| Form N-CSR Cover | 6 Months Ended |
| Jul. 31, 2024 | |
| 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 | Jul. 31, 2024 |
| Shareholder Report | 6 Months Ended | |
| Jul. 31, 2024 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 | Jul. 31, 2024 | |
| Class A | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Growth Fund | |
| Class Name | Class A | |
| Trading Symbol | SCHAX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $22 0.41% | [1],[2] |
| Expenses Paid, Amount | $ 22 | [1] |
| Expense Ratio, Percent | 0.41% | [1] |
| Net Assets | $ 848,713,783 | |
| Holdings Count | $ / shares | 20 | [3] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $848,713,783 Total Number of Portfolio Holdings * 20 Portfolio Turnover Rate 34% | [3] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class C | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Growth Fund | |
| Class Name | Class C | |
| Trading Symbol | SCHCX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $58 1.11% | [4],[5] |
| Expenses Paid, Amount | $ 58 | [4] |
| Expense Ratio, Percent | 1.11% | [4] |
| Net Assets | $ 848,713,783 | |
| Holdings Count | $ / shares | 20 | [6] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $848,713,783 Total Number of Portfolio Holdings * 20 Portfolio Turnover Rate 34% | [6] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class I | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Growth Fund | |
| Class Name | Class I | |
| Trading Symbol | LANIX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $7 0.13% | [7],[8] |
| Expenses Paid, Amount | $ 7 | [7] |
| Expense Ratio, Percent | 0.13% | [7] |
| Net Assets | $ 848,713,783 | |
| Holdings Count | $ / shares | 20 | [9] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $848,713,783 Total Number of Portfolio Holdings * 20 Portfolio Turnover Rate 34% | [9] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class R | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Growth Fund | |
| Class Name | Class R | |
| Trading Symbol | LLLRX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 R 1 $36 0.69% | [10],[11] |
| Expenses Paid, Amount | $ 36 | [10] |
| Expense Ratio, Percent | 0.69% | [10] |
| Net Assets | $ 848,713,783 | |
| Holdings Count | $ / shares | 20 | [12] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $848,713,783 Total Number of Portfolio Holdings * 20 Portfolio Turnover Rate 34% | [12] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class A | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Moderate Growth Fund | |
| Class Name | Class A | |
| Trading Symbol | SCGRX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Moderate Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $22 0.42% | [13],[14] |
| Expenses Paid, Amount | $ 22 | [13] |
| Expense Ratio, Percent | 0.42% | [13] |
| Net Assets | $ 501,374,305 | |
| Holdings Count | $ / shares | 21 | [15] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $501,374,305 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [15] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class C | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Moderate Growth Fund | |
| Class Name | Class C | |
| Trading Symbol | SCGCX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Moderate Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $60 1.16% | [16],[17] |
| Expenses Paid, Amount | $ 60 | [16] |
| Expense Ratio, Percent | 1.16% | [16] |
| Net Assets | $ 501,374,305 | |
| Holdings Count | $ / shares | 21 | [18] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $501,374,305 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [18] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class R | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Moderate Growth Fund | |
| Class Name | Class R | |
| Trading Symbol | LLMRX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Moderate Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 R 1 $42 0.80% | [19],[20],[21] |
| Expenses Paid, Amount | $ 42 | [19] |
| Expense Ratio, Percent | 0.80% | [19] |
| Net Assets | $ 501,374,305 | |
| Holdings Count | $ / shares | 21 | [22] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $501,374,305 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [22] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class I | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Moderate Growth Fund | |
| Class Name | Class I | |
| Trading Symbol | LLAIX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Moderate Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $6 0.12% | [23],[24] |
| Expenses Paid, Amount | $ 6 | [23] |
| Expense Ratio, Percent | 0.12% | [23] |
| Net Assets | $ 501,374,305 | |
| Holdings Count | $ / shares | 21 | [25] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $501,374,305 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [25] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class A | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Conservative Growth Fund | |
| Class Name | Class A | |
| Trading Symbol | SBBAX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Conservative Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $23 0.44% | [26],[27] |
| Expenses Paid, Amount | $ 23 | [26] |
| Expense Ratio, Percent | 0.44% | [26] |
| Net Assets | $ 291,613,068 | |
| Holdings Count | $ / shares | 21 | [28] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $291,613,068 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [28] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class C | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Conservative Growth Fund | |
| Class Name | Class C | |
| Trading Symbol | SCBCX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Conservative Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $62 1.21% | [29],[30] |
| Expenses Paid, Amount | $ 62 | [29] |
| Expense Ratio, Percent | 1.21% | [29] |
| Net Assets | $ 291,613,068 | |
| Holdings Count | $ / shares | 21 | [31] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $291,613,068 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [31] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class I | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Conservative Growth Fund | |
| Class Name | Class I | |
| Trading Symbol | LMEIX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Conservative Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $7 0.13% | [32],[33] |
| Expenses Paid, Amount | $ 7 | [32] |
| Expense Ratio, Percent | 0.13% | [32] |
| Net Assets | $ 291,613,068 | |
| Holdings Count | $ / shares | 21 | [34] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $291,613,068 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [34] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class R | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Conservative Growth Fund | |
| Class Name | Class R | |
| Trading Symbol | LLARX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Conservative Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 R 1 $40 0.78% | [35],[36] |
| Expenses Paid, Amount | $ 40 | [35] |
| Expense Ratio, Percent | 0.78% | [35] |
| Net Assets | $ 291,613,068 | |
| Holdings Count | $ / shares | 21 | [37] |
| Investment Company Portfolio Turnover | 34% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $291,613,068 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 34% | [37] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class A | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Defensive Growth Fund | |
| Class Name | Class A | |
| Trading Symbol | SBCPX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Defensive Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $29 0.57% | [38],[39] |
| Expenses Paid, Amount | $ 29 | [38] |
| Expense Ratio, Percent | 0.57% | [38] |
| Net Assets | $ 106,701,444 | |
| Holdings Count | $ / shares | 21 | [40] |
| Investment Company Portfolio Turnover | 36% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $106,701,444 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 36% | [40] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class C | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Defensive Growth Fund | |
| Class Name | Class C | |
| Trading Symbol | LWLAX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Defensive Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $69 1.36% | [41],[42] |
| Expenses Paid, Amount | $ 69 | [41] |
| Expense Ratio, Percent | 1.36% | [41] |
| Net Assets | $ 106,701,444 | |
| Holdings Count | $ / shares | 21 | [43] |
| Investment Company Portfolio Turnover | 36% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $106,701,444 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 36% | [43] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class C1 | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Defensive Growth Fund | |
| Class Name | Class C1 | |
| Trading Symbol | SBCLX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Defensive Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 C1 1 $64 1.25% | [44],[45],[46] |
| Expenses Paid, Amount | $ 64 | [44] |
| Expense Ratio, Percent | 1.25% | [44] |
| Net Assets | $ 106,701,444 | |
| Holdings Count | $ / shares | 21 | [47] |
| Investment Company Portfolio Turnover | 36% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $106,701,444 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 36% | [47] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class I | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Defensive Growth Fund | |
| Class Name | Class I | |
| Trading Symbol | LMGIX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Defensive Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 1 $13 0.25% | [48],[49],[50] |
| Expenses Paid, Amount | $ 13 | [48] |
| Expense Ratio, Percent | 0.25% | [48] |
| Net Assets | $ 106,701,444 | |
| Holdings Count | $ / shares | 21 | [51] |
| Investment Company Portfolio Turnover | 36% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $106,701,444 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 36% | [51] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| Class R | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Franklin Multi-Asset Defensive Growth Fund | |
| Class Name | Class R | |
| Trading Symbol | LMLRX | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Franklin Multi-Asset Defensive Growth Fund for the period February 1, 2024, to July 31, 2024. | |
| 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 R 1 $41 0.80% | [52],[53],[54] |
| Expenses Paid, Amount | $ 41 | [52] |
| Expense Ratio, Percent | 0.80% | [52] |
| Net Assets | $ 106,701,444 | |
| Holdings Count | $ / shares | 21 | [55] |
| Investment Company Portfolio Turnover | 36% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of July 31, 2024) Total Net Assets $106,701,444 Total Number of Portfolio Holdings * 21 Portfolio Turnover Rate 36% | [55] |
| Holdings [Text Block] | ||
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| [1] 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. * Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. * Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. * Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher. † Annualized. * Does not include derivatives, except purchased options, if any. 1 Excludes fees and expenses of the underlying funds in which the Fund invests. * Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher. † Annualized. * Does not include derivatives, except purchased options, if any. | ||
| Shareholder Report, Holdings (Details) | Jul. 31, 2024 |
| Class A | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 74% |
| Class A | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.10% |
| Class A | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.70% |
| Class A | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2% |
| Class A | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| Class C | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 74% |
| Class C | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.10% |
| Class C | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.70% |
| Class C | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2% |
| Class C | Short-Term Investment [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| Class I | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 74% |
| Class I | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.10% |
| Class I | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.70% |
| Class I | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2% |
| Class I | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| Class R | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 74% |
| Class R | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.10% |
| Class R | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.70% |
| Class R | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2% |
| Class R | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| Class A | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 62% |
| Class A | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17% |
| Class A | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 15.50% |
| Class A | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| Class A | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class C | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 62% |
| Class C | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17% |
| Class C | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 15.50% |
| Class C | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| Class C | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class R | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 62% |
| Class R | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17% |
| Class R | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 15.50% |
| Class R | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| Class R | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class I | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 62% |
| Class I | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17% |
| Class I | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 15.50% |
| Class I | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| Class I | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class A | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 45.80% |
| Class A | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 31% |
| Class A | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.40% |
| Class A | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.70% |
| Class A | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class C | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 45.80% |
| Class C | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 31% |
| Class C | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.40% |
| Class C | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.70% |
| Class C | Short-Term Investment [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class I | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 45.80% |
| Class I | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 31% |
| Class I | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.40% |
| Class I | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.70% |
| Class I | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class R | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 45.80% |
| Class R | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 31% |
| Class R | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.40% |
| Class R | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.70% |
| Class R | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class A | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 44.80% |
| Class A | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 29.50% |
| Class A | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.40% |
| Class A | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.20% |
| Class A | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class C | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 44.80% |
| Class C | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 29.50% |
| Class C | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.40% |
| Class C | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.20% |
| Class C | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class C1 | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 44.80% |
| Class C1 | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 29.50% |
| Class C1 | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.40% |
| Class C1 | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.20% |
| Class C1 | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class I | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 44.80% |
| Class I | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 29.50% |
| Class I | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.40% |
| Class I | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.20% |
| Class I | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| Class R | Domestic Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 44.80% |
| Class R | Domestic Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 29.50% |
| Class R | Foreign Fixed Income [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.40% |
| Class R | Foreign Equity [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.20% |
| Class R | Short-Term Investments [Member] | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
