Stock-based Compensation Expense (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Weighted Average Assumptions used in the Black-Scholes Option Pricing Model

The weighted average assumptions used in the Black-Scholes option pricing model are as follows: 

	2023		2022		2021
Expected stock price volatility	25	%	26	%	26	%
Risk free interest rate	4.2	%	2.0	%	0.8	%
Expected life of options (years)	4.7		4.7		4.3
Expected annual dividend	0.3	%	0.2	%	0.2	%

Summary of the Company's Option Activity

A summary of the company’s option activity for the year ended December 31, 2023 is presented below:

	Shares (in millions)	Weighted average exercise price		Weighted average remaining contractual term (in years)	Aggregate intrinsic value (in millions)
Outstanding at December 31, 2022	5.6	$	359.27
Granted	0.7	546.94
Exercised	(1.0)	218.82
Canceled/expired	(0.3)	543.25
Outstanding at December 31, 2023	5.0	$	401.30	3.9	$	714
Vested and unvested expected to vest at December 31, 2023	4.8	$	396.20	3.9	$	712
Exercisable at December 31, 2023	2.8	$	316.88	2.7	$	635

Summary of the Company's Restricted Unit Activity

A summary of the company’s restricted unit activity for the year ended December 31, 2023 is presented below:

	Units (in millions)	Weighted average grant-date fair value
Unvested at December 31, 2022	0.7	$	495.39
Granted	0.4	545.73
Vested	(0.4)	480.45
Forfeited	(0.1)	528.59
Unvested at December 31, 2023	0.6	$	533.65