Net Income Per Share

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Net Income Per Share

Net Income Per Share

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

	Year Ended December 31,
(In millions, except per share data)	2021		2020		2019
Net income - basic and diluted	$	8,075.3	$	3,513.2	$	2,115.8
Weighted average shares - basic	105.7		107.6		109.2
Effect of dilutive securities:
Stock options	5.4		7.0		5.4
Restricted stock awards and restricted stock units	1.1		0.5		—
Weighted average shares - diluted	112.2		115.1		114.6
Net income per share - basic	$	76.40	$	32.65	$	19.38
Net income per share - diluted	$	71.97	$	30.52	$	18.46

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

	Year Ended December 31,
(Shares in millions)	2021	2020	2019
Stock options	2.9	2.7	18.4