Property and Equipment - Depreciation Expense (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	[1]	$ 76	$ 168	$ 224	$ 435

[1] ncluded in depreciation and amortization, corporate expense, and income/(loss) from discontinued operations