Share-Based Associate Compensation Plans (Tables)

Below is a summary of option information for the year 2018:



(Dollars in millions, except exercise price. Shares in thousands)	Shares		Weighted- average exercise price		Aggregate intrinsic value		Weighted-average remaining contractual life
Outstanding option shares at January 1, 2018	3,066		$	49.14
Granted	757		71.19
Exercised	(384	)	37.00
Forfeited or expired	(165	)	40.90
Outstanding option shares at December 31, 2018	3,274		56.08		$	68	6.08 years

Options exercisable at end of period	2,004		$	47.09	$	60	4.47 years

elow is a summary of service-based and performance-based share information, assuming a target payout for performance-based shares, for the year 2018:



(Shares in thousands)	Service-based shares		Weighted- average grant date fair value		Performance-based shares		Weighted- average grant date fair value
Nonvested at January 1, 2018	843		$	56.16	206		$	53.35
Granted	314		65.31		57		63.29
Vested	(323	)	49.23		(81	)	45.73
Forfeited or canceled	(21	)	61.44		—		—
Nonvested at December 31, 2018	813		62.31		182		59.83

The following weighted average assumptions were used in determining fair value for option grants issued:



	2018	2017	2016
Weighted-average expected term	7-8 years	8 years	8 years
Expected volatility	15.04-15.10%	16.95%	24.88-25.75%
Dividend yield	2.98%	2.83%	2.58-3.12%
Risk-free rates	2.77-2.83%	2.33%	1.44-1.60%
Weighted-average fair value of options granted during the period	$9.87	$10.79	$13.21

he following assumptions were used in determining fair value for performance-based grants issued: