Property and Equipment - Depreciation Expense and Capitalized Interest(Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Capitalized Interest		$ 1	$ 2	$ 1	$ 11
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	[1]	$ 92	$ 74	$ 268	$ 217

[1] Included in depreciation and amortization and corporate expense.