Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consisted of the following as of December 31, 2017 and 2016 (in millions, except years):

	As of December 31,						Depreciation Period (Years)
	2017			2016
Software and internally developed software	$	766		$	600		1 to 8
Computer and network equipment	575			483			1 to 5
Land	137			136			N/A
Buildings and building improvements	289			259			2.5 to 40
Leasehold improvements	234			216			1 to 17
Equipment, aircraft and office furniture	275			242			1 to 12
	2,276			1,936
Less accumulated depreciation and amortization	(1,030		)	(807		)
Property and equipment, net	$	1,246		$	1,129