Risk Management Activities (Narrative) (Details) mMDth in Millions, $ in Millions	9 Months Ended
Sep. 30, 2023 USD ($) mMDth	Dec. 31, 2022 USD ($) mMDth
Derivative [Line Items]
Limit of GCA Volumes	20.00%
Derivative Asset, Subject to Master Netting Arrangement, after Offset \| $	$ 35.2	$ 81.8
Minimum
Derivative [Line Items]
Commodity Contract Length	1 year
Maximum
Derivative [Line Items]
Commodity Contract Length	4 years
Natural Gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| mMDth	85.2	99.0
Interest Rate Risk
Derivative [Line Items]
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge	344 months

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Fair value, after effect of master netting arrangement, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and contract can be net settled by means outside contract or delivery of asset. Includes derivative subject to master netting arrangement not elected or qualified to offset. Excludes derivative not subject to master netting arrangement or similar agreement.

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Nominal number of units used to calculate payment on derivative.

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Maximum period the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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