| Document and Entity Information | Sep. 26, 2023 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001181504 |
| Document Type | 8-K |
| Document Period End Date | Sep. 26, 2023 |
| Entity Registrant Name | PIMCO California Municipal Income Fund III |
| Entity Incorporation State Country Code | MA |
| Entity File Number | 811-21188 |
| Entity Tax Identification Number | 16-1624050 |
| Entity Address, Address Line One | 1633 Broadway |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10019 |
| City Area Code | (844) |
| Local Phone Number | 337-4626 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common shares |
| Trading Symbol | PZC |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
