Investments (Details) $ in Millions	3 Months Ended
Mar. 31, 2025 USD ($) investment	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of separate property or fund co-investments \| investment	50
Investments	$ 902.4		$ 812.7
Fair Value [Abstract]
Fair value investments at beginning of the period	742.0	$ 740.8
Investments in Real Estate Ventures, at Fair Value, Additions	115.7	15.6
Investments in Real Estate Ventures, at Fair Value, Distributions	(6.0)	(6.4)
Unrealized Gain (Loss) on Investments	(27.7)	(3.1)
Investments in Real Estate Ventures, at Fair Value, Foreign Currency Translation	7.4	(6.3)
Investments previously accounted at cost that are now being accounted for at Net Asset value	24.6
Fair value investments at end of the period	856.0	743.8
Equity Investments accounted for under the measurement alternative	9.9
Fair Value, Inputs, Level 3 [Member] \| Fair Value, Recurring [Member]
Fair Value [Abstract]
Fair value investments at beginning of the period	330.3	367.3
Fair value investments at end of the period	311.0	369.7
Fair Value, Inputs, Level 3 [Member] \| Fair Value, Recurring [Member] \| Investments [Member]
Fair Value [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0.0	$ 3.2
Software and Technology Solutions
Schedule of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	8.8
Investments	352.9		372.8
Investment Management
Schedule of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	192.2
Investments	514.5		406.1
Other Investments and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures
Schedule of Equity Method Investments [Line Items]
Investments	$ 35.0		$ 33.8

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