Debt - Additional Information (Detail)	3 Months Ended	6 Months Ended
Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Debt Instrument [Line Items]
Repayment of credit facility		$ 750,000,000
Covenant Relief Period \| Maximum
Debt Instrument [Line Items]
Net cash proceeds as a mandatory prepayment of amounts outstanding under the Credit Facility	$ 350,000,000
Credit Facilities [Member]
Debt Instrument [Line Items]
Debt instrument increase in interest rate	0.40%
Consent fee	0.075%
Credit Facilities [Member] \| Interest Rate Floor \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Interest rate floor	0.15%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayment of credit facility	$ 750,000,000
Line of credit facility remaining borrowing capacity	750,000,000	750,000,000
Revolving Credit Facility [Member] \| Covenant Relief Period
Debt Instrument [Line Items]
Credit facility, minimum liquidity covenant	$ 300,000,000	$ 300,000,000
Revolving Credit Facility [Member] \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate	1.30%
Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate	1.40%

Debt instrument interest rate floor.

No definition available.

Name:	hst_DebtInstrumentInterestRateFloor
Namespace Prefix:	hst_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the debt issuance fee, expressed as a percentage of the debt instrument face value.

+ References

No definition available.

+ Details

Name:	hst_DebtInstrumentIssuanceFeePercentage
Namespace Prefix:	hst_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum liquidity requirement under the credit facility.

+ References

No definition available.

+ Details

Name:	hst_LineOfCreditFacilityMinimumLiquidityCovenant
Namespace Prefix:	hst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Incremental percentage increase (decrease) in the stated rate on a debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentInterestRateIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateFloorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=hst_TermLoanMember
Namespace Prefix:
Data Type:	na
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Period Type: