Summary of Property and Equipment (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Land and land improvements	$ 2,047	$ 1,990
Buildings and leasehold improvements	13,665	13,336
Furniture and equipment	2,281	2,217
Construction in progress	165	209
Property, Plant and Equipment, Gross, Total	18,158	17,752
Less accumulated depreciation and amortization	(7,382)	(7,177)
Property and equipment, net	$ 10,776	$ 10,575