v3.26.1
Basis of Financial Statements - Corrections to Impacted Financial Statement (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Schedule of Equity Method Investments [Line Items]        
Income taxes receivable $ 48.1   $ 48.8  
Total assets 1,239.6 $ 2,096.4 1,308.9  
Retained earnings (27.5)   11.5  
Total equity 922.4 1,696.7 979.1 $ 1,815.3
Income tax expense 0.5 20.2 24.8  
Net loss (35.8) (115.0) (536.7)  
Net loss attributable to Cannae Holdings, Inc. common shareholders $ (32.1) $ (113.0) $ (525.0)  
Net loss per share (in usd per share) $ (0.70) $ (1.81) $ (9.29)  
Net loss per share (in usd per share) $ (0.70) $ (1.81) $ (9.29)  
As Reported        
Schedule of Equity Method Investments [Line Items]        
Income taxes receivable     $ 60.6  
Total assets     1,320.7  
Retained earnings     23.3  
Total equity     990.9  
Income tax expense     13.0  
Net loss     (524.9)  
Net loss attributable to Cannae Holdings, Inc. common shareholders     $ (513.2)  
Net loss per share (in usd per share)     $ (9.08)  
Net loss per share (in usd per share)     $ (9.08)  
Correction        
Schedule of Equity Method Investments [Line Items]        
Income taxes receivable     $ (11.8)  
Total assets     (11.8)  
Retained earnings     (11.8)  
Total equity     (11.8)  
Income tax expense     11.8  
Net loss     (11.8)  
Net loss attributable to Cannae Holdings, Inc. common shareholders     $ (11.8)  
Net loss per share (in usd per share)     $ (0.21)  
Net loss per share (in usd per share)     $ (0.21)