Earnings Per Share

12 Months Ended

Dec. 31, 2020

Earnings Per ShareBasic earnings per common share is computed by dividing net income available to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted earnings per share adjusts basic earnings per common share for the effects of potentially dilutive common shares, if the effect is not anti-dilutive. Potentially dilutive common shares include the dilutive effects of shares issuable under the 2008 and 2017 Equity Incentive Plans and shares issuable upon the conversion of preferred stock to common stock.

The following table reconciles the basic earnings per share computation to the diluted earnings per share computation (in millions, except share and per share amounts):


	2020		2019		2018
Net income available to common stockholders for purposes of computing basic and diluted earnings per share	$	616.8	$	538.7	$	627.2
Weighted-average number of shares outstanding (in thousands):
Basic shares	93,826		99,316		101,852
Effect of dilution	489		431		418
Diluted shares	94,315		99,747		102,270
Earnings per share:
Basic earnings per share	$	6.57	$	5.42	$	6.16
Diluted earnings per share	$	6.54	$	5.40	$	6.13


Potentially dilutive shares excluded from the calculation (in thousands):	2020	2019	2018
Stock options excluded as their inclusion would be anti-dilutive	75	121	117