Fair Value Measurements - Fair Value of Certain Financial Instrument and Hierarchy Level Used to Estimate Fair Values (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Carrying amount [Member] | SF CMBS Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	$ 725	$ 725
Carrying amount [Member] | HHV CMBS Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	1,275	1,275
Carrying amount [Member] | Term Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	750	750
Carrying amount [Member] | Mortgage Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	207	207
Fair Value [Member] | SF CMBS Loan [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	727	706
Fair Value [Member] | HHV CMBS Loan [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	1,271	1,214
Fair Value [Member] | Term Loan [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	748	732
Fair Value [Member] | Mortgage Loans [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan	$ 203	$ 201