v3.8.0.1
Share-based Compensation Expense (Tables)
 12 Months Ended
Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Summary of Share-based Compensation Expense for all Stock Awards
Share-based compensation expense for all stock awards consists of the following (in millions):
 
Years Ended
 
December 31,
2017
 
January 1,
2017
 
January 3,
2016
Cost of product revenue
$
12

 
$
9

 
$
10

Cost of service and other revenue
2

 
2

 
2

Research and development
51

 
42

 
42

Selling, general and administrative
99

 
76

 
79

Share-based compensation expense before taxes
164

 
129

 
133

Related income tax benefits
(48
)
 
(41
)
 
(39
)
Share-based compensation expense, net of taxes
$
116

 
$
88

 
$
94
Summary of Assumptions used to Estimate the Weighted-Average Fair Value Per Share for Stock Purchase under the Employee Stock Purchase Plan
The assumptions used for the specified reporting periods and the resulting estimates of weighted-average fair value per share for stock purchased under the ESPP are as follows:
 
Years Ended
 
December 31,
2017
 
January 1,
2017
 
January 3,
2016
Risk-free interest rate
0.50% - 1.22%

 
0.40% - 0.50%

 
0.07% - 0.33%

Expected volatility
29% - 44%

 
40% - 44%

 
29% - 38%

Expected term
0.5 - 1.0 year

 
0.5 - 1.0 year

 
0.5 - 1.0 year

Expected dividends
0
%
 
0
%
 
0
%
Weighted-average grant-date fair value per share
$
46.81

 
$
48.29

 
$
53.92