v3.25.1
Basic and Diluted Earnings Per Share (Detail) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Numerator    
Net Income $ 189.1 $ 395.2
Denominator    
Weighted Average Common Shares - Basic 178,291,500 192,550,200
Dilution for Assumed Exercises of Nonvested Stock Awards 590,900 716,900
Weighted Average Common Shares - Assuming Dilution 178,882,400 193,267,100
Net Income Per Common Share    
Basic $ 1.06 $ 2.05
Assuming Dilution $ 1.06 $ 2.04