Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 1,287	$ 1,294	$ 4,053	$ 4,034
Property and equipment, net	10,683		10,683		$ 10,575
United States
Segment Reporting Information [Line Items]
Revenues	1,234	1,225	3,886	3,826
Property and equipment, net	10,338		10,338		10,111
Australia
Segment Reporting Information [Line Items]
Revenues	8	10	25	29
Property and equipment, net	85		85		102
Brazil
Segment Reporting Information [Line Items]
Revenues	7	9	22	29
Property and equipment, net	54		54		82
Canada
Segment Reporting Information [Line Items]
Revenues	15	22	44	65
Property and equipment, net	65		65		82
Chile
Segment Reporting Information [Line Items]
Revenues	5	7	18	23
Property and equipment, net	41		41		44
Mexico
Segment Reporting Information [Line Items]
Revenues	7	7	21	21
Property and equipment, net	20		20		26
New Zealand
Segment Reporting Information [Line Items]
Revenues	11	$ 14	37	$ 41
Property and equipment, net	$ 80		$ 80		$ 128