Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and equipment, net

	As of December 31,
	2017			2016
	(In millions)
Property and equipment, net:
Computer equipment and software	$	2,301		$	2,049
Internal use software and website development costs	1,828			1,372
Land and buildings	364			357
Leasehold improvements	388			335
Furniture and fixtures	129			119
Development in progress and other	148			268
Total property and equipment, gross	5,158			4,500
Accumulated depreciation	(3,630		)	(3,018		)
Total property and equipment, net	$	1,528		$	1,482