Non-controlling Interests (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Total non-controlling interests	$ 127.2	$ 156.6
Total Non-Controlling Excluding Reciprocals
Noncontrolling Interest [Line Items]
Total non-controlling interests	$ 274.7	$ 280.6
HG Global
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	3.10%	3.10%
Total non-controlling interests	$ 5.4	$ 8.9
Ark
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	28.00%	28.00%
Total non-controlling interests	$ 224.1	$ 230.7
NSM Insurance Group [Member]
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	3.50%	3.50%
Total non-controlling interests	$ 16.7	$ 16.7
Asset Management (Kudu)
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	0.90%	0.70%
Total non-controlling interests	$ 17.3	$ 12.4
Other
Noncontrolling Interest [Line Items]
Total non-controlling interests	$ 11.2	$ 11.9
BAM
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	100.00%	100.00%
Total non-controlling interests	$ (147.5)	$ (124.0)