Percentage earned from carried interest profits.

No definition available.

Name:	hst_CarriedInterestEarnedPercentage
Namespace Prefix:	hst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Additional ownership percentage in equity method investee that may be exercised.

+ References

No definition available.

+ Details

Name:	hst_EquityMethodInvesteePotentialAdditionalOwnershipPercentage
Namespace Prefix:	hst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Equity method investee potential future ownership percentage.

+ References

No definition available.

+ Details

Name:	hst_EquityMethodInvesteePotentialFutureOwnershipPercentage
Namespace Prefix:	hst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of financial support to be provided in future by investment company to investee.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66023616&loc=SL35737436-115832

+ Details

Name:	us-gaap_InvestmentCompanyFinancialCommitmentToInvesteeFutureAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=hst_NobleManagementHoldingsLlcAndNobleInvestmentHoldingsLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=hst_NobleInvestmentGroupLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=hst_HostLimitedPartnershipInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments in Affiliates - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended
	Jan. 20, 2022	Mar. 31, 2022	Mar. 31, 2021
Investments in and Advances to Affiliates [Line Items]
Cash investments in affiliates		$ 44	$ 5
Noble Management Holdings LLC and Noble Investment Holdings LLC [Member]
Investments in and Advances to Affiliates [Line Items]
Cash investments in affiliates	$ 35
Business Combination, percentage of gross carried interest earned	40.00%
Investments in affiliates capital commitments	$ 150
Noble Management Holdings LLC and Noble Investment Holdings LLC [Member] \| Maximum [Member]
Investments in and Advances to Affiliates [Line Items]
Business Combination, percentage of aggregate interest acquired	26.00%
Noble Management Holdings LLC and Noble Investment Holdings LLC [Member] \| Noble Investment Group LLC
Investments in and Advances to Affiliates [Line Items]
Business Acquisition, Percentage of voting interests acquired	49.00%
Equity method investee potential future ownership percentage	100.00%
Noble Management Holdings LLC and Noble Investment Holdings LLC [Member] \| Noble Investment Group LLC \| Host L.P.
Investments in and Advances to Affiliates [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 56