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Shareholder Report
 6 Months Ended
Sep. 30, 2025
USD ($)
shares
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Fidelity Aberdeen Street Trust
Entity Central Index Key 0000880195
Entity Investment Company Type N-1A
Document Period End Date Sep. 30, 2025
Fidelity Sustainable Target Date Retirement Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity® Sustainable Target Date Retirement Fund
Trading Symbol FSUDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date Retirement Fund 
$ 21 
0.41%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.41%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Advisor Sustainable Target Date Retirement Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity Advisor® Sustainable Target Date Retirement Fund Class Z
Trading Symbol FSULX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 16 
0.31%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.31%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Advisor Sustainable Target Date Retirement Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity Advisor® Sustainable Target Date Retirement Fund Class M
Trading Symbol FSUHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 47 
0.91%
  
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.91%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Sustainable Target Date Retirement Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity® Sustainable Target Date Retirement Fund Class K6
Trading Symbol FSUWX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 11 
0.21%
  
Expenses Paid, Amount $ 11
Expense Ratio, Percent 0.21%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Sustainable Target Date Retirement Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity® Sustainable Target Date Retirement Fund Class K
Trading Symbol FSUOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 16 
0.31%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.31%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Advisor Sustainable Target Date Retirement Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity Advisor® Sustainable Target Date Retirement Fund Class I
Trading Symbol FSUJX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 21 
0.41%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.41%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Advisor Sustainable Target Date Retirement Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity Advisor® Sustainable Target Date Retirement Fund Class C
Trading Symbol FSUFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 73 
1.41%
  
Expenses Paid, Amount $ 73
Expense Ratio, Percent 1.41%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Advisor Sustainable Target Date Retirement Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date Retirement Fund
Class Name Fidelity Advisor® Sustainable Target Date Retirement Fund Class A
Trading Symbol FSUEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date Retirement Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 34 
0.66%
  
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.66%
Net Assets $ 1,395,674
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,395,674
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 70.3 International Equity Funds 13.0 Domestic Equity Funds 9.9 Short-Term Funds 6.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 70.3                          International Equity Funds - 13.0          Domestic Equity Funds - 9.9                Short-Term Funds - 6.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 41.4   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 20.4   Fidelity Series Sustainable U.S. Market Fund 9.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 8.8   Fidelity Series Treasury Bill Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.2   Fidelity Series Long-Term Treasury Bond Index Fund 3.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.4     100.0  
Fidelity Sustainable Target Date 2065 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity® Sustainable Target Date 2065 Fund
Trading Symbol FTGPX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2065 Fund 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2065 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2065 Fund Class Z
Trading Symbol FTHDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2065 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2065 Fund Class C
Trading Symbol FTGYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 81 
1.49%
  
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.49%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2065 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity® Sustainable Target Date 2065 Fund Class K6
Trading Symbol FTHHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 16 
0.29%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.29%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2065 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity® Sustainable Target Date 2065 Fund Class K
Trading Symbol FTHGX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2065 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2065 Fund Class I
Trading Symbol FTHBX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2065 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2065 Fund Class M
Trading Symbol FTGZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 54 
0.99%
  
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2065 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2065 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2065 Fund Class A
Trading Symbol FTGUX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2065 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.74%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.74%
Net Assets $ 5,592,435
Holdings Count | shares 6
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$5,592,435
  
Number of Holdings
6
  
Portfolio Turnover
14%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2060 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity® Sustainable Target Date 2060 Fund
Trading Symbol FSZSX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2060 Fund 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2060 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2060 Fund Class Z
Trading Symbol FTDLX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2060 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2060 Fund Class M
Trading Symbol FSZWX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 54 
0.99%
  
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2060 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity® Sustainable Target Date 2060 Fund Class K6
Trading Symbol FTGNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 16 
0.29%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.29%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2060 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity® Sustainable Target Date 2060 Fund Class K
Trading Symbol FTGKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2060 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2060 Fund Class I
Trading Symbol FSZYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2060 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2060 Fund Class C
Trading Symbol FSZVX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 81 
1.49%
  
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.49%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2060 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2060 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2060 Fund Class A
Trading Symbol FSZTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2060 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.74%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.74%
Net Assets $ 8,370,106
Holdings Count | shares 6
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$8,370,106
  
Number of Holdings
6
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2055 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity® Sustainable Target Date 2055 Fund
Trading Symbol FSZHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2055 Fund 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2055 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2055 Fund Class Z
Trading Symbol FSZNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2055 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2055 Fund Class M
Trading Symbol FSZLX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 54 
0.99%
  
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2055 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity® Sustainable Target Date 2055 Fund Class K6
Trading Symbol FSZRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 16 
0.29%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.29%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2055 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity® Sustainable Target Date 2055 Fund Class K
Trading Symbol FSZQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2055 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2055 Fund Class I
Trading Symbol FSZMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2055 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2055 Fund Class C
Trading Symbol FSZKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 81 
1.49%
  
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.49%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2055 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2055 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2055 Fund Class A
Trading Symbol FSZJX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2055 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.74%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.74%
Net Assets $ 10,009,909
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,009,909
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2050 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity® Sustainable Target Date 2050 Fund
Trading Symbol FSYWX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2050 Fund 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2050 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2050 Fund Class Z
Trading Symbol FSZCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2050 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2050 Fund Class M
Trading Symbol FSZAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 54 
0.99%
  
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2050 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity® Sustainable Target Date 2050 Fund Class K6
Trading Symbol FSZGX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 16 
0.29%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.29%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2050 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity® Sustainable Target Date 2050 Fund Class K
Trading Symbol FSZFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2050 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2050 Fund Class I
Trading Symbol FSZBX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2050 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2050 Fund Class C
Trading Symbol FSYZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 81 
1.49%
  
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.49%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2050 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2050 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2050 Fund Class A
Trading Symbol FSYYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2050 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.74%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.74%
Net Assets $ 13,882,240
Holdings Count | shares 7
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,882,240
  
Number of Holdings
7
  
Portfolio Turnover
13%
  
Holdings [Text Block]         Domestic Equity Funds 51.6 International Equity Funds 40.9 Bond Funds 6.4 Short-Term Funds 1.1 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.6               International Equity Funds - 40.9          Bond Funds - 6.4                           Short-Term Funds - 1.1                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.1   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2045 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity® Sustainable Target Date 2045 Fund
Trading Symbol FSYHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2045 Fund 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2045 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2045 Fund Class Z
Trading Symbol FSYSX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2045 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2045 Fund Class M
Trading Symbol FSYPX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 54 
0.99%
  
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2045 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity® Sustainable Target Date 2045 Fund Class K6
Trading Symbol FSYVX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 16 
0.29%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.29%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2045 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity® Sustainable Target Date 2045 Fund Class K
Trading Symbol FSYUX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2045 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2045 Fund Class I
Trading Symbol FSYQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2045 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2045 Fund Class C
Trading Symbol FSYOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 81 
1.49%
  
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.49%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2045 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2045 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2045 Fund Class A
Trading Symbol FSYLX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2045 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.74%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.74%
Net Assets $ 12,277,560
Holdings Count | shares 7
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$12,277,560
  
Number of Holdings
7
  
Portfolio Turnover
15%
  
Holdings [Text Block]         Domestic Equity Funds 51.5 International Equity Funds 40.8 Bond Funds 6.4 Short-Term Funds 1.3 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.5               International Equity Funds - 40.8          Bond Funds - 6.4                           Short-Term Funds - 1.3                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.5   Fidelity Series Sustainable Emerging Markets Fund 12.3   Fidelity Series Long-Term Treasury Bond Index Fund 6.4   Fidelity Series Treasury Bill Index Fund 1.3   Fidelity Series International Developed Markets Bond Index Fund 0.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2040 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity® Sustainable Target Date 2040 Fund
Trading Symbol FSXVX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2040 Fund 
$ 26 
0.48%
  
Expenses Paid, Amount $ 26
Expense Ratio, Percent 0.48%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Advisor Sustainable Target Date 2040 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2040 Fund Class Z
Trading Symbol FSYDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.38%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.38%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Advisor Sustainable Target Date 2040 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2040 Fund Class M
Trading Symbol FSXZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 53 
0.98%
  
Expenses Paid, Amount $ 53
Expense Ratio, Percent 0.98%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Sustainable Target Date 2040 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity® Sustainable Target Date 2040 Fund Class K6
Trading Symbol FSYGX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 15 
0.28%
  
Expenses Paid, Amount $ 15
Expense Ratio, Percent 0.28%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Sustainable Target Date 2040 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity® Sustainable Target Date 2040 Fund Class K
Trading Symbol FSYFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.38%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.38%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Advisor Sustainable Target Date 2040 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2040 Fund Class I
Trading Symbol FSYBX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 26 
0.48%
  
Expenses Paid, Amount $ 26
Expense Ratio, Percent 0.48%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Advisor Sustainable Target Date 2040 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2040 Fund Class C
Trading Symbol FSXYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 80 
1.48%
  
Expenses Paid, Amount $ 80
Expense Ratio, Percent 1.48%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Advisor Sustainable Target Date 2040 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2040 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2040 Fund Class A
Trading Symbol FSXWX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2040 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.73%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.73%
Net Assets $ 13,678,947
Holdings Count | shares 8
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$13,678,947
  
Number of Holdings
8
  
Portfolio Turnover
19%
  
Holdings [Text Block]         Domestic Equity Funds 46.5 International Equity Funds 37.6 Bond Funds 14.2 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 46.5               International Equity Funds - 37.6          Bond Funds - 14.2                          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 46.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 26.1   Fidelity Series Sustainable Emerging Markets Fund 11.5   Fidelity Series Long-Term Treasury Bond Index Fund 7.8   Fidelity Series Sustainable Investment Grade Bond Fund 3.6   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series International Developed Markets Bond Index Fund 1.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 1.4     100.0  
Fidelity Sustainable Target Date 2035 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity® Sustainable Target Date 2035 Fund
Trading Symbol FSXKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2035 Fund 
$ 25 
0.47%
  
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.47%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Advisor Sustainable Target Date 2035 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2035 Fund Class Z
Trading Symbol FSXRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 20 
0.37%
  
Expenses Paid, Amount $ 20
Expense Ratio, Percent 0.37%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Advisor Sustainable Target Date 2035 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2035 Fund Class M
Trading Symbol FSXOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 52 
0.97%
  
Expenses Paid, Amount $ 52
Expense Ratio, Percent 0.97%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Sustainable Target Date 2035 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity® Sustainable Target Date 2035 Fund Class K6
Trading Symbol FSXUX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 15 
0.27%
  
Expenses Paid, Amount $ 15
Expense Ratio, Percent 0.27%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Sustainable Target Date 2035 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity® Sustainable Target Date 2035 Fund Class K
Trading Symbol FSXTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 20 
0.37%
  
Expenses Paid, Amount $ 20
Expense Ratio, Percent 0.37%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Advisor Sustainable Target Date 2035 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2035 Fund Class I
Trading Symbol FSXQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 25 
0.47%
  
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.47%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Advisor Sustainable Target Date 2035 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2035 Fund Class C
Trading Symbol FSXNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 79 
1.47%
  
Expenses Paid, Amount $ 79
Expense Ratio, Percent 1.47%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Advisor Sustainable Target Date 2035 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2035 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2035 Fund Class A
Trading Symbol FSXLX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2035 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 39 
0.72%
  
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.72%
Net Assets $ 9,194,572
Holdings Count | shares 8
Investment Company Portfolio Turnover 29.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$9,194,572
  
Number of Holdings
8
  
Portfolio Turnover
29%
  
Holdings [Text Block]         Domestic Equity Funds 37.5 International Equity Funds 31.6 Bond Funds 29.3 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 37.5               International Equity Funds - 31.6          Bond Funds - 29.3                          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 37.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 21.9   Fidelity Series Sustainable Investment Grade Bond Fund 15.2   Fidelity Series Sustainable Emerging Markets Fund 9.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.7   Fidelity Series International Developed Markets Bond Index Fund 3.4   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 3.0   Fidelity Series Treasury Bill Index Fund 1.6     100.0  
Fidelity Sustainable Target Date 2030 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity® Sustainable Target Date 2030 Fund
Trading Symbol FSXAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2030 Fund 
$ 24 
0.46%
  
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.46%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2030 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2030 Fund Class Z
Trading Symbol FSXFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 19 
0.36%
  
Expenses Paid, Amount $ 19
Expense Ratio, Percent 0.36%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2030 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2030 Fund Class M
Trading Symbol FSXDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 51 
0.96%
  
Expenses Paid, Amount $ 51
Expense Ratio, Percent 0.96%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2030 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity® Sustainable Target Date 2030 Fund Class K6
Trading Symbol FSXJX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 14 
0.26%
  
Expenses Paid, Amount $ 14
Expense Ratio, Percent 0.26%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2030 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity® Sustainable Target Date 2030 Fund Class K
Trading Symbol FSXHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 19 
0.36%
  
Expenses Paid, Amount $ 19
Expense Ratio, Percent 0.36%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2030 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2030 Fund Class I
Trading Symbol FSXEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 25 
0.46%
  
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.46%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2030 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2030 Fund Class C
Trading Symbol FSXCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 78 
1.46%
  
Expenses Paid, Amount $ 78
Expense Ratio, Percent 1.46%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2030 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2030 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2030 Fund Class A
Trading Symbol FSXBX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2030 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 38 
0.71%
  
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.71%
Net Assets $ 10,773,632
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$10,773,632
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 37.7 Domestic Equity Funds 32.5 International Equity Funds 28.2 Short-Term Funds 1.6 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 37.7                          Domestic Equity Funds - 32.5               International Equity Funds - 28.2          Short-Term Funds - 1.6                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 32.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 19.5   Fidelity Series Sustainable Investment Grade Bond Fund 19.5   Fidelity Series Sustainable Emerging Markets Fund 8.7   Fidelity Series Long-Term Treasury Bond Index Fund 7.3   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 7.2   Fidelity Series International Developed Markets Bond Index Fund 3.7   Fidelity Series Treasury Bill Index Fund 1.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2025 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity® Sustainable Target Date 2025 Fund
Trading Symbol FSWOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2025 Fund 
$ 23 
0.44%
  
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.44%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Advisor Sustainable Target Date 2025 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2025 Fund Class Z
Trading Symbol FSWVX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 18 
0.34%
  
Expenses Paid, Amount $ 18
Expense Ratio, Percent 0.34%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Advisor Sustainable Target Date 2025 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2025 Fund Class M
Trading Symbol FSWSX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 50 
0.94%
  
Expenses Paid, Amount $ 50
Expense Ratio, Percent 0.94%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Sustainable Target Date 2025 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity® Sustainable Target Date 2025 Fund Class K6
Trading Symbol FSWZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 13 
0.24%
  
Expenses Paid, Amount $ 13
Expense Ratio, Percent 0.24%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Sustainable Target Date 2025 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity® Sustainable Target Date 2025 Fund Class K
Trading Symbol FSWYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 18 
0.34%
  
Expenses Paid, Amount $ 18
Expense Ratio, Percent 0.34%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Advisor Sustainable Target Date 2025 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2025 Fund Class I
Trading Symbol FSWUX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 23 
0.44%
  
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.44%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Advisor Sustainable Target Date 2025 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2025 Fund Class C
Trading Symbol FSWRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 76 
1.44%
  
Expenses Paid, Amount $ 76
Expense Ratio, Percent 1.44%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Advisor Sustainable Target Date 2025 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2025 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2025 Fund Class A
Trading Symbol FSWQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2025 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 37 
0.69%
  
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.69%
Net Assets $ 4,266,604
Holdings Count | shares 9
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,266,604
  
Number of Holdings
9
  
Portfolio Turnover
31%
  
Holdings [Text Block]         Bond Funds 44.1 Domestic Equity Funds 28.6 International Equity Funds 25.6 Short-Term Funds 1.7 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 44.1                          Domestic Equity Funds - 28.6               International Equity Funds - 25.6          Short-Term Funds - 1.7                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 28.6   Fidelity Series Sustainable Investment Grade Bond Fund 22.6   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 17.7   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 10.7   Fidelity Series Sustainable Emerging Markets Fund 7.9   Fidelity Series Long-Term Treasury Bond Index Fund 6.8   Fidelity Series International Developed Markets Bond Index Fund 3.8   Fidelity Series Treasury Bill Index Fund 1.7   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 0.2     100.0  
Fidelity Sustainable Target Date 2020 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity® Sustainable Target Date 2020 Fund
Trading Symbol FSWDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2020 Fund 
$ 23 
0.43%
  
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.43%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Advisor Sustainable Target Date 2020 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2020 Fund Class Z
Trading Symbol FSWKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 17 
0.33%
  
Expenses Paid, Amount $ 17
Expense Ratio, Percent 0.33%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Advisor Sustainable Target Date 2020 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2020 Fund Class M
Trading Symbol FSWHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 49 
0.93%
  
Expenses Paid, Amount $ 49
Expense Ratio, Percent 0.93%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Sustainable Target Date 2020 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity® Sustainable Target Date 2020 Fund Class K6
Trading Symbol FSWNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 12 
0.23%
  
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.23%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Sustainable Target Date 2020 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity® Sustainable Target Date 2020 Fund Class K
Trading Symbol FSWMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 17 
0.33%
  
Expenses Paid, Amount $ 17
Expense Ratio, Percent 0.33%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Advisor Sustainable Target Date 2020 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2020 Fund Class I
Trading Symbol FSWJX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 23 
0.43%
  
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.43%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Advisor Sustainable Target Date 2020 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2020 Fund Class C
Trading Symbol FSWGX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 75 
1.43%
  
Expenses Paid, Amount $ 75
Expense Ratio, Percent 1.43%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Advisor Sustainable Target Date 2020 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2020 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2020 Fund Class A
Trading Symbol FSWEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2020 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 36 
0.68%
  
Expenses Paid, Amount $ 36
Expense Ratio, Percent 0.68%
Net Assets $ 4,696,293
Holdings Count | shares 9
Investment Company Portfolio Turnover 35.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$4,696,293
  
Number of Holdings
9
  
Portfolio Turnover
35%
  
Holdings [Text Block]         Bond Funds 52.0 Domestic Equity Funds 23.5 International Equity Funds 22.1 Short-Term Funds 2.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 52.0                          Domestic Equity Funds - 23.5               International Equity Funds - 22.1          Short-Term Funds - 2.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 32.5   Fidelity Series Sustainable U.S. Market Fund 23.5   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 15.2   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 8.3   Fidelity Series Sustainable Emerging Markets Fund 6.9   Fidelity Series International Developed Markets Bond Index Fund 4.9   Fidelity Series Long-Term Treasury Bond Index Fund 3.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 2.8   Fidelity Series Treasury Bill Index Fund 2.4     100.0  
Fidelity Sustainable Target Date 2015 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity® Sustainable Target Date 2015 Fund
Trading Symbol FSVNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2015 Fund 
$ 22 
0.42%
  
Expenses Paid, Amount $ 22
Expense Ratio, Percent 0.42%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Advisor Sustainable Target Date 2015 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2015 Fund Class Z
Trading Symbol FSVWX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 17 
0.32%
  
Expenses Paid, Amount $ 17
Expense Ratio, Percent 0.32%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Advisor Sustainable Target Date 2015 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2015 Fund Class M
Trading Symbol FSVTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 48 
0.92%
  
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.92%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Sustainable Target Date 2015 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity® Sustainable Target Date 2015 Fund Class K6
Trading Symbol FSWBX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 12 
0.22%
  
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.22%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Sustainable Target Date 2015 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity® Sustainable Target Date 2015 Fund Class K
Trading Symbol FSVZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 17 
0.32%
  
Expenses Paid, Amount $ 17
Expense Ratio, Percent 0.32%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Advisor Sustainable Target Date 2015 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2015 Fund Class I
Trading Symbol FSVUX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 22 
0.42%
  
Expenses Paid, Amount $ 22
Expense Ratio, Percent 0.42%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Advisor Sustainable Target Date 2015 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2015 Fund Class C
Trading Symbol FSVPX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 74 
1.42%
  
Expenses Paid, Amount $ 74
Expense Ratio, Percent 1.42%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Advisor Sustainable Target Date 2015 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2015 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2015 Fund Class A
Trading Symbol FSVOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2015 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 35 
0.67%
  
Expenses Paid, Amount $ 35
Expense Ratio, Percent 0.67%
Net Assets $ 1,439,212
Holdings Count | shares 9
Investment Company Portfolio Turnover 26.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,439,212
  
Number of Holdings
9
  
Portfolio Turnover
26%
  
Holdings [Text Block]         Bond Funds 60.5 International Equity Funds 18.5 Domestic Equity Funds 18.2 Short-Term Funds 2.8 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 60.5                          International Equity Funds - 18.5          Domestic Equity Funds - 18.2               Short-Term Funds - 2.8                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 36.2   Fidelity Series Sustainable U.S. Market Fund 18.2   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 12.6   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 11.2   Fidelity Series Sustainable Emerging Markets Fund 5.9   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 4.7   Fidelity Series Long-Term Treasury Bond Index Fund 3.3   Fidelity Series Treasury Bill Index Fund 2.8     100.0  
Fidelity Sustainable Target Date 2010 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity® Sustainable Target Date 2010 Fund
Trading Symbol FSUYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity® Sustainable Target Date 2010 Fund 
$ 21 
0.41%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.41%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Advisor Sustainable Target Date 2010 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2010 Fund Class Z
Trading Symbol FSVHX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 16 
0.31%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.31%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Advisor Sustainable Target Date 2010 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2010 Fund Class M
Trading Symbol FSVEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 47 
0.91%
  
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.91%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Sustainable Target Date 2010 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity® Sustainable Target Date 2010 Fund Class K6
Trading Symbol FSVMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 11 
0.21%
  
Expenses Paid, Amount $ 11
Expense Ratio, Percent 0.21%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Sustainable Target Date 2010 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity® Sustainable Target Date 2010 Fund Class K
Trading Symbol FSVKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 16 
0.31%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.31%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Advisor Sustainable Target Date 2010 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2010 Fund Class I
Trading Symbol FSVGX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 21 
0.41%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.41%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Advisor Sustainable Target Date 2010 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2010 Fund Class C
Trading Symbol FSVCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 73 
1.41%
  
Expenses Paid, Amount $ 73
Expense Ratio, Percent 1.41%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Advisor Sustainable Target Date 2010 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2010 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2010 Fund Class A
Trading Symbol FSUZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2010 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 34 
0.66%
  
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.66%
Net Assets $ 1,268,400
Holdings Count | shares 9
Investment Company Portfolio Turnover 23.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,268,400
  
Number of Holdings
9
  
Portfolio Turnover
23%
  
Holdings [Text Block]         Bond Funds 66.7 International Equity Funds 15.0 Domestic Equity Funds 12.9 Short-Term Funds 5.4 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Bond Funds - 66.7                          International Equity Funds - 15.0          Domestic Equity Funds - 12.9               Short-Term Funds - 5.4                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable Investment Grade Bond Fund 39.5   Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund 16.9   Fidelity Series Sustainable U.S. Market Fund 12.9   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 10.2   Fidelity Series Treasury Bill Index Fund 5.4   Fidelity Series International Developed Markets Bond Index Fund 5.1   Fidelity Series Sustainable Emerging Markets Fund 4.8   Fidelity Series Long-Term Treasury Bond Index Fund 3.1   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 2.1     100.0  
Fidelity Sustainable Target Date 2070 Fund  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity® Sustainable Target Date 2070 Fund
Trading Symbol FRCQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-544-8544
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Fidelity®  Sustainable Target Date 2070 Fund 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2070 Fund - Class K  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity® Sustainable Target Date 2070 Fund Class K
Trading Symbol FRCRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Sustainable Target Date 2070 Fund - Class K6  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity® Sustainable Target Date 2070 Fund Class K6
Trading Symbol FRCVX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-800-835-5092
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class K6 
$ 16 
0.29%
  
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.29%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2070 Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2070 Fund Class A
Trading Symbol FRCWX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class A 
$ 40 
0.74%
  
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.74%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2070 Fund - Class M  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2070 Fund Class M
Trading Symbol FRCYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class M 
$ 54 
0.99%
  
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2070 Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2070 Fund Class C
Trading Symbol FRDCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class C 
$ 81 
1.49%
  
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.49%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2070 Fund - Class I  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2070 Fund Class I
Trading Symbol FRDDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class I 
$ 27 
0.49%
  
Expenses Paid, Amount $ 27
Expense Ratio, Percent 0.49%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0  
Fidelity Advisor Sustainable Target Date 2070 Fund - Class Z  
Shareholder Report [Line Items]  
Fund Name Fidelity® Sustainable Target Date 2070 Fund
Class Name Fidelity Advisor® Sustainable Target Date 2070 Fund Class Z
Trading Symbol FRDEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains information about Fidelity® Sustainable Target Date 2070 Fund for the period April 1, 2025 to September 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number 1-877-208-0098
Additional Information Email fidfunddocuments@fidelity.com
Additional Information Website fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block] What were your Fund costs for the last six months?
(based on hypothetical $10,000 investment)
 
 
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
 
Class Z 
$ 21 
0.39%
  
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.39%
Net Assets $ 1,132,361
Holdings Count | shares 6
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of September 30, 2025)
 
KEY FACTS 
  
  
Fund Size
$1,132,361
  
Number of Holdings
6
  
Portfolio Turnover
16%
  
Holdings [Text Block]         Domestic Equity Funds 51.7 International Equity Funds 41.0 Bond Funds 6.3 Short-Term Funds 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets)     Domestic Equity Funds - 51.7               International Equity Funds - 41.0          Bond Funds - 6.3                           Short-Term Funds - 1.0                     Short-Term Investments and Net Other Assets (Liabilities) - 0.0  
Largest Holdings [Text Block] TOP HOLDINGS(% of Fund's net assets)     Fidelity Series Sustainable U.S. Market Fund 51.7   Fidelity Series Sustainable Non-U.S. Developed Markets Fund 28.6   Fidelity Series Sustainable Emerging Markets Fund 12.4   Fidelity Series Long-Term Treasury Bond Index Fund 6.3   Fidelity Series Treasury Bill Index Fund 1.0   Fidelity Series 5+ Year Inflation-Protected Bond Index Fund 0.0     100.0