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Risk Management and Derivatives: Utilities (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) MMBTU mW	Dec. 31, 2020 mW MMBTU
Natural gas over-the-counter swaps, net
Derivative [Line Items]
Credit Risk Derivative Liabilities, at Fair Value | $	$ 1.4
Natural Gas, Distribution | Cash Flow Hedging
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	442,900
Natural Gas, Distribution | Natural gas futures purchased
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	620,000
Derivative, Remaining Maturity	0 months	3 months
Natural Gas, Distribution | Natural gas options purchased, net
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	3,160,000
Derivative, Remaining Maturity	0 months	3 months
Natural Gas, Distribution | Natural gas basis swaps purchased
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	900,000
Derivative, Remaining Maturity	0 months	3 months
Natural Gas, Distribution | Natural gas over-the-counter swaps, net
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	3,590,000	3,850,000
Derivative, Remaining Maturity	29 months	17 months
Natural Gas, Distribution | Natural gas physical contracts, net
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	3,107,817	17,513,061
Derivative, Remaining Maturity	12 months	22 months
Electricity | Electric wholesale contracts
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | mW	183,025	219,000
Derivative, Remaining Maturity	9 months	12 months

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-Topic 815
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-Topic 815
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