Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 1,441	$ 1,459	$ 2,789	$ 2,798
Property and equipment, net	10,251		10,251		$ 10,145
United States
Segment Reporting Information [Line Items]
Revenues	1,406	1,415	2,722	2,711
Property and equipment, net	10,105		10,105		9,913
Australia
Segment Reporting Information [Line Items]
Revenues	8	8	16	16
Property and equipment, net					85
Brazil
Segment Reporting Information [Line Items]
Revenues	5	7	11	14
Property and equipment, net	60		60		63
Canada
Segment Reporting Information [Line Items]
Revenues	15	14	26	24
Property and equipment, net	72		72		71
Chile
Segment Reporting Information [Line Items]
Revenues		4		9
Mexico
Segment Reporting Information [Line Items]
Revenues	7	8	14	15
Property and equipment, net	$ 14		$ 14		$ 13
New Zealand
Segment Reporting Information [Line Items]
Revenues		$ 3		$ 9