Investments - Principal Investments (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total	$ 3,179.3	$ 3,024.1
Global Private Equity
Segment Reporting Information [Line Items]
Total	1,828.6	1,798.3
Global Private Equity | NGP Management
Segment Reporting Information [Line Items]
Total	909.8	916.2
Global Credit
Segment Reporting Information [Line Items]
Total	1,097.0	987.4
Global Credit | Fortitude Group Holdings, LLC
Segment Reporting Information [Line Items]
Total	720.3	595.4
Global Investment Solutions
Segment Reporting Information [Line Items]
Total	$ 253.7	$ 238.4