Stockholders' Equity and Earnings Per Common Share (Tables)

3 Months Ended

Mar. 31, 2021

Stockholders' Equity and Earnings Per Common Share [Abstract]

Schedule of Basic and Diluted Earnings Per Share

Net income per common share is determined as follows:

	Three Months Ended March 31
	2021		2020
	(in millions of dollars, except share data)
Numerator
Net Income	$	153.0	$	161.0
Denominator (000s)
Weighted Average Common Shares - Basic	204,133.3		203,306.0
Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards	604.0		49.7
Weighted Average Common Shares - Assuming Dilution	204,737.3		203,355.7
Net Income Per Common Share
Basic	$	0.75	$	0.79
Assuming Dilution	$	0.75	$	0.79