Depreciation and amortization on property and equipment is calculated using the straight-line method over the estimated useful lives indicated below:
| | | | | | | Asset Category | Period | | Computer equipment | 5 years | | Computer software and capitalized internal-use software | 1.5 to 3 years | | Office furniture and equipment | 5 years | | Buildings | 25 to 40 years | Leasehold improvements | Lesser of estimated useful life or remaining lease term |
Property and equipment, net, consisted of the following (in millions):
| | | | | | | | | | December 31, | | 2021 | 2022 | | Computer software and capitalized internal-use software | $ | 175 | | $ | 164 | | | Leasehold improvements | 214 | | 152 | | | Computer equipment | 57 | | 32 | | | Office furniture and equipment | 43 | | 23 | | | Buildings and land | 17 | | 17 | | | Construction in progress | 30 | | 45 | | | Total | 536 | | 433 | | | Less: Accumulated depreciation and amortization | (379) | | (312) | | | Total property and equipment, net | $ | 157 | | $ | 121 | |
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