v3.26.1
OTHER COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balances $ 10,935.2 $ 10,555.1 $ 11,017.2 $ 10,506.1
Other comprehensive income (loss) before income taxes (8.6) 17.5 (10.8) 20.9
Net deferred tax benefits (income taxes) 1.1 (2.3) 1.5 (2.8)
Total other comprehensive income (loss) (7.5) 15.2 (9.3) 18.1
Ending balances 11,163.5 10,713.8 11,163.5 10,713.8
Currency translation adjustments        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balances (51.6) (51.9) (50.5) (51.7)
Other comprehensive income (loss) before reclassifications (7.7) 12.7 (9.0) 13.0
Reclassification adjustments recognized in non-operating income 0.0 (3.1) (0.2) (3.1)
Other comprehensive income (loss) before income taxes (7.7) 9.6 (9.2) 9.9
Net deferred tax benefits (income taxes) 1.1 (2.3) 1.5 (2.8)
Total other comprehensive income (loss) (6.6) 7.3 (7.7) 7.1
Ending balances (58.2) (44.6) (58.2) (44.6)
Currency translation adjustments | Equity method investments        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balances (57.9) (53.2) (57.4) (49.5)
Other comprehensive income (loss) before reclassifications (7.8) 0.8 (8.4) (3.5)
Reclassification adjustments recognized in non-operating income 0.0 0.0 0.0 0.0
Other comprehensive income (loss) before income taxes (7.8) 0.8 (8.4) (3.5)
Net deferred tax benefits (income taxes) 1.1 (0.1) 1.2 0.5
Total other comprehensive income (loss) (6.7) 0.7 (7.2) (3.0)
Ending balances (64.6) (52.5) (64.6) (52.5)
Currency translation adjustments | Consolidated investment products - variable interest entities        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balances 6.3 1.3 6.9 (2.2)
Other comprehensive income (loss) before reclassifications 0.1 11.9 (0.6) 16.5
Reclassification adjustments recognized in non-operating income 0.0 (3.1) (0.2) (3.1)
Other comprehensive income (loss) before income taxes 0.1 8.8 (0.8) 13.4
Net deferred tax benefits (income taxes) 0.0 (2.2) 0.3 (3.3)
Total other comprehensive income (loss) 0.1 6.6 (0.5) 10.1
Ending balances $ 6.4 $ 7.9 $ 6.4 $ 7.9