Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 1,449	$ 1,431	$ 2,766	$ 2,740
Property and equipment, net	10,776		10,776		$ 10,575
United States
Segment Reporting Information [Line Items]
Revenues	1,394	1,358	2,652	2,601
Property and equipment, net	10,373		10,373		10,111
Australia
Segment Reporting Information [Line Items]
Revenues	8	10	17	19
Property and equipment, net	95		95		102
Brazil
Segment Reporting Information [Line Items]
Revenues	8	12	15	19
Property and equipment, net	69		69		82
Canada
Segment Reporting Information [Line Items]
Revenues	15	24	29	44
Property and equipment, net	66		66		82
Chile
Segment Reporting Information [Line Items]
Revenues	6	8	13	16
Property and equipment, net	42		42		44
Mexico
Segment Reporting Information [Line Items]
Revenues	7	7	14	14
Property and equipment, net	22		22		26
New Zealand
Segment Reporting Information [Line Items]
Revenues	11	$ 12	26	$ 27
Property and equipment, net	$ 109		$ 109		$ 128