Consolidated Investment Products - Schedule of Valuation Techniques and Significant Unobservable Inputs used in Level 3 Fair Value Measurements (Details) $ in Millions | Mar. 31, 2023 USD ($) $ / shares | Sep. 30, 2022 USD ($) $ / shares |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | $ 987.1 | $ 613.5 |
CIPs [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | 8,421.3 | 7,898.1 |
Fair Value, Recurring [Member] | CIPs [Member] | Equity and debt securities [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | 1,299.8 | 1,685.7 |
Fair Value, Recurring [Member] | CIPs [Member] | Real Estate [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | | 268.6 |
Fair Value, Recurring [Member] | CIPs [Member] | Loans [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | 7,121.5 | 5,943.8 |
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 | | 539 | 555.8 |
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 | | $ 539 | $ 555.8 |
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 | | 0.01 | 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 | 558.45 |
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] | 45.98 | 33.31 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | Measurement Input, Discount for lack of liquidity | Minimum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | 0.130 | 0.235 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | Measurement Input, Discount for lack of liquidity | Maximum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | 0.251 | 0.251 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Equity and debt securities [Member] | Market comparable companies [Member] | Measurement Input, Discount for lack of liquidity | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | 0.232 | 0.249 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | | $ 268.6 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | | $ 268.6 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | Discount rate [Member] | Minimum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.045 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | Discount rate [Member] | Maximum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.063 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | Discount rate [Member] | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | [1] | | 0.051 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | Exit Capitalization Rate [Member] | Minimum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.055 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | Exit Capitalization Rate [Member] | Maximum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.068 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Real Estate [Member] | Discounted cash flow [Member] | Exit Capitalization Rate [Member] | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | [1] | | 0.060 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | $ 3.1 | $ 239.4 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Discounted cash flow [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | | $ 60.4 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Discounted cash flow [Member] | Discount rate [Member] | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 9.9 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Market pricing [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | | $ 147.2 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Market pricing [Member] | Private sale pricing [Member] | Minimum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | $ / shares | | | 0.97 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Market pricing [Member] | Private sale pricing [Member] | Maximum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | $ / shares | | | 0.98 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Market pricing [Member] | Private sale pricing [Member] | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | $ / shares | | | 0.98 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Yield capitalization [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Total investments, at fair value | | | $ 31.9 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Yield capitalization [Member] | Measurement Input, Credit Spread | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 6.3 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Yield capitalization [Member] | Measurement Input, Loan-to-value ratio | Minimum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.791 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Yield capitalization [Member] | Measurement Input, Loan-to-value ratio | Maximum [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.881 |
Fair Value, Recurring [Member] | CIPs [Member] | Level 3 [Member] | Loans [Member] | Yield capitalization [Member] | Measurement Input, Loan-to-value ratio | Weighted Average [Member] | | | |
Schedule Of Consolidated Investment Products [Line Items] | | | |
Investments, measurement input | | | 0.831 |
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[1]Based on the relative fair value of the instruments. | |