Investments in Real Estate Funds - Schedule of carrying amount and maximum exposure to loss relating to VIEs (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
Carrying Amount	$ 29,526.8	$ 33,033.6
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Carrying Amount	892.7
Maximum Exposure to Loss	$ 1,153.7
Variable Interest Entity, Not Primary Beneficiary | LCS SHIP Venture I, LLC
Variable Interest Entity [Line Items]
Account Interest	90.00%
Carrying Amount	$ 221.3
Maximum Exposure to Loss	$ 221.3
Variable Interest Entity, Not Primary Beneficiary | Veritas Trophy VI, LLC
Variable Interest Entity [Line Items]
Account Interest	90.40%
Carrying Amount	$ 67.8
Maximum Exposure to Loss	$ 80.3
Variable Interest Entity, Not Primary Beneficiary | SP V - II, LLC
Variable Interest Entity [Line Items]
Account Interest	61.80%
Carrying Amount	$ 106.0
Maximum Exposure to Loss	$ 115.6
Variable Interest Entity, Not Primary Beneficiary | Taconic New York City GP Fund, LP
Variable Interest Entity [Line Items]
Account Interest	60.00%
Carrying Amount	$ 24.9
Maximum Exposure to Loss	$ 24.9
Variable Interest Entity, Not Primary Beneficiary | Silverpeak NRE FundCo LLC
Variable Interest Entity [Line Items]
Account Interest	90.00%
Carrying Amount	$ 44.9
Maximum Exposure to Loss	$ 71.0
Variable Interest Entity, Not Primary Beneficiary | IDR - Core Property Index Fund, LLC
Variable Interest Entity [Line Items]
Account Interest	1.10%
Carrying Amount	$ 41.0
Maximum Exposure to Loss	$ 41.0
Variable Interest Entity, Not Primary Beneficiary | Townsend Group Value-Add Fund
Variable Interest Entity [Line Items]
Account Interest	99.00%
Carrying Amount	$ 180.7
Maximum Exposure to Loss	$ 259.7
Variable Interest Entity, Not Primary Beneficiary | Flagler - REA Healthcare Properties Partnership
Variable Interest Entity [Line Items]
Account Interest	90.00%
Carrying Amount	$ 20.5
Maximum Exposure to Loss	$ 20.5
Variable Interest Entity, Not Primary Beneficiary | Grubb Southeast Real Estate Fund VI, LLC
Variable Interest Entity [Line Items]
Account Interest	66.70%
Carrying Amount	$ 18.5
Maximum Exposure to Loss	$ 18.5
Variable Interest Entity, Not Primary Beneficiary | Silverpeak NRE FundCo 2 LLC
Variable Interest Entity [Line Items]
Account Interest	90.00%
Carrying Amount	$ 58.4
Maximum Exposure to Loss	$ 99.0
Variable Interest Entity, Not Primary Beneficiary | JCR Capital - REA Preferred Equity Parallel Fund
Variable Interest Entity [Line Items]
Account Interest	31.10%
Carrying Amount	$ 61.5
Maximum Exposure to Loss	$ 103.2
Variable Interest Entity, Not Primary Beneficiary | Silverpeak NRE FundCo 3 LLC
Variable Interest Entity [Line Items]
Account Interest	90.00%
Carrying Amount	$ 47.2
Maximum Exposure to Loss	$ 98.7