Basis Total FairValueLiabilitiesMeasuredOnRecurringBasisTotal	5574000	USD
CY2019Q3	nfg	Fair Value Assets Liabilities Measured On Recurring Basis Net FairValueAssetsLiabilitiesMeasuredOnRecurringBasisNet	164168000	USD
CY2018Q3	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	215272000	USD
CY2018Q3	us-gaap	Margin Deposit Assets MarginDepositAssets	3441000	USD
CY2018Q3	nfg	Fair Value Assets Measured On Recurring Basis Total FairValueAssetsMeasuredOnRecurringBasisTotal	320321000	USD
CY2018Q3	nfg	Fair Value Liabilities Measured On Recurring Basis Total FairValueLiabilitiesMeasuredOnRecurringBasisTotal	49036000	USD
CY2018Q3	nfg	Fair Value Assets Liabilities Measured On Recurring Basis Net FairValueAssetsLiabilitiesMeasuredOnRecurringBasisNet	271285000	USD
CY2019Q3	us-gaap	Long Term Debt LongTermDebt	2133718000	USD
CY2019Q3	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	2257085000	USD
CY2018Q3	us-gaap	Long Term Debt LongTermDebt	2131365000	USD
CY2018Q3	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	2121861000	USD
CY2019Q3	us-gaap	Cash Surrender Value Of Life Insurance CashSurrenderValueOfLifeInsurance	41074000	USD
CY2018Q3	us-gaap	Cash Surrender Value Of Life Insurance CashSurrenderValueOfLifeInsurance	39970000	USD
CY2019Q3	us-gaap	Other Investments OtherInvestments	144917000	USD
CY2019	us-gaap	Unrealized Gain Loss On Price Risk Cash Flow Derivatives Before Tax UnrealizedGainLossOnPriceRiskCashFlowDerivativesBeforeTax	47400000	USD
CY2019	nfg	After Tax Net Hedging Gains Losses In Accumulated Other Comprehensive Income Loss AfterTaxNetHedgingGainsLossesInAccumulatedOtherComprehensiveIncomeLoss	34700000	USD
CY2019	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	39100000	USD
CY2019	nfg	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months After Tax CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonthsAfterTax	28600000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	79301000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-74103000	USD
CY2019	us-gaap	Derivative Instruments Gain Loss Reclassified From Accumulated Oci Into Income Effective Portion Net DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet	-5464000	USD
CY2018	us-gaap	Derivative Instruments Gain Loss Reclassified From Accumulated Oci Into Income Effective Portion Net DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet	-1189000	USD
CY2019	us-gaap	Derivative Instruments Gain Loss Recognized In Income Ineffective Portion And Amount Excluded From Effectiveness Testing Net DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet	2096000	USD
CY2018	us-gaap	Derivative Instruments Gain Loss Recognized In Income Ineffective Portion And Amount Excluded From Effectiveness Testing Net DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet	-782000	USD
CY2019	us-gaap	Gain Loss On Fair Value Hedges Recognized In Earnings GainLossOnFairValueHedgesRecognizedInEarnings	1941000	USD
CY2019	nfg	Offsetting Gain Loss On Hedged Item Attributable To Hedged Risk OffsettingGainLossOnHedgedItemAttributableToHedgedRisk	-1941000	USD
CY2019Q3	us-gaap	Credit Risk Derivative Assets At Fair Value CreditRiskDerivativeAssetsAtFairValue	36600000	USD
CY2019Q3	us-gaap	Credit Risk Derivative Liabilities At Fair Value CreditRiskDerivativeLiabilitiesAtFairValue	400000	USD
CY2019	nfg	Amortization Period AmortizationPeriod	P10Y
CY2018	nfg	Estimated Gross Other Post Retirement Benefit Payments Rate Of Increase For Pre Age Sixty Five Participants EstimatedGrossOtherPostRetirementBenefitPaymentsRateOfIncreaseForPreAgeSixtyFiveParticipants	0.0559
CY2019	nfg	Estimated Gross Other Post Retirement Benefit Payments Rate Of Increase For Pre Age Sixty Five Participants EstimatedGrossOtherPostRetirementBenefitPaymentsRateOfIncreaseForPreAgeSixtyFiveParticipants	0.0550
CY2017	nfg	Estimated Gross Other Post Retirement Benefit Payments Rate Of Increase For Pre Age Sixty Five Participants EstimatedGrossOtherPostRetirementBenefitPaymentsRateOfIncreaseForPreAgeSixtyFiveParticipants	0.0567
CY2019	nfg	Estimated Gross Other Post Retirement Benefit Payments Rate Of Increase For Post Age Sixty Five Participants EstimatedGrossOtherPostRetirementBenefitPaymentsRateOfIncreaseForPostAgeSixtyFiveParticipants	0.0475
CY2018	nfg	Estimated Gross Other Post Retirement Benefit Payments Rate Of Increase For Post Age Sixty Five Participants EstimatedGrossOtherPostRetirementBenefitPaymentsRateOfIncreaseForPostAgeSixtyFiveParticipants	0.0475
CY2017	nfg	Estimated Gross Other Post Retirement Benefit Payments Rate Of Increase For Post Age Sixty Five Participants EstimatedGrossOtherPostRetirementBenefitPaymentsRateOfIncreaseForPostAgeSixtyFiveParticipants	0.0475
CY2019	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Cost Of Covered Prescription Drug Benefits EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaCostOfCoveredPrescriptionDrugBenefits	0.0735
CY2018	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Cost Of Covered Prescription Drug Benefits EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaCostOfCoveredPrescriptionDrugBenefits	0.0789
CY2017	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Cost Of Covered Prescription Drug Benefits EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaCostOfCoveredPrescriptionDrugBenefits	0.0845
CY2019	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Medicare Part B Reimbursement EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaMedicarePartBReimbursement	0.0475
CY2018	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Medicare Part B Reimbursement EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaMedicarePartBReimbursement	0.0475
CY2017	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Medicare Part B Reimbursement EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaMedicarePartBReimbursement	0.0475
CY2019	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Medicare Part D Subsidy EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaMedicarePartDSubsidy	0.0684
CY2018	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Medicare Part D Subsidy EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaMedicarePartDSubsidy	0.0718
CY2017	nfg	Estimated Gross Other Post Retirement Benefit Payments Annual Rate Of Increase In Per Capita Medicare Part D Subsidy EstimatedGrossOtherPostRetirementBenefitPaymentsAnnualRateOfIncreaseInPerCapitaMedicarePartDSubsidy	0.0733
CY2019Q3	us-gaap	Defined Benefit Plan Ultimate Health Care Cost Trend Rate1 DefinedBenefitPlanUltimateHealthCareCostTrendRate1	0.045
CY2019	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Accumulated Postretirement Benefit Obligation DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation	60800000	USD
CY2019	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Service And Interest Cost Components DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnServiceAndInterestCostComponents	2700000	USD
CY2019	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Decrease On Accumulated Postretirement Benefit Obligation1 DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1	49100000	USD
CY2019	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Decrease On Service And Interest Cost Components1 DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnServiceAndInterestCostComponents1	2100000	USD
CY2019Q3	us-gaap	Fair Value Assets Level1 To Level2 Transfers Amount FairValueAssetsLevel1ToLevel2TransfersAmount	0	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Net FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet	0	USD
CY2019Q3	us-gaap	Loss Contingency Estimate Of Possible Loss LossContingencyEstimateOfPossibleLoss	7000000.0	USD
CY2019Q3	us-gaap	Recorded Unconditional Purchase Obligation Due Within One Year RecordedUnconditionalPurchaseObligationDueWithinOneYear	256400000	USD
CY2019Q3	us-gaap	Recorded Unconditional Purchase Obligation Due In Second Year RecordedUnconditionalPurchaseObligationDueInSecondYear	78500000	USD
CY2019Q3	us-gaap	Recorded Unconditional Purchase Obligation Due In Third Year RecordedUnconditionalPurchaseObligationDueInThirdYear	111200000	USD
CY2019Q3	us-gaap	Recorded Unconditional Purchase Obligation Due In Fourth Year RecordedUnconditionalPurchaseObligationDueInFourthYear	110800000	USD
CY2019Q3	us-gaap	Recorded Unconditional Purchase Obligation Due In Fifth Year RecordedUnconditionalPurchaseObligationDueInFifthYear	115600000	USD
CY2019Q3	us-gaap	Recorded Unconditional Purchase Obligation Due After Fifth Year RecordedUnconditionalPurchaseObligationDueAfterFifthYear	1098800000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	12400000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	2800000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	2300000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	2300000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	2200000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	9700000	USD
CY2019	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	4
CY2019	us-gaap	Interest Income Domestic Deposits InterestIncomeDomesticDeposits	6065000	USD
CY2019	us-gaap	Interest Expense InterestExpense	106756000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	275660000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	85221000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	304290000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	153359000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	90595000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.05
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.04
CY2018Q4	us-gaap	Revenues Revenues	490247000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	63753000	USD
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.74
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.73
CY2019Q1	us-gaap	Revenues Revenues	552544000	USD
CY2019	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	781246000	USD
CY2019Q3	us-gaap	Assets Assets	6462157000	USD
CY2018	us-gaap	Interest Income Domestic Deposits InterestIncomeDomesticDeposits	6766000	USD
CY2018	us-gaap	Interest Expense InterestExpense	114522000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	240961000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-7494000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	391521000	USD
CY2018	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	600602000	USD
CY2018Q3	us-gaap	Assets Assets	6036486000	USD
CY2017	us-gaap	Interest Income Domestic Deposits InterestIncomeDomesticDeposits	4113000	USD
CY2017	us-gaap	Interest Expense InterestExpense	119837000	USD
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	224195000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	160682000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	283482000	USD
CY2017	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	462117000	USD
CY2017Q3	us-gaap	Assets Assets	6103320000	USD
CY2019Q3	us-gaap	Revenues Revenues	293341000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	83940000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	47282000	USD
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.55
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.54
CY2019Q2	us-gaap	Revenues Revenues	357200000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	112827000	USD
CY2018Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	161683000	USD
CY2018Q4	us-gaap	Net Income Loss NetIncomeLoss	102660000	USD
CY2018Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2018Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.18
CY2018Q3	us-gaap	Revenues Revenues	289196000	USD
CY2018Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	84662000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	37995000	USD
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.44
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.44
CY2018Q2	us-gaap	Revenues Revenues	342912000	USD
CY2018Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	114003000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	63025000	USD
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.73
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.73
CY2018Q1	us-gaap	Revenues Revenues	540905000	USD
CY2018Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	171589000	USD
CY2018Q1	us-gaap	Net Income Loss NetIncomeLoss	91847000	USD
CY2018Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.07
CY2018Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.06
CY2017Q4	us-gaap	Revenues Revenues	419655000	USD
CY2017Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	149469000	USD
CY2017Q4	us-gaap	Net Income Loss NetIncomeLoss	198654000	USD
CY2017Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.32
CY2017Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.30
CY2018Q4	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	-5000000.0	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	3500000	USD
CY2018Q1	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	4000000.0	USD
CY2017Q4	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	-111000000.0	USD
CY2019Q3	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	5623623000	USD
CY2018Q3	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	5114753000	USD
CY2019Q3	us-gaap	Capitalized Costs Unproved Properties CapitalizedCostsUnprovedProperties	53498000	USD
CY2018Q3	us-gaap	Capitalized Costs Unproved Properties CapitalizedCostsUnprovedProperties	62234000	USD
CY2019Q3	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	5677121000	USD
CY2018Q3	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	5176987000	USD
CY2019Q3	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	4012568000	USD
CY2018Q3	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	3862687000	USD
CY2019Q3	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	1664553000	USD
CY2018Q3	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	1314300000	USD
CY2019Q3	us-gaap	Capitalized Costs Asset Retirement Costs CapitalizedCostsAssetRetirementCosts	70500000	USD
CY2018Q3	us-gaap	Capitalized Costs Asset Retirement Costs CapitalizedCostsAssetRetirementCosts	44300000	USD
CY2019	us-gaap	Acquisition Costs AcquisitionCosts	0	USD
CY2018	us-gaap	Acquisition Costs AcquisitionCosts	0	USD
CY2017	us-gaap	Acquisition Costs AcquisitionCosts	0	USD
CY2019	us-gaap	Development Costs DevelopmentCosts	17819000	USD
CY2018	us-gaap	Development Costs DevelopmentCosts	481000	USD
CY2017	us-gaap	Development Costs DevelopmentCosts	43000	USD
CY2019	us-gaap	Exploration Costs ExplorationCosts	0	USD
CY2018	us-gaap	Exploration Costs ExplorationCosts	0	USD
CY2017	us-gaap	Exploration Costs ExplorationCosts	32000	USD
CY2019	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	41000	USD
CY2018	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	0	USD
CY2017	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	0	USD
CY2019	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortization	17860000	USD
CY2018	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortization	481000	USD
CY2017	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortization	75000	USD
CY2019	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties With Proved Reserves CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves	3136000	USD
CY2018	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties With Proved Reserves CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves	1544000	USD
CY2017	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties With Proved Reserves CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves	8908000	USD
CY2019	us-gaap	Costs Incurred Acquisition Of Unproved Oil And Gas Properties CostsIncurredAcquisitionOfUnprovedOilAndGasProperties	3679000	USD
CY2018	us-gaap	Costs Incurred Acquisition Of Unproved Oil And Gas Properties CostsIncurredAcquisitionOfUnprovedOilAndGasProperties	4286000	USD
CY2017	us-gaap	Costs Incurred Acquisition Of Unproved Oil And Gas Properties CostsIncurredAcquisitionOfUnprovedOilAndGasProperties	262000	USD
CY2019	us-gaap	Costs Incurred Exploration Costs CostsIncurredExplorationCosts	2060000	USD
CY2018	us-gaap	Costs Incurred Exploration Costs CostsIncurredExplorationCosts	29365000	USD
CY2017	us-gaap	Costs Incurred Exploration Costs CostsIncurredExplorationCosts	40975000	USD
CY2018	us-gaap	Costs Incurred Development Costs CostsIncurredDevelopmentCosts	332496000	USD
CY2018	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties CostsIncurredAcquisitionOfOilAndGasProperties	357584000	USD
CY2017	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties CostsIncurredAcquisitionOfOilAndGasProperties	241609000	USD
CY2017	us-gaap	Costs Incurred Development Costs CostsIncurredDevelopmentCosts	200639000	USD
CY2019	us-gaap	Costs Incurred Asset Retirement Obligation Incurred CostsIncurredAssetRetirementObligationIncurred	26192000	USD
CY2018	nfg	Costs Incurred Reductionin Asset Retirement Obligation Costs Incurred CostsIncurredReductioninAssetRetirementObligationCostsIncurred	10107000	USD
CY2017	nfg	Costs Incurred Reductionin Asset Retirement Obligation Costs Incurred CostsIncurredReductioninAssetRetirementObligationCostsIncurred	9175000	USD
CY2019	us-gaap	Costs Incurred Acquisition Of Oil And Gas Properties CostsIncurredAcquisitionOfOilAndGasProperties	503565000	USD
CY2019	us-gaap	Costs Incurred Development Costs CostsIncurredDevelopmentCosts	468498000	USD
CY2019	nfg	Costs Incurred Exploration Costs Capitalized Interest CostsIncurredExplorationCostsCapitalizedInterest	0	USD
CY2018	nfg	Costs Incurred Exploration Costs Capitalized Interest CostsIncurredExplorationCostsCapitalizedInterest	0	USD
CY2017	nfg	Costs Incurred Exploration Costs Capitalized Interest CostsIncurredExplorationCostsCapitalizedInterest	300000	USD
CY2019	nfg	Costs Incurred Development Costs Capitalized Interest CostsIncurredDevelopmentCostsCapitalizedInterest	200000	USD
CY2018	nfg	Costs Incurred Development Costs Capitalized Interest CostsIncurredDevelopmentCostsCapitalizedInterest	300000	USD
CY2017	nfg	Costs Incurred Development Costs Capitalized Interest CostsIncurredDevelopmentCostsCapitalizedInterest	200000	USD
CY2019	nfg	Amount Spent For Developing Proved Undeveloped Reserves AmountSpentForDevelopingProvedUndevelopedReserves	246000000.0	USD
CY2018	nfg	Amount Spent For Developing Proved Undeveloped Reserves AmountSpentForDevelopingProvedUndevelopedReserves	182300000	USD
CY2017	nfg	Amount Spent For Developing Proved Undeveloped Reserves AmountSpentForDevelopingProvedUndevelopedReserves	101100000	USD
CY2019	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	630126000	USD
CY2018	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	558896000	USD
CY2017	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	526492000	USD
CY2019	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	186626000	USD
CY2018	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	162721000	USD
CY2017	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	165991000	USD
CY2019	nfg	Results Of Operations Franchise Or Ad Valorem Taxes ResultsOfOperationsFranchiseOrAdValoremTaxes	17673000	USD
CY2018	nfg	Results Of Operations Franchise Or Ad Valorem Taxes ResultsOfOperationsFranchiseOrAdValoremTaxes	14355000	USD
CY2017	nfg	Results Of Operations Franchise Or Ad Valorem Taxes ResultsOfOperationsFranchiseOrAdValoremTaxes	15372000	USD
CY2019	nfg	Resultsof Operations Purchased Emission Allowance Expense ResultsofOperationsPurchasedEmissionAllowanceExpense	2527000	USD
CY2018	nfg	Resultsof Operations Purchased Emission Allowance Expense ResultsofOperationsPurchasedEmissionAllowanceExpense	1883000	USD
CY2017	nfg	Resultsof Operations Purchased Emission Allowance Expense ResultsofOperationsPurchasedEmissionAllowanceExpense	1391000	USD
CY2019	us-gaap	Results Of Operations Accretion Of Asset Retirement Obligations ResultsOfOperationsAccretionOfAssetRetirementObligations	3723000	USD
CY2018	us-gaap	Results Of Operations Accretion Of Asset Retirement Obligations ResultsOfOperationsAccretionOfAssetRetirementObligations	4266000	USD
CY2017	us-gaap	Results Of Operations Accretion Of Asset Retirement Obligations ResultsOfOperationsAccretionOfAssetRetirementObligations	4896000	USD
CY2019	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	149881000	USD
CY2018	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	119946000	USD
CY2017	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	108471000	USD
CY2019	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	64652000	USD
CY2018	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	72723000	USD
CY2017	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	86657000	USD
CY2019	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	205044000	USD
CY2018	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	183002000	USD
CY2017	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	143714000	USD
CY2018Q3	srt	Proved Undeveloped Reserve Volume ProvedUndevelopedReserveVolume	757000000000	ft3
CY2019Q3	srt	Proved Undeveloped Reserve Volume ProvedUndevelopedReserveVolume	1018000000000	ft3
CY2019	nfg	Proved Undeveloped Reserves As Percentage Of Total Proved Reserves ProvedUndevelopedReservesAsPercentageOfTotalProvedReserves	0.33
CY2018	nfg	Proved Undeveloped Reserves As Percentage Of Total Proved Reserves ProvedUndevelopedReservesAsPercentageOfTotalProvedReserves	0.30
CY2017Q3	srt	Proved Undeveloped Reserve Volume ProvedUndevelopedReserveVolume	612000000000	ft3
CY2018Q3	srt	Proved Undeveloped Reserve Volume ProvedUndevelopedReserveVolume	757000000000	ft3
CY2018	nfg	Proved Undeveloped Reserves As Percentage Of Total Proved Reserves ProvedUndevelopedReservesAsPercentageOfTotalProvedReserves	0.30
CY2017	nfg	Proved Undeveloped Reserves As Percentage Of Total Proved Reserves ProvedUndevelopedReservesAsPercentageOfTotalProvedReserves	0.28
CY2019Q3	nfg	Proved Undeveloped Reserves Increase ProvedUndevelopedReservesIncrease	261000000000	ft3
CY2019Q3	nfg	Proved Undeveloped Reserves Additions ProvedUndevelopedReservesAdditions	575000000000	ft3
CY2019Q3	nfg	Proved Undeveloped Reserves Upward Revisions ProvedUndevelopedReservesUpwardRevisions	38000000000	ft3
CY2019Q3	nfg	Proved Undeveloped Reserves Conversions To Developed Reserves ProvedUndevelopedReservesConversionsToDevelopedReserves	297000000000	ft3
CY2019Q3	nfg	Proved Undeveloped Reserves Removed ProvedUndevelopedReservesRemoved	55000000000	ft3
CY2019	nfg	Pud Well Locations Removed PUDWellLocationsRemoved	6
CY2018Q3	nfg	Proved Undeveloped Reserves Increase ProvedUndevelopedReservesIncrease	145000000000	ft3
CY2018Q3	nfg	Proved Undeveloped Reserves Additions ProvedUndevelopedReservesAdditions	431000000000	ft3
CY2018Q3	nfg	Proved Undeveloped Reserves Upward Revisions ProvedUndevelopedReservesUpwardRevisions	60000000000	ft3
CY2018Q3	nfg	Proved Undeveloped Reserves Conversions To Developed Reserves ProvedUndevelopedReservesConversionsToDevelopedReserves	284000000000	ft3
CY2018Q3	nfg	Proved Undeveloped Reserves Removed ProvedUndevelopedReservesRemoved	5000000000	ft3
CY2018Q3	nfg	Proved Undeveloped Reserves Sales ProvedUndevelopedReservesSales	57000000000	ft3
CY2019	nfg	Capital Expenditures Related To Proved Undeveloped Reserves CapitalExpendituresRelatedToProvedUndevelopedReserves	246000000	USD
CY2019Q3	nfg	Proved Undeveloped Reserves Conversions To Developed Reserves ProvedUndevelopedReservesConversionsToDevelopedReserves	297000000000	ft3
CY2019	nfg	Conversion Of Undeveloped Proved Reserves To Developed Proved Reserves After Revisions Volume ConversionOfUndevelopedProvedReservesToDevelopedProvedReservesAfterRevisionsVolume	380000000000	ft3
CY2019Q3	nfg	Proved Undeveloped Reserves Percentage ProvedUndevelopedReservesPercentage	0.39
CY2019	nfg	Well Locations Developed With Net Pud Reserves WellLocationsDevelopedWithNetPUDReserves	56
CY2019	nfg	Percentof Well Locations Developed With Net Pud Reserves PercentofWellLocationsDevelopedWithNetPUDReserves	0.50
CY2019	nfg	Upward Revisionsto Pud Reserves Convertedto Developed Reserves UpwardRevisionstoPUDReservesConvertedtoDevelopedReserves	83000000000	ft3
CY2018	nfg	Capital Expenditures Related To Proved Undeveloped Reserves CapitalExpendituresRelatedToProvedUndevelopedReserves	182000000	USD
CY2018Q3	nfg	Proved Undeveloped Reserves Conversions To Developed Reserves ProvedUndevelopedReservesConversionsToDevelopedReserves	284000000000	ft3
CY2018Q3	nfg	Proved Undeveloped Reserves Percentage ProvedUndevelopedReservesPercentage	0.46
CY2018Q3	nfg	Proved Undeveloped Reserves Sales ProvedUndevelopedReservesSales	57000000000	ft3
CY2018	nfg	Well Locations Developed With Net Pud Reserves WellLocationsDevelopedWithNetPUDReserves	53
CY2018	nfg	Percentof Well Locations Developed With Net Pud Reserves PercentofWellLocationsDevelopedWithNetPUDReserves	0.62
CY2015Q3	nfg	Proved Undeveloped Reserves Percentage ProvedUndevelopedReservesPercentage	0.33
CY2016Q3	nfg	Proved Undeveloped Reserves Percentage ProvedUndevelopedReservesPercentage	0.25
CY2017Q3	nfg	Proved Undeveloped Reserves Percentage ProvedUndevelopedReservesPercentage	0.27
CY2019Q3	nfg	Proved Undeveloped Reserves Percentage ProvedUndevelopedReservesPercentage	0.39
CY2019	nfg	Annual Discount For Estimated Timing Of Cash Flows AnnualDiscountForEstimatedTimingOfCashFlows	0.10
CY2019Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	8738182000	USD
CY2018Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	7822855000	USD
CY2017Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	6144317000	USD
CY2019Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	2989518000	USD
CY2018Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	2606411000	USD
CY2017Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	2378262000	USD
CY2019Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	797640000	USD
CY2018Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	559707000	USD
CY2017Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	411578000	USD
CY2019Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	1159882000	USD
CY2018Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	1125910000	USD
CY2017Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	1160469000	USD
CY2019Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	3791142000	USD
CY2018Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	3530827000	USD
CY2017Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	2194008000	USD
CY2019Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	2054823000	USD
CY2018Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	1810522000	USD
CY2017Q3	srt	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	1080962000	USD
CY2019Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1736319000	USD
CY2018Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1720305000	USD
CY2017Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1113046000	USD
CY2018Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1720305000	USD
CY2017Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1113046000	USD
CY2016Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	642528000	USD
CY2019	srt	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	-425773000	USD
CY2018	srt	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	-381775000	USD
CY2017	srt	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	-345075000	USD
CY2019	srt	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	-164428000	USD
CY2018	srt	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	541021000	USD
CY2017	srt	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	828187000	USD
CY2019	srt	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	202683000	USD
CY2018	srt	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	212494000	USD
CY2017	srt	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	170500000	USD
CY2019	srt	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	-69254000	USD
CY2018	srt	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	-43771000	USD
CY2017	srt	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	8816000	USD
CY2019	srt	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	0	USD
CY2018	srt	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	100816000	USD
CY2017	srt	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	9849000	USD
CY2019	srt	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	245964000	USD
CY2018	srt	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	182348000	USD
CY2017	srt	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	101134000	USD
CY2019	srt	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	21370000	USD
CY2018	srt	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	55558000	USD
CY2017	srt	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	-393353000	USD
CY2019	srt	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	53777000	USD
CY2018	srt	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	61363000	USD
CY2017	srt	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	39078000	USD
CY2019	srt	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	151675000	USD
CY2018	srt	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	80837000	USD
CY2017	srt	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	71080000	USD
CY2019Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1736319000	USD
CY2018Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1720305000	USD
CY2017Q3	srt	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	1113046000	USD
CY2019	nfg	Reversalof Estimate For Potential Sequestrationof Amt Credit Refunds Under2017 Tax Reform Ac ReversalofEstimateForPotentialSequestrationofAMTCreditRefundsUnder2017TaxReformAc	5000000.0	USD

Files In Submission

Name	View Source	Status
0000070145-19-000030-index-headers.html	Edgar Link	pending
0000070145-19-000030-index.html	Edgar Link	pending
0000070145-19-000030.txt	Edgar Link	pending
0000070145-19-000030-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
nfg-2016930_chartx09631a05.jpg	Edgar Link	pending
nfg-20190930.xsd	Edgar Link	pending
nfg-20190930_cal.xml	Edgar Link	unprocessable
nfg-20190930_def.xml	Edgar Link	unprocessable
nfg-20190930_lab.xml	Edgar Link	unprocessable
nfg-20190930_pre.xml	Edgar Link	unprocessable
nfg-2019930x10k.htm	Edgar Link	pending
nfg-2019930x10k_htm.xml	Edgar Link	completed
nfg-9302019xexhibit21.htm	Edgar Link	pending
nfg-9302019xexhibit231.htm	Edgar Link	pending
nfg-9302019xexhibit232.htm	Edgar Link	pending
nfg-9302019xexhibit311.htm	Edgar Link	pending
nfg-9302019xexhibit312.htm	Edgar Link	pending
nfg-9302019xexhibit32.htm	Edgar Link	pending
nfg-9302019xexhibit41.htm	Edgar Link	pending
nfg-9302019xexhibit991.htm	Edgar Link	pending
nfg93019exhibit992.htm	Edgar Link	pending
nfg93019exhibit992001.jpg	Edgar Link	pending
nfg93019exhibit992002.jpg	Edgar Link	pending
nfg93019exhibit992003.jpg	Edgar Link	pending
nfg93019exhibit992004.jpg	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R75.htm	Edgar Link	pending
R76.htm	Edgar Link	pending
R77.htm	Edgar Link	pending
R78.htm	Edgar Link	pending
R79.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R80.htm	Edgar Link	pending
R81.htm	Edgar Link	pending
R82.htm	Edgar Link	pending
R83.htm	Edgar Link	pending
R84.htm	Edgar Link	pending
R85.htm	Edgar Link	pending
R86.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$NFG
NATIONAL FUEL GAS CO Stock $nfg

2019 Form 10-K Financial Statement

#000007014519000030 Filed on November 15, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NFG NATIONAL FUEL GAS CO Stock $nfg

2019 Form 10-K Financial Statement

#000007014519000030 Filed on November 15, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NFG
NATIONAL FUEL GAS CO Stock $nfg