Premises, Equipment and Software Costs.
Premises and equipment consist of buildings, leasehold improvements, furniture, fixtures, computer and communications equipment, power plants, tugs, barges, terminals, pipelines and software (externally purchased and developed for internal use). Premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization are provided by the straight-line method over the estimated useful life of the asset. Estimated useful lives are generally as follows: buildings—39 years; furniture and fixtures—7 years; computer and communications equipment—3 to 9 years; power plants—15 years; tugs and barges—15 years; and terminals, pipelines and equipment—3 to 25 years. Estimated useful lives for software costs are generally 3 to 5 years.
Leasehold improvements are amortized over the lesser of the estimated useful life of the asset or, where applicable, the remaining term of the lease, but generally not exceeding: 25 years for building structural improvements and 15 years for other improvements.
Premises, equipment and software costs are tested for impairment whenever events or changes in circumstances suggest that an asset's carrying value may not be fully recoverable in accordance with current accounting guidance.