| N-2 - $ / shares | Dec. 13, 2023 | Dec. 11, 2023 |
| Cover [Abstract] | ||
| Entity Central Index Key | 0000925683 | |
| Amendment Flag | false | |
| Document Type | 424B3 | |
| Entity Registrant Name | John Hancock Financial Opportunities Fund | |
| General Description of Registrant [Abstract] | ||
| Share Price | $ 29.33 | |
| NAV Per Share | $ 28.03 | |
| Latest Premium (Discount) to NAV [Percent] | 4.64% |
