v3.26.3
Shareholder Report, Holdings (Details)
Aug. 31, 2026
Fidelity Total Market Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.30%
Fidelity Total Market Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.40%
Fidelity Total Market Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Total Market Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
Fidelity Total Market Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
Fidelity Total Market Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
Fidelity Total Market Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
Fidelity Total Market Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Total Market Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Total Market Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Total Market Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.60%
Fidelity Total Market Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 35.80%
Fidelity Total Market Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 9.90%
Fidelity Total Market Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
Fidelity Total Market Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.40%
Fidelity Total Market Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
Fidelity Total Market Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.10%
Fidelity Total Market Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Total Market Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity Total Market Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Total Market Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Total Market Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 99.70%
Fidelity Total Market Index Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Total Market Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Total Market Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | Korea, Republic of  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | Puerto Rico  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | Thailand  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | Bermuda  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.90%
Fidelity Total Market Index Fund | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Total Market Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Series Total Market Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.30%
Fidelity Series Total Market Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.40%
Fidelity Series Total Market Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Series Total Market Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
Fidelity Series Total Market Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
Fidelity Series Total Market Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
Fidelity Series Total Market Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
Fidelity Series Total Market Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Series Total Market Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Series Total Market Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Series Total Market Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.60%
Fidelity Series Total Market Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 35.90%
Fidelity Series Total Market Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 9.90%
Fidelity Series Total Market Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
Fidelity Series Total Market Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.40%
Fidelity Series Total Market Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
Fidelity Series Total Market Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.10%
Fidelity Series Total Market Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Series Total Market Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity Series Total Market Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Series Total Market Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Series Total Market Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 99.70%
Fidelity Series Total Market Index Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Series Total Market Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Series Total Market Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | Korea, Republic of  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | Puerto Rico  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | Thailand  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | Bermuda  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
Fidelity Series Total Market Index Fund | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Total Market Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity International Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity International Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity International Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity International Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity International Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity International Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity International Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity International Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity International Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity International Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity International Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 26.20%
Fidelity International Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 10.30%
Fidelity International Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 10.10%
Fidelity International Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity International Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 18.80%
Fidelity International Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.20%
Fidelity International Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.30%
Fidelity International Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.40%
Fidelity International Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity International Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity International Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity International Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 8.40%
Fidelity International Index Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 6.00%
Fidelity International Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
Fidelity International Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 10.90%
Fidelity International Index Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 23.60%
Fidelity International Index Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 8.70%
Fidelity International Index Fund | France  
Holdings [Line Items]  
Percent of Net Asset Value 8.20%
Fidelity International Index Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 7.30%
Fidelity International Index Fund | Spain  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
Fidelity International Index Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.90%
Fidelity International Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 98.50%
Fidelity International Index Fund | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity International Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Flex 500 Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.00%
Fidelity Flex 500 Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
Fidelity Flex 500 Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
Fidelity Flex 500 Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Flex 500 Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
Fidelity Flex 500 Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
Fidelity Flex 500 Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Flex 500 Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Flex 500 Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Flex 500 Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Flex 500 Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.10%
Fidelity Flex 500 Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 37.90%
Fidelity Flex 500 Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 9.20%
Fidelity Flex 500 Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Flex 500 Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.50%
Fidelity Flex 500 Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Flex 500 Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity Flex 500 Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
Fidelity Flex 500 Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.30%
Fidelity Flex 500 Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Flex 500 Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Flex 500 Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 99.70%
Fidelity Flex 500 Index Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Flex 500 Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Flex 500 Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Flex 500 Index Fund | Korea, Republic of  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Flex 500 Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Flex 500 Index Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Flex 500 Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.30%
Fidelity Flex 500 Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Extended Market Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Extended Market Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Extended Market Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Extended Market Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Extended Market Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Extended Market Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Extended Market Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Extended Market Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Extended Market Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Extended Market Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Extended Market Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Extended Market Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 19.00%
Fidelity Extended Market Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 14.90%
Fidelity Extended Market Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
Fidelity Extended Market Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 18.80%
Fidelity Extended Market Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Extended Market Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity Extended Market Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
Fidelity Extended Market Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
Fidelity Extended Market Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
Fidelity Extended Market Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Extended Market Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 97.90%
Fidelity Extended Market Index Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Extended Market Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Extended Market Index Fund | Korea, Republic of  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Extended Market Index Fund | Puerto Rico  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Extended Market Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Extended Market Index Fund | Thailand  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Extended Market Index Fund | Bermuda  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Extended Market Index Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Extended Market Index Fund | Sweden  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Extended Market Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.80%
Fidelity Extended Market Index Fund | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Extended Market Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity 500 Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.20%
Fidelity 500 Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
Fidelity 500 Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
Fidelity 500 Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity 500 Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity 500 Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity 500 Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
Fidelity 500 Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity 500 Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity 500 Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity 500 Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.30%
Fidelity 500 Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 37.90%
Fidelity 500 Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 9.30%
Fidelity 500 Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity 500 Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.30%
Fidelity 500 Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity 500 Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.10%
Fidelity 500 Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity 500 Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.50%
Fidelity 500 Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity 500 Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity 500 Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 99.80%
Fidelity 500 Index Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity 500 Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity 500 Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.90%
Fidelity 500 Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Flex Large Cap Focused Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
Fidelity Flex Large Cap Focused Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
Fidelity Flex Large Cap Focused Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
Fidelity Flex Large Cap Focused Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
Fidelity Flex Large Cap Focused Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
Fidelity Flex Large Cap Focused Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
Fidelity Flex Large Cap Focused Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
Fidelity Flex Large Cap Focused Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Flex Large Cap Focused Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Flex Large Cap Focused Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Flex Large Cap Focused Index Fund | MSFinancialsSectorMember  
Holdings [Line Items]  
Percent of Net Asset Value 11.50%
Fidelity Flex Large Cap Focused Index Fund | Information Technology Member  
Holdings [Line Items]  
Percent of Net Asset Value 36.10%
Fidelity Flex Large Cap Focused Index Fund | Healthcare Sector  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity Flex Large Cap Focused Index Fund | Real Estate Sector  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Flex Large Cap Focused Index Fund | Industrial Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.30%
Fidelity Flex Large Cap Focused Index Fund | Materials Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Flex Large Cap Focused Index Fund | Consumer Discretionary Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.80%
Fidelity Flex Large Cap Focused Index Fund | Consumer Staples Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
Fidelity Flex Large Cap Focused Index Fund | Communications Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.30%
Fidelity Flex Large Cap Focused Index Fund | Energy Sector  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
Fidelity Flex Large Cap Focused Index Fund | Utilities Sector Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Flex Large Cap Focused Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 99.80%
Fidelity Flex Large Cap Focused Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Flex Large Cap Focused Index Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 96.20%
Fidelity Flex Large Cap Focused Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%