3.24.4 html 273 69 1 true 83 0 false 3 false false R1.htm 000000 - Document - Document and Entity Information Sheet http://www.fidelity.com/role/DocumentInformation Document and Entity Information Risk/Return 1 false false R2.htm 000001 - Document - Risk/Return Summary - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000033635_FidelityInternationalIndexFunds-ComboPRO Risk/Return Summary - FidelityInternationalIndexFunds-ComboPRO Risk/Return 2 false false R3.htm 000002 - Schedule - Shareholder Fees - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000033635_FidelityInternationalIndexFunds-ComboPRO Shareholder Fees - FidelityInternationalIndexFunds-ComboPRO Risk/Return 3 false false R4.htm 000003 - Schedule - Annual Operating Expenses - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000033635_FidelityInternationalIndexFunds-ComboPRO Annual Operating Expenses - FidelityInternationalIndexFunds-ComboPRO Risk/Return 4 false false R5.htm 000004 - Schedule - Expense Example - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000033635_FidelityInternationalIndexFunds-ComboPRO Expense Example - FidelityInternationalIndexFunds-ComboPRO Risk/Return 5 false false R6.htm 000006 - Schedule - Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000033635_FidelityInternationalIndexFunds-ComboPRO Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Risk/Return 6 false false R7.htm 000007 - Schedule - Average Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000033635_FidelityInternationalIndexFunds-ComboPRO Average Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Risk/Return 7 false false R8.htm 000009 - Disclosure - Risk/Return Detail Data - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000033635_FidelityInternationalIndexFunds-ComboPRO Risk/Return Detail Data - FidelityInternationalIndexFunds-ComboPRO Risk/Return 8 false false R9.htm 000010 - Document - Risk/Return Summary - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/SummaryS000056355_FidelityFlexInternationalIndexFund-PRO Risk/Return Summary - FidelityFlexInternationalIndexFund-PRO Risk/Return 9 false false R10.htm 000011 - Schedule - Shareholder Fees - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/ShareholderFeesS000056355_FidelityFlexInternationalIndexFund-PRO Shareholder Fees - FidelityFlexInternationalIndexFund-PRO Risk/Return 10 false false R11.htm 000012 - Schedule - Annual Operating Expenses - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/OperatingExpensesS000056355_FidelityFlexInternationalIndexFund-PRO Annual Operating Expenses - FidelityFlexInternationalIndexFund-PRO Risk/Return 11 false false R12.htm 000013 - Schedule - Expense Example - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/ExpenseExampleS000056355_FidelityFlexInternationalIndexFund-PRO Expense Example - FidelityFlexInternationalIndexFund-PRO Risk/Return 12 false false R13.htm 000015 - Schedule - Annual Total Returns - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000056355_FidelityFlexInternationalIndexFund-PRO Annual Total Returns - FidelityFlexInternationalIndexFund-PRO Risk/Return 13 false false R14.htm 000016 - Schedule - Average Annual Total Returns - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000056355_FidelityFlexInternationalIndexFund-PRO Average Annual Total Returns - FidelityFlexInternationalIndexFund-PRO Risk/Return 14 false false R15.htm 000018 - Disclosure - Risk/Return Detail Data - FidelityFlexInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/DisclosureDetailS000056355_FidelityFlexInternationalIndexFund-PRO Risk/Return Detail Data - FidelityFlexInternationalIndexFund-PRO Risk/Return 15 false false R16.htm 000019 - Document - Risk/Return Summary - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000033636_FidelityInternationalIndexFunds-ComboPRO Risk/Return Summary - FidelityInternationalIndexFunds-ComboPRO Risk/Return 16 false false R17.htm 000020 - Schedule - Shareholder Fees - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000033636_FidelityInternationalIndexFunds-ComboPRO Shareholder Fees - FidelityInternationalIndexFunds-ComboPRO Risk/Return 17 false false R18.htm 000021 - Schedule - Annual Operating Expenses - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000033636_FidelityInternationalIndexFunds-ComboPRO Annual Operating Expenses - FidelityInternationalIndexFunds-ComboPRO Risk/Return 18 false false R19.htm 000022 - Schedule - Expense Example - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000033636_FidelityInternationalIndexFunds-ComboPRO Expense Example - FidelityInternationalIndexFunds-ComboPRO Risk/Return 19 false false R20.htm 000024 - Schedule - Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000033636_FidelityInternationalIndexFunds-ComboPRO Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Risk/Return 20 false false R21.htm 000025 - Schedule - Average Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000033636_FidelityInternationalIndexFunds-ComboPRO Average Annual Total Returns - FidelityInternationalIndexFunds-ComboPRO Risk/Return 21 false false R22.htm 000027 - Disclosure - Risk/Return Detail Data - FidelityInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000033636_FidelityInternationalIndexFunds-ComboPRO Risk/Return Detail Data - FidelityInternationalIndexFunds-ComboPRO Risk/Return 22 false false R23.htm 000028 - Document - Risk/Return Summary - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000057365_FidelitySustainabilityIndexFunds-ComboPRO Risk/Return Summary - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 23 false false R24.htm 000029 - Schedule - Shareholder Fees - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000057365_FidelitySustainabilityIndexFunds-ComboPRO Shareholder Fees - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 24 false false R25.htm 000030 - Schedule - Annual Operating Expenses - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000057365_FidelitySustainabilityIndexFunds-ComboPRO Annual Operating Expenses - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 25 false false R26.htm 000031 - Schedule - Expense Example - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000057365_FidelitySustainabilityIndexFunds-ComboPRO Expense Example - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 26 false false R27.htm 000033 - Schedule - Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000057365_FidelitySustainabilityIndexFunds-ComboPRO Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 27 false false R28.htm 000034 - Schedule - Average Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000057365_FidelitySustainabilityIndexFunds-ComboPRO Average Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 28 false false R29.htm 000036 - Disclosure - Risk/Return Detail Data - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000057365_FidelitySustainabilityIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 29 false false R30.htm 000037 - Document - Risk/Return Summary - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/SummaryS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return Summary - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 30 false false R31.htm 000038 - Schedule - Shareholder Fees - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/ShareholderFeesS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Shareholder Fees - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 31 false false R32.htm 000039 - Schedule - Annual Operating Expenses - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/OperatingExpensesS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Annual Operating Expenses - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 32 false false R33.htm 000040 - Schedule - Expense Example - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/ExpenseExampleS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Expense Example - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 33 false false R34.htm 000042 - Schedule - Annual Total Returns - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Annual Total Returns - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 34 false false R35.htm 000043 - Schedule - Average Annual Total Returns - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Average Annual Total Returns - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 35 false false R36.htm 000045 - Disclosure - Risk/Return Detail Data - FidelitySAIEmergingMarketsIndexFund-PRO Sheet http://www.fidelity.com/role/DisclosureDetailS000051995_FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return Detail Data - FidelitySAIEmergingMarketsIndexFund-PRO Risk/Return 36 false false R37.htm 000046 - Document - Risk/Return Summary - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return Summary - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 37 false false R38.htm 000047 - Schedule - Shareholder Fees - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Shareholder Fees - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 38 false false R39.htm 000048 - Schedule - Annual Operating Expenses - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Annual Operating Expenses - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 39 false false R40.htm 000049 - Schedule - Expense Example - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Expense Example - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 40 false false R41.htm 000051 - Schedule - Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 41 false false R42.htm 000052 - Schedule - Average Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Average Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 42 false false R43.htm 000054 - Disclosure - Risk/Return Detail Data - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000063743_FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 43 false false R44.htm 000055 - Document - Risk/Return Summary - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return Summary - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 44 false false R45.htm 000056 - Schedule - Shareholder Fees - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Shareholder Fees - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 45 false false R46.htm 000057 - Schedule - Annual Operating Expenses - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Annual Operating Expenses - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 46 false false R47.htm 000058 - Schedule - Expense Example - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Expense Example - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 47 false false R48.htm 000060 - Schedule - Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 48 false false R49.htm 000061 - Schedule - Average Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Average Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 49 false false R50.htm 000063 - Disclosure - Risk/Return Detail Data - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000068373_FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 50 false false R51.htm 000064 - Document - Risk/Return Summary - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/SummaryS000051996_FidelitySAIInternationalIndexFund-PRO Risk/Return Summary - FidelitySAIInternationalIndexFund-PRO Risk/Return 51 false false R52.htm 000065 - Schedule - Shareholder Fees - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/ShareholderFeesS000051996_FidelitySAIInternationalIndexFund-PRO Shareholder Fees - FidelitySAIInternationalIndexFund-PRO Risk/Return 52 false false R53.htm 000066 - Schedule - Annual Operating Expenses - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/OperatingExpensesS000051996_FidelitySAIInternationalIndexFund-PRO Annual Operating Expenses - FidelitySAIInternationalIndexFund-PRO Risk/Return 53 false false R54.htm 000067 - Schedule - Expense Example - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/ExpenseExampleS000051996_FidelitySAIInternationalIndexFund-PRO Expense Example - FidelitySAIInternationalIndexFund-PRO Risk/Return 54 false false R55.htm 000069 - Schedule - Annual Total Returns - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000051996_FidelitySAIInternationalIndexFund-PRO Annual Total Returns - FidelitySAIInternationalIndexFund-PRO Risk/Return 55 false false R56.htm 000070 - Schedule - Average Annual Total Returns - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000051996_FidelitySAIInternationalIndexFund-PRO Average Annual Total Returns - FidelitySAIInternationalIndexFund-PRO Risk/Return 56 false false R57.htm 000072 - Disclosure - Risk/Return Detail Data - FidelitySAIInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/DisclosureDetailS000051996_FidelitySAIInternationalIndexFund-PRO Risk/Return Detail Data - FidelitySAIInternationalIndexFund-PRO Risk/Return 57 false false R58.htm 000073 - Document - Risk/Return Summary - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return Summary - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 58 false false R59.htm 000074 - Schedule - Shareholder Fees - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Shareholder Fees - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 59 false false R60.htm 000075 - Schedule - Annual Operating Expenses - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Annual Operating Expenses - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 60 false false R61.htm 000076 - Schedule - Expense Example - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Expense Example - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 61 false false R62.htm 000078 - Schedule - Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 62 false false R63.htm 000079 - Schedule - Average Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Average Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 63 false false R64.htm 000081 - Disclosure - Risk/Return Detail Data - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000049310_FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 64 false false R65.htm 000082 - Document - Risk/Return Summary - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return Summary - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 65 false false R66.htm 000083 - Schedule - Shareholder Fees - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Shareholder Fees - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 66 false false R67.htm 000084 - Schedule - Annual Operating Expenses - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Annual Operating Expenses - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 67 false false R68.htm 000085 - Schedule - Expense Example - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Expense Example - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 68 false false R69.htm 000087 - Schedule - Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 69 false false R70.htm 000088 - Schedule - Average Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Average Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 70 false false R71.htm 000090 - Disclosure - Risk/Return Detail Data - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000068374_FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 71 false false R72.htm 000091 - Document - Risk/Return Summary - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return Summary - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 72 false false R73.htm 000092 - Schedule - Shareholder Fees - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Shareholder Fees - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 73 false false R74.htm 000093 - Schedule - Annual Operating Expenses - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Annual Operating Expenses - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 74 false false R75.htm 000094 - Schedule - Expense Example - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Expense Example - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 75 false false R76.htm 000096 - Schedule - Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 76 false false R77.htm 000097 - Schedule - Average Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Average Annual Total Returns - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 77 false false R78.htm 000099 - Disclosure - Risk/Return Detail Data - FidelitySAIInternationalIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000068375_FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySAIInternationalIndexFunds-ComboPRO Risk/Return 78 false false R79.htm 000100 - Document - Risk/Return Summary - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/SummaryS000059762_FidelitySAIInternationalValueIndexFund-PRO Risk/Return Summary - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 79 false false R80.htm 000101 - Schedule - Shareholder Fees - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/ShareholderFeesS000059762_FidelitySAIInternationalValueIndexFund-PRO Shareholder Fees - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 80 false false R81.htm 000102 - Schedule - Annual Operating Expenses - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/OperatingExpensesS000059762_FidelitySAIInternationalValueIndexFund-PRO Annual Operating Expenses - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 81 false false R82.htm 000103 - Schedule - Expense Example - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/ExpenseExampleS000059762_FidelitySAIInternationalValueIndexFund-PRO Expense Example - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 82 false false R83.htm 000105 - Schedule - Annual Total Returns - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000059762_FidelitySAIInternationalValueIndexFund-PRO Annual Total Returns - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 83 false false R84.htm 000106 - Schedule - Average Annual Total Returns - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000059762_FidelitySAIInternationalValueIndexFund-PRO Average Annual Total Returns - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 84 false false R85.htm 000108 - Disclosure - Risk/Return Detail Data - FidelitySAIInternationalValueIndexFund-PRO Sheet http://www.fidelity.com/role/DisclosureDetailS000059762_FidelitySAIInternationalValueIndexFund-PRO Risk/Return Detail Data - FidelitySAIInternationalValueIndexFund-PRO Risk/Return 85 false false R86.htm 000109 - Document - Risk/Return Summary - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return Summary - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 86 false false R87.htm 000110 - Schedule - Shareholder Fees - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Shareholder Fees - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 87 false false R88.htm 000111 - Schedule - Annual Operating Expenses - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Annual Operating Expenses - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 88 false false R89.htm 000112 - Schedule - Expense Example - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Expense Example - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 89 false false R90.htm 000114 - Schedule - Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 90 false false R91.htm 000115 - Schedule - Average Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Average Annual Total Returns - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 91 false false R92.htm 000117 - Disclosure - Risk/Return Detail Data - FidelitySAIVolatilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000049309_FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySAIVolatilityIndexFunds-ComboPRO Risk/Return 92 false false R93.htm 000118 - Document - Risk/Return Summary - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/SummaryS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return Summary - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 93 false false R94.htm 000119 - Schedule - Shareholder Fees - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/ShareholderFeesS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Shareholder Fees - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 94 false false R95.htm 000120 - Schedule - Annual Operating Expenses - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/OperatingExpensesS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Annual Operating Expenses - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 95 false false R96.htm 000121 - Schedule - Expense Example - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/ExpenseExampleS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Expense Example - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 96 false false R97.htm 000123 - Schedule - Annual Total Returns - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Annual Total Returns - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 97 false false R98.htm 000124 - Schedule - Average Annual Total Returns - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Average Annual Total Returns - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 98 false false R99.htm 000126 - Disclosure - Risk/Return Detail Data - FidelitySeriesGlobalexUSIndexFund-PRO Sheet http://www.fidelity.com/role/DisclosureDetailS000026422_FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return Detail Data - FidelitySeriesGlobalexUSIndexFund-PRO Risk/Return 99 false false R100.htm 000127 - Document - Risk/Return Summary - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/SummaryS000054097_FidelityTotalInternationalIndexFund-PRO Risk/Return Summary - FidelityTotalInternationalIndexFund-PRO Risk/Return 100 false false R101.htm 000128 - Schedule - Shareholder Fees - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/ShareholderFeesS000054097_FidelityTotalInternationalIndexFund-PRO Shareholder Fees - FidelityTotalInternationalIndexFund-PRO Risk/Return 101 false false R102.htm 000129 - Schedule - Annual Operating Expenses - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/OperatingExpensesS000054097_FidelityTotalInternationalIndexFund-PRO Annual Operating Expenses - FidelityTotalInternationalIndexFund-PRO Risk/Return 102 false false R103.htm 000130 - Schedule - Expense Example - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/ExpenseExampleS000054097_FidelityTotalInternationalIndexFund-PRO Expense Example - FidelityTotalInternationalIndexFund-PRO Risk/Return 103 false false R104.htm 000132 - Schedule - Annual Total Returns - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000054097_FidelityTotalInternationalIndexFund-PRO Annual Total Returns - FidelityTotalInternationalIndexFund-PRO Risk/Return 104 false false R105.htm 000133 - Schedule - Average Annual Total Returns - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000054097_FidelityTotalInternationalIndexFund-PRO Average Annual Total Returns - FidelityTotalInternationalIndexFund-PRO Risk/Return 105 false false R106.htm 000135 - Disclosure - Risk/Return Detail Data - FidelityTotalInternationalIndexFund-PRO Sheet http://www.fidelity.com/role/DisclosureDetailS000054097_FidelityTotalInternationalIndexFund-PRO Risk/Return Detail Data - FidelityTotalInternationalIndexFund-PRO Risk/Return 106 false false R107.htm 000136 - Document - Risk/Return Summary - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/SummaryS000057366_FidelitySustainabilityIndexFunds-ComboPRO Risk/Return Summary - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 107 false false R108.htm 000137 - Schedule - Shareholder Fees - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ShareholderFeesS000057366_FidelitySustainabilityIndexFunds-ComboPRO Shareholder Fees - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 108 false false R109.htm 000138 - Schedule - Annual Operating Expenses - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/OperatingExpensesS000057366_FidelitySustainabilityIndexFunds-ComboPRO Annual Operating Expenses - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 109 false false R110.htm 000139 - Schedule - Expense Example - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/ExpenseExampleS000057366_FidelitySustainabilityIndexFunds-ComboPRO Expense Example - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 110 false false R111.htm 000141 - Schedule - Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AnnualTotalReturnsBarChartS000057366_FidelitySustainabilityIndexFunds-ComboPRO Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 111 false false R112.htm 000142 - Schedule - Average Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/AverageAnnualTotalReturnsS000057366_FidelitySustainabilityIndexFunds-ComboPRO Average Annual Total Returns - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 112 false false R113.htm 000144 - Disclosure - Risk/Return Detail Data - FidelitySustainabilityIndexFunds-ComboPRO Sheet http://www.fidelity.com/role/DisclosureDetailS000057366_FidelitySustainabilityIndexFunds-ComboPRO Risk/Return Detail Data - FidelitySustainabilityIndexFunds-ComboPRO Risk/Return 113 false false All Reports Book All Reports filing8270.htm fmr-20241230.xsd fmr-20241230_cal.xml fmr-20241230_def.xml fmr-20241230_lab.xml fmr-20241230_pre.xml img103590_1.jpg img103591_1.jpg img103591_4.jpg img103603_1.jpg img103604_1.jpg img103604_4.jpg img103604_5.jpg img103615_1.jpg img103616_1.jpg img103616_4.jpg img103619_1.jpg img103620_1.jpg img103620_4.jpg img103620_5.jpg img103620_6.jpg img103621_1.jpg img103621_4.jpg img103624_1.jpg img103624_4.jpg img103625_1.jpg img103625_4.jpg img103636_1.jpg img103637_1.jpg img103637_4.jpg img103637_5.jpg img103653_1.jpg img103654_1.jpg img103654_4.jpg img103695_1.jpg img103695_4.jpg img103695_5.jpg img103695_6.jpg http://xbrl.sec.gov/dei/2023 http://xbrl.sec.gov/rr/2023 true true