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Common Shareholders’ Equity and Noncontrolling Interests - Noncontrolling Interests (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | $ 321.1 | $ 188.1
HG Global |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | 0.8 | (0.6)
Ark |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | 336.9 | 247.9
Subsidiary - Kudu Investment Management, LLC |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | 113.8 | 75.1
Other |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | 9.4 | 20.4
Total, excluding BAM |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | 460.9 | 342.8
Variable Interest Entity, Primary Beneficiary |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Equity | $ (139.8) | $ (154.7)
HG Global |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Percentage | 3.10% | 3.10%
Ark |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Percentage | 28.00% | 28.00%
Subsidiary - Kudu Investment Management, LLC |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Percentage | 10.50% | 10.80%
Build America Mutual Assurance Company |  |
Noncontrolling Interest [Line Items] |  |
Noncontrolling Percentage | 100.00% | 100.00%

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