v3.24.1.u1
Redeemable Noncontrolling Interests (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2024
Dec. 31, 2023
Mar. 31, 2023
Dec. 31, 2022
Mar. 31, 2024
Mar. 31, 2023
Noncontrolling Interest [Line Items]            
Balance at beginning of period   $ 1,026.1     $ 1,026.1  
Net income $ 42.8   $ 83.2   52.3 $ 81.7
Net subscriptions (distributions) and other 63.1 9.6 50.1 $ 97.1    
Net deconsolidations   (12.6) (324.2) (35.7)    
Adjustment to fair value (91.9) (65.9) 44.7      
Balance at End of Period 1,253.9       1,253.9  
Minority Interests [Member]            
Noncontrolling Interest [Line Items]            
Balance at beginning of period 523.2 446.0 599.5 583.6 446.0 583.6
Net income 10.1   13.0   22.5 23.7
Net subscriptions (distributions) and other (14.8)   (52.9)   (15.9) (47.7)
Net deconsolidations 0.0   0.0   0.0 0.0
Acquisition 0.0   0.0   0.0 0.0
Adjustment to fair value 91.9   (44.7)   157.8 (44.7)
Balance at End of Period 610.4 523.2 514.9 599.5 610.4 514.9
Redeemable Noncontrolling Interests [Member]            
Noncontrolling Interest [Line Items]            
Balance at beginning of period 1,078.5 1,026.1 1,979.2 1,525.8 1,026.1 1,525.8
Net income 42.8   83.2   52.3 81.7
Net subscriptions (distributions) and other (23.3)   236.7   13.7 420.3
Net deconsolidations 43.8   (1,293.9)   (16.2) (1,022.6)
Acquisition 20.2   0.0   20.2 0.0
Adjustment to fair value 91.9   (44.7)   157.8 (44.7)
Balance at End of Period 1,253.9 1,078.5 960.5 1,979.2 1,253.9 960.5
Retained Earnings [Member]            
Noncontrolling Interest [Line Items]            
Adjustment to fair value (91.9) (65.9) 44.7      
CIPs [Member]            
Noncontrolling Interest [Line Items]            
Balance at beginning of period 555.3 580.1 1,379.7 942.2 580.1 942.2
Net income 32.7   70.2   29.8 58.0
Net subscriptions (distributions) and other (8.5)   289.6   29.6 468.0
Net deconsolidations 43.8   (1,293.9)   (16.2) (1,022.6)
Acquisition 20.2   0.0   20.2 0.0
Adjustment to fair value 0.0   0.0   0.0 0.0
Balance at End of Period $ 643.5 $ 555.3 $ 445.6 $ 1,379.7 $ 643.5 $ 445.6