| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | JNL Investors Series Trust |
| Entity Central Index Key | 0001121257 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holdings | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | JNL Investors Series Trust |
| Entity Central Index Key | 0001121257 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Share Class I | |
| Shareholder Report [Line Items] | |
| Fund Name | JNL Government Money Market Fund |
| Class Name | Share Class I |
| No Trading Symbol | true |
| Annual or Semi-Annual Statement [Text Block] | Semi-Annual Shareholder Report |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | This shareholder report contains important information about JNL Government Money Market Fund for the period ended June 30, 2024. You can find additional information at https://www.jackson.com/fund-literature.html. 1-800-644-4565 DocumentRequest jackson.com. This report describes changes to the Fund that occurred during the period, if applicable. |
| Additional Information Phone Number | 1-800-644-4565 |
| Additional Information Email | DocumentRequest@jackson.com. |
| Additional Information Website | https://www.jackson.com/fund-literature.html. |
| Expenses [Text Block] | What were the Fund costs for the last six months? Share Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class I $10 0.19% |
| Expenses Paid, Amount | $ 10 |
| Expense Ratio, Percent | 0.19% |
| Net Assets | $ 2,809,633 |
| Holdings Count | Holdings | 53 |
| Advisory Fees Paid, Amount | $ 875 |
| Additional Fund Statistics [Text Block] | What are some key Fund statistics as of June 30, 2024? Fund Statistic Value ($ in thousands) Fund Size ($): 2,809,633 Number of Investments: 53 Total Advisory Fees Paid ($): 875 |
| Holdings [Text Block] | What did the Fund invest in as of June 30, 2024? Top 10 Holdings (%) Repurchase Agreement with FICC, 5.32%, 07/01/24 21.4 Repurchase Agreement with CTC, 5.32%, 07/01/24 17.8 Repurchase Agreement with CIB, 5.33%, 07/01/24 10.7 Repurchase Agreement with BNS, 5.32%, 07/01/24 7.1 Treasury, United States Department of, 5.46%, 04/30/26 2.1 FHLBanks Office of Finance, 5.32%, 09/27/24 1.9 Federal Home Loan Bank of New York, 5.36%, 12/03/24 1.7 Treasury, United States Department of, 5.20%, 08/15/24 1.6 Federal Home Loan Bank of Topeka, 5.34%, 10/08/24 1.5 Treasury, United States Department of, 5.32%, 09/05/24 1.5 Total Net Assets 67.3 JNL Government Money Market Fund true true true true true |
| Share Class SL | |
| Shareholder Report [Line Items] | |
| Fund Name | JNL Government Money Market Fund |
| Class Name | Share Class SL |
| No Trading Symbol | true |
| Annual or Semi-Annual Statement [Text Block] | Semi-Annual Shareholder Report |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | This shareholder report contains important information about JNL Government Money Market Fund for the period ended June 30, 2024. You can find additional information at https://www.jackson.com/fund-literature.html 1-800-644-4565 DocumentRequest jackson.com This report describes changes to the Fund that occurred during the period, if applicable. |
| Additional Information Phone Number | 1-800-644-4565 |
| Additional Information Email | DocumentRequest@jackson.com |
| Additional Information Website | https://www.jackson.com/fund-literature.html |
| Expenses [Text Block] | What were the Fund costs for the last six months? Share Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class SL $5 0.09% |
| Expenses Paid, Amount | $ 5 |
| Expense Ratio, Percent | 0.09% |
| Net Assets | $ 2,809,633 |
| Holdings Count | Holdings | 53 |
| Advisory Fees Paid, Amount | $ 875 |
| Additional Fund Statistics [Text Block] | What are some key Fund statistics as of June 30, 2024? Fund Statistic Value ($ in thousands) Fund Size ($): 2,809,633 Number of Investments: 53 Total Advisory Fees Paid ($): 875 |
| Holdings [Text Block] | What did the Fund invest in as of June 30, 2024? Top 10 Holdings (%) Repurchase Agreement with FICC, 5.32%, 07/01/24 21.4 Repurchase Agreement with CTC, 5.32%, 07/01/24 17.8 Repurchase Agreement with CIB, 5.33%, 07/01/24 10.7 Repurchase Agreement with BNS, 5.32%, 07/01/24 7.1 Treasury, United States Department of, 5.46%, 04/30/26 2.1 FHLBanks Office of Finance, 5.32%, 09/27/24 1.9 Federal Home Loan Bank of New York, 5.36%, 12/03/24 1.7 Treasury, United States Department of, 5.20%, 08/15/24 1.6 Federal Home Loan Bank of Topeka, 5.34%, 10/08/24 1.5 Treasury, United States Department of, 5.32%, 09/05/24 1.5 Total Net Assets 67.3 JNL Government Money Market Fund true |
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| Share Class I | Repurchase Agreementwith F I C C 5320701242 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.40% |
| Share Class I | Repurchase Agreementwith C T C 5320701243 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.80% |
| Share Class I | Repurchase Agreementwith C I B 5330701244 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.70% |
| Share Class I | Repurchase Agreementwith B N S 5320701245 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.10% |
| Share Class I | Treasury United States Departmentof 5460430266 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| Share Class I | F H L Banks Officeof Finance 5320927247 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| Share Class I | Federal Home Loan Bankof New York 5361203248 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| Share Class I | Treasury United States Departmentof 5200815249 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| Share Class I | Federal Home Loan Bankof Topeka 53410082410 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Share Class I | Treasury United States Departmentof 53209052411 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Share Class I | Total Net Assets 12 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 67.30% |
| Share Class SL | Repurchase Agreementwith F I C C 53207012447 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.40% |
| Share Class SL | Repurchase Agreementwith C T C 53207012448 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.80% |
| Share Class SL | Repurchase Agreementwith C I B 53307012449 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.70% |
| Share Class SL | Repurchase Agreementwith B N S 53207012450 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.10% |
| Share Class SL | Treasury United States Departmentof 54604302651 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| Share Class SL | F H L Banks Officeof Finance 53209272452 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| Share Class SL | Federal Home Loan Bankof New York 53612032453 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| Share Class SL | Treasury United States Departmentof 52008152454 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| Share Class SL | Federal Home Loan Bankof Topeka 53410082455 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Share Class SL | Treasury United States Departmentof 53209052456 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Share Class SL | Total Net Assets 57 [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 67.30% |
