Consolidated Variable Interest Entities ("VIEs") and Investments in Affiliates - Schedule of Assets and Liabilities Included in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Property and equipment, net	$ 8,549	$ 9,193
Cash and cash equivalents	772	951
Restricted cash	70	30
Accounts receivable, net	62	26
Prepaid expenses	34	39
Other assets	34	60
Debt	4,670	5,121
Accounts payable and accrued expenses	204	147
Other liabilities	115	134
Consolidated VIEs [Member]
Variable Interest Entity [Line Items]
Property and equipment, net	211	216
Cash and cash equivalents	19	8
Restricted cash	4	2
Accounts receivable, net	4	1
Prepaid expenses	1	1
Other assets	0	1
Debt	208	207
Accounts payable and accrued expenses	7	5
Other liabilities	$ 3	$ 1