Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2018

The following table sets forth the assumptions used to determine compensation cost for the market condition component of the PSP plan:



	Twelve Months Ended December 31, 2018
Expected volatility	22.75%-22.99%
Risk-free interest rate	1.31%-1.98%

The following summarizes PSP activity for the three years ending December 31, 2018:



	Share/Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2015	5,857,733			$38.69
Granted	2,617,982		37.26
Shares issued	(2,316,085	)	43.82
Forfeited	(209,500	)	43.61
Outstanding at December 31, 2016	5,950,130		35.89
Granted	2,163,912		51.78
Shares issued	(1,876,134	)	51.00
Forfeited	(438,024	)	45.96
Outstanding at December 31, 2017	5,799,884		36.17
Granted	1,751,235		62.97
Shares issued	(1,588,642	)	53.67
Forfeited	(196,000	)	56.57
Outstanding at December 31, 2018	5,766,477			$38.79

The following summarizes the activity of the RSA program for the three years ending December 31, 2018:



	Shares		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2015	120,368			$48.24
Granted	117,881		42.81
Shares issued	(59,418	)	47.14
Forfeited	(9,500	)	39.36
Outstanding at December 31, 2016	169,331		45.34
Granted	63,319		57.24
Shares issued	(59,650	)	47.90
Forfeited	(6,700	)	53.53
Outstanding at December 31, 2017	166,300		48.63
Granted	66,100		51.43
Shares issued	(100,289	)	48.44
Forfeited	—		—
Outstanding at December 31, 2018	132,111			$50.17

Stock-based compensation expense and related income tax benefits were as follows:



In millions	2018		2017		2016
Total stock-based compensation expense (included in selling and administrative expense)	$	135	$	147	$	124
Income tax benefits related to stock-based compensation	16		45		34