Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2019

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,
	2019		2018		2019		2018
Net income - basic and diluted	$	193.1	$	551.4	$	654.2	$	1,029.4
(Shares in millions)
Weighted average shares - basic	109.2		107.8		109.1		107.7
Effect of dilutive securities:
Stock options	5.4		6.7		5.9		7.0
Weighted average shares - diluted	114.6		114.5		115.0		114.7
Net income per share - basic	$	1.77	$	5.12	$	6.00	$	9.56
Net income per share - diluted	$	1.68	$	4.82	$	5.69	$	8.97

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)	2019	2018	2019	2018
Stock options	18.3	14.9	18.1	14.9
Restricted stock	0.4	0.1	—	0.1