Segment Reporting - Reportable Segments Financial Data (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Fund level fee revenues
Investment income (loss)	$ 1,965.2	$ (1,190.9)
Interest income	20.4	27.4
Total revenues	2,437.2	(745.7)
Compensation and benefits
Cash-based compensation and benefits	228.5	204.3
Realized performance revenues related compensation	866.6	(442.5)
Total compensation and benefits	1,127.5	(209.1)
General, administrative and other expenses	91.7	69.6
Interest	23.0	23.9
Total expenses	1,285.2	(69.8)
Realized net performance revenues	919.5	(495.1)
Consolidated VIEs, assets	16,975.3		$ 15,644.8
Total Reportable Segments
Fund level fee revenues
Total fund level fee revenues	411.9	388.3
Interest income	2.2	5.3
Total revenues	612.5	581.1
Compensation and benefits
Cash-based compensation and benefits	212.2	203.8
Realized performance revenues related compensation	92.4	123.4
Total compensation and benefits	304.6	327.2
General, administrative and other expenses	61.6	48.3
Depreciation and amortization expense	9.1	7.4
Interest	22.3	23.2
Total expenses	397.6	406.1
Distributable Earnings	214.9	175.0
Realized net performance revenues	76.0	48.2
Realized principal investment income (loss)	30.0	15.9
Net interest	20.1	17.9
Fee Related Earnings	129.0	128.8
Consolidated VIEs, assets	10,986.5
Total Reportable Segments | Global Private Equity
Fund level fee revenues
Total fund level fee revenues	270.8	272.9
Interest income	0.2	1.8
Total revenues	428.8	350.1
Compensation and benefits
Cash-based compensation and benefits	129.1	129.7
Realized performance revenues related compensation	60.2	29.7
Total compensation and benefits	189.3	159.4
General, administrative and other expenses	41.4	37.2
Depreciation and amortization expense	6.1	4.8
Interest	13.8	13.9
Total expenses	250.6	215.3
Distributable Earnings	178.2	134.8
Realized net performance revenues	73.9	35.5
Realized principal investment income (loss)	23.7	10.2
Net interest	13.6	12.1
Fee Related Earnings	94.2	101.2
Consolidated VIEs, assets	7,768.5
Total Reportable Segments | Global Credit
Fund level fee revenues
Total fund level fee revenues	88.8	75.6
Interest income	2.0	3.1
Total revenues	96.8	104.8
Compensation and benefits
Cash-based compensation and benefits	53.7	49.1
Realized performance revenues related compensation	0.0	9.7
Total compensation and benefits	53.7	58.8
General, administrative and other expenses	11.8	5.6
Depreciation and amortization expense	1.9	1.6
Interest	6.3	7.0
Total expenses	73.7	73.0
Distributable Earnings	23.1	31.8
Realized net performance revenues	0.1	11.3
Realized principal investment income (loss)	5.9	5.1
Net interest	4.3	3.9
Fee Related Earnings	21.4	19.3
Consolidated VIEs, assets	1,861.5
Total Reportable Segments | Investment Solutions
Fund level fee revenues
Total fund level fee revenues	52.3	39.8
Interest income	0.0	0.4
Total revenues	86.9	126.2
Compensation and benefits
Cash-based compensation and benefits	29.4	25.0
Realized performance revenues related compensation	32.2	84.0
Total compensation and benefits	61.6	109.0
General, administrative and other expenses	8.4	5.5
Depreciation and amortization expense	1.1	1.0
Interest	2.2	2.3
Total expenses	73.3	117.8
Distributable Earnings	13.6	8.4
Realized net performance revenues	2.0	1.4
Realized principal investment income (loss)	0.4	0.6
Net interest	2.2	1.9
Fee Related Earnings	13.4	8.3
Consolidated VIEs, assets	1,356.5
Fund management fees
Fund level fee revenues
Total fund level fee revenues	381.0	355.9
Fund management fees | Total Reportable Segments
Fund level fee revenues
Total fund level fee revenues	392.2	381.5
Fund management fees | Total Reportable Segments | Global Private Equity
Fund level fee revenues
Total fund level fee revenues	260.2	268.7
Fund management fees | Total Reportable Segments | Global Credit
Fund level fee revenues
Total fund level fee revenues	80.0	73.0
Fund management fees | Total Reportable Segments | Investment Solutions
Fund level fee revenues
Total fund level fee revenues	52.0	39.8
Portfolio advisory and transaction fees, net and other | Total Reportable Segments
Fund level fee revenues
Total fund level fee revenues	19.7	6.8
Portfolio advisory and transaction fees, net and other | Total Reportable Segments | Global Private Equity
Fund level fee revenues
Total fund level fee revenues	10.6	4.2
Portfolio advisory and transaction fees, net and other | Total Reportable Segments | Global Credit
Fund level fee revenues
Total fund level fee revenues	8.8	2.6
Portfolio advisory and transaction fees, net and other | Total Reportable Segments | Investment Solutions
Fund level fee revenues
Total fund level fee revenues	0.3	0.0
Performance allocations
Fund level fee revenues
Investment income (loss)	1,786.1	(937.6)
Performance allocations | Total Reportable Segments
Fund level fee revenues
Investment income (loss)	168.4	171.6
Performance allocations | Total Reportable Segments | Global Private Equity
Fund level fee revenues
Investment income (loss)	134.1	65.2
Performance allocations | Total Reportable Segments | Global Credit
Fund level fee revenues
Investment income (loss)	0.1	21.0
Performance allocations | Total Reportable Segments | Investment Solutions
Fund level fee revenues
Investment income (loss)	34.2	85.4
Principal investment income (loss)
Fund level fee revenues
Investment income (loss)	179.1	(253.3)
Principal investment income (loss) | Total Reportable Segments
Fund level fee revenues
Investment income (loss)	30.0	15.9
Principal investment income (loss) | Total Reportable Segments | Global Private Equity
Fund level fee revenues
Investment income (loss)	23.7	10.2
Principal investment income (loss) | Total Reportable Segments | Global Credit
Fund level fee revenues
Investment income (loss)	5.9	5.1
Principal investment income (loss) | Total Reportable Segments | Investment Solutions
Fund level fee revenues
Investment income (loss)	$ 0.4	$ 0.6