Commitments and Contingencies - Additional Information (Details) £ in Thousands, € in Millions				1 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended		31 Months Ended
	Apr. 02, 2020 GBP (£)	Sep. 03, 2019 USD ($)	Jul. 07, 2010 USD ($)	Apr. 30, 2015 EUR (€)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 numberOfOffices	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) numberOfObligations	Dec. 31, 2018 USD ($)	Mar. 31, 2020 GBP (£)	Jul. 31, 2019 EUR (€)	Dec. 31, 2017 USD ($) vehicle
Guarantor Obligations [Line Items]
Liability for potential repayment of previously received performance fees					$ 17,500,000				$ 17,500,000		$ 22,200,000
Unbilled receivable for giveback obligations from current and former employees					0				0		1,400,000
Amount of accrued giveback obligation of various current and former senior Carlyle professionals and other limited partners of Carlyle Holdings partnerships					9,400,000				9,400,000
Amount of net accrued giveback obligation attributable to Carlyle Holdings					$ 8,100,000				$ 8,100,000
Amount paid to satisfy giveback obligations											$ 41,300,000
Number of giveback obligations satisfied | numberOfObligations											2
Options to extend (up to)					5 years				5 years
Options to terminate (within)									1 year
Lease transfer expense							$ 63,500,000
Lease not yet commenced, term					15 years				15 years
Lease incentive payable					$ 3,500,000				$ 3,500,000
Maximum amount of potential damages according to the liquidator’s expert report (more than)			$ 1,000,000,000.0
Amount received from the plaintiff | £													£ 23,300
Settlement funds deposited as security | £	£ 850
Gain on settlement									29,900,000
Investment income (loss)					584,100,000	$ 324,600,000			72,400,000	$ 1,565,100,000
Number of structured finance vehicles invested In petroleum commodities believed stolen | vehicle															2
Loss contingency accrual					$ 35,000,000				$ 35,000,000
Vermillion Legal Matter
Guarantor Obligations [Line Items]
Amount of investment in petroleum commodities believed stolen															$ 400,000,000
Alleged Misappropriation of Investments in Petroleum Commodities
Guarantor Obligations [Line Items]
Estimated insurance recoveries							$ 55,000,000					$ 55,000,000
Insurance proceeds												$ 32,000,000
Guaranteed employee loans
Guarantor Obligations [Line Items]
Guaranteed loans, aggregate program limit		$ 100,000,000.0
Guaranteed loans, initial period		1 year
Guaranteed loans, floor interest rate		3.50%
Guaranteed loans, interest rate at period end					2.25%				2.25%
Guaranteed loans, floor interest rate at period end					2.74%				2.74%
Guarantor obligations, current carrying value					$ 13,000,000.0				$ 13,000,000.0
Guaranteed employee credit facility
Guarantor Obligations [Line Items]
Guaranteed loans, aggregate program limit					700,000				700,000
Guarantor obligations, current carrying value					30,600,000				30,600,000
Contingent Obligations (Giveback)
Guarantor Obligations [Line Items]
Cash withheld from carried interest distributions for potential giveback obligations					172,800,000				172,800,000		$ 164,400,000
Amount of realized and distributed carried interest subject to potential giveback on after-tax basis					$ 400,000,000				$ 400,000,000
Ministry of the Economy, Finance and Industry, France
Guarantor Obligations [Line Items]
Maximum amount of potential damages according to the liquidator’s expert report (more than) | €				€ 105.0
Payments for legal settlements | €				75.0
Carlyle Holdings
Guarantor Obligations [Line Items]
Amount paid to satisfy giveback obligations											19,200,000
CEREP I | Ministry of the Economy, Finance and Industry, France
Guarantor Obligations [Line Items]
Payments for legal settlements | €				€ 30.0
Minimum
Guarantor Obligations [Line Items]
Term of lease					1 year				1 year
Maximum
Guarantor Obligations [Line Items]
Term of lease					15 years				15 years
Final | Ministry of the Economy, Finance and Industry, France
Guarantor Obligations [Line Items]
Refund adjustment from settlement with taxing authority | €														€ 37.1
Investment income (loss)											71,500,000
Final | Partnership And CEREP I | Ministry of the Economy, Finance and Industry, France
Guarantor Obligations [Line Items]
Refund adjustment from settlement with taxing authority | €														€ 80.5
WSJ Prime Rate | Guaranteed employee loans
Guarantor Obligations [Line Items]
Guaranteed loans, plus (minus) spread on interest rate		(1.00%)
12MAT Index | Guaranteed employee loans
Guarantor Obligations [Line Items]
Guaranteed loans, plus (minus) spread on interest rate		2.00%
Current and former senior Carlyle professionals
Guarantor Obligations [Line Items]
Amount paid to satisfy giveback obligations											22,100,000
Current and former senior Carlyle professionals | Contingent Obligations (Giveback)
Guarantor Obligations [Line Items]
Amount of realized and distributed carried interest subject to potential giveback on after-tax basis					$ 200,000,000				$ 200,000,000
Real Assets
Guarantor Obligations [Line Items]
Liability for potential repayment of previously received performance fees					16,900,000				16,900,000		17,200,000
Real Assets | Guaranteed revolving credit facility
Guarantor Obligations [Line Items]
Guaranteed loans, aggregate program limit					$ 83,500,000				$ 83,500,000		$ 130,000,000.0
Forecast
Guarantor Obligations [Line Items]
Number of offices relocated | numberOfOffices								1