Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenues	$ 649	$ 103	$ 1,048	$ 1,155
Property and equipment, net	10,071		10,071		$ 9,416
United States
Segment Reporting Information [Line Items]
Revenues	646	101	1,043	1,139
Property and equipment, net	9,988		9,988		9,331
Brazil
Segment Reporting Information [Line Items]
Revenues	1	1	2	5
Property and equipment, net	35		35		34
Canada
Segment Reporting Information [Line Items]
Revenues	2	$ 1	3	$ 11
Property and equipment, net	$ 48		$ 48		$ 51