XML 78 R53.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock Options and Other Share-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Fair market values of stock options and stock appreciation rights granted
The fair market values of stock options and stock appreciation rights granted in 2018, 2017 and 2016 were measured on the date of grant using the Black-Scholes option-pricing model, with the following weighted-average assumptions:
 
Year ended December 31
 
2018

 
 
2017

 
2016

 
Expected term in years1
6.5



6.3


6.3


Volatility2
21.2

%

21.7

%
21.7

%
Risk-free interest rate based on zero coupon U.S. treasury note
2.6

%

2.2

%
1.6

%
Dividend yield
3.8

%

4.2

%
4.5

%
Weighted-average fair value per option granted
$
18.18



$
15.31


$
9.53


1    Expected term is based on historical exercise and post-vesting cancellation data.
2    Volatility rate is based on historical stock prices over an appropriate period, generally equal to the expected term.
Summary of option activity
A summary of option activity during 2018 is presented below:
 
Shares (Thousands)

Weighted-Average
 Exercise Price
 
 
Averaged Remaining Contractual Term (Years)
Aggregate Intrinsic Value
 
Outstanding at January 1, 2018
103,765

 
$
97.40

 

 

Granted
4,665

 
$
125.35

 

 

Exercised
(12,991
)
 
$
88.11

 

 

Forfeited
(715
)
 
$
115.25

 

 

Outstanding at December 31, 2018
94,724

 
$
99.92

 
5.07
 
$
1,101

Exercisable at December 31, 2018
81,074

 
$
99.34

 
4.60
 
$
933