Property and Equipment, net (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Capital Leased Assets, Gross	$ 37	$ 46
Leasehold for land lease terms, maximum years	99 years
Property, Plant and Equipment [Member]
Depreciation	$ 266	$ 233	$ 172