Stock-based Compensation Expense (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-based Compensation Expense by Line Item

The effect of stock-based compensation expense during the three years ended December 31, 2022 was as follows:

	2022		2021		2020
	(in millions)
Stock-based compensation expense by line item:
Cost of sales	$	9.4	$	6.3	$	5.6
Research and development expenses	297.9		268.3		262.7
Selling, general and administrative expenses	184.0		166.8		161.2
Total stock-based compensation expense included in costs and expenses	491.3		441.4		429.5
Income tax effect	(144.1)		(82.9)		(147.0)
Total stock-based compensation included in costs and expenses, net of tax	$	347.2	$	358.5	$	282.5

The stock-based compensation expense by type of award during the three years ended December 31, 2022 was as follows:

	2022		2021		2020
	(in millions)
Stock-based compensation expense by type of award:
Restricted stock units (including PSUs)	$	456.1	$	384.3	$	360.4
Stock options	17.6		36.8		59.7
ESPP share issuances	16.7		24.4		13.0
Stock-based compensation expense related to inventories	0.9		(4.1)		(3.6)
Total stock-based compensation expense included in costs and expenses	$	491.3	$	441.4	$	429.5

Schedule of Unrecognized Stock-Based Compensation Expense

The following table sets forth our unrecognized stock-based compensation expense as of December 31, 2022, by type of award and the weighted-average period over which that expense is expected to be recognized:

	As of December 31, 2022
	Unrecognized Expense		Weighted-average Recognition Period
	(in millions)		(in years)
Type of award:
Restricted stock units (including PSUs)	$	477.9	1.93
Stock options	2.2		0.42
ESPP share issuances	11.3		0.61
Total unrecognized stock-based compensation expense	$	491.4

Schedule of Assumptions Used to Estimate the Grant Date Fair Value of Options

The fair value of each option granted during 2022, 2021 and 2020 was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:

	2022	2021	2020
Stock options granted	20,079	27,302	22,636
Expected stock price volatility	34.03%	35.03%	35.87%
Risk-free interest rate	2.93%	0.86%	0.43%
Expected term of options (in years)	4.36	4.50	4.67
Expected annual dividends	—	—	—

Schedule of Assumptions Used to Estimate the Grant Date Fair Value Employee Stock Purchase Plan

The following table reflects the weighted-average assumptions used in the Black-Scholes option pricing model for 2022, 2021 and 2020:

	2022	2021	2020
Expected stock price volatility	33.55%	34.06%	37.70%
Risk-free interest rate	4.05%	0.05%	0.11%
Expected term (in years)	0.71	0.69	0.71
Expected annual dividends	—	—	—