Host Inc. Earnings (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
NET INCOME (LOSS)	$ (316)	$ 372	$ (675)	$ 851
Less: Net (income) loss attributable to non-controlling interests	3	(4)	7	(11)
NET INCOME (LOSS) ATTRIBUTABLE TO HOST HOTELS & RESORTS, INC.	$ (313)	$ 368	$ (668)	$ 840
Basic weighted average shares outstanding	705.2	725.5	706.1	735.0
Assuming distribution of common shares granted under the comprehensive stock plans, less shares assumed purchased at market		0.3		0.4
Diluted weighted average shares/units outstanding	705.2	725.8	706.1	735.4
Basic earnings (loss) per common share	$ (0.44)	$ 0.51	$ (0.95)	$ 1.14
Diluted earnings (loss) per common share	$ (0.44)	$ 0.51	$ (0.95)	$ 1.14