Net Income Per Share of Class A and Class B Common Stock (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

Following is a reconciliation of net income and weighted average shares used for our basic earnings per share (EPS) and diluted EPS (in millions, except per share amounts):

	Year Ended December 31,
	2020				2019				2018
(Dollars in millions, except for per share amounts)	Class A		Class B		Class A		Class B		Class A		Class B
Net income from continuing operations applicable to common stockholders	$	460.9	$	9.4	$	264.5	$	7.0	$	254.8	$	10.9
Reallocation of distributed net income due to conversion of class B to class A common shares outstanding	0.6		—		0.7		—		1.1		—
Conversion of class B common shares into class A common shares	8.9		—		6.3		—		9.8		—
Net income applicable to common stockholders - diluted	$	470.3	$	9.4	$	271.5	$	7.0	$	265.7	$	10.9
Weighted average common shares outstanding – basic	23.3		0.5		22.6		0.6		23.4		1.0
Conversion of class B common shares into class A common shares	0.5		—		0.6		—		1.0		—
Effect of employee stock purchases and restricted stock units on weighted average common shares	0.3		—		0.2		—		0.1		—
Weighted average common shares outstanding – diluted	24.1		0.5		23.4		0.6		24.5		1.0
Net income per common share - basic	$	19.74	$	19.74	$	11.70	$	11.70	$	10.91	$	10.91
Net income per common share - diluted	$	19.53	$	19.53	$	11.60	$	11.60	$	10.86	$	10.86