Investments - Investments in unconsolidated entities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	$ 361.9	$ 377.2
Equity method eligible unconsolidated entities, using the fair value option
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	146.4	147.9
Equity method investments
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	45.2	41.8
Other unconsolidated investments, at fair value
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	120.5	124.5
Other Unconsolidated Investments, at cost
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	$ 49.8	$ 63.0