Dispositions - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Sep. 24, 2018	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sales of assets, net				$ 1,130	$ 472
Retail
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sales of assets, net	$ 442
Gain (loss) on sale of assets, net	386
Future real estate tax rebates liability	$ 35
W New York Union Square
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sales of assets, net			$ 171
Gain (loss) on sale of assets, net			(4)
JW Marriott Mexico City
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sales of assets, net			183
Gain (loss) on sale of assets, net			163
JW Marriott Mexico City | Non-controlling Partner​
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (loss) on sale of assets, net			$ 53
Westin New York Grand Central | Scenario Forecast
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sales of assets, net		$ 300
Furniture, fixtures and equipment replacement fund		$ 20