Host Inc. Earnings (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
NET INCOME	$ 189	$ 256
Less: Net income attributable to non-controlling interests	(3)	(3)
NET INCOME ATTRIBUTABLE TO REPORTING ENTITY	$ 186	$ 253
Basic weighted average shares outstanding	740.6	739.2
Assuming distribution of common shares granted under the comprehensive stock plans, less shares assumed purchased at market	0.2	0.4
Diluted weighted average shares/units outstanding	740.8	739.6
Basic earnings per common share	$ 0.25	$ 0.34
Diluted earnings per common share	$ 0.25	$ 0.34