Historical Cost and Redemption Values for Non-Controlling Interests (Detail) $ / shares in Units, shares in Millions, $ in Millions		Sep. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Book value (millions)		$ 170	$ 167
HOST HOTELS & RESORTS L.P.
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Common OP units outstanding (millions) | shares		7.9	8.2
Market price per Host Inc. common share | $ / shares		$ 21.10	$ 19.85
Shares issuable upon conversion of one common OP unit		1.021494	1.021494
Redemption value (millions)		$ 170	$ 167
Historical cost (millions)		81	80
Book value (millions)	[1]	$ 170	$ 167

[1] The book value recorded is equal to the greater of redemption value or historical cost.