8. Property and Equipment

Property and equipment consists of the following:

	Estimated useful		December 31,
(in millions)	life-in years		2015		2014
Property and equipment:
Land	N/A		$	6	$	4
Building		39		17		17
Building improvements		15		15		14
Leasehold improvements	1-15			491		478
Equipment and computer software		3		374		387
Other transportation equipment		10		135		56
Furniture and fixtures		7		62		93
Construction in progress	N/A			51		5
Total				1,151		1,054
Less: accumulated depreciation and amortization				570		587
Property and equipment, net			$	581	$	467

N/A	– Not Applicable

Qualifying software costs of approximately $48 million, $45 million and $35 million have been capitalized within equipment and computer software during 2015, 2014 and 2013, respectively, and are being amortized over an estimated useful life of three years.

Depreciation and amortization expense was $115 million, $117 million and $128 million for 2015, 2014 and 2013, respectively.