Derivative Instruments Credit Rating - USD ($)	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Collateral Posted with NW Natural Counterparties [Member]
Derivative [Line Items]
Additional Collateral, Aggregate Fair Value	$ 0		$ 0
Northwest Natural Gas Company [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	8,400,000	$ 153,300,000	47,800,000
Derivative liability	$ 61,200,000	$ 3,600,000	$ 3,400,000

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.

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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.

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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.

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