Investments - Summary of Transactions with Affiliates (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Amounts due from affiliates	$ 16.2	$ 8.4
Amounts due to affiliates	4.1	0.5
BRI
Related Party Transaction [Line Items]
Amounts due from affiliates	3.3	6.0
Amounts due to affiliates	0.4	0.0
BDL
Related Party Transaction [Line Items]
Amounts due from affiliates	6.2	2.1
Amounts due to affiliates	3.1	0.0
Other
Related Party Transaction [Line Items]
Amounts due from affiliates	6.7	0.3
Amounts due to affiliates	$ 0.6	$ 0.5