Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment

Property, plant and equipment are stated at cost less accumulated depreciation. Depreciation is applied using a straight-line method over the useful lives of the respective assets as described in the following table:



	Estimated Useful Life
Land improvements	20 years
Buildings	45 years
Machinery and equipment	3-20 years
Tooling — Airplane program — B787, Rolls-Royce	5-20 years
Tooling — Airplane program — all others	2-10 years
Capitalized software	3-7 years

The Company capitalizes certain costs, such as software coding, installation, and testing, that are incurred to purchase or to create and implement internal-use computer software. The Company’s capitalization policy includes specifications that the software must have a service life greater than one year, is legally and substantially owned by Spirit, and has an acquisition cost of greater than $0.1.

Where the Company is involved in build-to-suit leasing arrangements, the Company is deemed the owner of the asset for accounting purposes during the construction period of the asset. The Company records the related assets and liabilities for construction costs incurred under these build-to-suit leasing arrangements during the construction period. Upon completion of the asset, the Company considers whether the assets and liabilities qualify for derecognition under the sale-leaseback accounting guidance.