Debt - Junior Convertible Securities (Details) $ / shares in Units, $ in Millions	6 Months Ended
Jun. 30, 2024 USD ($) d $ / shares	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Debt	$ 2,525.2	$ 2,537.5
Junior convertible securities
Debt Instrument [Line Items]
Debt	339.0	338.9
Junior Convertible Trust Preferred Securities \| Junior convertible securities
Debt Instrument [Line Items]
Debt	$ 341.7
Debt interest rate	5.15%
Unamortized debt issuance costs	$ 2.8	$ 2.9
Conversion ratio per share of common stock	0.2558
Face amount of convertible security (in dollars per share) \| $ / shares	$ 50.00
Adjusted conversion price (in dollars per share) \| $ / shares	$ 195.47
Convertible debt, threshold trading days \| d	20
Convertible debt, threshold consecutive trading days \| d	30
Debt instrument, convertible, threshold percentage	1.30

Debt Instrument, Convertible, Threshold Percentage

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Debt Instrument, Individual Security, Face Amount

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

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

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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.

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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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