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- Definition

Target Hedge Achieved

+ References

No definition available.

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- Definition

Amount, after tax, of accumulated gain (loss) on derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

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- Definition

Amount of credit risk valuation adjustment to derivative liabilities to properly reflect the credit quality of the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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-Section 35
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- Definition

Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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- Definition

Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

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- Definition

Fixed interest rate related to the interest rate derivative.

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- Definition

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

+ References

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- Definition

Amount of decrease in the fair value of derivatives recognized in the income statement.

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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- Definition

Amount, after tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

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Derivative Instruments - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
Derivative Instruments - Narrative (Details) - USD ($)	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025	Jan. 31, 2023
Derivative [Line Items]
Derivative, loss on derivative		$ 11,600,000		$ 57,800,000
Derivative credit risk valuation adjustment, derivative liabilities	$ 200,000		$ 200,000
Derivative, fair value, net	(46,300,000)	(22,600,000)	(46,300,000)	(22,600,000)	$ (73,300,000)
Long-term debt	2,502,400,000		2,502,400,000
AOCI, cash flow hedge, cumulative gain (Loss), after tax	0	0	0	0	0
Reclassification out of Accumulated Other Comprehensive Income
Derivative [Line Items]
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, after tax	0	100,000	0	100,000
NWN Water Term Loan Due 2026
Derivative [Line Items]
Derivative, fixed interest rate						3.80%
Corporate Nonsegment \| NWN Water Term Loan Due 2026 \| NWN Water Utility
Derivative [Line Items]
Long-term debt						$ 55,000,000.0
Collateral Posted with NW Natural Counterparties
Derivative [Line Items]
Additional collateral, aggregate fair value	0	0	0	0
Financial
Derivative [Line Items]
Incremental cost or benefit to collect or refund to customers			0
NW Natural
Derivative [Line Items]
Derivative, loss on derivative	17,100,000		58,600,000
Derivative asset, fair value, amount not off set against collateral	4,000,000.0	5,000,000.0	4,000,000.0	5,000,000.0	2,800,000
Derivative liability	50,300,000	27,600,000	50,300,000	27,600,000	76,100,000
Long-term debt	$ 1,535,300,000	$ 1,365,700,000	$ 1,535,300,000	$ 1,365,700,000	$ 1,534,900,000
Gas Year 2025 - 2026 \| NW Natural
Derivative [Line Items]
Target hedge achieved	79.00%		79.00%
Gas Year 2025 - 2026 \| NW Natural \| Oregon
Derivative [Line Items]
Target hedge achieved	84.00%		84.00%
Gas Year 2025 - 2026 \| NW Natural \| WASHINGTON
Derivative [Line Items]
Target hedge achieved	33.00%		33.00%
Gas Year 2025 - 2026 \| NW Natural \| Financial
Derivative [Line Items]
Target hedge achieved	64.00%		64.00%
Gas Year 2025 - 2026 \| NW Natural \| Financial \| Oregon
Derivative [Line Items]
Target hedge achieved	69.00%		69.00%
Gas Year 2025 - 2026 \| NW Natural \| Financial \| WASHINGTON
Derivative [Line Items]
Target hedge achieved	20.00%		20.00%
Gas Year 2025 - 2026 \| NW Natural \| Physical
Derivative [Line Items]
Target hedge achieved	15.00%		15.00%
Gas Year 2025 - 2026 \| NW Natural \| Physical \| Oregon
Derivative [Line Items]
Target hedge achieved	15.00%		15.00%
Gas Year 2025 - 2026 \| NW Natural \| Physical \| WASHINGTON
Derivative [Line Items]
Target hedge achieved	13.00%		13.00%