v3.25.2
Note 13 - Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Balance $ 4,826.5 $ 4,427.4 $ 4,718.1 $ 4,538.3
Total other comprehensive income 135.4 9.4 197.3 (35.8)
Less: other comprehensive income attributable to noncontrolling interests 24.2 0.4 33.6 (0.7)
Balance 4,899.9 4,474.8 4,899.9 4,474.8
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]        
Balance (336.0) (523.4) (387.9) (478.9)
Other comprehensive income 135.1 3.5 196.0 (20.1)
Reclassifications to net income(1) [1] (0.4) 5.5 0.0 (16.5)
Total other comprehensive income 134.7 9.0 196.0 (36.6)
Less: other comprehensive income attributable to noncontrolling interests (24.2) (0.4) (33.6) 0.7
Balance (225.5) (514.8) (225.5) (514.8)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]        
Balance (96.7) (84.3) (97.3) (84.7)
Other comprehensive income 0.0 0.0 0.0 0.0
Reclassifications to net income(1) [1] 0.7 0.4 1.3 0.8
Total other comprehensive income 0.7 0.4 1.3 0.8
Less: other comprehensive income attributable to noncontrolling interests 0.0 0.0 0.0 0.0
Balance (96.0) (83.9) (96.0) (83.9)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]        
Balance (432.7) (607.7) (485.2) (563.6)
Other comprehensive income 135.1 3.5 196.0 (20.1)
Reclassifications to net income(1) [1] 0.3 5.9 1.3 (15.7)
Total other comprehensive income 135.4 9.4 197.3 (35.8)
Less: other comprehensive income attributable to noncontrolling interests (24.2) (0.4) (33.6) 0.7
Balance $ (321.5) $ (598.7) $ (321.5) $ (598.7)
[1] Reclassifications to net income are primarily related to the release of accumulated foreign currency translation reserves during the period in which a JHG entity liquidated.