Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total Revenues	$ 1,390	$ 1,346
Property and equipment, net	10,296		$ 9,760
United States
Segment Reporting Information [Line Items]
Total Revenues	1,371	1,320
Property and equipment, net	10,189		9,651
Brazil
Segment Reporting Information [Line Items]
Total Revenues	6	5
Property and equipment, net	47		49
Canada
Segment Reporting Information [Line Items]
Total Revenues	13	14
Property and equipment, net	$ 60		$ 60
Mexico
Segment Reporting Information [Line Items]
Total Revenues		$ 7