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Operations and Significant Accounting Policies - Concentration of Credit Risk (Details) - Customer Concentration Risk [Member] - Large Power Customers [Member] $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) Customers	Dec. 31, 2020 USD ($) Customers	Dec. 31, 2019 Customers
Concentration Risk [Line Items]
Number of Large Power Customers	8	9	9
Receivables from Large Power Customers | $	$ 7.8	$ 10.3
Number of entities	2
Largest Customer [Member] | Consolidated Operating Revenue [Member]
Concentration Risk [Line Items]
Percent of Operating Revenue	28.00%	25.00%	12.00%
Largest Customer [Member] | Consolidated Operating Revenue [Member] | Regulated Operations [Member]
Concentration Risk [Line Items]
Percent of Operating Revenue	32.00%	29.00%	14.00%

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Number of Customers

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Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

+ References

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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