Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 1,254	$ 1,295	$ 4,043	$ 4,093
Property and equipment, net	10,014		10,014		$ 10,145
United States
Segment Reporting Information [Line Items]
Revenues	1,225	1,247	3,947	3,959
Property and equipment, net	9,864		9,864		9,913
Australia
Segment Reporting Information [Line Items]
Revenues	2	8	18	24
Property and equipment, net					85
Brazil
Segment Reporting Information [Line Items]
Revenues	5	15	16	29
Property and equipment, net	62		62		63
Canada
Segment Reporting Information [Line Items]
Revenues	16	16	42	40
Property and equipment, net	73		73		71
Chile
Segment Reporting Information [Line Items]
Revenues				9
Mexico
Segment Reporting Information [Line Items]
Revenues	6	6	20	21
Property and equipment, net	$ 15		$ 15		$ 13
New Zealand
Segment Reporting Information [Line Items]
Revenues		$ 3		$ 11