Statements of Condition [Abstract] Assets [Abstract] Assets Federal Funds Sold Federal funds sold Available-for-sale Securities Available-for-sale securities, net of unrealized gains (losses) of $16,141 at September 30, 2011 and $22,965 at December 31, 2010 (Note 5) Held-to-maturity securities (Note 4) Held-to-Maturity Securities [Abstract] Assets Total assets Liabilities and Stockholders' Equity [Abstract] Liabilities and capital Liabilities [Abstract] Liabilities Deposits [Abstract] Deposits (Note 8) Consolidated obligations, net (Note 10) Consolidated Obligations [Abstract] Interest Payable Accrued interest payable Liabilities Total liabilities Stockholders' Equity Attributable to Parent [Abstract] Capital stock: Capital (Note 11) Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Total retained earnings Retained earnings Accumulated Other Comprehensive Income (Loss), Defined Benefit Pension and Other Postretirement Plans, Net of Tax Employee supplemental retirement plans (Note 14) Stockholders' Equity Attributable to Parent Ending Balance Beginning Balance Total capital Liabilities and Stockholders' Equity Total liabilities and capital Statements of Income [Abstract] Interest and Dividend Income, Operating [Abstract] Interest income Interest Income, Federal Funds Sold Federal funds sold Interest and Dividend Income, Securities, Available-for-sale Available-for-sale securities (Note 5) Interest and Fee Income, Loans, Consumer, Real Estate Mortgage loans held-for-portfolio (Note 7) Interest and Dividend Income, Operating Total interest income Interest Expense [Abstract] Interest expense Interest Expense, Other Short-term Borrowings Consolidated obligations-discount notes (Note 10) Interest Expense, Capital Securities Mandatorily redeemable capital stock (Note 11) Interest Income (Expense), Net Net interest income before provision for credit losses Interest Income (Expense), after Provision for Loan Loss Net interest income after provision for credit losses Noninterest Income [Abstract] Other income (loss) Noninterest Income Total other income (loss) Noninterest Expense [Abstract] Other expenses Noninterest Expense Total other expenses Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Income before assessments Statements of Capital [Abstract] Statement [Table] Statement, Equity Components [Axis] Equity Component [Domain] Parent [Member] Retained Earnings Accumulated Other Comprehensive Income (Loss) Total Comprehensive Income (Loss) Statement [Line Items] Shares, Issued Ending Balance, shares Beginning Balance, shares Stock Issued During Period, Value, New Issues Proceeds from sale of capital stock Stock Issued During Period, Shares, New Issues Proceeds from sale of capital stock, shares Dividends, Common Stock, Cash Cash dividends ($3.60 and $3.69 per share for 2010 and 2011 respectively ) on capital stock Statements of Cash Flows [Abstract] Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Depreciation, Amortization and Accretion, Net [Abstract] Depreciation and amortization: Increase (Decrease) in Operating Capital [Abstract] Net change in: Increase (Decrease) in Interest Payable, Net Accrued interest payable Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Financing activities Proceeds from Other Short-term Debt Proceeds from issuance Proceeds from Issuance of Common Stock Proceeds from issuance Cash dividends paid Payments of Dividends, Common Stock Net increase (decrease) in cash and due from banks Supplemental Cash Flow Information [Abstract] Supplemental disclosures: Bonds Fair Value Option Bonds at fair value under fair value option Reflects the aggregate fair value of Bonds where the fair value option has been elected. Common Stock, Shares putable Capital stock, shares putable Common stock, shares putable Common Stock, Dividends, Per Share, Cash Paid Cash dividends paid per share Document and Entity Information [Abstract] Document and Entity Information. Amortization of concessions on consolidated obligations Concessions on consolidated obligations Amortization of concessions on consolidated obligations. Increase Decrease in Derivative Assets Due to Accrued Interest Derivative assets due to accrued interest Increase Decrease in Derivative Liabilities Due to Accrued Interest Derivative liabilities due to accrued interest Increase Decrease in Affordable Housing Program Liability Affordable Housing Program liability Affordable Housing Program liability. Increase Decrease in Refcorp Liability REFCORP liability Refcorp Liability. Transfer of Mortgage Loans to Real Estate Owned Transfers of mortgage loans to real estate owned Consolidated Obligation Bonds [Abstract] Consolidated obligation bonds: Proceeds Made Federal Home Loan Bank Advances [Abstract] Advances: Proceeds Made Federal Home Loan Bank Advances. Payments to Acquire Available-for-sale Securities [Abstract] Available-for-sale securities: Payments to Acquire Marketable Securities [Abstract] Held-to-maturity securities: Payments to Acquire Loans Held-for-investment Purchased Proceeds from (Payments for) in Interest-bearing Deposits in Banks Interest-bearing deposits Increase (Decrease) in Federal Funds Sold Federal funds sold Segment Information and Concentration [Abstract] Segment information and concentration. Segment information and concentration [Text Block] Segment Information and Concentration Segment information and concentration. Related Party Transactions Disclosure [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Fair Values of Financial Instruments Fair Value Disclosures [Text Block] Derivatives and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Employee Retirement Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Earnings Per Share [Text Block] Total Comprehensive Income Comprehensive Income Note [Text Block] Borrowings [Abstract] Borrowings. Borrowings [Text Block] Borrowings Borrowings. Long term securities [Abstract] Long-term securities. Long-term securities Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Document Fiscal Year Focus Document Fiscal Period Focus Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Shares Reclassified to Mandatorily Redeemable Capital Stock Shares Shares reclassified to mandatorily redeemable capital stock, shares Shares Reclassified To Mandatorily Redeemable Capital Stock Shares. Common Class B [Member] Capital Stock Class B Cash outflows from derivatives containing financing elements Cash outflows from derivatives containing financing elements. Cash outflows from derivatives containing financing elements Class of Stock [Axis] Class of Stock [Domain] Total adjustments Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Held-to-maturity Securities, Sold Security, Realized Gain (Loss) Net realized (gains) from redemption of held-to-maturity securities Notes Payable, Fair Value Disclosure Discount notes at fair value under fair value option Regulator Expenses Cost Assessed on Federal Home Loan Bank Office of Finance Assessments Cost Assessed on Federal Home Loan Bank Finance Agency and Office of Finance Regulator expenses cost assessed on federal home loan bank office of finance assessments cost assessed on federal home loan bank. Stock Repurchased During Period, Shares Redemption of capital stock, shares In Substance Maturities In-substance maturities. In-substance maturities Payments for Maturing and Retiring Consolidated Obligations [Abstract] Consolidated obligation discount notes: Payments For Maturing And Retiring Consolidated Obligations. Federal Home Loan Bank Advances Advances (Note 6) Proceeds from Federal Home Loan Bank Advances Principal collected Depreciation Premises Software and Equipment Premises, software, and equipment Depreciation premises software and equipment. Payments for Federal Home Loan Bank Advances Made Increase (Decrease) in Deposits with Other Federal Home Loan Banks Deposits with other FHLBanks Payments for Congressionally Mandated Federal Home Loan Bank Assessments REFCORP payments Affordable Housing Program payments Payments for Affordable Housing Programs Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Net impairment losses recognized in earnings Credit impairment losses on held-to-maturity securities Interest Income, Federal Home Loan Bank Advances Advances (Note 6) Total Comprehensive Income [Abstract] Net change in Accumulated other comprehensive income (loss): Interest and Dividend Income, Securities, Held-to-maturity Long-term securities Increase (Decrease) in Fair Value Adjustments on Assets and Liabilities Carried at Fair Value under Fair Value Option Change in fair value adjustments on financial instruments held at fair value Net payments on bonds transferred to other FHLBanks Proceeds from Bonds Transferred from Other Federal Home Loan Banks Other Assets Other assets Time Deposits Term Other Liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities Other liabilities Stock Repurchased During Period, Value Redemption of capital stock Cash and Due from Banks Cash and due from banks (Note 3) Held-to-maturity Securities Long-term securities Accrued Investment Income Receivable Accrued interest receivable Property, Plant and Equipment, Net Premises, software, and equipment Interest-bearing Deposit Liabilities Interest-bearing demand Noninterest-bearing Deposit Liabilities Non-interest bearing demand Shares Subject to Mandatory Redemption, Settlement Terms, Amount Mandatorily redeemable capital stock (Note 11) Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities Non-credit portion of OTTI on held-to-maturity securities, net of accretion Loans and Leases Receivable, Allowance Allowance for credit losses on mortgage loans held-for-portfolio Interest Expense, Deposits Deposits (Note 8) Interest Expense Total interest expense Provision for Loan Losses Expensed Provision for credit losses on mortgage loans Impairment of Investments Total OTTI losses Other Cost and Expense, Operating Operating Federal Home Loan Bank Assessments Total assessments Depreciation, Amortization and Accretion, Net Net premiums and discounts on consolidated obligations, investments, mortgage loans and other adjustments Unrealized Gain (Loss) on Securities Net realized (gains) from sale of available-for-sale securities Unrealized Gain (Loss) on Derivatives Change in net fair value adjustments on derivatives and hedging activities Increase (Decrease) in Accrued Interest Receivable, Net Accrued interest receivable Increase (Decrease) in Other Operating Assets Other assets Payments for (Proceeds from) Productive Assets Premises, software, and equipment Payments to Acquire Held-to-maturity Securities Purchased Payments to Acquire Available-for-sale Securities Purchased Proceeds from Sale of Available-for-sale Securities Proceeds from sales Proceeds from Issuance of Long-term Debt and Capital Securities, Net Proceeds from issuance Repayments of Other Long-term Debt Payments for maturing and early retirement Repayments of Other Short-term Debt Payments for maturing Repayments of Mandatory Redeemable Capital Securities Redemption of Mandatorily redeemable capital stock Cash and Cash Equivalents, at Carrying Value Cash and due from banks at end of the period Cash and due from banks at beginning of the period Interest Paid, Net Interest paid Basis of Presentation and Significant Accounting Policies [Text Block] Significant Accounting Policies and Estimates Mortgage Loans on Real Estate, by Loan Disclosure [Text Block] Deposit Liabilities Disclosures [Text Block] Deposits Consolidated Obligations Debt and Capital Leases Disclosures [Text Block] Stockholders' Equity Note Disclosure [Text Block] Capital Stock, Mandatorily Redeemable Capital Stock and Restricted retained earnings Subsequent Events [Text Block] Common Stock, Other Value, Outstanding Capital stock ($100 par value), putable, issued and outstanding shares: 45,717 at September 30, 2011 and 45,290 at December 31, 2010 Long Term Debt Fair Value Bonds (Includes $14,341,126 at September 30, 2011 and $14,281,463 at December 31, 2010 at fair value under the fair value option) Short Term Debt Fair Value Discount notes (Includes $4,125,354 at September 30, 2011 and $956,338 at December 31, 2010 at fair value under the fair value option) Interest Expense, Other Long-term Debt Consolidated obligations-bonds (Note 10) Net Cash Provided by (Used in) Operating Activities [Abstract] Operating activities Net Cash Provided by (Used in) Operating Activities Net cash provided by operating activities Net Cash Provided by (Used in) Investing Activities [Abstract] Net change in: Proceeds from Sale and Maturity of Held-to-maturity Securities Repayments Proceeds from Principal Repayments on Loans and Leases Held-for-investment Principal collected Payments for (Proceeds from) Loans and Leases [Abstract] Mortgage loans held-for-portfolio: Net Cash Provided by (Used in) Investing Activities Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Net Cash Provided by (Used in) Financing Activities [Abstract] Net change in: Investing Activities Advances [Text Block] Advances Advances. Commitments and Contingencies [Abstract] Net Cash Provided By Used In Financing Activities Net cash used by financing activities Capital Stock, Mandatorily Redeemable Capital Stock and Restricted retained earnings [Abstract] Significant Accounting Policies and Estimates [Abstract] Advances [Abstract] Advances disclosure. Available for Sale Securities Disclosure [Text Block] Available-for-Sale Securities This item represents the entire disclosure related to available-for-sale securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. Held to Maturity Securities Disclosure [Text Block] Held-to-Maturity Securities This item represents the entire disclosure related to all investments in certain debt and equity securities for which the entity has the positive intent and ability to hold until maturity. Derivative Assets Derivative assets (Note 15) Affordable Housing Program Obligation Affordable Housing Program Payables for Congressionally Mandated Assessments Payable to REFCORP Derivative Liabilities Derivative liabilities (Note 15) Commitments and Contingencies Commitments and Contingencies (Notes 11, 15 and 17) Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated other comprehensive income (loss) (Note 12) Common Stock, Par or Stated Value Per Share Capital stock, par value Common Stock, Shares, Issued Capital stock, shares issued Common Stock, Shares, Outstanding Capital stock, shares outstanding Interest Income, Deposits with Financial Institutions Interest-bearing deposits Interest Expense, Other Cash collateral held and other borrowings (Note 18) Gain (Loss) on Derivative Instruments, Net, Pretax Net realized and unrealized gains (losses) on derivatives and hedging activities (Note 15) Earnings Per Share, Basic Basic earnings per share (Note 13) Congressionally Mandated Federal Home Loan Bank Assessments REFCORP Affordable Housing Program Assessments Affordable Housing Program Losses from Extinguishment of Debt and Other Losses from extinguishment of debt and other Losses from extinguishment of debt and other. Net Realized Gain from Sale of Available for Sale Securities and Redemption of Held to Maturity Securities Net realized gains from sale of available-for-sale securities and redemption of held-to-maturity securities (Note 4 and 5) Net realized gain from sale of available-for-sale securities and redemption of held-to-maturity securities. Gains (Losses) on Extinguishment of Debt Losses from extinguishment of debt Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Repayments Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans Proceeds from sales of REO Description of New Accounting Pronouncements Not yet Adopted [Text Block] Recently Issued Accounting Standards and Interpretations Cash and Due from Banks [Abstract] Cash and Cash Equivalents Disclosure [Text Block] Cash and Due from Banks Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Unrealized gains (losses) on available-for-sale securities Net unrealized gain on available-for-sale securities Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Net unrealized losses on hedging activities Held-to-maturity Securities, Sold Security, Realized Gain (Loss), Excluding Other than Temporary Impairments Instruments held at fair value - Unrealized gains (losses)(Note 16) Payments for Repurchase of Common Stock Payments for redemption / repurchase Increase (Decrease) in Deposits Deposits and other borrowings Subsequent Events [Abstract] Subsequent Events Related Party Transactions Earnings Per Share of Capital [Abstract] Earnings Per Share of Capital Mortgage Loans Held-for-Portfolio [Abstract] Mortgage Loans Held-for-Portfolio Deposits Total deposits Debt and Capital Lease Obligations Total consolidated obligations Cash and Cash Equivalents, Period Increase (Decrease) Shares Reclassified to Mandatorily Redeemable Capital Stock Value Shares reclassified to mandatorily redeemable capital stock Shares reclassified to mandatorily redeemable capital stock value. Fees and Commissions, Correspondent Clearing Service fees and other Labor and Related Expense Labor and Related Expense, Total Compensation and Benefits Loans and Leases Receivable, Net Reported Amount Loans and Leases Receivable, Net Reported Amount, Total Mortgage loans held-for-portfolio, net of allowance for credit losses of $6,728 at September 30, 2011 and $5,760 at December 31, 2010 (Note7) Net unrealized gains on available-for-sale securities Available-for-sale Securities, Gross Unrealized Gain (Loss) Available-for-sale Securities, Gross Unrealized Gain (Loss), Total Retained Earnings (Accumulated Deficit) [Abstract] Retained earnings Retained Earnings, Unappropriated Unrestricted Retained Earnings, Appropriated Restricted (Note 11) Derivative contracts with financing element Payments for (Proceeds from) Hedge, Financing Activities Reclassification of non- credit OTTI to net income Prior Period Reclassification Adjustment Other than Temporary Impairment Losses Investments Portion in Other Comprehensive Income Loss before Tax Portion of non-credit OTTI (gains) losses on held-to-maturity securities Other Than Temporary Impairment Losses Investments Portion In Other Comprehensive Income Loss Before Tax. Recently Issued Accounting Standards and Interpretations [Abstract] Recently Issued Accounting Standards and Interpretations [Abstract ] Available-for-Sale Securities [Abstract] Employee Retirement Plans [Abstract] Derivatives and Hedging Activities [Abstract] Related Party Transactions [Abstract] Fair Values of Financial Instruments [Abstract] Retained Earnings, Unrestricted Retained Earnings, Restricted Increase (Decrease) in Shareholders' Equity Background Information [Abstract] Nature of Operations [Text Block] Background Information Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Net amount of impairment losses reclassified (from) to Accumulated other comprehensive loss Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent, Total Net Income (Loss) Available to Common Stockholders, Basic Net income Net income Net Income Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Net change in Accumulated other comprehensive income (loss): Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent, Held-to-maturity Securities Non-credit portion of OTTI on held-to-maturity securities, net of accretion Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total comprehensive income Loans to Other Fhlbanks and Other Loans to other FHLBanks and other (Note 8) Loans To Other Fhlbanks and other. Net unrealized gain/losses on available-for-sale securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent, Total Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax, Portion Attributable to Parent Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax, Portion Attributable to Parent, Total Hedging activities