NORTHROP GRUMMAN CORP /DE/ | 2013 | FY | 3

Property, Plant and Equipment
Property, plant and equipment are depreciated over the estimated useful lives of individual assets. Most of these assets are depreciated using declining-balance methods, with the remainder using the straight-line method. Major classes of property, plant and equipment and their useful lives are as follows:
 
 
 
 
December 31
Useful life in years, $ in millions
 
Useful Life
 
2013
 
2012
Land and land improvements
 
   Up to 40(1)
 

$ 373

 

$ 373

Buildings and improvements
 
Up to 45
 
1,450

 
1,421

Machinery and other equipment
 
Up to 20
 
4,243

 
4,233

Capitalized software costs
 
3-5
 
418

 
413

Leasehold improvements
 
Length of Lease(1)
 
659

 
593

Property, plant and equipment, at cost
 
 
 
7,143

 
7,033

Accumulated depreciation
 
 
 
(4,337
)
 
(4,146
)
Property, plant and equipment, net
 
 
 

$2,806

 

$2,887


(1)
Land is not a depreciable asset. Leasehold improvements are depreciated over the useful life of the asset if it is shorter than the length of the lease.

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