EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2017

Retirement Benefits [Abstract]

Stock-Based Compensation Expense

The compensation expense that has been charged against income for these plans was as follows for the years ended December 31,2017, 2016, and 2015:

	2017			2016			2015
	(in millions)
Stock-based compensation expense by type:
Restricted stock	$	145		$	106		$	99
Stock options	12			9			10
Total stock-based compensation expense	157			115			109
Tax benefit recognized	(32		)	(20		)	(26		)
Stock-based compensation expense, net of tax	$	125		$	95		$	83

Activity for Restricted Stock Awards

Activity for our restricted stock was as follows for the year ended December 31, 2017:

	Shares		Weighted- Average Grant-Date Fair Value
	(shares in thousands)
Nonvested restricted stock at December 31, 2016	2,492		$	121.94
Granted	731		222.35
Vested	(1,386	)	128.08
Forfeited	(184	)	138.99
Nonvested restricted stock at December 31, 2017	1,653		$	171.68

Weighted-Average Fair Value of Stock Options

The fair value was estimated on the date of grant using the Black-Scholes pricing model with the weighted-average assumptions indicated below:

	2017			2016			2015
Weighted-average fair value at grant date	$	49.81		$	37.12		$	36.91
Expected option life (years)	4.1 years			4.2 years			4.2 years
Expected volatility	27.1		%	27.6		%	27.4		%
Risk-free interest rate at grant date	2.0		%	1.1		%	1.4		%
Dividend yield	0.7		%	0.7		%	0.7		%

Activity for Option Plans

Activity for our option plans was as follows for the year ended December 31, 2017:

	Shares  Under Option		Weighted-Average Exercise Price
	(shares in thousands)
Options outstanding at December 31, 2016	1,022		$	143.04
Granted	358		218.06
Exercised	(492	)	128.34
Forfeited	(25	)	182.46
Options outstanding at December 31, 2017	863		$	181.44
Options exercisable at December 31, 2017	182		$	137.54