Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2020

Earnings Per Share [Abstract]

Basic and Diluted Net Income (Loss) Per Share

The calculations of basic and diluted net income per share are as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Net income - basic and diluted	$	897.3	$	193.1	$	1,521.9	$	654.2
(Shares in millions)
Weighted average shares - basic	109.6		109.2		109.7		109.1
Effect of dilutive securities:
Stock options	7.8		5.4		6.7		5.9
Restricted stock	0.5		—		0.4		—
Weighted average shares - diluted	117.9		114.6		116.8		115.0
Net income per share - basic	$	8.19	$	1.77	$	13.87	$	6.00
Net income per share - diluted	$	7.61	$	1.68	$	13.03	$	5.69

Antidilutive Securities

Shares which have been excluded from diluted per share amounts because their effect would have been antidilutive, include the following:

	Three Months Ended June 30,		Six Months Ended June 30,
(Shares in millions)	2020	2019	2020	2019
Stock options	0.1	18.3	3.5	18.1
Restricted stock	—	0.4	—	—