v3.25.2
Shareholder Report
 6 Months Ended
Jun. 30, 2025
USD ($)
$ / shares
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Legg Mason Partners Investment Trust
Entity Central Index Key 0000880366
Entity Investment Company Type N-1A
Document Period End Date Jun. 30, 2025
Class A  
Shareholder Report [Line Items]  
Fund Name BrandywineGLOBAL - Corporate Credit Fund
Class Name Class A
Trading Symbol BCAAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BrandywineGLOBAL - Corporate Credit Fund for the period January 1, 2025, to June 30, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
Expenses [Text Block]
WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment)
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment*,†
Class A
$40
0.80%
[1],[2]
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.80%
Net Assets $ 2,423,028,817
Holdings Count | $ / shares 228 [3]
Investment Company Portfolio Turnover 56.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of June 30, 2025)
Total Net Assets
$2,423,028,817
Total Number of Portfolio Holdings*
228
Portfolio Turnover Rate
56%
[3]
Holdings [Text Block]
image
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class C  
Shareholder Report [Line Items]  
Fund Name BrandywineGLOBAL - Corporate Credit Fund
Class Name Class C
Trading Symbol BGGCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BrandywineGLOBAL - Corporate Credit Fund for the period January 1, 2025, to June 30, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
Expenses [Text Block]
WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment)
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment*,†
Class C
$76
1.53%
[4],[5]
Expenses Paid, Amount $ 76
Expense Ratio, Percent 1.53%
Net Assets $ 2,423,028,817
Holdings Count | $ / shares 228 [6]
Investment Company Portfolio Turnover 56.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of June 30, 2025)
Total Net Assets
$2,423,028,817
Total Number of Portfolio Holdings*
228
Portfolio Turnover Rate
56%
[6]
Holdings [Text Block]
image
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class I  
Shareholder Report [Line Items]  
Fund Name BrandywineGLOBAL - Corporate Credit Fund
Class Name Class I
Trading Symbol BCGIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BrandywineGLOBAL - Corporate Credit Fund for the period January 1, 2025, to June 30, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
Expenses [Text Block]
WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment)
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment*,†
Class I
$29
0.57%
[7],[8]
Expenses Paid, Amount $ 29
Expense Ratio, Percent 0.57%
Net Assets $ 2,423,028,817
Holdings Count | $ / shares 228 [9]
Investment Company Portfolio Turnover 56.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of June 30, 2025)
Total Net Assets
$2,423,028,817
Total Number of Portfolio Holdings*
228
Portfolio Turnover Rate
56%
[9]
Holdings [Text Block]
image
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class IS  
Shareholder Report [Line Items]  
Fund Name BrandywineGLOBAL - Corporate Credit Fund
Class Name Class IS
Trading Symbol BGISX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BrandywineGLOBAL - Corporate Credit Fund for the period January 1, 2025, to June 30, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
Expenses [Text Block]
WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment)
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment*,†
Class IS
$24
0.47%
[10],[11]
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.47%
Net Assets $ 2,423,028,817
Holdings Count | $ / shares 228 [12]
Investment Company Portfolio Turnover 56.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of June 30, 2025)
Total Net Assets
$2,423,028,817
Total Number of Portfolio Holdings*
228
Portfolio Turnover Rate
56%
[12]
Holdings [Text Block]
image
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
[1]
* Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher.
[2]
† Annualized.
[3]
* Does not include derivatives, except purchased options, if any.
[4]
* Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher.
[5]
† Annualized.
[6]
* Does not include derivatives, except purchased options, if any.
[7]
* Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher.
[8]
† Annualized.
[9]
* Does not include derivatives, except purchased options, if any.
[10]
* Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher.
[11]
† Annualized.
[12]
* Does not include derivatives, except purchased options, if any.