Debt and Credit Facility - Summary of Senior Notes (Details) - Senior Notes - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Total debt	$ 1,050.0	$ 1,050.0
Unamortized issuance costs	(7.6)	(8.4)
Total carrying amount	$ 1,042.4	1,041.6
4.50% Senior Notes
Debt Instrument [Line Items]
Issuance Date	May 31, 2021
Debt Instrument, Maturity Date	Jun. 30, 2031
Effective interest rate (percent)	4.70%
Total debt	$ 550.0	550.0
4.625% Senior Notes
Debt Instrument [Line Items]
Issuance Date	Nov. 30, 2019
Debt Instrument, Maturity Date	Mar. 31, 2028
Effective interest rate (percent)	4.80%
Total debt	$ 500.0	$ 500.0

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

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Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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