Non-controlling Interests (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Total non-controlling interests	$ 158.3	$ 156.6
Total Non-Controlling Excluding Reciprocals
Noncontrolling Interest [Line Items]
Total non-controlling interests	$ 318.4	$ 280.6
HG Global
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	3.10%	3.10%
Total non-controlling interests	$ (0.3)	$ 8.9
Ark
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	28.00%	28.00%
Total non-controlling interests	$ 217.1	$ 230.7
Asset Management (Kudu)
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	10.70%	0.70%
Total non-controlling interests	$ 80.8	$ 12.4
NSM Insurance Group
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	0.00%	3.50%
Total non-controlling interests	$ 0.0	$ 16.7
Other
Noncontrolling Interest [Line Items]
Total non-controlling interests	$ 20.8	$ 11.9
BAM
Noncontrolling Interest [Line Items]
Noncontrolling equity percentage	100.00%	100.00%
Total non-controlling interests	$ (160.1)	$ (124.0)