STOCK-BASED COMPENSATION PLANS (Tables)

Presented below is a summary of the stock-based compensation expense and associated tax benefit in the accompanying Consolidated Statements of Operations:


	Year Ended December 31,
	2020		2019		2018
Stock-based compensation expense	$	154	$	136	$	130
Tax benefit	$	30	$	29	$	32

The following weighted average assumptions were used for options granted:


	Year Ended December 31,
	2020			2019			2018
Expected dividend yield	0.80 %			1.14 %			1.05 %
Expected stock volatility	23		%	24		%	26		%
Risk-free interest rate	1.43 %			2.56 %			2.82 %
Expected holding period -in years	5.7			6.2			6.2
Grant date fair value	$	60.66		$	43.29		$	45.73

A summary of option activity as of December 31, 2020 and changes during the year then ended is presented below:


Options	Shares	Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding, December 31, 2019	1.6	$	93.51
Granted	0.1	280.37
Exercised	(0.7)	59.57
Outstanding, December 31, 2020	1.0	133.95		5.6 years	$	160
Vested and expected to vest, December 31, 2020	1.0	132.80		5.6 years	$	158
Exercisable, December 31, 2020	0.7	$	101.13	4.6 years	$	125

The following table summarizes information relating to stock option exercises:


	Year Ended December 31,
	2020	2019	2018
Proceeds from stock option exercises	39	36	38
Aggregate intrinsic value	132	114	99
Tax benefit realized upon exercise	32	27	24

A summary of nonvested restricted stock activity for the year ended December 31, 2020 is presented below:


Nonvested Restricted Stock	Shares	Weighted Average Grant Date Fair Value Per Share
Balance, December 31, 2019	1.8	$	124.63
Granted	0.5	279.00
Vested	(0.8)	132.50

Balance, December 31, 2020	1.5	$	201.30

The following table summarizes information relating to the vesting of restricted stock awards:


	Year Ended December 31,
	2020	2019	2018
Fair value of shares vested	202	156	151
Tax benefit realized upon vesting	46	36	35

A summary of performance-based restricted stock activity for the year ended December 31, 2020 is presented below:


Performance-based restricted stock	Shares	Weighted Average Grant Date Fair Value Per Share
Balance, December 31, 2019	0.5	$	134.35
Granted	0.1	273.81
Vested	(0.3)	109.43
Balance, December 31, 2020	0.3	$	197.19

The following table summarizes information relating to the vesting of the Company’s performance-based restricted stock awards:


	Year Ended December 31,
	2020	2019	2018
Fair value of shares vested	70	47	23
Tax benefit realized upon vesting	17	11	6