Host Inc. Earnings Per Common Share (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 145		$ 18		$ 489		$ 199
Less: Net (income) loss attributable to non-controlling interests	(1)		1		(11)		(5)
Net income attributable to Host Inc.	144		19		478		194
Diluted income attributable to Host Inc.	$ 144		$ 19		$ 478		$ 194
Basic weighted average shares outstanding	755.6		749.0		755.3		740.9
Assuming weighted average shares for conversion of exchangeable senior debentures							3.2
Assuming distribution of common shares granted under the comprehensive stock plans, less shares assumed purchased at market	0.8		0.7		0.7		0.8
Diluted weighted average shares outstanding	756.4	[1]	749.7	[1]	756.0	[1]	744.9	[1]
Basic earnings per common share	$ 0.19		$ 0.03		$ 0.63		$ 0.26
Diluted earnings per common share	$ 0.19		$ 0.03		$ 0.63		$ 0.26

[1] There were approximately 30 million potentially dilutive shares for both the quarter and year-to-date periods ended September 30, 2014, and approximately 30 million and 29 million potentially dilutive shares for the quarter and year-to-date periods ended September 30, 2013, respectively, related to our exchangeable senior debentures, which shares were not included in the computation of diluted earnings per share because to do so would have been anti-dilutive for the period. Net income allocated to non-controlling interests of Host L.P. has been excluded from the numerator and common OP units in Host L.P. have been omitted from the denominator for the purpose of computing diluted earnings per share since the effect of including these amounts would have no impact.