Useful

 

December 31,

 

(Millions of dollars)

    

Lives

    

2016

    

2015

 

Land and improvements

 
3

-

15

years

 

$
214

 

$
185

 

Buildings and improvements

 

 

 

30

years

 

 
486

 

 
405

 

Machinery and equipment

 
3

-

20

years

 

 
1,142

 

 
1,025

 

Vessels and vehicles

 
3

-

18

years

 

 
140

 

 
150

 

Office furniture and fixtures

 

 

 

5

years

 

 
32

 

 
27

 

Construction in progress

 

 

 

 

 

 

 
58

 

 
38

 

 

 

 

 

 

 

 

 
2,072

 

 
1,830

 

Accumulated depreciation and amortization

 

 

 

 

 

 

 
(1,066)

 

 
(999)

 

Net property, plant and equipment

 

 

 

 

 

 

$
1,006

 

$
831