Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 582.8		$ 582.8		$ 494.0
Income (loss) from equity method investments	4.2	$ (7.1)	(0.4)	$ (36.1)
Hagerty, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 235.4		$ 235.4		$ 245.1
Equity method investment, ownership percentage	23.00%		23.00%		23.00%
Equity method investment, quoted market value	$ 637.3		$ 637.3		$ 656.0

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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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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