<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.19.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>306</ContextCount>
  <ElementCount>462</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>70</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>8</UnitCount>
  <MyReports>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Statements of Condition (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/StatementsOfConditionUnaudited</Role>
      <ShortName>Statements of Condition (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001501 - Statement - Statements of Condition (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/StatementsOfConditionUnauditedParenthetical</Role>
      <ShortName>Statements of Condition (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - Statement - Statements of Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/StatementsOfIncomeUnaudited</Role>
      <ShortName>Statements of Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003000 - Statement - Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/StatementsOfComprehensiveIncomeUnaudited</Role>
      <ShortName>Statements of Comprehensive Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1004000 - Statement - Statements of Stockholders' Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/StatementsOfStockholdersEquityUnaudited</Role>
      <ShortName>Statements of Stockholders' Equity (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1005000 - Statement - Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/StatementsOfCashFlowsUnaudited</Role>
      <ShortName>Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/BasisOfPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - Recently Issued and Adopted Accounting Guidance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/RecentlyIssuedAndAdoptedAccountingGuidance</Role>
      <ShortName>Recently Issued and Adopted Accounting Guidance</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - Trading Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TradingSecurities</Role>
      <ShortName>Trading Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2103100 - Disclosure - Available-for-sale Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AvailableForSaleSecurities</Role>
      <ShortName>Available-for-sale Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Held-to-maturity Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/HeldToMaturitySecurities</Role>
      <ShortName>Held-to-maturity Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - Other-than-temporary Impairment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/OtherThanTemporaryImpairment</Role>
      <ShortName>Other-than-temporary Impairment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Advances</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/Advances</Role>
      <ShortName>Advances</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - Mortgage Loans Held for Portfolio</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/MortgageLoansHeldForPortfolio</Role>
      <ShortName>Mortgage Loans Held for Portfolio</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Allowance for Credit Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AllowanceForCreditLosses</Role>
      <ShortName>Allowance for Credit Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - Consolidated Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligations</Role>
      <ShortName>Consolidated Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2115100 - Disclosure - Capital and Mandatorily Redeemable Capital Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStock</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Accumulated Other Comprehensive Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2118100 - Disclosure - Derivatives and Hedging Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivities</Role>
      <ShortName>Derivatives and Hedging Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Estimated Fair Values</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/EstimatedFairValues</Role>
      <ShortName>Estimated Fair Values</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2120100 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2121100 - Disclosure - Transactions With Shareholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TransactionsWithShareholders</Role>
      <ShortName>Transactions With Shareholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2122100 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2201201 - Disclosure - Basis of Presentation (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/BasisOfPresentationPolicies</Role>
      <ShortName>Basis of Presentation (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/RecentlyIssuedAndAdoptedAccountingGuidance</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2302301 - Disclosure - Trading Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TradingSecuritiesTables</Role>
      <ShortName>Trading Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/TradingSecurities</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - Available-for-sale Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesTables</Role>
      <ShortName>Available-for-sale Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AvailableForSaleSecurities</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - Held-to-maturity Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesTables</Role>
      <ShortName>Held-to-maturity Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/HeldToMaturitySecurities</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - Other-than-Temporary Impairment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/OtherThanTemporaryImpairmentTables</Role>
      <ShortName>Other-than-Temporary Impairment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Advances (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AdvancesTables</Role>
      <ShortName>Advances (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/Advances</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - Mortgage Loans Held for Portfolio (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/MortgageLoansHeldForPortfolioTables</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/MortgageLoansHeldForPortfolio</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - Allowance for Credit Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AllowanceForCreditLossesTables</Role>
      <ShortName>Allowance for Credit Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AllowanceForCreditLosses</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2313301 - Disclosure - Consolidated Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</Role>
      <ShortName>Consolidated Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligations</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2315301 - Disclosure - Capital and Mandatorily Redeemable Capital Stock (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockTables</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStock</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AccumulatedOtherComprehensiveIncome</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2318301 - Disclosure - Derivatives and Hedging Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</Role>
      <ShortName>Derivatives and Hedging Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivities</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2319301 - Disclosure - Estimated Fair Values (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/EstimatedFairValuesTables</Role>
      <ShortName>Estimated Fair Values (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/EstimatedFairValues</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2320301 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2321301 - Disclosure - Transactions With Shareholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TransactionsWithShareholdersTables</Role>
      <ShortName>Transactions With Shareholders (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/TransactionsWithShareholders</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2402402 - Disclosure - Trading Securities (Trading Securities by Major Security Type) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TradingSecuritiesTradingSecuritiesByMajorSecurityTypeDetails</Role>
      <ShortName>Trading Securities (Trading Securities by Major Security Type) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/TradingSecuritiesTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2402403 - Disclosure - Trading Securities (Net Losses on Trading Securities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TradingSecuritiesNetLossesOnTradingSecuritiesDetails</Role>
      <ShortName>Trading Securities (Net Losses on Trading Securities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/TradingSecuritiesTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - Available-for-sale Securities (Available-for-sale by Major Security Type) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesAvailableForSaleByMajorSecurityTypeDetails</Role>
      <ShortName>Available-for-sale Securities (Available-for-sale by Major Security Type) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2403403 - Disclosure - Available-for-sale Securities (Summary of Available-for-sale Securities in a Continuous Unrealized Loss Position) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesSummaryOfAvailableForSaleSecuritiesInContinuousUnrealizedLossPositionDetails</Role>
      <ShortName>Available-for-sale Securities (Summary of Available-for-sale Securities in a Continuous Unrealized Loss Position) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2403404 - Disclosure - Available-for-sale Securities (Summary of Available-for-sale MBS issued by Members or Affiliates of Members) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesSummaryOfAvailableForSaleMbsIssuedByMembersOrAffiliatesOfMembersDetails</Role>
      <ShortName>Available-for-sale Securities (Summary of Available-for-sale MBS issued by Members or Affiliates of Members) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AvailableForSaleSecuritiesTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Held-to-maturity Securities (Held-to-maturity by Major Security Type) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesHeldToMaturityByMajorSecurityTypeDetails</Role>
      <ShortName>Held-to-maturity Securities (Held-to-maturity by Major Security Type) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2405403 - Disclosure - Held-to-maturity Securities (Summary of Held-to-maturity Securities in a Continuous Unrealized Loss Position) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesSummaryOfHeldToMaturitySecuritiesInContinuousUnrealizedLossPositionDetails</Role>
      <ShortName>Held-to-maturity Securities (Summary of Held-to-maturity Securities in a Continuous Unrealized Loss Position) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2405404 - Disclosure - Held-to-maturity Securities (Redemption Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesRedemptionTermsDetails</Role>
      <ShortName>Held-to-maturity Securities (Redemption Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2405405 - Disclosure - Held-to-maturity Securities (Summary of Held-to-Maturity MBS issued by Members or Affliates of Members (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesSummaryOfHeldToMaturityMbsIssuedByMembersOrAffliatesOfMembersDetails</Role>
      <ShortName>Held-to-maturity Securities (Summary of Held-to-Maturity MBS issued by Members or Affliates of Members (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/HeldToMaturitySecuritiesTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2406404 - Disclosure - Other-than-temporary Impairment (Roll-forward of Credit Losses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/OtherThanTemporaryImpairmentRollForwardOfCreditLossesDetails</Role>
      <ShortName>Other-than-temporary Impairment (Roll-forward of Credit Losses) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/OtherThanTemporaryImpairment</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - Advances Advances (Redemption Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AdvancesAdvancesRedemptionTermsDetails</Role>
      <ShortName>Advances Advances (Redemption Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Advances (Advances by Year of Contractual Maturity for Convertible Advances) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AdvancesAdvancesByYearOfContractualMaturityForConvertibleAdvancesDetails</Role>
      <ShortName>Advances (Advances by Year of Contractual Maturity for Convertible Advances) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AdvancesTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2407404 - Disclosure - Advances (Interest-rate Payment Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AdvancesInterestRatePaymentTermsDetails</Role>
      <ShortName>Advances (Interest-rate Payment Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AdvancesTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2407405 - Disclosure - Advances (Credit Risk Narrative) (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AdvancesCreditRiskNarrativeDetailsTextual</Role>
      <ShortName>Advances (Credit Risk Narrative) (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AdvancesTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - Mortgage Loans Held for Portfolio (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/MortgageLoansHeldForPortfolioDetails</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/MortgageLoansHeldForPortfolioTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - Allowance for Credit Losses (Roll-forward of Allowance for Credit Losses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AllowanceForCreditLossesRollForwardOfAllowanceForCreditLossesDetails</Role>
      <ShortName>Allowance for Credit Losses (Roll-forward of Allowance for Credit Losses) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AllowanceForCreditLossesTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2410403 - Disclosure - Allowance for Credit Losses (Mortgage Loan Portfolio by Impairment Methodology) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AllowanceForCreditLossesMortgageLoanPortfolioByImpairmentMethodologyDetails</Role>
      <ShortName>Allowance for Credit Losses (Mortgage Loan Portfolio by Impairment Methodology) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AllowanceForCreditLossesTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Allowance for Credit Losses (Credit Quality Indicators) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AllowanceForCreditLossesCreditQualityIndicatorsDetails</Role>
      <ShortName>Allowance for Credit Losses (Credit Quality Indicators) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AllowanceForCreditLossesTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2413402 - Disclosure - Consolidated Obligations (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsNarrativeDetails</Role>
      <ShortName>Consolidated Obligations (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2413403 - Disclosure - Consolidated Obligations (Interest-rate Payment Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsInterestRatePaymentTermsDetails</Role>
      <ShortName>Consolidated Obligations (Interest-rate Payment Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2413404 - Disclosure - Consolidated Obligations (Redemption Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsRedemptionTermsDetails</Role>
      <ShortName>Consolidated Obligations (Redemption Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2413405 - Disclosure - Consolidated Obligations (Bonds by Callable Feature) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsBondsByCallableFeatureDetails</Role>
      <ShortName>Consolidated Obligations (Bonds by Callable Feature) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2413406 - Disclosure - Consolidated Obligations (Bonds by Maturity or Call Date) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsBondsByMaturityOrCallDateDetails</Role>
      <ShortName>Consolidated Obligations (Bonds by Maturity or Call Date) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2413407 - Disclosure - Consolidated Obligations (Discount Notes) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.fhlbatl.com/role/ConsolidatedObligationsDiscountNotesDetails</Role>
      <ShortName>Consolidated Obligations (Discount Notes) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2415402 - Disclosure - Capital and Mandatorily Redeemable Capital Stock (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockNarrativeDetails</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockTables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2415403 - Disclosure - Capital and Mandatorily Redeemable Capital Stock (Regulatory Capital Rules and Requirements) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockRegulatoryCapitalRulesAndRequirementsDetails</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock (Regulatory Capital Rules and Requirements) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockTables</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2415404 - Disclosure - Capital and Mandatorily Redeemable Capital Stock Schedule of Declared and Paid Quarterly Dividends (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockScheduleOfDeclaredAndPaidQuarterlyDividendsDetails</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock Schedule of Declared and Paid Quarterly Dividends (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2415405 - Disclosure - Capital and Mandatorily Redeemable Capital Stock (Mandatorily Redeemable Capital Stock Roll-forward) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockMandatorilyRedeemableCapitalStockRollForwardDetails</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock (Mandatorily Redeemable Capital Stock Roll-forward) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2415406 - Disclosure - Capital and Mandatorily Redeemable Capital Stock (Mandatorily Redeemable Capital Stock by Year of Redemption) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockMandatorilyRedeemableCapitalStockByYearOfRedemptionDetails</Role>
      <ShortName>Capital and Mandatorily Redeemable Capital Stock (Mandatorily Redeemable Capital Stock by Year of Redemption) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CapitalAndMandatorilyRedeemableCapitalStockTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - Accumulated Other Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/AccumulatedOtherComprehensiveIncomeDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/AccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2418402 - Disclosure - Derivatives and Hedging Activities (Fair Value of Derivative Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesFairValueOfDerivativeInstrumentsDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Fair Value of Derivative Instruments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2418403 - Disclosure - Derivatives and Hedging Activities (Net Gains (Losses) on Fair Value Hedging Relationships) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesNetGainsLossesOnFairValueHedgingRelationshipsDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Net Gains (Losses) on Fair Value Hedging Relationships) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2418404 - Disclosure - Derivatives and Hedging Activities (Cumulative Basis Adjustments for Fair Value Hedges) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesCumulativeBasisAdjustmentsForFairValueHedgesDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Cumulative Basis Adjustments for Fair Value Hedges) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>72</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>2418405 - Disclosure - Derivatives and Hedging Activities (Net Gains (Losses) on Derivatives and Hedging Activities Recorded in Non-interest Income) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesNetGainsLossesOnDerivativesAndHedgingActivitiesRecordedInNonInterestIncomeDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Net Gains (Losses) on Derivatives and Hedging Activities Recorded in Non-interest Income) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>2418406 - Disclosure - Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesOffsettingOfDerivativeAssetsAndDerivativeLiabilitiesDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>2418407 - Disclosure - Derivatives and Hedging Activities (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesNarrativeDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - Estimated Fair Values (Estimated Fair Value Measurements on a Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/EstimatedFairValuesEstimatedFairValueMeasurementsOnRecurringBasisDetails</Role>
      <ShortName>Estimated Fair Values (Estimated Fair Value Measurements on a Recurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/EstimatedFairValuesTables</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>2419403 - Disclosure - Estimated Fair Values (Roll-forward of Level 3 Assets and Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/EstimatedFairValuesRollForwardOfLevel3AssetsAndLiabilitiesDetails</Role>
      <ShortName>Estimated Fair Values (Roll-forward of Level 3 Assets and Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/EstimatedFairValuesTables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>2419404 - Disclosure - Estimated Fair Values (Fair Value Summary) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/EstimatedFairValuesFairValueSummaryDetails</Role>
      <ShortName>Estimated Fair Values (Fair Value Summary) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/EstimatedFairValuesTables</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>2420402 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CommitmentsAndContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CommitmentsAndContingenciesTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>2420403 - Disclosure - Commitments and Contingencies (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/CommitmentsAndContingenciesNarrativeDetails</Role>
      <ShortName>Commitments and Contingencies (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/CommitmentsAndContingenciesTables</ParentRole>
      <Position>80</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>2421402 - Disclosure - Transactions With Shareholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/TransactionsWithShareholdersDetails</Role>
      <ShortName>Transactions With Shareholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/TransactionsWithShareholdersTables</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="fhlb-atlq22019.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>2422401 - Disclosure - Subsequent (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbatl.com/role/SubsequentDetails</Role>
      <ShortName>Subsequent (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbatl.com/role/SubsequentEvents</ParentRole>
      <Position>82</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="fhlb-atlq22019.htm">fhlb-atlq22019.htm</File>
    <File>fhlb-atlq22019ex311.htm</File>
    <File>fhlb-atlq22019ex312.htm</File>
    <File>fhlb-atlq22019ex321.htm</File>
    <File>fhlba-20190630.xsd</File>
    <File>fhlba-20190630_cal.xml</File>
    <File>fhlba-20190630_def.xml</File>
    <File>fhlba-20190630_lab.xml</File>
    <File>fhlba-20190630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/invest/2013-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
