v3.25.2
Note 4 - Investments and Fair Value Measurements - Long-term Debt (Details) - Fair Value, Inputs, Level 2 [Member] - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Reported Value Measurement [Member]    
Senior notes (Note 9) $ 3,214.3 $ 3,021.0
Estimate of Fair Value Measurement [Member]    
Senior notes (Note 9) $ 3,133.5 $ 2,866.5