    <SEC-DOCUMENT>0001193125-24-130254-index.html : 20240503
    <SEC-HEADER>0001193125-24-130254.hdr.sgml : 20240503
    <ACCEPTANCE-DATETIME>20240503104414
    ACCESSION NUMBER:		0001193125-24-130254
    CONFORMED SUBMISSION TYPE:	N-CSR
    PUBLIC DOCUMENT COUNT:		30
    CONFORMED PERIOD OF REPORT:	20240229
    FILED AS OF DATE:		20240503
    DATE AS OF CHANGE:		20240503
    EFFECTIVENESS DATE:		20240503

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			NUVEEN CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    		CENTRAL INDEX KEY:			0000885732
    		ORGANIZATION NAME:
    		IRS NUMBER:				363828111
    		STATE OF INCORPORATION:			MA

    	FILING VALUES:
    		FORM TYPE:		N-CSR
    		SEC ACT:		1940 Act
    		SEC FILE NUMBER:	811-06623
    		FILM NUMBER:		24911380

    	BUSINESS ADDRESS:
    		STREET 1:		333 W WACKER DR
    		CITY:			CHICAGO
    		STATE:			IL
    		ZIP:			60606
    		BUSINESS PHONE:		3129178200

    	MAIL ADDRESS:
    		STREET 1:		333 W WACKER DRIVE
    		CITY:			CHICAGO
    		STATE:			IL
    		ZIP:			60606

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	NUVEEN INSURED CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    		DATE OF NAME CHANGE:	19920929

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	NUVEEN CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    		DATE OF NAME CHANGE:	19600201
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>N-CSR
    <SEQUENCE>1
    <FILENAME>d804833dncsr.htm
    <DESCRIPTION>NUVEEN CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO
    <TEXT>
    Document 1 - file: d804833dncsr.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.CERT
    <SEQUENCE>2
    <FILENAME>d804833dex99cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT
    <TEXT>
    Document 2 - file: d804833dex99cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.906 CERT
    <SEQUENCE>3
    <FILENAME>d804833dex99906cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT
    <TEXT>
    Document 3 - file: d804833dex99906cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.PROXYVOTE
    <SEQUENCE>4
    <FILENAME>d804833dex99proxyvote.htm
    <DESCRIPTION>EX-99.PROXYVOTE
    <TEXT>
    Document 4 - file: d804833dex99proxyvote.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.13C
    <SEQUENCE>5
    <FILENAME>d804833dex9913c.htm
    <DESCRIPTION>CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
    <TEXT>
    Document 5 - file: d804833dex9913c.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>6
    <FILENAME>ncstfip-20240229.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA
    <TEXT>
    Document 6 - file: ncstfip-20240229.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.DEF
    <SEQUENCE>7
    <FILENAME>ncstfip-20240229_def.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION DEFINITION LINKBASE
    <TEXT>
    Document 7 - file: ncstfip-20240229_def.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>8
    <FILENAME>ncstfip-20240229_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE
    <TEXT>
    Document 8 - file: ncstfip-20240229_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>9
    <FILENAME>ncstfip-20240229_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE
    <TEXT>
    Document 9 - file: ncstfip-20240229_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>g804833g1dsp14-1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: g804833g1dsp14-1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>g804833g1dsp14-2.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: g804833g1dsp14-2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>g804833g1g02h87.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: g804833g1g02h87.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>g804833g1g21i12.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: g804833g1g21i12.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>g804833g1g27b67.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: g804833g1g27b67.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>g804833g1g30p15.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: g804833g1g30p15.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>g804833g1g46q90.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: g804833g1g46q90.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>g804833g1g50u63.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: g804833g1g50u63.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>g804833g1g85c24.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 18 - file: g804833g1g85c24.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>g804833g1g98h16.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 19 - file: g804833g1g98h16.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>g804833g1stp1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 20 - file: g804833g1stp1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>21
    <FILENAME>g804833g1stp1b.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 21 - file: g804833g1stp1b.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>23
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 23 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>24
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 24 - file: Financial_Report.xlsx

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>25
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 25 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>26
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 26 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>28
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 28 - file: FilingSummary.html

    Document 28 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>31
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 31 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>32
    <FILENAME>0001193125-24-130254-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 32 - file: 0001193125-24-130254-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>34
    <FILENAME>d804833dncsr_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 34 - file: d804833dncsr_htm.html

    Document 34 - RAW XML: d804833dncsr_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>