| N-2 - $ / shares | 6 Months Ended | ||||||
| Jun. 30, 2024 | Jun. 30, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | |
| Prospectus [Line Items] | |||||||
| Document Period End Date | Jun. 30, 2024 | ||||||
| Cover [Abstract] | |||||||
| Entity Central Index Key | 0000813623 | ||||||
| Amendment Flag | false | ||||||
| Document Type | N-CSRS | ||||||
| Entity Registrant Name | Swiss Helvetia Fund, Inc | ||||||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |||||||
| Capital Stock [Table Text Block] | Note 4—Capital Share Transactions The Fund is authorized to issue up to 50 million shares of capital stock. Transactions in capital shares were as follows: For the Period Ended For the Year Ended June 30, 2024 December 31, 2023 Shares Amount Shares Amount Dividends Reinvested — $ — — $ — Repurchased through Stock Repurchase Program (Note 6) — — (205,045 ) (1,687,724 ) Repurchased from Tender Offer — — — — Net Increase/(Decrease) — $ — (205,045 ) $ (1,687,724 ) | ||||||
| Common Shares [Member] | |||||||
| General Description of Registrant [Abstract] | |||||||
| Share Price | $ 8.07 | $ 8.07 | $ 8.20 | $ 7.56 | $ 9.94 | $ 8.94 | $ 8.41 |
| NAV Per Share | $ 9.59 | $ 9.59 | $ 9.76 | $ 8.80 | $ 11.50 | $ 10.45 | $ 9.71 |
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |||||||
| Outstanding Security, Authorized [Shares] | 50,000,000 | ||||||
| Outstanding Security, Not Held [Shares] | 12,990,705 |
