v3.24.1.u1
Consolidated Investment Products - Schedule of Valuation Techniques and Significant Unobservable Inputs used in Level 3 Fair Value Measurements (Details)
$ in Millions
Mar. 31, 2024
USD ($)
$ / shares
Sep. 30, 2023
USD ($)
$ / shares
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value $ 899.7 $ 872.8
CIPs [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value 11,149.1 9,637.2
Fair Value, Recurring [Member] | CIPs [Member] | Equity and debt securities [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value 1,924.7 1,592.4
Fair Value, Recurring [Member] | CIPs [Member] | Loans [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value 9,224.4 8,044.8
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value 591.0 584.9
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value $ 298.3 $ 346.0
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member] | Private sale pricing [Member] | Minimum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input | $ / shares 0.37 0.01
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member] | Private sale pricing [Member] | Maximum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input | $ / shares 1,000 1,000
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member] | Private sale pricing [Member] | Weighted Average [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input | $ / shares [1] 60.33 23.88
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member] | Measurement Input, Discount for lack of liquidity | Minimum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 0.188  
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member] | Measurement Input, Discount for lack of liquidity | Maximum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 0.245  
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market pricing [Member] | Measurement Input, Discount for lack of liquidity | Weighted Average [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 0.222 0.219
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value $ 248.7 $ 238.9
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | EBITDA multiple [Member] | Minimum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 1.5 11.4
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | EBITDA multiple [Member] | Maximum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 22.4 13.5
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | EBITDA multiple [Member] | Weighted Average [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 15.1 12.1 [1]
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | Discount for lack of marketability [Member] | Minimum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 0.074 0.112
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | Discount for lack of marketability [Member] | Maximum [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 0.099 0.136
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | Discount for lack of marketability [Member] | Weighted Average [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 0.088 0.122 [1]
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Discounted cash flow [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value $ 44.0  
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Discounted cash flow [Member] | Discount rate [Member] | Weighted Average [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Investments, measurement input 6.4  
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member]    
Schedule Of Consolidated Investment Products [Line Items]    
Total investments, at fair value $ 0.0 $ 0.0
[1] Based on the relative fair value of the instruments.