v3.26.3
Segment and Geographical Area Information (Details) (Table 2) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Revenue $ 672.1 $ 617.4 $ 1,980.1 $ 1,804.4
Amortization expense (19.2) (15.1) (59.1) (44.8)
Business Combination, Acquisition and Integration Related Costs (3.3) (8.2) (9.1) (18.9)
Operating income 167.4 127.8 483.9 367.0
Nonoperating Income (Expense) (15.0) (4.7) (42.7) (18.9)
Equity in investments of unconsolidated entities 1.5 (0.1) 0.5 (3.9)
Income Loss From Continuing Operations Before Income Taxes Domestic And Foreign 153.9 123.0 441.7 344.2
Unallocated Corporate Expenses 50.7 47.1 148.1 139.0
Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Revenue 606.8 567.5 1,792.1 1,655.0
Reportable Segment Profitability 228.2 194.7 656.5 567.3
Morningstar Data and Analytics Segment | Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Reportable Segment Profitability 104.2 93.7 295.5 277.1
PitchBook Segment | Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Reportable Segment Profitability 52.3 52.9 156.9 158.0
Morningstar Credit Segment | Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Reportable Segment Profitability 7.4 3.1 20.9 5.3
Morningstar Wealth Segment | Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Reportable Segment Profitability 40.6 28.1 120.3 80.0
Morningstar Retirement Segment | Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Reportable Segment Profitability 23.7 16.9 62.9 46.9
Corporate and Other | Operating Segments        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Revenue 65.3 49.9 188.0 149.4
Reportable Segment Profitability (38.3) (44.1) (112.1) (137.9)
Sustainalytics        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Revenue 26.3 28.1 78.4 84.2
Morningstar Indexes [Member]        
Reconciliation of Select Segment Information to Consolidated [Line Items]        
Revenue $ 39.0 $ 21.8 $ 109.6 $ 65.2