Debt - First Mortgage Bonds (Details) - Subsequent Event $ in Thousands	Apr. 12, 2022 USD ($)
Debt
Repayments of commercial paper	$ 493,405
Mortgage Bonds \| Series 2022A First Mortgage Bonds
Debt
Debt instrument, face amount	$ 500,000
Interest rate	4.50%

Face (par) amount of debt instrument at time of issuance.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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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

No definition available.

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- Definition

The cash outflow due to repaying amounts borrowed by issuing commercial paper.

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