Label	Element	Value
Prospectus [Line Items]	rr_ProspectusLineItems
Document Type	dei_DocumentType	497
Document Period End Date	dei_DocumentPeriodEndDate	May 31, 2022
Entity Registrant Name	dei_EntityRegistrantName	JOHN HANCOCK CALIFORNIA TAX-FREE INCOME FUND
Entity Central Index Key	dei_EntityCentralIndexKey	0000856671
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Jun. 23, 2022
Document Effective Date	dei_DocumentEffectiveDate	Jun. 23, 2022
JOHN HANCOCK CALIFORNIA TAX-FREE INCOME FUND
Prospectus [Line Items]	rr_ProspectusLineItems
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder fees (%) (fees paid directly from your investment)
JOHN HANCOCK CALIFORNIA TAX-FREE INCOME FUND \| Class A
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum Cumulative Sales Charge (as a percentage)	rr_MaximumCumulativeSalesChargeOverOther	4.00%
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	1.00%
Shareholder Fee, Other	rr_ShareholderFeeOther	$ 20
JOHN HANCOCK CALIFORNIA TAX-FREE INCOME FUND \| Class C
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum Cumulative Sales Charge (as a percentage)	rr_MaximumCumulativeSalesChargeOverOther	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	1.00%
Shareholder Fee, Other	rr_ShareholderFeeOther	$ 20
JOHN HANCOCK CALIFORNIA TAX-FREE INCOME FUND \| Class I
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum Cumulative Sales Charge (as a percentage)	rr_MaximumCumulativeSalesChargeOverOther	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	none
Shareholder Fee, Other	rr_ShareholderFeeOther	none
JOHN HANCOCK CALIFORNIA TAX-FREE INCOME FUND \| Class R6
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum Cumulative Sales Charge (as a percentage)	rr_MaximumCumulativeSalesChargeOverOther	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	none
Shareholder Fee, Other	rr_ShareholderFeeOther	none

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

No definition available.

Name:	dei_AmendmentFlag
Namespace Prefix:	dei_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

- Definition

The date the document was made available and submitted, in YYYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.

+ References

No definition available.

+ Details

Name:	dei_DocumentCreationDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The date when a document, upon receipt and acceptance, becomes officially effective, in YYYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.

+ References

No definition available.

+ Details

Name:	dei_DocumentEffectiveDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:	dei_DocumentPeriodEndDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:	dei_DocumentType
Namespace Prefix:	dei_
Data Type:	dei:submissionTypeItemType
Balance Type:	na
Period Type:	duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2

+ Details

Name:	dei_EntityCentralIndexKey
Namespace Prefix:	dei_
Data Type:	dei:centralIndexKeyItemType
Balance Type:	na
Period Type:	duration

- Definition

One of: N-1A (Mutual Fund), N-1 (Open-End Separate Account with No Variable Annuities), N-2 (Closed-End Investment Company), N-3 (Separate Account Registered as Open-End Management Investment Company), N-4 (Variable Annuity UIT Separate Account), N-5 (Small Business Investment Company), N-6 (Variable Life UIT Separate Account), S-1 or S-3 (Face Amount Certificate Company), S-6 (UIT, Non-Insurance Product).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-T
-Number 232
-Section 313

+ Details

Name:	dei_EntityInvCompanyType
Namespace Prefix:	dei_
Data Type:	dei:invCompanyType
Balance Type:	na
Period Type:	duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2

+ Details

Name:	dei_EntityRegistrantName
Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price). If a sales charge (load) is imposed on shares purchased with reinvested capital gains distributions or returns of capital, include the bracketed words in the third caption.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Subsection table
-Paragraph 1
-Subparagraph 1

+ Details

Name:	rr_MaximumCumulativeSalesChargeOverOther
Namespace Prefix:	rr_
Data Type:	rr:NonNegativePure4Type
Balance Type:	na
Period Type:	duration

- Definition

Maximum Deferred Sales Charge (Load) (as a percentage of ____) "Maximum Deferred Sales Charge (Load)" includes the maximum total deferred sales charge (load) payable upon redemption, in installments, or both, expressed as a percentage of the amount or amounts stated in response to Item 7(a), except that, for a sales charge (load) based on net asset value at the time of purchase, show the sales charge (load) as a percentage of the offering price at the time of purchase. A Fund may include in a footnote to the table, if applicable, a tabular presentation showing the amount of deferred sales charges (loads) over time or a narrative explanation of the sales charges (loads) (e.g., __% in the first year after purchase, declining to __% in the __ year and eliminated thereafter). If more than one type of sales charge (load) is imposed (e.g., a deferred sales charge (load) and a front-end sales charge (load)), the first caption in the table should read "Maximum Sales Charge (Load)" and show the maximum cumulative percentage. Show the percentage amounts and the terms of each sales charge (load) comprising that figure on separate lines below.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Subsection instructions
-Paragraph 2
-Subparagraph a
-Clause i

+ Details

Name:	rr_MaximumDeferredSalesChargeOverOther
Namespace Prefix:	rr_
Data Type:	rr:NonNegativePure4Type
Balance Type:	na
Period Type:	duration

- References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A

+ Details

Name:	rr_ProspectusLineItems
Namespace Prefix:	rr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Other Expenses

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Subsection table
-Paragraph 1
-Subparagraph 10

+ Details

Name:	rr_ShareholderFeeOther
Namespace Prefix:	rr_
Data Type:	rr:NonNegativeMonetaryType
Balance Type:	na
Period Type:	duration

- Definition

Shareholder Fees (fees paid directly from your investment).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Subsection table
-Paragraph 1

+ Details

Name:	rr_ShareholderFeesCaption
Namespace Prefix:	rr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=jhctif_S000000616Member
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	rr_ProspectusShareClassAxis=jhctif_C000001742Member
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	rr_ProspectusShareClassAxis=jhctif_C000001744Member
Namespace Prefix:
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- Details

Name:	rr_ProspectusShareClassAxis=jhctif_C000178768Member
Namespace Prefix:
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- Details

Name:	rr_ProspectusShareClassAxis=jhctif_C000193017Member
Namespace Prefix:
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