v3.10.0.1
Goodwill and Intangible Assets
 9 Months Ended
Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]  
Goodwill and Intangible Assets Goodwill and Intangible Assets

Goodwill

The following table presents goodwill activities during the nine months ended September 30, 2018 (in millions):
 
December 31,
2017
 
Goodwill
Acquired
 
Adjustments
 
September 30,
2018
Goodwill
$
4,773

 
$
532

 
$
(135
)
 
$
5,170



The adjustments to goodwill during the nine months ended September 30, 2018 were primarily due to foreign currency translation.

Intangible Assets

The components of identifiable intangible assets as of September 30, 2018 and December 31, 2017 are as follows (in millions, except years): 
 
September 30, 2018
 
December 31, 2017
 
Gross Carrying Amount  
 
Accumulated Amortization 
 
Net Carrying Amount
 
Weighted Average Useful Life (Years)
 
Gross Carrying Amount
 
Accumulated Amortization 
 
Net Carrying Amount
 
Weighted Average Useful Life (Years)
Intangible assets:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Customer lists and user base
$
522

 
$
(441
)
 
$
81

 
5
 
$
458

 
$
(430
)
 
$
28

 
5
Marketing related
588

 
(579
)
 
9

 
5
 
607

 
(587
)
 
20

 
5
Developed technologies
279

 
(268
)
 
11

 
3
 
273

 
(258
)
 
15

 
3
All other
160

 
(155
)
 
5

 
4
 
156

 
(150
)
 
6

 
4
Total
$
1,549

 
$
(1,443
)
 
$
106

 
 
 
$
1,494

 
$
(1,425
)
 
$
69

 
 


Amortization expense for intangible assets was $15 million and $16 million for the three months ended September 30, 2018 and 2017, respectively. Amortization expense for intangible assets was $49 million and $48 million for the nine months ended September 30, 2018 and 2017, respectively.

Expected future intangible asset amortization as of September 30, 2018 is as follows (in millions):
Fiscal year:
 
 
Remaining 2018
 
$
14

2019
 
49

2020
 
34

2021
 
9

Total
 
$
106