Other Income, Net (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest and investment income	$ (82.0)	$ (100.9)	$ (58.1)
Realized Investment Gains (Losses)	(6.7)	(0.7)	(2.3)
Equity Method Investment, Other-than-Temporary Impairment	0.0	0.0	11.9
Financing Receivable, Allowance for Credit Loss, Writeoff	0.0	0.0	7.5
Gain on divestiture of division	0.0	0.0	(1.4)
Escrow Deposit Disbursements Related to Property Acquisition	0.0	(2.5)	0.0
Other Nonoperating Income	(1.6)	(2.4)	(2.3)
Other Nonoperating Income (Expense)	$ (90.3)	$ (106.5)	$ (44.7)

Amount of other-than-temporary decline in value that has been recognized against investment accounted for under equity method of accounting.

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Amount of escrow deposit disbursements related to property acquisition in noncash investing or financing transactions.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities.

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