3.20.4 html 249 172 1 true 122 0 false 2 false true R1.htm 00002 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashAdministration Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Administration) 1 false false R6.htm 00007 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Administration) 2 false true R7.htm 00008 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Administration) 3 false false R9.htm 0001 - Document - Document and Entity Information {Elements} Sheet http://www.blackrock.com/role/DocumentAndEntityInformationElements Document and Entity Information 4 false false R13.htm 00013 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Administration) 5 false true R14.htm 00014 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Administration) 6 false false R19.htm 00019 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Administration) 7 false true R20.htm 00020 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Administration) 8 false false R25.htm 00025 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Administration) 9 false true R26.htm 00026 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Administration) 10 false false R31.htm 00031 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Administration) 11 false true R32.htm 00032 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Administration) 12 false false R37.htm 00037 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Administration) 13 false true R38.htm 00038 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Administration) 14 false false R43.htm 00043 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Administration) 15 false true R44.htm 00044 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashAdministration Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Administration) 16 false false R49.htm 00049 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Administration) 17 false true R50.htm 00050 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Administration) 18 false false R55.htm 00055 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Administration) 19 false true R56.htm 00056 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundAdministration Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Administration) 20 false false R61.htm 00061 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Administration) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundAdministration Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Administration) 21 false true R62.htm 00062 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Cash Management) 22 false false R67.htm 00067 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Cash Management) 23 false true R68.htm 00068 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Cash Management) 24 false false R73.htm 00073 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Cash Management) 25 false true R74.htm 00074 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Management) 26 false false R79.htm 00079 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Management) 27 false true R80.htm 00080 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Cash Management) 28 false false R85.htm 00085 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Cash Management) 29 false true R86.htm 00086 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Cash Management) 30 false false R91.htm 00091 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Cash Management) 31 false true R92.htm 00092 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Management) 32 false false R97.htm 00097 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Management) 33 false true R98.htm 00098 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Management) 34 false false R103.htm 00103 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Management) 35 false true R104.htm 00104 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Cash Management) 36 false false R109.htm 00109 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Cash Management) 37 false true R110.htm 00110 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Cash Management) 38 false false R115.htm 00115 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Cash Management) 39 false true R116.htm 00116 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundCashManagement Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Management) 40 false false R121.htm 00121 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Management) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundCashManagement Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Management) 41 false true R122.htm 00122 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashCashPlus Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Cash Plus) 42 false false R127.htm 00127 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashCashPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Cash Plus) 43 false true R128.htm 00128 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundCashPlus Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Cash Plus) 44 false false R133.htm 00133 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundCashPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Cash Plus) 45 false true R134.htm 00134 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundCashPlus Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Plus) 46 false false R139.htm 00139 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundCashPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Plus) 47 false true R140.htm 00140 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashCashPlus Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Cash Plus) 48 false false R145.htm 00145 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashCashPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Cash Plus) 49 false true R146.htm 00146 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundCashPlus Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Plus) 50 false false R151.htm 00151 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundCashPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Plus) 51 false true R152.htm 00152 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Cash Reserve) 52 false false R157.htm 00157 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Cash Reserve) 53 false true R158.htm 00158 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Cash Reserve) 54 false false R163.htm 00163 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Cash Reserve) 55 false true R164.htm 00164 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Reserve) 56 false false R169.htm 00169 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Cash Reserve) 57 false true R170.htm 00170 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Cash Reserve) 58 false false R175.htm 00175 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Cash Reserve) 59 false true R176.htm 00176 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Cash Reserve) 60 false false R181.htm 00181 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Cash Reserve) 61 false true R182.htm 00182 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Reserve) 62 false false R187.htm 00187 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Cash Reserve) 63 false true R188.htm 00188 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Reserve) 64 false false R193.htm 00193 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Cash Reserve) 65 false true R194.htm 00194 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Cash Reserve) 66 false false R199.htm 00199 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Cash Reserve) 67 false true R200.htm 00200 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Cash Reserve) 68 false false R205.htm 00205 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Cash Reserve) 69 false true R206.htm 00206 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundCashReserve Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Reserve) 70 false false R211.htm 00211 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Reserve) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundCashReserve Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Cash Reserve) 71 false true R212.htm 00212 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashDollar Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Dollar) 72 false false R217.htm 00217 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Dollar) 73 false true R218.htm 00218 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundDollar Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Dollar) 74 false false R223.htm 00223 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Dollar) 75 false true R224.htm 00224 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundDollar Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Dollar) 76 false false R229.htm 00229 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Dollar) 77 false true R230.htm 00230 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundDollar Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Dollar) 78 false false R235.htm 00235 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Dollar) 79 false true R236.htm 00236 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundDollar Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Dollar) 80 false false R241.htm 00241 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Dollar) 81 false true R242.htm 00242 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundDollar Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Dollar) 82 false false R247.htm 00247 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Dollar) 83 false true R248.htm 00248 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundDollar Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Dollar) 84 false false R253.htm 00253 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Dollar) 85 false true R254.htm 00254 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashDollar Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Dollar) 86 false false R259.htm 00259 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Dollar) 87 false true R260.htm 00260 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundDollar Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Dollar) 88 false false R265.htm 00265 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Dollar) 89 false true R266.htm 00266 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundDollar Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Dollar) 90 false false R271.htm 00271 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Dollar) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundDollar Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Dollar) 91 false true R272.htm 00272 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Institutional) 92 false false R277.htm 00277 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Institutional) 93 false true R278.htm 00278 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Institutional) 94 false false R283.htm 00283 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Institutional) 95 false true R284.htm 00284 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Institutional) 96 false false R289.htm 00289 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Institutional) 97 false true R290.htm 00290 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Institutional) 98 false false R295.htm 00295 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Institutional) 99 false true R296.htm 00296 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Institutional) 100 false false R301.htm 00301 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Institutional) 101 false true R302.htm 00302 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Institutional) 102 false false R307.htm 00307 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Institutional) 103 false true R308.htm 00308 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Institutional) 104 false false R313.htm 00313 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Institutional) 105 false true R314.htm 00314 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Institutional) 106 false false R319.htm 00319 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Institutional) 107 false true R320.htm 00320 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Institutional) 108 false false R325.htm 00325 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Institutional) 109 false true R326.htm 00326 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundInstitutional Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Institutional) 110 false false R331.htm 00331 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Institutional) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundInstitutional Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Institutional) 111 false true R332.htm 00332 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundPlus Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Plus) 112 false false R337.htm 00337 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Plus) 113 false true R338.htm 00338 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundPlus Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Plus) 114 false false R343.htm 00343 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Plus) 115 false true R344.htm 00344 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundPlus Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Plus) 116 false false R349.htm 00349 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Plus) 117 false true R350.htm 00350 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundPlus Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Plus) 118 false false R355.htm 00355 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Plus) 119 false true R356.htm 00356 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundPlus Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Plus) 120 false false R361.htm 00361 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Plus) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundPlus Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Plus) 121 false true R362.htm 00362 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashCapital Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Capital) 122 false false R367.htm 00367 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Capital) 123 false true R368.htm 00368 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundCapital Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Capital) 124 false false R373.htm 00373 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Capital) 125 false true R374.htm 00374 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundCapital Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Capital) 126 false false R379.htm 00379 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Capital) 127 false true R380.htm 00380 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundCapital Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Capital) 128 false false R385.htm 00385 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Capital) 129 false true R386.htm 00386 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundCapital Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Capital) 130 false false R391.htm 00391 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Capital) 131 false true R392.htm 00392 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundCapital Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Capital) 132 false false R397.htm 00397 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Capital) 133 false true R398.htm 00398 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundCapital Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Capital) 134 false false R403.htm 00403 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Capital) 135 false true R404.htm 00404 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashCapital Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Capital) 136 false false R409.htm 00409 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Capital) 137 false true R410.htm 00410 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundCapital Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Capital) 138 false false R415.htm 00415 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Capital) 139 false true R416.htm 00416 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundCapital Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Capital) 140 false false R421.htm 00421 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Capital) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundCapital Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Capital) 141 false true R422.htm 00422 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundSelect Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Select) 142 false false R427.htm 00427 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Select) 143 false true R428.htm 00428 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundSelect Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Select) 144 false false R433.htm 00433 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Select) 145 false true R434.htm 00434 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundSelect Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Select) 146 false false R439.htm 00439 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Select) 147 false true R440.htm 00440 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundSelect Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Select) 148 false false R445.htm 00445 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Select) 149 false true R446.htm 00446 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundSelect Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Select) 150 false false R451.htm 00451 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Select) 151 false true R452.htm 00452 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundSelect Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Select) 152 false false R457.htm 00457 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Select) 153 false true R458.htm 00458 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundSelect Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Select) 154 false false R463.htm 00463 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Select) 155 false true R464.htm 00464 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashSelect Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Select) 156 false false R469.htm 00469 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Select) 157 false true R470.htm 00470 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundSelect Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Select) 158 false false R475.htm 00475 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Select) 159 false true R476.htm 00476 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Select) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashSelect Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Select) 160 false false R481.htm 00481 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Select) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashSelect Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Select) 161 false true R482.htm 00482 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashPremier Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Premier) 162 false false R487.htm 00487 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Premier) 163 false true R488.htm 00488 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundPremier Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Premier) 164 false false R493.htm 00493 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Premier) 165 false true R494.htm 00494 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundPremier Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Premier) 166 false false R499.htm 00499 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Premier) 167 false true R500.htm 00500 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundPremier Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Premier) 168 false false R505.htm 00505 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Premier) 169 false true R506.htm 00506 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundPremier Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Premier) 170 false false R511.htm 00511 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Premier) 171 false true R512.htm 00512 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundPremier Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Premier) 172 false false R517.htm 00517 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Premier) 173 false true R518.htm 00518 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashPremier Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Premier) 174 false false R523.htm 00523 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Premier) 175 false true R524.htm 00524 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundPremier Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Premier) 176 false false R529.htm 00529 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Premier) 177 false true R530.htm 00530 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundPremier Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Premier) 178 false false R535.htm 00535 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Premier) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundPremier Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Premier) 179 false true R536.htm 00536 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPFUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempfundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY TEMPFUND (Private Client) 180 false false R541.htm 00541 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPFUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempfundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPFUND (Private Client) 181 false true R542.htm 00542 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Private Client) 182 false false R547.htm 00547 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Private Client) 183 false true R548.htm 00548 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY T-FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTFundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY T-FUND (Private Client) 184 false false R553.htm 00553 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY T-FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTFundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY T-FUND (Private Client) 185 false true R554.htm 00554 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityCaliforniaMoneyFundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Private Client) 186 false false R559.htm 00559 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityCaliforniaMoneyFundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY CALIFORNIA MONEY FUND (Private Client) 187 false true R560.htm 00560 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNIFUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunifundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY MUNIFUND (Private Client) 188 false false R565.htm 00565 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNIFUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunifundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNIFUND (Private Client) 189 false true R566.htm 00566 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityNewYorkMoneyFundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Private Client) 190 false false R571.htm 00571 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityNewYorkMoneyFundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY NEW YORK MONEY FUND (Private Client) 191 false true R572.htm 00572 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TEMPCASH (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTempcashPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY TEMPCASH (Private Client) 192 false false R577.htm 00577 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TEMPCASH (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTempcashPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY TEMPCASH (Private Client) 193 false true R578.htm 00578 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFederalTrustFundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Private Client) 194 false false R583.htm 00583 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFederalTrustFundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDERAL TRUST FUND (Private Client) 195 false true R584.htm 00584 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityTreasuryTrustFundPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Private Client) 196 false false R589.htm 00589 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY TREASURY TRUST FUND (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityTreasuryTrustFundPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY TREASURY TRUST FUND (Private Client) 197 false true R590.htm 00590 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY MUNICASH (Private Client) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityMunicashPrivateClient Risk/Return Summary- BLACKROCK LIQUIDITY MUNICASH (Private Client) 198 false false R595.htm 00595 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY MUNICASH (Private Client) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityMunicashPrivateClient Risk/Return Detail Data- BLACKROCK LIQUIDITY MUNICASH (Private Client) 199 false true R596.htm 00596 - Document - Risk/Return Summary {Unlabeled} - BLACKROCK LIQUIDITY FEDFUND (Mischler Financial Group Shares) Sheet http://www.blackrock.com/role/RiskReturnSummaryUnlabeledBlackrockLiquidityFedfundMischlerFinancialGroupShares Risk/Return Summary- BLACKROCK LIQUIDITY FEDFUND (Mischler Financial Group Shares) 200 false false R601.htm 00601 - Disclosure - Risk/Return Detail Data {Elements} - BLACKROCK LIQUIDITY FEDFUND (Mischler Financial Group Shares) Sheet http://www.blackrock.com/role/RiskReturnDetailDataElementsBlackrockLiquidityFedfundMischlerFinancialGroupShares Risk/Return Detail Data- BLACKROCK LIQUIDITY FEDFUND (Mischler Financial Group Shares) 201 false false R602.htm 040000 - Disclosure - Risk/Return Detail Data {Elements} Sheet http://xbrl.sec.gov/rr/role/RiskReturnDetailData Risk/Return Detail Data 202 false false All Reports Book All Reports d80048d485bpos.htm brlf-20201031.xsd brlf-20201031_cal.xml brlf-20201031_def.xml brlf-20201031_lab.xml brlf-20201031_pre.xml d80048dex99d2.htm d80048dex99j.htm g80048g04w32.jpg g80048g10g18x48.jpg g80048g10g31w51.jpg g80048g10g40u61.jpg g80048g10g56p99.jpg g80048g10g60j20.jpg g80048g10g60o25.jpg g80048g10g63c76.jpg g80048g10g84l22.jpg g80048g10g87z06.jpg g80048g10g96d97.jpg g80048g11g02z75.jpg g80048g11g08_91.jpg g80048g11g27p53.jpg g80048g11g56p99.jpg g80048g11g85_17.jpg g80048g11g87n30.jpg g80048g11g94s48.jpg g80048g12g30f14.jpg g80048g12g32t91.jpg g80048g12g50d28.jpg g80048g12g52i74.jpg g80048g12g56p99.jpg g80048g13g29v76.jpg g80048g13g56p99.jpg g80048g13g98e77.jpg g80048g18x48.jpg g80048g1g05e63.jpg g80048g1g09o96.jpg g80048g1g13w97.jpg g80048g1g17v08.jpg g80048g1g35i26.jpg g80048g1g56p99.jpg g80048g1g64p05.jpg g80048g1g71m06.jpg g80048g1g72x01.jpg g80048g1g80e18.jpg g80048g1g92e99.jpg g80048g2g01w34.jpg g80048g2g18i48.jpg g80048g2g56p99.jpg g80048g2g80g69.jpg g80048g2g84p46.jpg g80048g2g96j21.jpg g80048g31w51.jpg g80048g3g01r73.jpg g80048g3g02t16.jpg g80048g3g16t99.jpg g80048g3g17x83.jpg g80048g3g40t76.jpg g80048g3g56p99.jpg g80048g3g60x68.jpg g80048g3g65r56.jpg g80048g3g76s53.jpg g80048g3g80n68.jpg g80048g3g85e85.jpg g80048g40u61.jpg g80048g4g01p63.jpg g80048g4g04y71.jpg g80048g4g20b73.jpg g80048g4g44e27.jpg g80048g4g44v36.jpg g80048g4g56p99.jpg g80048g4g60j20.jpg g80048g4g61r50.jpg g80048g4g77g68.jpg g80048g4g95x86.jpg g80048g4g96t22.jpg g80048g56p99.jpg g80048g5g00x67.jpg g80048g5g14w72.jpg g80048g5g15o02.jpg g80048g5g34r81.jpg g80048g5g44w40.jpg g80048g5g45k86.jpg g80048g5g56p99.jpg g80048g5g61d29.jpg g80048g5g63s30.jpg g80048g5g82t24.jpg g80048g5g91n89.jpg g80048g60j20.jpg g80048g60o25.jpg g80048g63c76.jpg g80048g6g01l45.jpg g80048g6g08r30.jpg g80048g6g13d29.jpg g80048g6g56p99.jpg g80048g6g88p09.jpg g80048g6g92n63.jpg g80048g7g00p22.jpg g80048g7g01r27.jpg g80048g7g20k33.jpg g80048g7g26o09.jpg g80048g7g27l27.jpg g80048g7g28_57.jpg g80048g7g32n87.jpg g80048g7g47i74.jpg g80048g7g56p99.jpg g80048g7g77y35.jpg g80048g7g99v00.jpg g80048g84l22.jpg g80048g87z06.jpg g80048g8g00g26.jpg g80048g8g16t99.jpg g80048g8g17x83.jpg g80048g8g30n92.jpg g80048g8g56p99.jpg g80048g8g63l59.jpg g80048g8g66a30.jpg g80048g8g96t22.jpg g80048g96d97.jpg g80048g9g40j11.jpg g80048g9g51j43.jpg g80048g9g56p99.jpg g80048g9g72b43.jpg BarChart1.png BarChart2.png BarChart3.png BarChart4.png BarChart5.png BarChart6.png BarChart7.png BarChart8.png BarChart9.png BarChart10.png BarChart11.png BarChart12.png BarChart13.png BarChart14.png BarChart15.png BarChart16.png BarChart17.png BarChart18.png BarChart19.png BarChart20.png BarChart21.png BarChart22.png BarChart23.png BarChart24.png BarChart25.png BarChart26.png BarChart27.png BarChart28.png BarChart29.png BarChart30.png BarChart31.png BarChart32.png BarChart33.png BarChart34.png BarChart35.png BarChart36.png BarChart37.png BarChart38.png BarChart39.png BarChart40.png BarChart41.png BarChart42.png BarChart43.png BarChart44.png BarChart45.png BarChart46.png BarChart47.png BarChart48.png BarChart49.png BarChart50.png BarChart51.png BarChart52.png BarChart53.png BarChart54.png BarChart55.png BarChart56.png BarChart57.png BarChart58.png BarChart59.png BarChart60.png BarChart61.png BarChart62.png BarChart63.png BarChart64.png BarChart65.png BarChart66.png BarChart67.png BarChart68.png BarChart69.png BarChart70.png BarChart71.png BarChart72.png BarChart73.png BarChart74.png BarChart75.png BarChart76.png BarChart77.png BarChart78.png BarChart79.png BarChart80.png BarChart81.png BarChart82.png BarChart83.png BarChart84.png BarChart85.png BarChart86.png BarChart87.png BarChart88.png BarChart89.png BarChart90.png BarChart91.png BarChart92.png BarChart93.png BarChart94.png BarChart95.png BarChart96.png BarChart97.png BarChart98.png BarChart99.png BarChart100.png http://xbrl.sec.gov/rr/2018-01-31 http://xbrl.sec.gov/dei/2020-01-31 true true