Common Shareholders’ Equity and Noncontrolling Interests - Noncontrolling Interests (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Noncontrolling Interest [Line Items]
Noncontrolling Equity	$ 647.3	$ 321.1
Ark
Noncontrolling Interest [Line Items]
Noncontrolling Equity	410.4	336.9
HG Global
Noncontrolling Interest [Line Items]
Noncontrolling Equity	(13.4)	0.8
Kudu
Noncontrolling Interest [Line Items]
Noncontrolling Equity	127.6	113.8
Bamboo
Noncontrolling Interest [Line Items]
Noncontrolling Equity	113.6	0.0
Other
Noncontrolling Interest [Line Items]
Noncontrolling Equity	9.1	9.4
Total, excluding BAM
Noncontrolling Interest [Line Items]
Noncontrolling Equity	647.3	460.9
BAM
Noncontrolling Interest [Line Items]
Noncontrolling Equity	0.0	(139.8)
Ark - Management Equity Incentive
Noncontrolling Interest [Line Items]
Noncontrolling Equity	42.9	21.0
Kudu - Management Equity Incentive
Noncontrolling Interest [Line Items]
Noncontrolling Equity	$ 47.9	$ 38.7
Ark
Noncontrolling Interest [Line Items]
Noncontrolling Percentage	27.90%	28.00%
HG Global
Noncontrolling Interest [Line Items]
Noncontrolling Percentage	3.10%	3.10%
Kudu
Noncontrolling Interest [Line Items]
Noncontrolling Percentage	9.60%	10.50%
Bamboo
Noncontrolling Interest [Line Items]
Noncontrolling Percentage	27.20%	0.00%
BAM
Noncontrolling Interest [Line Items]
Noncontrolling Percentage	100.00%	100.00%