Federal Home Loan Bank of Chicago 10-Q 7 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Entity Information [Line Items]
Entity Registrant Name	Federal Home Loan Bank of Chicago
Entity Central Index Key	1331451
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		17,866,377
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Statements_of_Condition

Statements of Condition (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Assets
Cash and due from banks	$1,458	$342
Interest bearing deposits	560	560
Federal Funds sold	3,022	1,525
Securities purchased under agreements to resell	1,400	3,400
Investment securities -
Trading, $76 and $71 pledged	162	167
Available-for-sale	19,449	19,975
Held-to-maturity, $6,932 and $7,824 fair value	6,223	7,118
Total investment securities	25,834	27,260
Advances, $85 and $83 carried at fair value	31,941	32,485
MPF Loans held in portfolio, net of allowance for credit losses of $(4) and $(15)	5,728	6,057
Derivative assets	8	29
Other assets	196	183
Total assets	70,147	71,841
Liabilities
Noninterest bearing	53	49
Interest bearing, $15 and $13 from other FHLBs	593	617
Total Deposits	646	666
Consolidated obligations, net -
Discount notes, $7,655 and $1,799 carried at fair value	30,474	31,054
Bonds, $2,903 and $2,785 carried at fair value	33,043	34,251
Total consolidated obligations, net	63,517	65,305
Derivative liabilities	45	55
Affordable Housing Program assessment payable	95	90
Other liabilities	321	256
Subordinated notes	944	944
Total liabilities	65,568	67,316
Commitments and contingencies - see notes to the financial statements
Capital
Class B1 activity stock - putable $100 par value - 8 million and 8 million shares issued and outstanding	827	827
Class B2 membership stock - putable $100 par value - 11 million and 11 million shares issued and outstanding	1,096	1,075
Total capital stock	1,923	1,902
Retained earnings - unrestricted	2,214	2,152
Retained earnings - restricted	270	254
Total retained earnings	2,484	2,406
Accumulated other comprehensive income (loss) (AOCI)	172	217
Total capital	4,579	4,525
Total liabilities and capital	$70,147	$71,841

Statements_of_Condition_Parent

Statements of Condition (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Trading securities pledged	$76	$71
Held-to-Maturity Fair Value	6,932	7,824
Advances carried at fair value	85	83
Allowance for credit losses on MPF Loans	-4	-15
Interest bearing deposits from other FHLBs	15	13
Discount notes carried at fair value	7,655	1,799
Consolidated obligation bonds carried at fair value	$2,903	$2,785
Capital stock par value	$100	$100
Class B1 activity shares issued	8	8
Class B1 activity shares outstanding	8	8
Class B2 membership shares issued	11	11
Class B2 membership shares outstanding	11	11

Statements_of_Income

Statements of Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Interest income	$321	$355
Interest expense	191	228
Net interest income before provision for (reversal of) credit losses	130	127
Provision for (reversal of) credit losses	0	-3
Net interest income	130	130
Noninterest gain (loss) on -
Trading securities	-1	-5
Derivatives and hedging activities	-11	-14
Instruments held under fair value option	3	4
Other, net	4	5
Noninterest gain (loss)	-5	-10
Noninterest expense -
Compensation and benefits	19	16
Other operating expenses	11	10
Other	3	4
Noninterest expense	33	30
Income before assessments	92	90
Affordable Housing Program assessment	9	9
Net income	$83	$81

Statements_of_Comprehensive_In

Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$83	$81
Other comprehensive income (loss) -
Net unrealized gain (loss) on available-for-sale securities	-22	55
Non-credit OTTI on held-to-maturity securities	13	14
Net unrealized gain (loss) on cash flow hedges	-28	21
Post-retirement plans	-8	1
Other comprehensive income (loss)	-45	91
Comprehensive income	$38	$172

Statements_of_Stockholders_Equ

Statements of Stockholders' Equity (USD $)	Total	Total Capital Stock	Retained Earnings, Unrestricted	Retained Earnings, Restricted	Retained Earnings, Total	AOCI	Capital Stock - Putable - B1 Activity	Capital Stock - Putable - B2 Membership
In Millions, unless otherwise specified							Total Capital Stock	Total Capital Stock
Balance, beginning at Dec. 31, 2013	$3,765	$1,670	$1,853	$175	$2,028	$67	$629	$1,041
Shares, beginning at Dec. 31, 2013		17					7	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	172		64	17	81	91
Proceeds from issuance of capital stock	85	85					84	1
Proceeds from issuance of capital stock (shares)		1					1	0
Repurchases of capital stock	-50	-50					-17	-33
Repurchases of capital stock (shares)		-1					-1	0
Transfers between classes of capital stock							-108	108
Transfers between B1 and B2 capital stock (shares)							-1	1
Cash dividends - class B1	-1		-1		-1
Cash dividends - class B2	-1		-1		-1
Balance, ending at Mar. 31, 2014	3,970	1,705	1,915	192	2,107	158	588	1,117
Shares, ending at Mar. 31, 2014		17					6	11
Balance, beginning at Dec. 31, 2014	4,525	1,902	2,152	254	2,406	217	827	1,075
Shares, beginning at Dec. 31, 2014		19					8	11
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	38		67	16	83	-45
Proceeds from issuance of capital stock	38	38					32	6
Proceeds from issuance of capital stock (shares)		0					0	0
Repurchases of capital stock	-17	-17					-1	-16
Repurchases of capital stock (shares)		0					0	0
Transfers between classes of capital stock							-31	31
Transfers between B1 and B2 capital stock (shares)							0	0
Cash dividends - class B1	-4		-4		-4
Cash dividends - class B2	-1		-1		-1
Balance, ending at Mar. 31, 2015	$4,579	$1,923	$2,214	$270	$2,484	$172	$827	$1,096
Shares, ending at Mar. 31, 2015		19					8	11

Statements_of_Stockholders_Equ1

Statements of Stockholders' Equity (Parenthetical)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Capital Stock - Putable - B1 Activity
Capital Unit [Line Items]
Cash dividend - annualized rate per $100 par value share	2.25%	1.30%
Capital Stock - Putable - B2 Membership
Capital Unit [Line Items]
Cash dividend - annualized rate per $100 par value share	0.50%	0.30%

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Operating
Net cash provided by (used in) operating activities	$121		$257
Investing
Net change interest bearing deposits	0		-560
Net change Federal Funds sold	-1,497		-2,384
Net change securities purchased under agreements to resell	2,000		-1,850
Advances -
Principal collected	52,328		59,419
Issued	-51,723		-58,271
MPF Loans held in portfolio -
Principal collected	337		410
Purchases	-13		-11
Trading securities -
Sales	0		550
Proceeds from maturities and paydowns	3		13
Purchases	0		-1,812
Held-to-maturity securities -
Short-term held-to-maturity securities, net	705	[1]	555	[1]
Proceeds from maturities and paydowns	232		262
Purchases	-6		-11
Available-for-sale securities -
Proceeds from maturities and paydowns	517		287
Proceeds from sale of foreclosed assets	13		14
Other assets	-2		-2
Net cash provided by (used in) investing activities	2,894		-3,391
Financing
Net change deposits	-20		16
Net proceeds from issuance of consolidated obligations -
Discount notes	149,597		218,709
Bonds	4,885		8,425
Payments for maturing and retiring consolidated obligations -
Discount notes	-150,180		-222,910
Bonds	-6,179		-1,369
Net proceeds (payments) on derivative contracts with financing element	-18		-15
Proceeds from issuance of capital stock	38		85
Repurchase or redemption of capital stock	-17		-50
Cash dividends paid	-5		-2
Net cash provided by (used in) financing activities	-1,899		2,889
Net increase (decrease) in cash and due from banks	1,116		-245
Cash and due from banks at beginning of period	342		971
Cash and due from banks at end of period	$1,458		$726
[1]	Short-term held-to-maturity securities, net, consists of investment securities with a maturity of less than 90 days when purchased.

Background_and_Basis_of_Presen

Background and Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation [Text Block]	Background and Basis of Presentation
	The Federal Home Loan Bank of Chicago a is a federally chartered corporation and one of 12 Federal Home Loan Banks (the FHLBs) that, with the Office of Finance, comprise the Federal Home Loan Bank System (the System).  The FHLBs are government-sponsored enterprises (GSE) of the United States of America and were organized under the Federal Home Loan Bank Act of 1932, as amended (FHLB Act), in order to improve the availability of funds to support home ownership.  The FHLBs are regulated by the Federal Housing Finance Agency (FHFA), an independent federal agency. We provide credit to members principally in the form of secured loans called advances. We also provide liquidity for home mortgage loans to members approved as Participating Financial Institutions (PFIs) through the Mortgage Partnership Finance® (MPF®) Program b.
	Our accounting and financial reporting policies conform to generally accepted accounting principles in the United States of America (GAAP). Amounts in prior periods may be reclassified to conform to the current presentation and if material are disclosed in the following notes.
	In the opinion of management, all normal recurring adjustments have been included for a fair statement of this interim financial information. These unaudited financial statements and the following footnotes should be read in conjunction with the audited financial statements and footnotes for the year ended December 31, 2014, included in our Annual Report on Form 10-K (2014 Form 10-K) starting on page F-1, as filed with the SEC.
	Use of Estimates
	The preparation of financial statements in accordance with GAAP requires us to make assumptions and estimates that may affect the
	reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported amounts of income and expense. The most significant of these assumptions and estimates apply to the following:
	•	Fair value measurements;
	•	Determination of other-than-temporary impairments of securities; and
	•	Allowance for credit losses.
	Actual results could differ from these assumptions and estimates.
	Consolidation of Variable Interest Entities
	We do not consolidate any of our investments in variable interest entities since we are not the primary beneficiary. We classify variable interest entities as investment securities in our statements of condition. Such investment securities include, but are not limited to, senior interests in private label mortgage backed securities (MBS) and Federal Family Education Loan Program - asset backed securities (FFELP ABS).
	The carrying amount for these investment securities is driven by our investment intent - that is, whether we hold the investment security as held-to-maturity, available-for-sale or trading. We have no liabilities related to these investments in variable interest entities. We have not provided financial or other support (explicitly or implicitly) to these investment securities that we were not previously contractually required to provide nor do we intend to provide such support in the future. Our maximum loss exposure for these investment securities is limited to their carrying amounts.
	Gross versus Net Presentation of Financial Instruments
	We present our derivative assets and liabilities on a net basis in our statements of condition. GAAP requires disclosure of both gross information and net information related to derivatives, repurchase agreements and reverse repurchase agreements, and securities borrowing or lending transactions regardless of whether we offset these transactions in our statements of condition. For the periods presented to date, these rights of offset only apply to our derivatives.
	a	Unless otherwise specified, references to we, us, our, and the Bank are to the Federal Home Loan Bank of Chicago.
	b	“Mortgage Partnership Finance”, “MPF”, and “MPF Xtra” are registered trademarks of the Federal Home Loan Bank of Chicago. “Community First” is a trademark of the Federal Home Loan Bank of Chicago.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies
	Our Summary of Significant Accounting Policies through December 31, 2014, can be found in our 2014 Form 10-K starting on page F-10. We adopted the following policies in 2015:
	Asset Classification and Charge-off Provisions
	On April 9, 2012, the FHFA issued Advisory Bulletin 2012-02, Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention (AB 2012-02). The guidance in AB 2012-02 is generally consistent with the Uniform Retail Credit Classification and Account Management Policy issued by the federal banking regulators in June 2000. AB 2012-02 establishes a standard and uniform methodology for classifying assets, prescribes the timing of asset charge-offs (excluding investment securities), and provides measurement guidance with respect to determining our allowance for credit losses, and fair value measurement guidance for conventional MPF Loans that are classified as Substandard, Doubtful, or Loss, and Real Estate Owned (REO) related to conventional MPF Loans. Subsequent to the issuance of AB 2012-02, the FHFA issued interpretative guidance clarifying that implementation of the asset classification framework may occur in two phases. We implemented the asset classification provisions effective January 1, 2014. We prospectively adopted the remaining provisions of AB 2012-02 on January 1, 2015. The effect of implementing the remaining provisions was as follows:
	•	The AB 2012-02 allowance for credit losses measurement guidance did not have a material effect on our financial condition, results of operations, or cash flows at the time of adoption.
	•	We recorded a $10 million charge-off to our allowance for credit losses on MPF Loans to conform our charge-off policies to AB 2012-02. In particular, we now write-down a conventional MPF Loan to its fair value less estimated selling costs when such a loan is classified as "Loss" and when a conventional MPF Loan is transferred to REO. Our prior practice was to record a charge-off when a conventional MPF Loan was transferred to REO. Exposures classified "Loss" are considered uncollectible and of such little value that the exposures continuance as a balance sheet asset is not warranted. This classification does not mean that the exposure has absolutely no recovery or salvage value; rather, it is not practical or desirable to defer charging off this asset, even though partial recovery may occur in the future. Examples of confirming events indicating that a "Loss" exists include, but are not limited to, the following:
	▪	A current assessment of value is made before a single family residential loan is more than 180 days past due. Any outstanding loan balance in excess of the fair value of the property, less cost to sell, is classified as "Loss" when the loan is no more than 180 days delinquent.
	•	When a borrower is in bankruptcy, loans are written down to the fair value of the collateral, less costs to sell, within 60 days of receipt of the notification of filing from the bankruptcy court or within the delinquency time frames specified in the guidance, whichever is shorter.
	•	Fraudulent loans, not covered by any existing representations and warranties in the loan purchase agreement, are charged off within 90 days of discovery of the fraud, or within the delinquency time frames specified in the adverse classification guidance, whichever is shorter.
	•	We began using an Automated Valuation Methodology (AVM) to determine the fair value of our impaired conventional MPF Loans held in portfolio and REO. Our prior practice was to determine fair value using broker price opinions, if available, to measure impaired conventional MPF Loans held in portfolio and REO. If a current broker price opinion was not available, we estimated fair value based on our current actual loss severity rates we experienced on sales, excluding any estimated selling costs. The use of AVM's to determine fair value may result in increased volatility with respect to our provision for credit losses.
	•	We now place a conventional MPF Loan held in portfolio on nonaccrual when it is adversely classified as either "Substandard," "Doubtful", or "Loss". An adverse classification means that such a loan is not considered well secured and in the process of collection. Exposures classified "Substandard" are inadequately protected by the current worth and paying capacity of the obligor or by the collateral pledged, if any. Exposure so classified must have a well-defined weakness or weaknesses that jeopardize the liquidation of the exposure. These weaknesses are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected. Exposures classified "Doubtful" have all the weaknesses inherent in those exposures classified "Substandard" with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently known facts, conditions and values, highly questionable and improbable. Our prior practice was to place conventional MPF Loans held in portfolio on nonaccrual when the loan was 90 or more days past due (or 60 days past due in the case of a bankruptcy) and the loan was not well-secured and in the process of collection. This change in nonaccrual practice did not have a material effect on our nonaccrual loans outstanding at the time of adoption.
	Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure
	In August of 2014, the FASB issued new guidance that requires certain government-guaranteed mortgage loans to be derecognized upon foreclosure and established as a separate receivable. Specifically, such accounting treatment is applied to a government-guaranteed mortgage loan in which the loan guarantee is not separable from the loan prior to foreclosure, the creditor has the intent to make a claim on the guarantee and the ability to recover under the claim, and at the time of foreclosure any amount of the claim that is determined on the basis of the fair value of the real estate is fixed. We prospectively adopted this new guidance on January 1, 2015 for our government MPF Loans. Specifically, our foreclosed government MPF Loans meet the conditions specified by the new guidance and will be classified as a receivable rather than REO. The new guidance did not have a material effect on our operating activities or our financial statements since our credit risk on government MPF Loans is limited to whether or not the servicing PFI fails to pay for losses not covered by Federal Housing Administration (FHA) insurance, or Department of Veteran Affairs (VA), Department of Housing and Urban Development (HUD) or Department of Agriculture Rural Housing Service (RHS) guarantees. Our foreclosed government MPF Loans were previously classified in REO in Other Assets.
	Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure
	In January of 2014, the FASB issued new accounting guidance clarifying that consumer mortgage loans collateralized by real estate should be reclassified to REO when either the creditor obtains legal title to the residential real estate property upon completion of a foreclosure or the borrower conveys all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. We adopted the new guidance effective January 1, 2015, on a prospective basis. The new guidance is consistent with our previous accounting and did not have an effect on our operating activities or financial statements.
	Held for Sale Mortgage Loans
	We classify MPF Xtra, MPF Direct, and government mortgage loans obtained for a Ginnie Mae securitization transaction as mortgage loans held for sale (HFS), as we intend to sell such loans in an outright sale or in a securitization transaction. If material, HFS mortgage loans will be classified as a separate line item in our statements of condition; otherwise, we will classify HFS mortgage loans in Other Assets. We have elected the fair value option for HFS mortgage loans. Since these HFS mortgage loans are carried at fair value, the loans do not require an allowance for credit losses. We measure the fair value of HFS mortgage loans based on to-be-announced (TBA) securities, which represent quoted market prices for new mortgage-backed securities issued by U.S. government sponsored enterprises. Any initial premium or discount is recognized as part of the fair value measurement process rather than amortized as a yield adjustment. Any transaction fees, such as extension fees, or costs are immediately recognized into other noninterest income. HFS mortgage loans are classified as an operating activity within our statements of cash flows.

Recently_Issued_but_Not_Yet_Ad

Recently Issued but Not Yet Adopted Accounting Standards	3 Months Ended
	Mar. 31, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Issued but Not Yet Adopted Accounting Standards [Text Block]	Recently Issued but Not Yet Adopted Accounting Standards
	Simplifying the Presentation of Debt Issuance Cost
	In April of 2015, the FASB issued new guidance requiring us to present concession fees in our statements of condition as a direct deduction from the carrying amount of the related debt liability similar to debt discounts or premiums. Our current practice is to classify concession fees (i.e., debt issuance costs) in Other Assets. The new guidance becomes effective for annual and interim periods within those annual periods beginning after December 15, 2015 with earlier adoption permitted. The new guidance requires us to apply the new guidance retrospectively to all periods presented in our financial statements. We expect to adopt the new guidance January 1, 2016. The new guidance is not expected to have a material effect on our financial statements but may effect the effective yield on our outstanding debt since directly deducting concession fees from the related debt would reduce the average carrying amount of our debt outstanding thereby increasing the effective interest rate on our outstanding debt.
	Amendments to Consolidation Analysis
	In February of 2015, the FASB issued amended guidance concerning consolidation analysis. The new guidance is intended to enhance consolidation guidance for legal entities such as limited partnerships, limited liability corporations, and securitization structures (collateralized debt obligations, collateralized loan obligations, and mortgage-backed security transactions). The new guidance will be effective for periods beginning after December 15, 2015. Early adoption is permitted, including adoption in an interim period. We do not expect the new guidance to affect our financial condition, results of operations, or cash flows.
	Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern
	In August of 2014, the FASB issued guidance that requires an entity's management to assess the entity's ability to continue as a going concern. Specifically, for each annual and interim reporting period, an entity’s management should evaluate whether there are conditions or events, considered in the aggregate, that raise “substantial doubt” about the entity’s ability to continue as a going concern. Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity is unable to meet its obligations as they become due within one year after the date that the financial statements are issued. The guidance becomes effective for the interim and annual periods ending after December 15, 2016, and early application is permitted. This guidance is not expected to have any effect on our financial condition or results of operations at the time of adoption.
	Revenue from Contracts with Customers
	In May of 2014, the FASB issued new guidance governing revenue recognition from contracts with customers. Financial instruments and other contractual rights within the scope of other GAAP guidance are excluded from the scope of this new revenue recognition guidance. In this regard, it is expected that a majority of our contracts with members would be excluded from the scope of this new guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled, in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps:
	•	Step 1: Identify the contract(s) with a customer.
	•	Step 2: Identify the performance obligations in the contract.
	•	Step 3: Determine the transaction price.
	•	Step 4: Allocate the transaction price to the performance obligations in the contract.
	•	Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation.
	The new revenue recognition guidance becomes effective for annual interim reporting periods beginning January 1, 2017. We are in the process of reviewing our contracts with members to determine the effect, if any, on our operating activities and financial statements.

Interest_Income_and_Interest_E

Interest Income and Interest Expense	3 Months Ended
	Mar. 31, 2015
Interest Income (Expense), Net [Abstract]
Interest Income and Interest Expense Disclosure [Text Block]	Interest Income and Interest Expense
	The following table presents interest income and interest expense for the periods indicated:
		Three months ended March 31,
		2015		2014
	Interest income -
	Interest bearing deposits, Federal Funds sold and securities purchased under agreements to resell	$	3	$	1
	Investment securities -
	Trading	1		7
	Available-for-sale	134		143
	Held-to-maturity	69		77
	Total investment securities	204		227
	Advances -
	Advance interest income	39		38
	Advance prepayment fees, including related hedge adjustment gains (losses) of $1 and $0	6		1
	Total Advances	45		39
	MPF Loans held in portfolio	69		88
	Total interest income	321		355
	Interest expense -
	Consolidated obligations -
	Discount notes	72		67
	Bonds	105		147
	Total consolidated obligations	177		214
	Subordinated notes	14		14
	Total interest expense	191		228
	Net interest income before provision for (reversal of) credit losses	130		127
	Provision for (reversal of) credit losses	—		(3		)
	Net interest income	$	130	$	130

Investment_Securities

Investment Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Marketable Securities [Text Block]	Investment Securities
	Our major security types presented in the tables below are defined as follows:
	•	U.S. Government & other government related may consist of the sovereign debt of the United States; debt issued by Fannie Mae, Freddie Mac, and the Federal Farm Credit Banks Funding Corporation; and non-mortgage-backed securities of the Small Business Administration and Tennessee Valley Authority.
	•	Federal Family Education Loan Program - asset backed securities (FFELP ABS).
	•	Government Sponsored Enterprises (GSE) residential mortgage-backed securities (MBS) issued by Fannie Mae and Freddie Mac.
	•	Government-guaranteed residential, multifamily, and reverse mortgage MBS.
	•	Private-label residential MBS.
	•	State or local housing agency obligations.
	Pledged Collateral
	We transact most of our derivatives with large banks and major broker-dealers. Derivative transactions may be entered into either through an over-the-counter bilateral agreement with an individual counterparty or through a Futures Commission Merchant (FCM or clearing member) with a derivatives clearing organization (clearinghouse). We may pledge investment securities as collateral under these agreements, and in such cases, the amount pledged will be noted on the face of the statements of condition. We pledged $76 million of investment securities as collateral for our initial margin with derivative clearing organizations as of March 31, 2015, and $71 million as of December 31, 2014. See Note 9 - Derivatives and Hedging Activities for further details.
	Trading Securities
	The following table presents the fair value of our trading securities. We had no material gains or losses realized from the sales of trading securities.
	As of		March 31, 2015				December 31, 2014
	U.S. Government & other government related		$	101			$	102
	Residential MBS:
	GSE		59				63
	Government-guaranteed		2				2
	Total Residential MBS		61				65
	Trading securities		$	162			$	167
	At March 31, 2015, and 2014, we had net year-to-date unrealized gains (losses) of $(1) million and $(5) million on trading securities still held at period end.
	Amortized Cost Basis and Fair Value – Available-for-Sale Securities (AFS)
		Amortized Cost Basis				Gross Unrealized Gains in AOCI				Gross Unrealized (Losses) in AOCI			Carrying Amount and Fair Value
	As of March 31, 2015
	U.S. Government & other government related	$	450			$	30			$	(1	)	$	479
	State or local housing agency	4				—				—			4
	FFELP ABS	5,640				363				(9		)	5,994
	Residential MBS:
	GSE	10,086				572				(10		)	10,648
	Government-guaranteed	2,167				88				—			2,255
	Private-label	64				5				—			69
	Total Residential MBS	12,317				665				(10		)	12,972
	Total	$	18,411			$	1,058			$	(20	)	$	19,449
	As of December 31, 2014
	U.S. Government & other government related	$	479			$	29			$	—		$	508
	State or local housing agency	3				—				—			3
	FFELP ABS	5,824				408				(11		)	6,221
	Residential MBS:
	GSE	10,285				550				(8		)	10,827
	Government-guaranteed	2,258				87				—			2,345
	Private-label	66				5				—			71
	Total Residential MBS	12,609				642				(8		)	13,243
	Total	$	18,915			$	1,079			$	(19	)	$	19,975
	We had no sales of AFS securities for the periods presented.
	Amortized Cost Basis, Carrying Amount, and Fair Value - Held-to-Maturity Securities (HTM)
		Amortized				Non-credit OTTI Recognized in AOCI (Loss)				Carrying			Gross			Gross			Fair Value
		Cost Basis								Amount			Unrecognized			Unrecognized
													Holding			Holding
													Gains			(Losses)
	As of March 31, 2015
	U.S. Government & other government related	$	1,482			$	—			$	1,482		$	83		$	—		$	1,565
	State or local housing agency	17				—				17			—			—			17
	Residential MBS:
	GSE	2,607				—				2,607			200			—			2,807
	Government-guaranteed	1,097				—				1,097			28			—			1,125
	Private-label	1,271				(251		)		1,020			399			(1		)	1,418
	Total Residential MBS	4,975				(251		)		4,724			627			(1		)	5,350
	Total	$	6,474			$	(251	)		$	6,223		$	710		$	(1	)	$	6,932
	As of December 31, 2014
	U.S. Government & other government related	$	2,222			$	—			$	2,222		$	76		$	(1	)	$	2,297
	State or local housing agency	18				—				18			—			—			18
	Residential MBS:
	GSE	2,695				—				2,695			189			—			2,884
	Government-guaranteed	1,129				—				1,129			28			—			1,157
	Private-label	1,318				(264		)		1,054			415			(1		)	1,468
Total Residential MBS	5,142				(264		)		4,878			632			(1		)	5,509
Total	$	7,382			$	(264	)		$	7,118		$	708		$	(2	)	$	7,824
We had no sales of HTM securities for the periods presented.
Aging of Unrealized Temporary Losses
The following tables present unrealized temporary losses on our AFS and HTM portfolio for periods less than 12 months and for 12 months or more. We recognized no OTTI charges on these unrealized loss positions because we expect to recover the entire amortized cost basis, we do not intend to sell these securities, and we believe it is more likely than not that we will not be required to sell them prior to recovering their amortized cost basis. In the tables below, in cases where the gross unrealized losses for an investment category are less than $1 million, the losses are not reported.
Available-for-Sale Securities
	Less than 12 Months								12 Months or More						Total
	Fair Value				Gross Unrealized Losses				Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
As of March 31, 2015
U.S. Government & other government related	$	49			$	(1	)		$	—		$	—		$	49		$	(1	)
FFELP ABS	12				—				858			(9		)	870			(9		)
Residential MBS:
GSE	—				—				1,900			(10		)	1,900			(10		)
Private-label	—				—				16			—			16			—
Total Residential MBS	—				—				1,916			(10		)	1,916			(10		)
Total	$	61			$	(1	)		$	2,774		$	(19	)	$	2,835		$	(20	)
As of December 31, 2014
U.S. Government & other government related	$	48			$	—			$	—		$	—		$	48		$	—
State or local housing agency	3				—				—			—			3			—
FFELP ABS	14				—				877			(11		)	891			(11		)
Residential MBS:
GSE	—				—				1,996			(8		)	1,996			(8		)
Private-label	—				—				16			—			16			—
Total Residential MBS	—				—				2,012			(8		)	2,012			(8		)
Total	$	65			$	—			$	2,889		$	(19	)	$	2,954		$	(19	)
Held-to-Maturity Securities
	Less than 12 Months								12 Months or More						Total
	Fair Value				Gross Unrealized Losses				Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
As of March 31, 2015
U.S. Government & other government related	$	1			$	—			$	15		$	—		$	16		$	—
State or local housing agency	10				—				—			—			10			—
Residential MBS:
GSE	—				—				5			—			5			—
Private-label	10				—				1,341			(252		)	1,351			(252		)
Total Residential MBS	10				—				1,346			(252		)	1,356			(252		)
Total	$	21			$	—			$	1,361		$	(252	)	$	1,382		$	(252	)
As of December 31, 2014
U.S. Government & other government related	$	13			$	—			$	5		$	(1	)	$	18		$	(1	)
State or local housing agency	10				—				—			—			10			—
Residential MBS:
GSE	—				—				5			—			5			—
Private-label	12				—				1,384			(265		)	1,396			(265		)
Total Residential MBS	12				—				1,389			(265		)	1,401			(265		)
Total	$	35			$	—			$	1,394		$	(266	)	$	1,429		$	(266	)
Contractual Maturity Terms
The table below presents the amortized cost basis and fair value of AFS and HTM securities by contractual maturity, excluding ABS and MBS securities. These securities are excluded because their expected maturities may differ from their contractual maturities if borrowers of the underlying loans elect to prepay their loans.
		Available-for-Sale								Held-to-Maturity
As of March 31, 2015		Amortized Cost Basis				Carrying Amount and Fair Value				Carrying Amount			Fair
													Value
Year of Maturity -
Due in one year or less		$	—			$	—			$	117		$	117
Due after one year through five years		81				86				71			73
Due after five years through ten years		2				2				358			374
Due after ten years		371				395				953			1,018
ABS and MBS without a single maturity date		17,957				18,966				4,724			5,350
Total securities		$	18,411			$	19,449			$	6,223		$	6,932
Other-Than-Temporary Impairment Analysis
Significant Inputs Used to Determine OTTI
Our analysis for OTTI on our private-label MBS includes key modeling assumptions, significant inputs, and methodologies provided by an FHLB System OTTI Committee. We use the information provided to generate cash flow projections used in analyzing credit losses and determining OTTI for private-label MBS. The OTTI Committee was formed by the FHLBs to achieve consistency among the FHLBs in their analyses of the OTTI of private-label MBS. We are responsible for making our own determination of impairment, which includes determining the reasonableness of assumptions, significant inputs, and methodologies used, and performing the required present value calculations using appropriate historical cost bases and yields.
As of March 31, 2015, we had a short-term housing price forecast with projected changes ranging from -3.0% to +8.0% over the twelve month period beginning January 1, 2015 for all markets. For the vast majority of markets, the short-term forecast has changes ranging from +1.0% to +5.0%.  Previously, long-term home price projections following the short-term period were projected to recover using one of five different recovery paths. Starting with the second quarter of 2014, a unique path was projected for each geographic area based on an internally developed framework derived from historical data.
Based on these inputs and assumptions, we had no OTTI charges for the three months ended March 31, 2015, and 2014.
The following table presents the changes in the cumulative amount of credit losses (recognized into earnings) on OTTI investment securities for the periods stated.
		Three months ended March 31,
		2015				2014
Beginning Balance		$	620			$	677
Reductions:
Increases in cash flows expected to be collected that have been recognized as accretion income into interest income		(15		)		(14		)
Ending Balance		$	605			$	663

Advances

Advances	3 Months Ended
	Mar. 31, 2015
Federal Home Loan Banks [Abstract]
Advances [Text Block]	Advances
	We offer a wide range of fixed- and variable-rate advance products with different maturities, interest rates, payment characteristics and optionality. The following table presents our advances by callable/putable features:
	As of		March 31, 2015		December 31, 2014
	Noncallable/nonputable		$	29,093	$	29,666
	Callable		961		964
	Putable		1,643		1,673
	Total par value		31,697		32,303
	Hedging adjustments		223		166
	Other adjustments		21		16
	Total advances		$	31,941	$	32,485
	The following table presents our advances by redemption terms:
	As of March 31, 2015		Amount		Weighted Average Interest Rate			Next Maturity or Call Date		Next Maturity or Put Date
	Due in one year or less		$	6,628	0.51	%		$	7,540	$	7,834
	One to two years		2,568		2.15	%		2,368		2,112
	Two to three years		4,369		1.09	%		3,984		3,730
	Three to four years		8,989		0.33	%	a	8,689		8,908
	Four to five years		6,861		0.29	%	a	6,839		6,872
	More than five years		2,282		2.31	%		2,277		2,241
	Total par value		$	31,697	0.75	%		$	31,697	$	31,697
	a	The weighted average interest rate is relatively lower when compared to other categories due to a majority of advances in this category consisting of variable rate advances which reset periodically at current interest rates.
	We lend to members within our district according to federal statutes, including the FHLB Act, and FHFA regulations. The FHLB Act requires us to obtain sufficient collateral to fully secure our advances, and we do not expect to incur any credit losses on advances. We perfect our security interest in pledged collateral and enter into control agreements for securities collateral. We take a risk-based approach in requiring delivery of pledged collateral. We have policies and procedures in place that are designed to manage our credit risk, including requirements for restrictions on borrowing, verifications of collateral and monitoring of borrowings and the borrower's financial condition. Based on the collateral pledged as security for advances and our credit analyses of our borrowers' financial condition and our credit extension and collateral policies, we expect to collect all amounts due according to the contractual terms of our advances. See Note 8 - Allowance for Credit Losses for information related to our credit risk on advances and allowance methodology for credit losses.

MPF_Loans

MPF Loans	3 Months Ended
	Mar. 31, 2015
Mortgage Loans on Real Estate [Abstract]
MPF Loans [Text Block]	MPF Loans
	The following table presents information on MPF Loans held in our portfolio by contractual maturity at the time of purchase. All are fixed-rate. Government is comprised of loans insured by the FHA and loans guaranteed by the VA, HUD or RHS.
	As of	March 31, 2015			December 31, 2014
	Medium term (15 years or less)	$	971		$	1,094
	Long term (greater than 15 years)	4,692			4,905
	Total unpaid principal balance	5,663			5,999
	Net premiums, credit enhancement and deferred loan fees	22			23
	Hedging adjustments	47			50
	Total before allowance for credit losses	5,732			6,072
	Allowance for credit losses on MPF Loans	(4		)	(15		)
	Total MPF Loans held in portfolio, net	$	5,728		$	6,057
	Conventional mortgage loans	$	4,323		$	4,619
	Government insured mortgage loans	1,340			1,380
	Total unpaid principal balance	$	5,663		$	5,999
	See Note 8 - Allowance for Credit Losses for information related to our credit risk on MPF Loans and allowance for credit losses methodology.
	In addition to our portfolio MPF products, PFIs sell eligible MPF Loans to us through the MPF Program infrastructure and we concurrently sell them to Fannie Mae under the MPF Xtra product and to third party investors under the MPF Direct product. Under our MPF Government MBS product, PFIs sell us Government Loans that we intend to hold in our portfolio for a short period of time until such loans are pooled into Ginnie Mae MBS. Other MPF Banks that offer these three products allow their PFIs to sell MPF Loans directly to us. For the period ending March 31, 2015, we held an immaterial amount of MPF Loans held for sale, recorded in Other Assets in our statements of condition. See Note 2 - Summary of Significant Accounting Policies for information related to our accounting for MPF Loans that are held for sale.

Allowance_for_Credit_Losses

Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Allowance for Credit Losses [Text Block]	Allowance for Credit Losses
	We have established an allowance methodology for each of our portfolio segments:
	•member credit products (advances, letters of credit and other extensions of credit to borrowers);
	•conventional MPF Loans held for portfolio;
	•government MPF Loans held for portfolio; and
	•term Federal Funds sold and term securities purchased under agreements to resell.
	For detailed information on these methodologies and our accounting policies please see Note 8 - Allowance for Credit Losses to the financial statements in our 2014 Form 10-K. Any updates to these accounting policies are noted below.
	Member Credit Products
	For the periods presented, we had no credit products that were past due, on nonaccrual status, or considered impaired. In addition, there have been no troubled debt restructurings related to our credit products during the periods then ended. Based upon the collateral we held as security, our credit extension and collateral policies, our credit analysis and the repayment history on credit products, we do not believe that any credit losses have been incurred on our credit products; accordingly, we have not recorded any allowance for credit losses for our credit products. Additionally, no liability was recorded to reflect an allowance for credit losses for our credit products with off-balance sheet credit exposures.
	Conventional MPF Loans
	MPF Risk Sharing Structure
	We share the risk of credit losses on conventional MPF Loan products held in portfolio with our PFIs by structuring potential losses on conventional MPF Loans into layers with respect to each master commitment (MC). The credit risk analysis determines the degree to which layers of the MPF Risk Sharing Structure are available to recover losses on MPF Loans. PFIs deliver MPF Loans into pools designated by product specific MCs. The credit risk analysis is performed at an individual MC level as loss recovery is MC-specific and no risk layer can be applied across a PFI's MCs. With respect to participation interests in MPF Loans, losses are allocated amongst the participating MPF Banks pro-ratably based upon their respective percentage participation interest in the related MC. For further detail of our MPF Risk Sharing Structure see page F-31 in our 2014 Form 10-K.
	The following table presents the changes in the allowance for credit losses on conventional MPF Loans.
		For the three months ended
		March 31, 2015			March 31, 2014
	Balance, beginning of period	$	15		$	29
	Losses charged to the allowance	(11		)	(2		)
	Provision for (reversal of) credit losses	—			(3		)
	Balance, end of period	$	4		$	24
	The following table presents the recorded investment by impairment methodology on conventional MPF Loans.
	As of	March 31, 2015			December 31, 2014
	Specifically identified and individually evaluated for impairment	$	—		$	12
	Homogeneous pools of loans and collectively evaluated for impairment	4			3
	Allowance for credit losses on conventional MPF Loans	$	4		$	15
	Individually evaluated for impairment	$	144		$	160
	Collectively evaluated for impairment	4,252			4,538
	Total recorded investment	$	4,396		$	4,698
	Government MPF Loans Held in Portfolio
	The PFI provides and maintains insurance or a guaranty from governmental agencies, which includes ensuring compliance with all of their requirements, and obtaining the benefit of the applicable insurance or guaranty with respect to defaulted government MPF Loans. Any losses incurred on government MPF Loans that are not recovered from the government insurer or guarantor are absorbed by the servicing PFI. Accordingly, our credit risk on government MPF Loans is limited to whether or not the servicing PFI fails to pay for losses not covered by FHA insurance, or VA, HUD or RHS guarantees. In this regard, based on our assessment of the servicing PFIs, we did not establish an allowance for credit losses for our government MPF Loan portfolio as of the periods presented. Further, due to the government guarantee or insurance and the servicing PFIs ability to absorb losses, government MPF Loans are not placed on nonaccrual status or disclosed as troubled debt restructurings.
	Credit Quality Indicators - MPF Loans
	The table below summarizes our recorded investment in MPF Loans by our key credit quality indicators. Serious delinquency rate is defined as 90 days or more past due or in the process of foreclosure, as a percentage of the total recorded investment. Past due 90 days or more still accruing interest is defined as MPF Loans that are either government guaranteed or conventional mortgage loans that are well secured (by collateral that have a realizable value sufficient to discharge the debt or by the guarantee or insurance, such as PMI, of a financially responsible party) and in the process of collection.
		March 31, 2015									December 31, 2014
	As of	Conventional			Government			Total			Conventional			Government			Total
	Past due 30-59 days	$	114		$	74		$	188		$	138		$	92		$	230
	Past due 60-89 days	37			20			57			43			23			66
	Past due 90 days or more	133			42			175			153			44			197
	Total past due	284			136			420			334			159			493
	Total current	4,112			1,229			5,341			4,364			1,246			5,610
	Total recorded investment	$	4,396		$	1,365		$	5,761		$	4,698		$	1,405		$	6,103
	Also in process of foreclosure	$	66		$	14		$	80		$	77		$	11		$	88
	Serious delinquency rate	3.04		%	3.06		%	3.04		%	3.28		%	3.15		%	3.25		%
	Past due 90 days or more still accruing interest	$	11		$	42		$	53		$	25		$	44		$	69
	On nonaccrual status	$	144		$	—		$	144		$	163		$	—		$	163
	Troubled Debt Restructurings
	As of March 31, 2015 and December 31, 2014, our recorded investment balances of mortgage loans classified as troubled debt restructurings were $68 million and $73 million, respectively. The financial amounts related to troubled debt restructurings are not material to our financial condition, results of operations, or cash flows.
	Individually Evaluated Impaired Loans
	The following table summarizes the recorded investment, unpaid principal balance, and related allowance of impaired MPF Loans individually assessed for impairment, which includes impaired collateral dependent MPF Loans and troubled debt restructurings. As of March 31, 2015, we did not have an allowance for our impaired MPF Loans. For further details see
	Note 2 - Summary of Significant Accounting Policies to the financial statements.
	As of	March 31, 2015			December 31, 2014
	Recorded investment with an allowance	$	—		$	160
	Recorded investment without an allowance	144			—
	Unpaid principal balance with an allowance	—			158
	Unpaid principal balance without an allowance	152			—
	Related allowance	—			12
	The following table summarizes the average recorded investment of impaired conventional MPF Loans. No interest income was recognized on impaired loans.
		For the three months ended
		31-Mar-15			31-Mar-14
	Average recorded investment with an allowance	$	—		$	204
	Average recorded investment without an allowance	148			—
	Term Federal Funds Sold and Term Securities Purchased Under Agreements to Resell
	Federal Funds sold are only evaluated for purposes of an allowance for credit losses if payment is not made when due. In this regard, all Federal Funds sold were repaid according to their contractual terms. We did not establish an allowance for credit losses for Securities Purchased Under Agreements to Resell since all payments due under the contractual terms have been received and because we hold sufficient underlying collateral.

Derivatives_and_Hedging_Activi

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities
	Refer to Note 2 - Summary of Significant Accounting Polices to the financial statements in our 2014 Form 10-K for our accounting policies for derivatives.
	We transact most of our derivatives with large banks and major broker-dealers. Some of these banks and broker-dealers or their affiliates buy, sell, and distribute consolidated obligations. Derivative transactions may be entered into through an over-the-counter bilateral agreement with an individual counterparty. Additionally, we clear derivatives transactions through an FCM with a derivatives clearing organization (clearinghouse). We are not a derivatives dealer and do not trade derivatives for speculative purposes.
	Managing Credit Risk on Derivative Agreements
	We are subject to credit risk due to the risk of nonperformance by counterparties to our derivative agreements. For bilateral derivative agreements, the degree of counterparty risk depends on the extent to which master netting arrangements are included in such contracts to mitigate the risk. We manage counterparty credit risk through credit analysis, collateral requirements and adherence to the requirements set forth in our policies and FHFA regulations. We require collateral agreements on all derivatives that establish collateral delivery thresholds. Additionally, collateral related to derivatives with member institutions includes collateral assigned to us, as evidenced by a written security agreement, and held by the member institution for our benefit. Based on credit analyses and collateral requirements, we do not anticipate any credit losses on our derivative agreements. See Note 16 - Fair Value Accounting to the financial statements in our 2014 Form 10-K for discussion regarding our fair value methodology for derivative assets and liabilities, including an evaluation of the potential for the fair value of these instruments to be affected by counterparty credit risk.
	Our over-the-counter bilateral derivative agreements contain provisions that require us to post additional collateral with our counterparties if there is deterioration in our credit rating, except for those derivative agreements with a zero unsecured collateral threshold for both parties, in which case positions are required to be fully collateralized regardless of credit rating. If our credit rating is lowered by a major credit rating agency, such as Standard and Poor's or Moody’s, we would be required to deliver additional collateral on derivatives in net liability positions. If our credit rating had been lowered from its current rating to the next lower rating, we would have been required to deliver up to an additional $32 million of collateral at fair value to our derivatives counterparties at March 31, 2015.
	Cleared swaps are subject to initial and variation margin requirements established by the clearinghouse and its clearing members. We post initial and variation margin through the clearing member, on behalf of the clearinghouse, which could expose us to institutional credit risk in the event that a clearing member or the clearinghouse fail to meet their obligations. Clearing derivatives through a clearinghouse mitigates counterparty credit risk exposure because a central clearinghouse counterparty is substituted for individual counterparties and collateral is posted daily for changes in the value of cleared derivatives through an FCM. The clearinghouse determines initial margin requirements for cleared derivatives. In this regard, clearing agents may require additional initial margin to be posted based on credit considerations, including but not limited to, credit rating downgrades.  We were not required to post additional initial margin by our clearing agents at March 31, 2015.
	We present our derivative assets and liabilities on a net basis in our statements of condition. Refer to Note 1 - Background and Basis of Presentation and Note 2 - Summary of Significant Accounting Policies to the financial statements in our 2014 Form 10-K for further discussion. In addition to the cash collateral as noted in the following table, we also pledged $76 million of investment securities at March 31, 2015, of which $76 million can be sold or repledged, as part of our initial margin related to cleared derivative transactions.
	The following table presents our gross and net derivative assets and liabilities by contract type and amount for our derivative agreements.
			March 31, 2015											31-Dec-14
	As of		Notional Amount			Derivative Assets				Derivative Liabilities				Notional Amount				Derivative Assets				Derivative Liabilities
	Derivatives in hedge accounting relationships-
	Interest rate swaps		$	31,559		$	71			$	1,394			$	30,940			$	53			$	1,348
	Derivatives not in hedge accounting relationships-
	Interest rate swaps		25,297			547				407				19,159				487				329
	Interest rate swaptions		1,810			66				—				1,850				56				—
	Interest rate caps or floors		1,164			104				—				1,164				105				—
	Interest rate futures		1			—				—				3				—				—
	Mortgage delivery commitments		501			6				6				284				3				3
	Other		3			—				—				—				—				—
	Derivatives not in hedge accounting relationships		28,776			723				413				22,460				651				332
	Gross derivative amount before adjustments		$	60,335		794				1,807				$	53,400			704				1,680
	Netting adjustments and cash collateral					(786		)	a	(1,762		)	a					(675		)	a	(1,625		)	a
	Derivatives on statements of condition					$	8			$	45							$	29			$	55
	a	Amounts represent the application of the netting requirements that allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed by us with the same clearing agent and/or counterparty. Cash collateral posted was $1.0 billion at March 31, 2015, and $978 million at December 31, 2014. Cash collateral received was $55 million at March 31, 2015, and $29 million at December 31, 2014.
	The following table presents our gross recognized amount of offsetting derivative assets and liabilities for derivatives with legal right of offset as well as derivatives without the legal right of offset. Any over-collateralization received by or paid from us to an individual clearing member and/or at a counterparty arrangement level is not included in the determination of the net amount.  Specifically, any such over-collateralization amount received by us is not offset against another derivative asset counterparty exposure for which there is no legal right of offset, while any over-collateralization delivered by us is not offset against another derivative liability counterparty exposure for which there is no legal right of offset.
			Derivative Assets											Derivative Liabilities
	As of March 31, 2015		Bilateral			Cleared				Total				Bilateral				Cleared				Total
	Derivatives with legal right of offset -
	Gross recognized amount		$	707		$	81			$	788			$	1,491			$	310			$	1,801
	Netting adjustments and cash collateral		(705		)	(81		)		(786		)		(1,455		)		(307		)		(1,762		)
	Derivatives with legal right of offset - net		2			—				2				36				3				39
	Derivatives without legal right of offset		6			—				6				6				—				6
	Derivatives on statements of condition		8			—				8				42				3				45
	Noncash collateral received (pledged) and cannot be sold or repledged		1			—				1				—				3				3
	Net amount		$	7		$	—			$	7			$	42			$	—			$	42
	As of December 31, 2014
	Derivatives with legal right of offset -
	Gross recognized amount		$	656		$	45			$	701			$	1,466			$	211			$	1,677
	Netting adjustments and cash collateral		(632		)	(43		)		(675		)		(1,414		)		(211		)		(1,625		)
	Derivatives with legal right of offset - net		24			2				26				52				—				52
	Derivatives without legal right of offset		3			—				3				3				—				3
	Derivatives on statements of condition		27			2				29				55				—				55
	Noncash collateral received (pledged) and cannot be sold or repledged		23			—				23				—				—				—
	Net amount		$	4		$	2			$	6			$	55			$	—			$	55
	At March 31, 2015, we had $74 million of additional net credit exposure on cleared derivatives due to instances where our pledged non-cash collateral to a counterparty exceeded our net derivative liability position. We had $4 million comparable exposure at December 31, 2014.
	The tables below present the gains (losses) of derivatives and hedging activities as presented in the statements of income.
			Three months ended March 31,
	For the periods ending		2015			2014
	Fair value hedges -
	Interest rate swaps		$	(19	)	$	(6	)
	Cash flow hedges		—			1
	Economic hedges -
	Interest rate swaps		(23		)	1
	Interest rate swaptions		8			(15		)
	Interest rate caps or floors		(1		)	(10		)
	Net interest settlements		24			15
	Economic hedges		8			(9		)
	Gains (losses) on derivatives and hedging activities		$	(11	)	$	(14	)
	Fair Value Hedges
	The following table presents, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair value hedging relationships and the effect of those derivatives on our net interest income. We had no gain (loss) for hedged firm commitments on forward-starting advances that no longer qualified as a fair value hedge.
			Gain (loss)
			On Derivative			On Hedged Item				Total Ineffectiveness Recognized in Derivatives and Hedging Activities				Net Interest Settlements Recorded in Net Interest Income				Closed Hedge Adjustments Amortized into Net Interest Income
	Three months ended
March 31, 2015
Hedged item type -
Available-for-sale securities		$	(36	)	$	31			$	(5	)		$	(34	)	a	$	(10	)	b
Advances		(61		)	57				(4		)		(20		)	a	1			b
MPF Loans held for portfolio		—			—				—				—			a	(4		)	b
Consolidated obligation bonds		74			(84		)		(10		)		58			a	—			b
Total		$	(23	)	$	4			$	(19	)		$	4		a	$	(13	)	b
Three months ended
March 31, 2014
Hedged item type -
Available-for-sale securities		$	(2	)	$	1			$	(1	)		$	(35	)	a	$	—		b
Advances		(30		)	32				2				(20		)	a	(1		)	b
MPF Loans held for portfolio		—			—				—				—			a	(5		)	b
Consolidated obligation bonds		133			(140		)		(7		)		61			a	(5		)	b
Total		$	101		$	(107	)		$	(6	)		$	6		a	$	(11	)	b
a	Represents the effect of net interest settlements attributable to open derivative hedging instruments on net interest income. The effect of derivatives on net interest income is included in the interest income/expense line item of the respective hedged item type.
b	Amortization of hedge adjustments is included in the interest income/expense line item of the respective hedged item type.
Cash Flow Hedges
The following table presents our gains (losses) on our cash-flow hedging relationships recorded in income and other comprehensive income (loss). In cases where amounts are insignificant in the aggregate, we do not report a balance.
		Amortization of Effective Portion Reclassified From AOCI to Interest			Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities				Total Reclassified From AOCI to Statements of Income				Net Change in Other Comprehensive Income				Effective Portion Recorded in AOCI				Net Interest Settlements Classified in Net Interest Income
Three months ended March 31, 2015
Advances -		$	3		$	—			$	3			$	(3	)		$	—			$	—
interest rate floors
Discount notes -		(1		)	—				(1		)		(26		)		(27		)		(62		)	a
interest rate swaps
Bonds -		(1		)	—				(1		)		1				—				—
interest rate swaps
Total		$	1		$	—			$	1			$	(28	)		$	(27	)		$	(62	)	a
Three months ended March 31, 2014
Advances -		$	3		$	—			$	3			$	(3	)		$	—			$	—
interest rate floors
Discount notes -		(1		)	1				—				24				24				(61		)	a
interest rate swaps
Total		$	2		$	1			$	3			$	21			$	24			$	(61	)	a
a	Represents the effect of net interest settlements attributable to open derivative hedging instruments on net interest income. The effect of derivatives on net interest income is included in the interest income/expense line item of the respective hedged item type.
There were no amounts reclassified from AOCI into earnings for the periods presented as a result of the discontinuance of cash-flow hedges because the original forecasted transactions failed to occur by the end of the originally specified time period or within a two-month period thereafter. The deferred net gains (losses) on derivative instruments in AOCI that are expected to be reclassified to earnings during the next twelve months were $(1) million as of March 31, 2015. The maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, is 5 years.

Consolidated_Obligations

Consolidated Obligations	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Consolidated Obligations [Text Block]	Consolidated Obligations
	The FHLBs issue consolidated obligations through the Office of Finance as their agent. Consolidated obligations consist of discount notes and consolidated obligation bonds. Consolidated discount notes are issued primarily to raise short-term funds. Discount notes are issued at less than their face amount and redeemed at par value when they mature. The maturity of consolidated bonds range from less than one year to over 20 years, but they are not subject to any statutory or regulatory limits on maturity.
	The following table presents our consolidated obligation bonds, for which we are the primary obligor, including callable bonds that are redeemable in whole, or in part, at our discretion on predetermined call dates.
	As of March 31, 2015	Contractual Maturity			Weighted Average Interest Rate			By Next Maturity or Call Date
	Due in one year or less	$	2,190		3	%		$	23,807
	One to two years	3,795			2.44	%		2,898
	Two to three years	8,074			1.94	%		2,834
	Three to four years	3,907			1.17	%		980
	Four to five years	6,599			1.56	%		1,374
	Thereafter	8,540			2.49	%		1,212
	Total par value	$	33,105		2.04	%		$	33,105
	The following table presents our consolidated obligation discount notes for which we are the primary obligor. All are due in one year or less.
	As of	31-Mar-15			December 31, 2014
	Carrying Amount	$	30,474		$	31,054
	Par Value	30,486			31,060
	Weighted Average Interest Rate	0.11		%	0.09		%
	The following table presents consolidated obligation bonds outstanding by call feature:
	As of	31-Mar-15			31-Dec-14
	Noncallable	$	10,763		$	11,046
	Callable	22,342			23,355
	Par value	33,105			34,401
	Bond premiums (discounts), net	15			17
	Hedging adjustments	(93		)	(177		)
	Fair value option adjustments	16			10
	Total consolidated obligation bonds	$	33,043		$	34,251
	Joint and Several Liability
	We do not expect to pay any additional amounts on behalf of other FHLBs under our joint and several liability as of March 31, 2015. As a result, we did not accrue a liability for our joint and several liability related to the other FHLBs’ share of the consolidated obligations as of March 31, 2015 and December 31, 2014.
	The following table summarizes the consolidated obligations of the FHLBs and those for which we are the primary obligor:
		March 31, 2015										31-Dec-14
	Par values as of	Bonds			Discount				Total			Bonds			Discount			Total
					Notes										Notes
	FHLB System total consolidated obligations	$	459,021		$	353,175			$	812,196		$	484,812		$	362,363		$	847,175
	FHLB Chicago as primary obligor	33,105			30,486				63,591			34,401			31,060			65,461
	As a percent of the FHLB System	7		%	9		%		8		%	7		%	9		%	8		%

Capital_and_Mandatorily_Redeem

Capital and Mandatorily Redeemable Capital Stock	3 Months Ended
	Mar. 31, 2015
Capital [Abstract]
Capital Stock and Mandatorily Redeemable Capital Stock [Text Block]	Capital
	Under our Capital Plan our stock consists of two sub-classes of stock, Class B1 activity stock and Class B2 membership stock (together, Class B stock), both with a par value of $100 and redeemable on five years' written notice, subject to certain conditions. Under the Capital Plan, each member is required to own capital stock in an amount equal to the greater of a membership stock requirement or an activity stock requirement. Class B1 activity stock is available for purchase only to support a member's activity stock requirement. Class B2 membership stock is available to be purchased to support a member's membership stock requirement and any activity stock requirement.
	Minimum Capital Requirements
	For details on our minimum capital requirements, including how the ratios below were calculated, see Minimum Capital Requirements on page F-44 of our 2014 Form 10-K. We complied with our minimum regulatory capital requirements as shown below:
		March 31, 2015						December 31, 2014
		Requirement			Actual			Requirement			Actual
	Risk-based capital	$	1,135		$	4,416		$	1,127		$	4,317
	Total regulatory capital	$	2,806		$	4,416		$	2,874		$	4,317
	Total regulatory capital ratio	4		%	6.29		%	4		%	6.01		%
	Leverage capital	$	3,507		$	6,623		$	3,592		$	6,475
	Leverage capital ratio	5		%	9.44		%	5		%	9.01		%
	Total regulatory capital and leverage capital do not include accumulated other comprehensive income (loss). Under the FHFA regulation on capital classifications and critical capital levels for the FHLBs, we are adequately capitalized.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Income (Loss)
	The following table summarizes the income (loss) in AOCI for the periods indicated:
		Net Unrealized Gain (Loss)			Non-credit OTTI			Net Unrealized on Cash Flow Hedges
		Available-for-sale Securities			Held-to-maturity Securities						Post-Retirement Plans			Total AOCI
	Three months ended March 31, 2015
	Beginning balance	$	1,060		$	(264	)	$	(580	)	$	1		$	217
	Change in the period recorded to the statements of condition, before reclassifications to statements of income	(22		)	13			(27		)	(8		)	(44		)
	Amounts reclassified in period to statements of income:
	Net interest income	—			—			(1		)	—			(1		)
	Total other comprehensive income in the period	(22		)	13			(28		)	(8		)	(45		)
	Ending balance	$	1,038		$	(251	)	$	(608	)	$	(7	)	$	172
	Three months ended March 31, 2014
	Beginning balance	$	1,052		$	(320	)	$	(665	)	$	—		$	67
	Change in the period recorded to the statements of condition, before reclassifications to statements of income	55			14			24			—			93
	Amounts reclassified in period to statements of income:
	Net interest income	—			—			(2		)	—			(2		)
	Non-interest gain (loss)	—			—			(1		)	—			(1		)
	Non-interest expense	—			—			—			1			1
	Total other comprehensive income in the period	55			14			21			1			91
	Ending balance	$	1,107		$	(306	)	$	(644	)	$	1		$	158

Fair_Value_Accounting

Fair Value Accounting	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Accounting [Text Block]	Fair Value Accounting
	For accounting policies regarding fair values see Note 2 - Summary of Significant Accounting Policies to the financial statements in our 2014 Form 10-K. For a description of the valuation techniques and significant inputs see Note 16 - Fair Value Accounting to the financial statements in our 2014 Form 10-K. There has been one significant change in our valuation technique since then.
	The fair values of all interest rate derivative agreements are netted by clearing member and/or by counterparty, including cash collateral received from or delivered to the counterparty. If these netted amounts are positive, they are classified as an asset, and if negative, they are classified as a liability. We generally use a midmarket pricing convention based on the bid-ask spread for fair-value measurements. Because these estimates are made at a specific point in time, they are susceptible to material near-term changes. We evaluated the potential for the fair value of the instruments to be affected by changes in our counterparty credit risk and our own credit risk, and we made no adjustments as they were insignificant to the overall fair-value measurements. When midmarket pricing inputs are unavailable, we use a discounted cash-flow model which uses market-observable inputs (inputs that are actively quoted and can be validated to external sources), including the following:
	•	Discount rate assumption. At March 31, 2015 we used the overnight-index swap (OIS) curve and at December 31, 2014 we used the LIBOR swap curve.
	We operationally implemented using the OIS curve to determine the fair value of derivative contracts in the first quarter of 2015. The initial effect of using the OIS curve did not have a material effect on our operating activities or financial statements.
	The tables below are a summary of the fair value estimates and related levels in the fair value hierarchy. The carrying amounts are as recorded in the statements of condition. These tables do not represent an estimate of our overall market value as a going concern; as they do not take into account future business opportunities and future net profitability of assets and liabilities.  The tables below are presented in the following order:
	•	Fair values of financial instruments.
	•	Financial instruments measured at fair value on a recurring basis on our statements of condition.
	•	Assets measured at fair value on a nonrecurring basis on our statements of condition.
	We had no transfers between Levels 1, 2, and/or 3 for the periods presented.
	Fair values of financial instruments
		Carrying Amount								Fair Value Hierarchy
						Fair Value				Level 1				Level 2				Level 3
	March 31, 2015
	Financial Assets -
	Cash and due from banks	$	1,458			$	1,458			$	1,458			$	—			$	—
	Interest bearing deposits	560				560				560				—				—
	Federal Funds sold	3,022				3,022				—				3,022				—
	Securities purchased under agreements to resell	1,400				1,400				—				1,400				—
	Held-to-maturity securities	6,223				6,932				—				5,514				1,418
	Advances	31,941				31,995				—				31,995				—
	MPF Loans held in portfolio, net	5,728				6,266								6,111				155
	Financial Liabilities -
	Deposits	(646		)		(646		)		—				(646		)		—
	Consolidated obligation discount notes	(30,474		)		(30,473		)		—				(30,473		)		—
	Consolidated obligation bonds	(33,043		)		(33,672		)		—				(33,613		)		(59		)	a
	Subordinated notes	(944		)		(1,002		)		—				(1,002		)		—
	December 31, 2014
	Financial Assets -
	Cash and due from banks	$	342			$	342			$	342			$	—			$	—
	Interest bearing deposits	560				560				560				—				—
	Federal Funds sold	1,525				1,525				—				1,525				—
	Securities purchased under agreements to resell	3,400				3,400				—				3,400				—
	Held-to-maturity securities	7,118				7,824				—				6,356				1,468
	Advances	32,485				32,546				—				32,546				—
	MPF Loans held in portfolio, net	6,057				6,585				—				6,435				150
	Financial Liabilities -
	Deposits	(666		)		(666		)		—				(666		)		—
	Consolidated obligation discount notes	(31,054		)		(31,055		)		—				(31,055		)		—
	Consolidated obligation bonds	(34,251		)		(34,831		)		—				(34,768		)		(63		)	a
	Subordinated notes	(944		)		(1,013		)		—				(1,013		)		—
	a	Amount represents debt carried at fair value under a full fair value hedge strategy, not at fair value under the fair value option.
	Financial instruments measured at fair value on a recurring basis on our statements of condition
	As of March 31, 2015		Level 2				Level 3				Netting				Fair Value
	Financial assets -
	Trading securities:
	U.S. Government & other government related non-MBS		$	101			$	—							$	101
	GSE residential MBS		59				—								59
	U.S. Governmental-guaranteed residential MBS		2				—								2
	Trading securities		162				—								162
	Available-for-sale securities:
	U.S. Government & other government related non-MBS		479				—								479
	State or local housing agency non-MBS		4				—								4
	FFELP ABS		5,994				—								5,994
	GSE residential MBS		10,648				—								10,648
	U.S. Government-guaranteed residential MBS		2,255				—								2,255
	Private-label residential MBS		—				69								69
	Available-for-sale securities		19,380				69								19,449
	Advances		85				—								85
	Derivative assets		785				9				$	(786	)	a	8
	Total financial assets at fair value		$	20,412			$	78			$	(786	)		$	19,704
	Level 3 as a percent of total assets at fair value						0.4		%
	Financial liabilities -
	Consolidated obligation discount notes		$	(7,655	)		$	—							$	(7,655	)
Consolidated obligation bonds		(2,903		)		(59		)	b					(2,962		)
Derivative liabilities		(1,807		)		—				$	1,762		a	(45		)
Total financial liabilities at fair value		$	(12,365	)		$	(59	)		$	1,762			$	(10,662	)
Level 3 as a percent of total liabilities at fair value						0.6		%
As of December 31, 2014
Financial assets -
Trading securities:
U.S. Government & other government related non-MBS		$	102			$	—							$	102
GSE residential MBS		63				—								63
U.S. Governmental-guaranteed residential MBS		2				—								2
Trading securities		167				—								167
Available-for-sale securities:
U.S. Government & other government related non-MBS		508				—								508
State or local housing agency non-MBS		3				—								3
FFELP ABS		6,221				—								6,221
GSE residential MBS		10,827				—								10,827
U.S. Government-guaranteed residential MBS		2,345				—								2,345
Private-label residential MBS		—				71								71
Available-for-sale securities		19,904				71								19,975
Advances		83				—								83
Derivative assets		691				13				$	(675	)	a	29
Total financial assets at fair value		$	20,845			$	84			$	(675	)		$	20,254
Level 3 as a percent of total assets at fair value						0.4		%
Financial liabilities -
Consolidated obligation discount notes		$	(1,799	)		$	—							$	(1,799	)
Consolidated obligation bonds		(2,785		)		(63		)	b					(2,848		)
Derivative liabilities		(1,680		)		—				$	1,625		a	(55		)
Total financial liabilities at fair value		$	(6,264	)		$	(63	)		$	1,625			$	(4,702	)
Level 3 as a percent of total liabilities at fair value						1.3		%
a	The netting adjustment amount includes cash collateral (either received or paid by us) and related accrued interest in cases where we have a legal right of setoff, by contract (e.g., master netting agreement) or otherwise, to discharge all or a portion of the debt owed to our counterparty by applying against the debt an amount that our counterparty owes to us. See Note 9 - Derivatives and Hedging Activities for further details.
b	Amount represents debt carried at fair value under a full fair value hedge strategy, not at fair value under the fair value option.
Financial instruments carried at fair value on a recurring basis using Level 3 inputs were immaterial and there were no significant changes in balances in unobservable inputs (Level 3) in the three months ended March 31, 2015, or 2014.
Assets measured at fair value on a nonrecurring basis on our statements of condition
Assets that are not carried at fair value in our statements of condition may be required to be measured at fair value under certain circumstances. Examples include, but are not limited to, conventional MPF Loans that become impaired or REO that have declined in fair value during the reporting period. We measure such assets at fair value on a nonrecurring basis. Effective January 1, 2015, we began using an Automated Valuation Methodology (AVM) to determine the fair value of our impaired conventional MPF Loans and REO pursuant to the guidance provided by Advisory Bulletin 2012-02, Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention (AB 2012-02). Refer to Note 2 - Summary of Significant Accounting Policies for further details. The table below presents assets that typically are not carried at fair value that were measured at fair value in our statements of condition as of the dates shown.
		Level 3
As of		March 31, 2015				December 31, 2014
Impaired conventional MPF Loans held in portfolio		$	155			$	150
REO (recorded in Other Assets)		31				9
Fair Value Option
We elected the fair value option for advances, discount notes, and consolidated obligation bonds for which hedge accounting treatment may not be achieved. Specifically, hedge accounting may not be achieved in cases where it may be difficult to pass prospective or retrospective effectiveness testing under derivative hedge accounting guidance even though the interest rate swaps used to hedge these financial instruments have matching terms. Accordingly, electing the fair value option allows us to better match the change in fair value of the advance, discount note, and short-term consolidated obligation bonds with the interest rate swap economically hedging it. We made no adjustments to the fair values of our instruments under the fair value option for credit risk as of the dates presented.
The following table summarizes the activity related to financial assets and liabilities for which we elected the fair value option.
	March 31, 2015												March 31, 2014
					Consolidated Obligation												Consolidated Obligation
	Advances				Bonds				Discount Notes				Advances				Bonds				Discount Notes
For the three months ended
Balance beginning of period	$	83			$	(2,785	)		$	(1,799	)		$	30			$	(1,021	)		$	(75	)
New transactions elected for fair value option	—				(628		)		(5,855		)		—				(2,660		)		—
Maturities and extinguishments (if any)	—				515				—				—				270				75
Net gain (loss) on instruments held at fair value	1				2				—				—				4				—
Change in accrued interest and other	1				(7		)		(1		)		—				(1		)		—
Balance end of period	$	85			$	(2,903	)		$	(7,655	)		$	30			$	(3,408	)		$	—
The following table reflects the difference between the aggregate unpaid principal balance (UPB) outstanding and the aggregate fair value for advances and consolidated obligation bonds for which the fair value option has been elected. None of the advances were 90 days or more past due and none were on nonaccrual status.
		March 31, 2015												December 31, 2014
As of		Advances				Consolidated Obligation Bonds				Consolidated Obligation Discount Notes				Advances				Consolidated Obligation Bonds				Consolidated Obligation Discount Notes
Unpaid Principal Balance		$	81			$	2,887			$	7,656			$	80			$	2,775			$	1,800
Fair Value Over (Under) UPB		4				16				(1		)		3				10				(1		)
Fair Value		85				2,903				7,655				83				2,785				1,799

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies
	The table below shows our commitments outstanding, which represent off-balance sheet obligations, for the periods presented.
			March 31, 2015							December 31, 2014
	As of		Expire within one year		Expire after one year			Total		Expire within one year		Expire after one year			Total
	Unsettled consolidated obligation bonds		$	610	$	—		$	610	$	91	$	—		$	91
	Member standby letters of credit		3,615		1,398		a	5,013		2,410		1,207		a	3,617
	Housing authority standby bond purchase agreements		17		436			453		155		262			417
	Committed unused member lines of credit		—		—			—		4,000		—			4,000
	Advance commitments		85		108			193		158		104			262
	Other commitments		314		—			314		211		—			211
	Commitments		$	4,641	$	1,942		$	6,583	$	7,025	$	1,573		$	8,598
	a	Contains $981 million and $974 million of member standby letters of credit at March 31, 2015, and December 31, 2014, which were renewable annually.
	For a description of previously defined terms see Note 17 - Commitments and Contingencies to the financial statements in our 2014 Form 10-K.

Transactions_with_Members_and_

Transactions with Members and Other FHLBs	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Transactions with Members and Other FHLBs
	We define related parties as members that own 10% or more of our capital stock or members whose officers or directors also serve on our Board of Directors. Capital stock ownership is a prerequisite to transacting any member business with us. Members and former members own all of our capital stock. See Note 11 - Capital for further details.
	In the normal course of business, we extend credit to or enter into other transactions with these related parties. All transactions are done at market terms that are no more favorable than the terms of comparable transactions with other members who are not considered related parties.
	Members
	The table below summarizes balances we had with our members as defined above as related parties (including their affiliates). Members represented in these tables may change between periods presented, to the extent that our related parties change, based on changes in the composition of our Board membership.
	As of	March 31, 2015		December 31, 2014
	Assets - Interest bearing deposits	$	560	$	560
	Assets - Advances	11,170		11,159
	Assets - Advance Interest Receivable	3		2
	Liabilities - Deposits	20		26
	Equity - Capital Stock	268		267
	Other FHLBs
	From time to time, we may loan to, or borrow from, other FHLBs at market rates. These transactions are overnight, maturing the following business day.  These and other transactions with other FHLBs, if any, are identified on the face of our Financial Statements.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Loans and Leases Receivable, Valuation, Policy [Policy Text Block]	Asset Classification and Charge-off Provisions
	On April 9, 2012, the FHFA issued Advisory Bulletin 2012-02, Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention (AB 2012-02). The guidance in AB 2012-02 is generally consistent with the Uniform Retail Credit Classification and Account Management Policy issued by the federal banking regulators in June 2000. AB 2012-02 establishes a standard and uniform methodology for classifying assets, prescribes the timing of asset charge-offs (excluding investment securities), and provides measurement guidance with respect to determining our allowance for credit losses, and fair value measurement guidance for conventional MPF Loans that are classified as Substandard, Doubtful, or Loss, and Real Estate Owned (REO) related to conventional MPF Loans. Subsequent to the issuance of AB 2012-02, the FHFA issued interpretative guidance clarifying that implementation of the asset classification framework may occur in two phases. We implemented the asset classification provisions effective January 1, 2014. We prospectively adopted the remaining provisions of AB 2012-02 on January 1, 2015. The effect of implementing the remaining provisions was as follows:
	•	The AB 2012-02 allowance for credit losses measurement guidance did not have a material effect on our financial condition, results of operations, or cash flows at the time of adoption.
	•	We recorded a $10 million charge-off to our allowance for credit losses on MPF Loans to conform our charge-off policies to AB 2012-02. In particular, we now write-down a conventional MPF Loan to its fair value less estimated selling costs when such a loan is classified as "Loss" and when a conventional MPF Loan is transferred to REO. Our prior practice was to record a charge-off when a conventional MPF Loan was transferred to REO. Exposures classified "Loss" are considered uncollectible and of such little value that the exposures continuance as a balance sheet asset is not warranted. This classification does not mean that the exposure has absolutely no recovery or salvage value; rather, it is not practical or desirable to defer charging off this asset, even though partial recovery may occur in the future. Examples of confirming events indicating that a "Loss" exists include, but are not limited to, the following:
	▪	A current assessment of value is made before a single family residential loan is more than 180 days past due. Any outstanding loan balance in excess of the fair value of the property, less cost to sell, is classified as "Loss" when the loan is no more than 180 days delinquent.
	•	When a borrower is in bankruptcy, loans are written down to the fair value of the collateral, less costs to sell, within 60 days of receipt of the notification of filing from the bankruptcy court or within the delinquency time frames specified in the guidance, whichever is shorter.
	•	Fraudulent loans, not covered by any existing representations and warranties in the loan purchase agreement, are charged off within 90 days of discovery of the fraud, or within the delinquency time frames specified in the adverse classification guidance, whichever is shorter.
	•	We began using an Automated Valuation Methodology (AVM) to determine the fair value of our impaired conventional MPF Loans held in portfolio and REO. Our prior practice was to determine fair value using broker price opinions, if available, to measure impaired conventional MPF Loans held in portfolio and REO. If a current broker price opinion was not available, we estimated fair value based on our current actual loss severity rates we experienced on sales, excluding any estimated selling costs. The use of AVM's to determine fair value may result in increased volatility with respect to our provision for credit losses.
	•	We now place a conventional MPF Loan held in portfolio on nonaccrual when it is adversely classified as either "Substandard," "Doubtful", or "Loss". An adverse classification means that such a loan is not considered well secured and in the process of collection. Exposures classified "Substandard" are inadequately protected by the current worth and paying capacity of the obligor or by the collateral pledged, if any. Exposure so classified must have a well-defined weakness or weaknesses that jeopardize the liquidation of the exposure. These weaknesses are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected. Exposures classified "Doubtful" have all the weaknesses inherent in those exposures classified "Substandard" with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently known facts, conditions and values, highly questionable and improbable. Our prior practice was to place conventional MPF Loans held in portfolio on nonaccrual when the loan was 90 or more days past due (or 60 days past due in the case of a bankruptcy) and the loan was not well-secured and in the process of collection. This change in nonaccrual practice did not have a material effect on our nonaccrual loans outstanding at the time of adoption.
Finance, Loan and Lease Receivables, Held for Investments, Foreclosed Assets Policy [Policy Text Block]	Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure
	In August of 2014, the FASB issued new guidance that requires certain government-guaranteed mortgage loans to be derecognized upon foreclosure and established as a separate receivable. Specifically, such accounting treatment is applied to a government-guaranteed mortgage loan in which the loan guarantee is not separable from the loan prior to foreclosure, the creditor has the intent to make a claim on the guarantee and the ability to recover under the claim, and at the time of foreclosure any amount of the claim that is determined on the basis of the fair value of the real estate is fixed. We prospectively adopted this new guidance on January 1, 2015 for our government MPF Loans. Specifically, our foreclosed government MPF Loans meet the conditions specified by the new guidance and will be classified as a receivable rather than REO. The new guidance did not have a material effect on our operating activities or our financial statements since our credit risk on government MPF Loans is limited to whether or not the servicing PFI fails to pay for losses not covered by Federal Housing Administration (FHA) insurance, or Department of Veteran Affairs (VA), Department of Housing and Urban Development (HUD) or Department of Agriculture Rural Housing Service (RHS) guarantees. Our foreclosed government MPF Loans were previously classified in REO in Other Assets.
	Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure
	In January of 2014, the FASB issued new accounting guidance clarifying that consumer mortgage loans collateralized by real estate should be reclassified to REO when either the creditor obtains legal title to the residential real estate property upon completion of a foreclosure or the borrower conveys all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. We adopted the new guidance effective January 1, 2015, on a prospective basis. The new guidance is consistent with our previous accounting and did not have an effect on our operating activities or financial statements.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	Held for Sale Mortgage Loans
	We classify MPF Xtra, MPF Direct, and government mortgage loans obtained for a Ginnie Mae securitization transaction as mortgage loans held for sale (HFS), as we intend to sell such loans in an outright sale or in a securitization transaction. If material, HFS mortgage loans will be classified as a separate line item in our statements of condition; otherwise, we will classify HFS mortgage loans in Other Assets. We have elected the fair value option for HFS mortgage loans. Since these HFS mortgage loans are carried at fair value, the loans do not require an allowance for credit losses. We measure the fair value of HFS mortgage loans based on to-be-announced (TBA) securities, which represent quoted market prices for new mortgage-backed securities issued by U.S. government sponsored enterprises. Any initial premium or discount is recognized as part of the fair value measurement process rather than amortized as a yield adjustment. Any transaction fees, such as extension fees, or costs are immediately recognized into other noninterest income. HFS mortgage loans are classified as an operating activity within our statements of cash flows.

Interest_Income_and_Interest_E1

Interest Income and Interest Expense (Tables)	3 Months Ended
	Mar. 31, 2015
Interest Income (Expense), Net [Abstract]
Interest Income and Interest Expense [Table Text Block]	The following table presents interest income and interest expense for the periods indicated:
		Three months ended March 31,
		2015		2014
	Interest income -
	Interest bearing deposits, Federal Funds sold and securities purchased under agreements to resell	$	3	$	1
	Investment securities -
	Trading	1		7
	Available-for-sale	134		143
	Held-to-maturity	69		77
	Total investment securities	204		227
	Advances -
	Advance interest income	39		38
	Advance prepayment fees, including related hedge adjustment gains (losses) of $1 and $0	6		1
	Total Advances	45		39
	MPF Loans held in portfolio	69		88
	Total interest income	321		355
	Interest expense -
	Consolidated obligations -
	Discount notes	72		67
	Bonds	105		147
	Total consolidated obligations	177		214
	Subordinated notes	14		14
	Total interest expense	191		228
	Net interest income before provision for (reversal of) credit losses	130		127
	Provision for (reversal of) credit losses	—		(3		)
	Net interest income	$	130	$	130

Investment_Securities_Tables

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Trading Securities by Major Security Type [Table Text Block]	The following table presents the fair value of our trading securities. We had no material gains or losses realized from the sales of trading securities.
	As of		March 31, 2015				December 31, 2014
	U.S. Government & other government related		$	101			$	102
	Residential MBS:
	GSE		59				63
	Government-guaranteed		2				2
	Total Residential MBS		61				65
	Trading securities		$	162			$	167
	At March 31, 2015, and 2014, we had net year-to-date unrealized gains (losses) of $(1) million and $(5) million on trading securities still held at period end.
Available-for-sale Securities by Major Security Type [Table Text Block]	Amortized Cost Basis and Fair Value – Available-for-Sale Securities (AFS)
		Amortized Cost Basis				Gross Unrealized Gains in AOCI				Gross Unrealized (Losses) in AOCI			Carrying Amount and Fair Value
	As of March 31, 2015
	U.S. Government & other government related	$	450			$	30			$	(1	)	$	479
	State or local housing agency	4				—				—			4
	FFELP ABS	5,640				363				(9		)	5,994
	Residential MBS:
	GSE	10,086				572				(10		)	10,648
	Government-guaranteed	2,167				88				—			2,255
	Private-label	64				5				—			69
	Total Residential MBS	12,317				665				(10		)	12,972
	Total	$	18,411			$	1,058			$	(20	)	$	19,449
	As of December 31, 2014
	U.S. Government & other government related	$	479			$	29			$	—		$	508
	State or local housing agency	3				—				—			3
	FFELP ABS	5,824				408				(11		)	6,221
	Residential MBS:
	GSE	10,285				550				(8		)	10,827
	Government-guaranteed	2,258				87				—			2,345
	Private-label	66				5				—			71
	Total Residential MBS	12,609				642				(8		)	13,243
	Total	$	18,915			$	1,079			$	(19	)	$	19,975
	We had no sales of AFS securities for the periods presented.
Held-to-maturity Securities by Major Security Type [Table Text Block]	Amortized Cost Basis, Carrying Amount, and Fair Value - Held-to-Maturity Securities (HTM)
		Amortized				Non-credit OTTI Recognized in AOCI (Loss)				Carrying			Gross			Gross			Fair Value
		Cost Basis								Amount			Unrecognized			Unrecognized
													Holding			Holding
													Gains			(Losses)
	As of March 31, 2015
	U.S. Government & other government related	$	1,482			$	—			$	1,482		$	83		$	—		$	1,565
	State or local housing agency	17				—				17			—			—			17
	Residential MBS:
	GSE	2,607				—				2,607			200			—			2,807
	Government-guaranteed	1,097				—				1,097			28			—			1,125
	Private-label	1,271				(251		)		1,020			399			(1		)	1,418
	Total Residential MBS	4,975				(251		)		4,724			627			(1		)	5,350
	Total	$	6,474			$	(251	)		$	6,223		$	710		$	(1	)	$	6,932
	As of December 31, 2014
	U.S. Government & other government related	$	2,222			$	—			$	2,222		$	76		$	(1	)	$	2,297
	State or local housing agency	18				—				18			—			—			18
	Residential MBS:
	GSE	2,695				—				2,695			189			—			2,884
	Government-guaranteed	1,129				—				1,129			28			—			1,157
	Private-label	1,318				(264		)		1,054			415			(1		)	1,468
	Total Residential MBS	5,142				(264		)		4,878			632			(1		)	5,509
	Total	$	7,382			$	(264	)		$	7,118		$	708		$	(2	)	$	7,824
	We had no sales of HTM securities for the periods presented.
Securities in a Continuous Unrealized Loss Position [Table Text Block]	The following tables present unrealized temporary losses on our AFS and HTM portfolio for periods less than 12 months and for 12 months or more. We recognized no OTTI charges on these unrealized loss positions because we expect to recover the entire amortized cost basis, we do not intend to sell these securities, and we believe it is more likely than not that we will not be required to sell them prior to recovering their amortized cost basis. In the tables below, in cases where the gross unrealized losses for an investment category are less than $1 million, the losses are not reported.
	Available-for-Sale Securities
		Less than 12 Months								12 Months or More						Total
		Fair Value				Gross Unrealized Losses				Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
	As of March 31, 2015
	U.S. Government & other government related	$	49			$	(1	)		$	—		$	—		$	49		$	(1	)
	FFELP ABS	12				—				858			(9		)	870			(9		)
	Residential MBS:
	GSE	—				—				1,900			(10		)	1,900			(10		)
	Private-label	—				—				16			—			16			—
	Total Residential MBS	—				—				1,916			(10		)	1,916			(10		)
	Total	$	61			$	(1	)		$	2,774		$	(19	)	$	2,835		$	(20	)
	As of December 31, 2014
	U.S. Government & other government related	$	48			$	—			$	—		$	—		$	48		$	—
	State or local housing agency	3				—				—			—			3			—
	FFELP ABS	14				—				877			(11		)	891			(11		)
	Residential MBS:
	GSE	—				—				1,996			(8		)	1,996			(8		)
	Private-label	—				—				16			—			16			—
	Total Residential MBS	—				—				2,012			(8		)	2,012			(8		)
	Total	$	65			$	—			$	2,889		$	(19	)	$	2,954		$	(19	)
	Held-to-Maturity Securities
		Less than 12 Months								12 Months or More						Total
		Fair Value				Gross Unrealized Losses				Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
	As of March 31, 2015
	U.S. Government & other government related	$	1			$	—			$	15		$	—		$	16		$	—
	State or local housing agency	10				—				—			—			10			—
	Residential MBS:
	GSE	—				—				5			—			5			—
	Private-label	10				—				1,341			(252		)	1,351			(252		)
	Total Residential MBS	10				—				1,346			(252		)	1,356			(252		)
	Total	$	21			$	—			$	1,361		$	(252	)	$	1,382		$	(252	)
	As of December 31, 2014
	U.S. Government & other government related	$	13			$	—			$	5		$	(1	)	$	18		$	(1	)
	State or local housing agency	10				—				—			—			10			—
	Residential MBS:
	GSE	—				—				5			—			5			—
	Private-label	12				—				1,384			(265		)	1,396			(265		)
	Total Residential MBS	12				—				1,389			(265		)	1,401			(265		)
	Total	$	35			$	—			$	1,394		$	(266	)	$	1,429		$	(266	)
Securities by Contractual Maturity [Table Text Block]	The table below presents the amortized cost basis and fair value of AFS and HTM securities by contractual maturity, excluding ABS and MBS securities. These securities are excluded because their expected maturities may differ from their contractual maturities if borrowers of the underlying loans elect to prepay their loans.
			Available-for-Sale								Held-to-Maturity
	As of March 31, 2015		Amortized Cost Basis				Carrying Amount and Fair Value				Carrying Amount			Fair
														Value
	Year of Maturity -
	Due in one year or less		$	—			$	—			$	117		$	117
	Due after one year through five years		81				86				71			73
	Due after five years through ten years		2				2				358			374
	Due after ten years		371				395				953			1,018
	ABS and MBS without a single maturity date		17,957				18,966				4,724			5,350
	Total securities		$	18,411			$	19,449			$	6,223		$	6,932
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block]	The following table presents the changes in the cumulative amount of credit losses (recognized into earnings) on OTTI investment securities for the periods stated.
			Three months ended March 31,
			2015				2014
	Beginning Balance		$	620			$	677
	Reductions:
	Increases in cash flows expected to be collected that have been recognized as accretion income into interest income		(15		)		(14		)
	Ending Balance		$	605			$	663

Advances_Tables

Advances (Tables)	3 Months Ended
	Mar. 31, 2015
Federal Home Loan Banks [Abstract]
Schedule of Advances by Callable and Putable Features [Table Text Block]	We offer a wide range of fixed- and variable-rate advance products with different maturities, interest rates, payment characteristics and optionality. The following table presents our advances by callable/putable features:
	As of		March 31, 2015		December 31, 2014
	Noncallable/nonputable		$	29,093	$	29,666
	Callable		961		964
	Putable		1,643		1,673
	Total par value		31,697		32,303
	Hedging adjustments		223		166
	Other adjustments		21		16
	Total advances		$	31,941	$	32,485
Advances by Year of Contractual Maturity, Next Call Date, or Next Put or Convert Date [Table Text Block]	The following table presents our advances by redemption terms:
	As of March 31, 2015		Amount		Weighted Average Interest Rate			Next Maturity or Call Date		Next Maturity or Put Date
	Due in one year or less		$	6,628	0.51	%		$	7,540	$	7,834
	One to two years		2,568		2.15	%		2,368		2,112
	Two to three years		4,369		1.09	%		3,984		3,730
	Three to four years		8,989		0.33	%	a	8,689		8,908
	Four to five years		6,861		0.29	%	a	6,839		6,872
	More than five years		2,282		2.31	%		2,277		2,241
	Total par value		$	31,697	0.75	%		$	31,697	$	31,697
	a	The weighted average interest rate is relatively lower when compared to other categories due to a majority of advances in this category consisting of variable rate advances which reset periodically at current interest rates.

MPF_Loans_Tables

MPF Loans (Tables)	3 Months Ended
	Mar. 31, 2015
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	The following table presents information on MPF Loans held in our portfolio by contractual maturity at the time of purchase. All are fixed-rate. Government is comprised of loans insured by the FHA and loans guaranteed by the VA, HUD or RHS.
	As of	March 31, 2015			December 31, 2014
	Medium term (15 years or less)	$	971		$	1,094
	Long term (greater than 15 years)	4,692			4,905
	Total unpaid principal balance	5,663			5,999
	Net premiums, credit enhancement and deferred loan fees	22			23
	Hedging adjustments	47			50
	Total before allowance for credit losses	5,732			6,072
	Allowance for credit losses on MPF Loans	(4		)	(15		)
	Total MPF Loans held in portfolio, net	$	5,728		$	6,057
	Conventional mortgage loans	$	4,323		$	4,619
	Government insured mortgage loans	1,340			1,380
	Total unpaid principal balance	$	5,663		$	5,999

Allowance_for_Credit_Losses_Ta

Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Rollforward of Allowance for Credit Losses on Mortgage Loans [Table Text Block]	The following table presents the changes in the allowance for credit losses on conventional MPF Loans.
		For the three months ended
		March 31, 2015			March 31, 2014
	Balance, beginning of period	$	15		$	29
	Losses charged to the allowance	(11		)	(2		)
	Provision for (reversal of) credit losses	—			(3		)
	Balance, end of period	$	4		$	24
Schedule of Accounts, Notes, Loans and Financing Receivable by Impairment Methodology [Table Text Block]	The following table presents the recorded investment by impairment methodology on conventional MPF Loans.
	As of	March 31, 2015			December 31, 2014
	Specifically identified and individually evaluated for impairment	$	—		$	12
	Homogeneous pools of loans and collectively evaluated for impairment	4			3
	Allowance for credit losses on conventional MPF Loans	$	4		$	15
	Individually evaluated for impairment	$	144		$	160
	Collectively evaluated for impairment	4,252			4,538
	Total recorded investment	$	4,396		$	4,698
Past Due Financing Receivables [Table Text Block]	The table below summarizes our recorded investment in MPF Loans by our key credit quality indicators. Serious delinquency rate is defined as 90 days or more past due or in the process of foreclosure, as a percentage of the total recorded investment. Past due 90 days or more still accruing interest is defined as MPF Loans that are either government guaranteed or conventional mortgage loans that are well secured (by collateral that have a realizable value sufficient to discharge the debt or by the guarantee or insurance, such as PMI, of a financially responsible party) and in the process of collection.
		March 31, 2015									December 31, 2014
	As of	Conventional			Government			Total			Conventional			Government			Total
	Past due 30-59 days	$	114		$	74		$	188		$	138		$	92		$	230
	Past due 60-89 days	37			20			57			43			23			66
	Past due 90 days or more	133			42			175			153			44			197
	Total past due	284			136			420			334			159			493
	Total current	4,112			1,229			5,341			4,364			1,246			5,610
	Total recorded investment	$	4,396		$	1,365		$	5,761		$	4,698		$	1,405		$	6,103
	Also in process of foreclosure	$	66		$	14		$	80		$	77		$	11		$	88
	Serious delinquency rate	3.04		%	3.06		%	3.04		%	3.28		%	3.15		%	3.25		%
	Past due 90 days or more still accruing interest	$	11		$	42		$	53		$	25		$	44		$	69
	On nonaccrual status	$	144		$	—		$	144		$	163		$	—		$	163
Impaired Financing Receivables [Table Text Block]	The following table summarizes the recorded investment, unpaid principal balance, and related allowance of impaired MPF Loans individually assessed for impairment, which includes impaired collateral dependent MPF Loans and troubled debt restructurings. As of March 31, 2015, we did not have an allowance for our impaired MPF Loans. For further details see
	Note 2 - Summary of Significant Accounting Policies to the financial statements.
	As of	March 31, 2015			December 31, 2014
	Recorded investment with an allowance	$	—		$	160
	Recorded investment without an allowance	144			—
	Unpaid principal balance with an allowance	—			158
	Unpaid principal balance without an allowance	152			—
	Related allowance	—			12
	The following table summarizes the average recorded investment of impaired conventional MPF Loans. No interest income was recognized on impaired loans.
		For the three months ended
		31-Mar-15			31-Mar-14
	Average recorded investment with an allowance	$	—		$	204
	Average recorded investment without an allowance	148			—

Derivatives_and_Hedging_Activi1

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table presents our gross and net derivative assets and liabilities by contract type and amount for our derivative agreements.
			March 31, 2015											31-Dec-14
	As of		Notional Amount			Derivative Assets				Derivative Liabilities				Notional Amount				Derivative Assets				Derivative Liabilities
	Derivatives in hedge accounting relationships-
	Interest rate swaps		$	31,559		$	71			$	1,394			$	30,940			$	53			$	1,348
	Derivatives not in hedge accounting relationships-
	Interest rate swaps		25,297			547				407				19,159				487				329
	Interest rate swaptions		1,810			66				—				1,850				56				—
	Interest rate caps or floors		1,164			104				—				1,164				105				—
	Interest rate futures		1			—				—				3				—				—
	Mortgage delivery commitments		501			6				6				284				3				3
	Other		3			—				—				—				—				—
	Derivatives not in hedge accounting relationships		28,776			723				413				22,460				651				332
	Gross derivative amount before adjustments		$	60,335		794				1,807				$	53,400			704				1,680
	Netting adjustments and cash collateral					(786		)	a	(1,762		)	a					(675		)	a	(1,625		)	a
	Derivatives on statements of condition					$	8			$	45							$	29			$	55
	a	Amounts represent the application of the netting requirements that allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed by us with the same clearing agent and/or counterparty. Cash collateral posted was $1.0 billion at March 31, 2015, and $978 million at December 31, 2014. Cash collateral received was $55 million at March 31, 2015, and $29 million at December 31, 2014.
Balance Sheet Offsetting [Table Text Block]	The following table presents our gross recognized amount of offsetting derivative assets and liabilities for derivatives with legal right of offset as well as derivatives without the legal right of offset. Any over-collateralization received by or paid from us to an individual clearing member and/or at a counterparty arrangement level is not included in the determination of the net amount.  Specifically, any such over-collateralization amount received by us is not offset against another derivative asset counterparty exposure for which there is no legal right of offset, while any over-collateralization delivered by us is not offset against another derivative liability counterparty exposure for which there is no legal right of offset.
			Derivative Assets											Derivative Liabilities
	As of March 31, 2015		Bilateral			Cleared				Total				Bilateral				Cleared				Total
	Derivatives with legal right of offset -
	Gross recognized amount		$	707		$	81			$	788			$	1,491			$	310			$	1,801
	Netting adjustments and cash collateral		(705		)	(81		)		(786		)		(1,455		)		(307		)		(1,762		)
	Derivatives with legal right of offset - net		2			—				2				36				3				39
	Derivatives without legal right of offset		6			—				6				6				—				6
	Derivatives on statements of condition		8			—				8				42				3				45
	Noncash collateral received (pledged) and cannot be sold or repledged		1			—				1				—				3				3
	Net amount		$	7		$	—			$	7			$	42			$	—			$	42
	As of December 31, 2014
	Derivatives with legal right of offset -
	Gross recognized amount		$	656		$	45			$	701			$	1,466			$	211			$	1,677
	Netting adjustments and cash collateral		(632		)	(43		)		(675		)		(1,414		)		(211		)		(1,625		)
	Derivatives with legal right of offset - net		24			2				26				52				—				52
	Derivatives without legal right of offset		3			—				3				3				—				3
	Derivatives on statements of condition		27			2				29				55				—				55
	Noncash collateral received (pledged) and cannot be sold or repledged		23			—				23				—				—				—
	Net amount		$	4		$	2			$	6			$	55			$	—			$	55
	At March 31, 2015, we had $74 million of additional net credit exposure on cleared derivatives due to instances where our pledged non-cash collateral to a counterparty exceeded our net derivative liability position. We had $4 million comparable exposure at December 31, 2014.
Derivatives And Hedging Activities as Presented in the Statements of Income [Table Text Block]	The tables below present the gains (losses) of derivatives and hedging activities as presented in the statements of income.
			Three months ended March 31,
	For the periods ending		2015			2014
	Fair value hedges -
	Interest rate swaps		$	(19	)	$	(6	)
	Cash flow hedges		—			1
	Economic hedges -
	Interest rate swaps		(23		)	1
	Interest rate swaptions		8			(15		)
	Interest rate caps or floors		(1		)	(10		)
	Net interest settlements		24			15
	Economic hedges		8			(9		)
	Gains (losses) on derivatives and hedging activities		$	(11	)	$	(14	)
Fair Value Hedges [Table Text Block]	The following table presents, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair value hedging relationships and the effect of those derivatives on our net interest income. We had no gain (loss) for hedged firm commitments on forward-starting advances that no longer qualified as a fair value hedge.
			Gain (loss)
			On Derivative			On Hedged Item				Total Ineffectiveness Recognized in Derivatives and Hedging Activities				Net Interest Settlements Recorded in Net Interest Income				Closed Hedge Adjustments Amortized into Net Interest Income
	Three months ended
	March 31, 2015
	Hedged item type -
	Available-for-sale securities		$	(36	)	$	31			$	(5	)		$	(34	)	a	$	(10	)	b
	Advances		(61		)	57				(4		)		(20		)	a	1			b
	MPF Loans held for portfolio		—			—				—				—			a	(4		)	b
	Consolidated obligation bonds		74			(84		)		(10		)		58			a	—			b
	Total		$	(23	)	$	4			$	(19	)		$	4		a	$	(13	)	b
	Three months ended
	March 31, 2014
	Hedged item type -
	Available-for-sale securities		$	(2	)	$	1			$	(1	)		$	(35	)	a	$	—		b
	Advances		(30		)	32				2				(20		)	a	(1		)	b
	MPF Loans held for portfolio		—			—				—				—			a	(5		)	b
	Consolidated obligation bonds		133			(140		)		(7		)		61			a	(5		)	b
	Total		$	101		$	(107	)		$	(6	)		$	6		a	$	(11	)	b
	a	Represents the effect of net interest settlements attributable to open derivative hedging instruments on net interest income. The effect of derivatives on net interest income is included in the interest income/expense line item of the respective hedged item type.
	b	Amortization of hedge adjustments is included in the interest income/expense line item of the respective hedged item type.
Cash Flow Hedges [Table Text Block]	The following table presents our gains (losses) on our cash-flow hedging relationships recorded in income and other comprehensive income (loss). In cases where amounts are insignificant in the aggregate, we do not report a balance.
			Amortization of Effective Portion Reclassified From AOCI to Interest			Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities				Total Reclassified From AOCI to Statements of Income				Net Change in Other Comprehensive Income				Effective Portion Recorded in AOCI				Net Interest Settlements Classified in Net Interest Income
	Three months ended March 31, 2015
	Advances -		$	3		$	—			$	3			$	(3	)		$	—			$	—
	interest rate floors
	Discount notes -		(1		)	—				(1		)		(26		)		(27		)		(62		)	a
	interest rate swaps
	Bonds -		(1		)	—				(1		)		1				—				—
	interest rate swaps
	Total		$	1		$	—			$	1			$	(28	)		$	(27	)		$	(62	)	a
	Three months ended March 31, 2014
	Advances -		$	3		$	—			$	3			$	(3	)		$	—			$	—
	interest rate floors
	Discount notes -		(1		)	1				—				24				24				(61		)	a
	interest rate swaps
	Total		$	2		$	1			$	3			$	21			$	24			$	(61	)	a
	a	Represents the effect of net interest settlements attributable to open derivative hedging instruments on net interest income. The effect of derivatives on net interest income is included in the interest income/expense line item of the respective hedged item type.
	There were no amounts reclassified from AOCI into earnings for the periods presented as a result of the discontinuance of cash-flow hedges because the original forecasted transactions failed to occur by the end of the originally specified time period or within a two-month period thereafter. The deferred net gains (losses) on derivative instruments in AOCI that are expected to be reclassified to earnings during the next twelve months were $(1) million as of March 31, 2015. The maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, is 5 years.

Consolidated_Obligations_Table

Consolidated Obligations (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt [Table Text Block]	The following table presents our consolidated obligation bonds, for which we are the primary obligor, including callable bonds that are redeemable in whole, or in part, at our discretion on predetermined call dates.
	As of March 31, 2015	Contractual Maturity			Weighted Average Interest Rate			By Next Maturity or Call Date
	Due in one year or less	$	2,190		3	%		$	23,807
	One to two years	3,795			2.44	%		2,898
	Two to three years	8,074			1.94	%		2,834
	Three to four years	3,907			1.17	%		980
	Four to five years	6,599			1.56	%		1,374
	Thereafter	8,540			2.49	%		1,212
	Total par value	$	33,105		2.04	%		$	33,105
Consolidated Obligation Discount Notes [Table Text Block]	The following table presents our consolidated obligation discount notes for which we are the primary obligor. All are due in one year or less.
	As of	31-Mar-15			December 31, 2014
	Carrying Amount	$	30,474		$	31,054
	Par Value	30,486			31,060
	Weighted Average Interest Rate	0.11		%	0.09		%
Consolidated Obligation Bonds Outstanding by Call Feature [Table Text Block]	The following table presents consolidated obligation bonds outstanding by call feature:
	As of	31-Mar-15			31-Dec-14
	Noncallable	$	10,763		$	11,046
	Callable	22,342			23,355
	Par value	33,105			34,401
	Bond premiums (discounts), net	15			17
	Hedging adjustments	(93		)	(177		)
	Fair value option adjustments	16			10
	Total consolidated obligation bonds	$	33,043		$	34,251
Schedule of Guarantor Obligations [Table Text Block]	The following table summarizes the consolidated obligations of the FHLBs and those for which we are the primary obligor:
		March 31, 2015										31-Dec-14
	Par values as of	Bonds			Discount				Total			Bonds			Discount			Total
					Notes										Notes
	FHLB System total consolidated obligations	$	459,021		$	353,175			$	812,196		$	484,812		$	362,363		$	847,175
	FHLB Chicago as primary obligor	33,105			30,486				63,591			34,401			31,060			65,461
	As a percent of the FHLB System	7		%	9		%		8		%	7		%	9		%	8		%

Capital_and_Mandatorily_Redeem1

Capital and Mandatorily Redeemable Capital Stock (Tables)	3 Months Ended
	Mar. 31, 2015
Capital [Abstract]
Schedule of Minimum Capital Requirements [Table Text Block]	For details on our minimum capital requirements, including how the ratios below were calculated, see Minimum Capital Requirements on page F-44 of our 2014 Form 10-K. We complied with our minimum regulatory capital requirements as shown below:
		March 31, 2015						December 31, 2014
		Requirement			Actual			Requirement			Actual
	Risk-based capital	$	1,135		$	4,416		$	1,127		$	4,317
	Total regulatory capital	$	2,806		$	4,416		$	2,874		$	4,317
	Total regulatory capital ratio	4		%	6.29		%	4		%	6.01		%
	Leverage capital	$	3,507		$	6,623		$	3,592		$	6,475
	Leverage capital ratio	5		%	9.44		%	5		%	9.01		%
	Total regulatory capital and leverage capital do not include accumulated other comprehensive income (loss). Under the FHFA regulation on capital classifications and critical capital levels for the FHLBs, we are adequately capitalized.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table summarizes the income (loss) in AOCI for the periods indicated:
		Net Unrealized Gain (Loss)			Non-credit OTTI			Net Unrealized on Cash Flow Hedges
		Available-for-sale Securities			Held-to-maturity Securities						Post-Retirement Plans			Total AOCI
	Three months ended March 31, 2015
	Beginning balance	$	1,060		$	(264	)	$	(580	)	$	1		$	217
	Change in the period recorded to the statements of condition, before reclassifications to statements of income	(22		)	13			(27		)	(8		)	(44		)
	Amounts reclassified in period to statements of income:
	Net interest income	—			—			(1		)	—			(1		)
	Total other comprehensive income in the period	(22		)	13			(28		)	(8		)	(45		)
	Ending balance	$	1,038		$	(251	)	$	(608	)	$	(7	)	$	172
	Three months ended March 31, 2014
	Beginning balance	$	1,052		$	(320	)	$	(665	)	$	—		$	67
	Change in the period recorded to the statements of condition, before reclassifications to statements of income	55			14			24			—			93
	Amounts reclassified in period to statements of income:
	Net interest income	—			—			(2		)	—			(2		)
	Non-interest gain (loss)	—			—			(1		)	—			(1		)
	Non-interest expense	—			—			—			1			1
	Total other comprehensive income in the period	55			14			21			1			91
	Ending balance	$	1,107		$	(306	)	$	(644	)	$	1		$	158

Fair_Value_Accounting_Tables

Fair Value Accounting (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurement [Table Text Block]	The tables below are a summary of the fair value estimates and related levels in the fair value hierarchy. The carrying amounts are as recorded in the statements of condition. These tables do not represent an estimate of our overall market value as a going concern; as they do not take into account future business opportunities and future net profitability of assets and liabilities.  The tables below are presented in the following order:
	•	Fair values of financial instruments.
	•	Financial instruments measured at fair value on a recurring basis on our statements of condition.
	•	Assets measured at fair value on a nonrecurring basis on our statements of condition.
	We had no transfers between Levels 1, 2, and/or 3 for the periods presented.
	Fair values of financial instruments
		Carrying Amount								Fair Value Hierarchy
						Fair Value				Level 1				Level 2				Level 3
	March 31, 2015
	Financial Assets -
	Cash and due from banks	$	1,458			$	1,458			$	1,458			$	—			$	—
	Interest bearing deposits	560				560				560				—				—
	Federal Funds sold	3,022				3,022				—				3,022				—
	Securities purchased under agreements to resell	1,400				1,400				—				1,400				—
	Held-to-maturity securities	6,223				6,932				—				5,514				1,418
	Advances	31,941				31,995				—				31,995				—
	MPF Loans held in portfolio, net	5,728				6,266								6,111				155
	Financial Liabilities -
	Deposits	(646		)		(646		)		—				(646		)		—
	Consolidated obligation discount notes	(30,474		)		(30,473		)		—				(30,473		)		—
	Consolidated obligation bonds	(33,043		)		(33,672		)		—				(33,613		)		(59		)	a
	Subordinated notes	(944		)		(1,002		)		—				(1,002		)		—
	December 31, 2014
	Financial Assets -
	Cash and due from banks	$	342			$	342			$	342			$	—			$	—
	Interest bearing deposits	560				560				560				—				—
	Federal Funds sold	1,525				1,525				—				1,525				—
	Securities purchased under agreements to resell	3,400				3,400				—				3,400				—
	Held-to-maturity securities	7,118				7,824				—				6,356				1,468
	Advances	32,485				32,546				—				32,546				—
	MPF Loans held in portfolio, net	6,057				6,585				—				6,435				150
	Financial Liabilities -
	Deposits	(666		)		(666		)		—				(666		)		—
	Consolidated obligation discount notes	(31,054		)		(31,055		)		—				(31,055		)		—
	Consolidated obligation bonds	(34,251		)		(34,831		)		—				(34,768		)		(63		)	a
	Subordinated notes	(944		)		(1,013		)		—				(1,013		)		—
	a	Amount represents debt carried at fair value under a full fair value hedge strategy, not at fair value under the fair value option.
Assets and Liabilities Measured at Fair Value on a Recurring Basis [Table Text Block]	Financial instruments measured at fair value on a recurring basis on our statements of condition
	As of March 31, 2015		Level 2				Level 3				Netting				Fair Value
	Financial assets -
	Trading securities:
	U.S. Government & other government related non-MBS		$	101			$	—							$	101
	GSE residential MBS		59				—								59
	U.S. Governmental-guaranteed residential MBS		2				—								2
	Trading securities		162				—								162
	Available-for-sale securities:
	U.S. Government & other government related non-MBS		479				—								479
	State or local housing agency non-MBS		4				—								4
	FFELP ABS		5,994				—								5,994
	GSE residential MBS		10,648				—								10,648
	U.S. Government-guaranteed residential MBS		2,255				—								2,255
	Private-label residential MBS		—				69								69
	Available-for-sale securities		19,380				69								19,449
	Advances		85				—								85
	Derivative assets		785				9				$	(786	)	a	8
	Total financial assets at fair value		$	20,412			$	78			$	(786	)		$	19,704
	Level 3 as a percent of total assets at fair value						0.4		%
	Financial liabilities -
	Consolidated obligation discount notes		$	(7,655	)		$	—							$	(7,655	)
	Consolidated obligation bonds		(2,903		)		(59		)	b					(2,962		)
	Derivative liabilities		(1,807		)		—				$	1,762		a	(45		)
	Total financial liabilities at fair value		$	(12,365	)		$	(59	)		$	1,762			$	(10,662	)
	Level 3 as a percent of total liabilities at fair value						0.6		%
	As of December 31, 2014
	Financial assets -
	Trading securities:
	U.S. Government & other government related non-MBS		$	102			$	—							$	102
	GSE residential MBS		63				—								63
	U.S. Governmental-guaranteed residential MBS		2				—								2
	Trading securities		167				—								167
	Available-for-sale securities:
	U.S. Government & other government related non-MBS		508				—								508
	State or local housing agency non-MBS		3				—								3
	FFELP ABS		6,221				—								6,221
	GSE residential MBS		10,827				—								10,827
	U.S. Government-guaranteed residential MBS		2,345				—								2,345
	Private-label residential MBS		—				71								71
	Available-for-sale securities		19,904				71								19,975
	Advances		83				—								83
	Derivative assets		691				13				$	(675	)	a	29
	Total financial assets at fair value		$	20,845			$	84			$	(675	)		$	20,254
	Level 3 as a percent of total assets at fair value						0.4		%
	Financial liabilities -
	Consolidated obligation discount notes		$	(1,799	)		$	—							$	(1,799	)
	Consolidated obligation bonds		(2,785		)		(63		)	b					(2,848		)
	Derivative liabilities		(1,680		)		—				$	1,625		a	(55		)
	Total financial liabilities at fair value		$	(6,264	)		$	(63	)		$	1,625			$	(4,702	)
	Level 3 as a percent of total liabilities at fair value						1.3		%
	a	The netting adjustment amount includes cash collateral (either received or paid by us) and related accrued interest in cases where we have a legal right of setoff, by contract (e.g., master netting agreement) or otherwise, to discharge all or a portion of the debt owed to our counterparty by applying against the debt an amount that our counterparty owes to us. See Note 9 - Derivatives and Hedging Activities for further details.
	b	Amount represents debt carried at fair value under a full fair value hedge strategy, not at fair value under the fair value option.
Assets Measured at Fair Value on a Nonrecurring Basis [Table Text Block]	Assets that are not carried at fair value in our statements of condition may be required to be measured at fair value under certain circumstances. Examples include, but are not limited to, conventional MPF Loans that become impaired or REO that have declined in fair value during the reporting period. We measure such assets at fair value on a nonrecurring basis. Effective January 1, 2015, we began using an Automated Valuation Methodology (AVM) to determine the fair value of our impaired conventional MPF Loans and REO pursuant to the guidance provided by Advisory Bulletin 2012-02, Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention (AB 2012-02). Refer to Note 2 - Summary of Significant Accounting Policies for further details. The table below presents assets that typically are not carried at fair value that were measured at fair value in our statements of condition as of the dates shown.
			Level 3
	As of		March 31, 2015				December 31, 2014
	Impaired conventional MPF Loans held in portfolio		$	155			$	150
	REO (recorded in Other Assets)		31				9
Beginning and ending balances reconciliation of assets and liabilities held under fair value option [Table Text Block]	The following table summarizes the activity related to financial assets and liabilities for which we elected the fair value option.
		March 31, 2015												March 31, 2014
						Consolidated Obligation												Consolidated Obligation
		Advances				Bonds				Discount Notes				Advances				Bonds				Discount Notes
	For the three months ended
	Balance beginning of period	$	83			$	(2,785	)		$	(1,799	)		$	30			$	(1,021	)		$	(75	)
	New transactions elected for fair value option	—				(628		)		(5,855		)		—				(2,660		)		—
	Maturities and extinguishments (if any)	—				515				—				—				270				75
	Net gain (loss) on instruments held at fair value	1				2				—				—				4				—
	Change in accrued interest and other	1				(7		)		(1		)		—				(1		)		—
	Balance end of period	$	85			$	(2,903	)		$	(7,655	)		$	30			$	(3,408	)		$	—
Fair Value Option [Table Text Block]	The following table reflects the difference between the aggregate unpaid principal balance (UPB) outstanding and the aggregate fair value for advances and consolidated obligation bonds for which the fair value option has been elected. None of the advances were 90 days or more past due and none were on nonaccrual status.
			March 31, 2015												December 31, 2014
	As of		Advances				Consolidated Obligation Bonds				Consolidated Obligation Discount Notes				Advances				Consolidated Obligation Bonds				Consolidated Obligation Discount Notes
	Unpaid Principal Balance		$	81			$	2,887			$	7,656			$	80			$	2,775			$	1,800
	Fair Value Over (Under) UPB		4				16				(1		)		3				10				(1		)
	Fair Value		85				2,903				7,655				83				2,785				1,799

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	The table below shows our commitments outstanding, which represent off-balance sheet obligations, for the periods presented.
			March 31, 2015							December 31, 2014
	As of		Expire within one year		Expire after one year			Total		Expire within one year		Expire after one year			Total
	Unsettled consolidated obligation bonds		$	610	$	—		$	610	$	91	$	—		$	91
	Member standby letters of credit		3,615		1,398		a	5,013		2,410		1,207		a	3,617
	Housing authority standby bond purchase agreements		17		436			453		155		262			417
	Committed unused member lines of credit		—		—			—		4,000		—			4,000
	Advance commitments		85		108			193		158		104			262
	Other commitments		314		—			314		211		—			211
	Commitments		$	4,641	$	1,942		$	6,583	$	7,025	$	1,573		$	8,598
	a	Contains $981 million and $974 million of member standby letters of credit at March 31, 2015, and December 31, 2014, which were renewable annually.

Transactions_with_Members_and_1

Transactions with Members and Other FHLBs (Tables)	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions, by Balance Sheet Grouping [Table Text Block]	The table below summarizes balances we had with our members as defined above as related parties (including their affiliates). Members represented in these tables may change between periods presented, to the extent that our related parties change, based on changes in the composition of our Board membership.
	As of	March 31, 2015		December 31, 2014
	Assets - Interest bearing deposits	$	560	$	560
	Assets - Advances	11,170		11,159
	Assets - Advance Interest Receivable	3		2
	Liabilities - Deposits	20		26
	Equity - Capital Stock	268		267

Interest_Income_and_Interest_E2

Interest Income and Interest Expense (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest income -
Interest bearing deposits, Federal Funds sold and securities purchased under agreements to resell	$3	$1
Investment securities -
Trading	1	7
Available-for-sale	134	143
Held-to-maturity	69	77
Total investment securities	204	227
Advances -
Advance interest income	39	38
Advance prepayment fees, including related hedge adjustment gains (losses) of $1 and $0	6	1
Total Advances	45	39
MPF Loans held in portfolio	69	88
Total interest income	321	355
Consolidated obligations -
Discount notes	72	67
Bonds	105	147
Total consolidated obligations	177	214
Subordinated notes	14	14
Total interest expense	191	228
Net interest income before provision for (reversal of) credit losses	130	127
Provision for (reversal of) credit losses	0	-3
Net interest income	$130	$130

Interest_Income_and_Interest_E3

Interest Income and Interest Expense (Hedge adjustments on advance prepayment fees) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest Income Parenthetical [Abstract]
Hedge adjustment gains (losses) related to advance prepayment fees	$1	$0

Investment_Securities_Pledged_

Investment Securities (Pledged securities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]
Financial Instruments, Owned and Pledged as Collateral, at Fair Value	$76	$71

Investment_Securities_Trading_

Investment Securities (Trading Securities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Trading Securities [Line Items]
Trading securities	$162	$167
U.S. Government & other government related
Trading Securities [Line Items]
Trading securities	101	102
Residential MBS: | GSE
Trading Securities [Line Items]
Trading securities	59	63
Residential MBS: | Government-guaranteed
Trading Securities [Line Items]
Trading securities	2	2
Residential MBS: | Total Residential MBS
Trading Securities [Line Items]
Trading securities	$61	$65

Investment_Securities_Net_year

Investment Securities (Net year-to-date unrealized gains (losses) trading securities) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Trading Securities, Change in Unrealized Holding Gain (Loss) [Abstract]
Trading Securities, Change in Unrealized Holding Gain (Loss)	($1)	($5)

Investment_Securities_Availabl

Investment Securities (Available-for-sale Securities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	$18,411	$18,915
Gross Unrealized Gains in AOCI	1,058	1,079
Gross Unrealized (Losses) in AOCI	-20	-19
Carrying Amount and Fair Value	19,449	19,975
U.S. Government & other government related
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	450	479
Gross Unrealized Gains in AOCI	30	29
Gross Unrealized (Losses) in AOCI	-1	0
Carrying Amount and Fair Value	479	508
State or local housing agency
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	4	3
Gross Unrealized Gains in AOCI	0	0
Gross Unrealized (Losses) in AOCI	0	0
Carrying Amount and Fair Value	4	3
FFELP ABS
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	5,640	5,824
Gross Unrealized Gains in AOCI	363	408
Gross Unrealized (Losses) in AOCI	-9	-11
Carrying Amount and Fair Value	5,994	6,221
Residential MBS: | GSE
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	10,086	10,285
Gross Unrealized Gains in AOCI	572	550
Gross Unrealized (Losses) in AOCI	-10	-8
Carrying Amount and Fair Value	10,648	10,827
Residential MBS: | Government-guaranteed
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	2,167	2,258
Gross Unrealized Gains in AOCI	88	87
Gross Unrealized (Losses) in AOCI	0	0
Carrying Amount and Fair Value	2,255	2,345
Residential MBS: | Private-label
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	64	66
Gross Unrealized Gains in AOCI	5	5
Gross Unrealized (Losses) in AOCI	0	0
Carrying Amount and Fair Value	69	71
Residential MBS: | Total Residential MBS
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Amortized Cost Basis	12,317	12,609
Gross Unrealized Gains in AOCI	665	642
Gross Unrealized (Losses) in AOCI	-10	-8
Carrying Amount and Fair Value	$12,972	$13,243

Investment_Securities_HeldtoMa

Investment Securities (Held-to-Maturities Securities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	$6,474	$7,382
Non-credit OTTI Recognized in AOCI (Loss)	-251	-264
Held-to-Maturity Carrying Amount	6,223	7,118
Gross Unrecognized Holding Gains	710	708
Gross Unrecognized Holding (Losses)	-1	-2
Held-to-Maturity Fair Value	6,932	7,824
U.S. Government & other government related
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	1,482	2,222
Non-credit OTTI Recognized in AOCI (Loss)	0	0
Held-to-Maturity Carrying Amount	1,482	2,222
Gross Unrecognized Holding Gains	83	76
Gross Unrecognized Holding (Losses)	0	-1
Held-to-Maturity Fair Value	1,565	2,297
State or local housing agency
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	17	18
Non-credit OTTI Recognized in AOCI (Loss)	0	0
Held-to-Maturity Carrying Amount	17	18
Gross Unrecognized Holding Gains	0	0
Gross Unrecognized Holding (Losses)	0	0
Held-to-Maturity Fair Value	17	18
Residential MBS: | GSE
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	2,607	2,695
Non-credit OTTI Recognized in AOCI (Loss)	0	0
Held-to-Maturity Carrying Amount	2,607	2,695
Gross Unrecognized Holding Gains	200	189
Gross Unrecognized Holding (Losses)	0	0
Held-to-Maturity Fair Value	2,807	2,884
Residential MBS: | Government-guaranteed
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	1,097	1,129
Non-credit OTTI Recognized in AOCI (Loss)	0	0
Held-to-Maturity Carrying Amount	1,097	1,129
Gross Unrecognized Holding Gains	28	28
Gross Unrecognized Holding (Losses)	0	0
Held-to-Maturity Fair Value	1,125	1,157
Residential MBS: | Private-label
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	1,271	1,318
Non-credit OTTI Recognized in AOCI (Loss)	-251	-264
Held-to-Maturity Carrying Amount	1,020	1,054
Gross Unrecognized Holding Gains	399	415
Gross Unrecognized Holding (Losses)	-1	-1
Held-to-Maturity Fair Value	1,418	1,468
Residential MBS: | Total Residential MBS
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost Basis	4,975	5,142
Non-credit OTTI Recognized in AOCI (Loss)	-251	-264
Held-to-Maturity Carrying Amount	4,724	4,878
Gross Unrecognized Holding Gains	627	632
Gross Unrecognized Holding (Losses)	-1	-1
Held-to-Maturity Fair Value	$5,350	$5,509

Investment_Securities_Aging_of

Investment Securities (Aging of Unrealized Temporary Losses on Available-for-sale Securities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Less than 12 Months
Fair Value	$61	$65
Gross Unrealized Losses	-1	0
12 Months or More
Fair Value	2,774	2,889
Gross Unrealized Losses	-19	-19
Total
Fair Value	2,835	2,954
Gross Unrealized Losses	-20	-19
U.S. Government & other government related
Less than 12 Months
Fair Value	49	48
Gross Unrealized Losses	-1	0
12 Months or More
Fair Value	0	0
Gross Unrealized Losses	0	0
Total
Fair Value	49	48
Gross Unrealized Losses	-1	0
State or local housing agency
Less than 12 Months
Fair Value		3
Gross Unrealized Losses		0
12 Months or More
Fair Value		0
Gross Unrealized Losses		0
Total
Fair Value		3
Gross Unrealized Losses		0
FFELP ABS
Less than 12 Months
Fair Value	12	14
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	858	877
Gross Unrealized Losses	-9	-11
Total
Fair Value	870	891
Gross Unrealized Losses	-9	-11
Residential MBS: | GSE
Less than 12 Months
Fair Value	0	0
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	1,900	1,996
Gross Unrealized Losses	-10	-8
Total
Fair Value	1,900	1,996
Gross Unrealized Losses	-10	-8
Residential MBS: | Private-label
Less than 12 Months
Fair Value	0	0
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	16	16
Gross Unrealized Losses	0	0
Total
Fair Value	16	16
Gross Unrealized Losses	0	0
Residential MBS: | Total Residential MBS
Less than 12 Months
Fair Value	0	0
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	1,916	2,012
Gross Unrealized Losses	-10	-8
Total
Fair Value	1,916	2,012
Gross Unrealized Losses	($10)	($8)

Investment_Securities_Aging_of1

Investment Securities (Aging of Unrealized Temporary Losses on Held-to-maturity Securities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Less than 12 Months
Fair Value	$21	$35
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	1,361	1,394
Gross Unrealized Losses	-252	-266
Total
Fair Value	1,382	1,429
Gross Unrealized Losses	-252	-266
U.S. Government & other government related
Less than 12 Months
Fair Value	1	13
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	15	5
Gross Unrealized Losses	0	-1
Total
Fair Value	16	18
Gross Unrealized Losses	0	-1
State or local housing agency
Less than 12 Months
Fair Value	10	10
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	0	0
Gross Unrealized Losses	0	0
Total
Fair Value	10	10
Gross Unrealized Losses	0	0
Residential MBS: | GSE
Less than 12 Months
Fair Value	0	0
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	5	5
Gross Unrealized Losses	0	0
Total
Fair Value	5	5
Gross Unrealized Losses	0	0
Residential MBS: | Private-label
Less than 12 Months
Fair Value	10	12
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	1,341	1,384
Gross Unrealized Losses	-252	-265
Total
Fair Value	1,351	1,396
Gross Unrealized Losses	-252	-265
Residential MBS: | Total Residential MBS
Less than 12 Months
Fair Value	10	12
Gross Unrealized Losses	0	0
12 Months or More
Fair Value	1,346	1,389
Gross Unrealized Losses	-252	-265
Total
Fair Value	1,356	1,401
Gross Unrealized Losses	($252)	($265)

Investment_Securities_Contract

Investment Securities (Contractual Maturity Terms) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Contractual Maturity Terms [Abstract]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	$0
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	81
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis	2
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis	371
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	17,957
Available-for-Sale Amortized Cost Basis	18,411	18,915
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	0
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	86
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	2
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	395
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	18,966
Carrying Amount and Fair Value	19,449	19,975
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount	117
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount	71
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	358
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount	953
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Net Carrying Amount	4,724
Held-to-Maturity Carrying Amount	6,223	7,118
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	117
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	73
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value	374
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	1,018
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Fair Value	5,350
Held-to-Maturity Fair Value	$6,932	$7,824

Investment_Securities_Signific

Investment Securities (Significant Inputs Used to Determine OTTI) (Details)	Mar. 31, 2015
Minimum [Member]
Recovery Range Annualized % [Line Items]
Assumed Home Price Change Rate all markets	-3.00%
Projected House Price Change Rate majority of markets	1.00%
Maximum [Member]
Recovery Range Annualized % [Line Items]
Assumed Home Price Change Rate all markets	8.00%
Projected House Price Change Rate majority of markets	5.00%

Investment_Securities_OTTI_rol

Investment Securities (OTTI rollforward) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Beginning Balance	$620	$677
Reductions:
Increases in cash flows expected to be collected that have been recognized as accretion income into interest income	-15	-14
Ending Balance	$605	$663

Advances_By_callable_putable_f

Advances (By callable putable feature) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Federal Home Loan Bank, Advances [Line Items]
Total par value	$31,697	$32,303
Hedging adjustments	223	166
Other adjustments	21	16
Total advances	31,941	32,485
Noncallable/nonputable
Federal Home Loan Bank, Advances [Line Items]
Total par value	29,093	29,666
Callable
Federal Home Loan Bank, Advances [Line Items]
Total par value	961	964
Putable
Federal Home Loan Bank, Advances [Line Items]
Total par value	$1,643	$1,673

Advances_By_redemption_terms_D

Advances (By redemption terms) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Federal Home Loan Bank, Advances, Rolling Maturity [Abstract]
Federal Home Loan Bank, Advances, Maturities Summary, in Next Rolling Twelve Months	$6,628
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Two	2,568
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Three	4,369
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Four	8,989
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Five	6,861
Federal Home Loan Bank, Advances, Maturities Summary, after Rolling Year Five	2,282
Total par value	31,697		32,303
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Next Twelve Rolling Months	0.51%
Federal Home Loan Bank Advances, Weighted Average Interest Rate, Maturing in Rolling Year Two	2.15%
Federal Home Loan Bank Advances, Weighted Average Interest Rate, Maturing in Rolling Year Three	1.09%
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Four	0.33%	[1]
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Five	0.29%	[1]
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing after Rolling Year Five	2.31%
Federal Home Loan Bank, Advances, Weighted Average Interest Rate	0.75%
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Next Rolling Twelve Months	7,540
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Two	2,368
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Three	3,984
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Four	8,689
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Five	6,839
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, after Rolling Year Five	2,277
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Next Rolling Twelve Months	7,834
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Two	2,112
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Three	3,730
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Four	8,908
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Five	6,872
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, after Rolling Year Five	$2,241
[1]	The weighted average interest rate is relatively lower when compared to other categories due to a majority of advances in this category consisting of variable rate advances which reset periodically at current interest rates.

MPF_Loans_Details

MPF Loans (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Mortgage Loans on Real Estate [Line Items]
Total unpaid principal balance	$5,663	$5,999
Net premiums, credit enhancement and deferred loan fees	22	23
Hedging adjustments	47	50
Total before allowance for credit losses	5,732	6,072
Allowance for credit losses on MPF Loans	-4	-15
Total MPF Loans held in portfolio, net	5,728	6,057
Medium term (15 years or less)
Mortgage Loans on Real Estate [Line Items]
Total unpaid principal balance	971	1,094
Long term (greater than 15 years)
Mortgage Loans on Real Estate [Line Items]
Total unpaid principal balance	4,692	4,905
Conventional mortgage loans
Mortgage Loans on Real Estate [Line Items]
Total unpaid principal balance	4,323	4,619
Government insured mortgage loans
Mortgage Loans on Real Estate [Line Items]
Total unpaid principal balance	$1,340	$1,380

Allowance_for_Credit_Losses_Al

Allowance for Credit Losses (Allowance roll forward) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	$15
Provision for (reversal of) credit losses	0	-3
Balance, end of period	4
Conventional
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	15	29
Losses charged to the allowance	-11	-2
Provision for (reversal of) credit losses	0	-3
Balance, end of period	$4	$24

Allowance_for_Credit_Losses_Lo

Allowance for Credit Losses (Loans evaluated for impairment) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Allowance for credit losses on conventional MPF Loans	$4	$15
Total recorded investment	5,761	6,103
Conventional
Specifically identified and individually evaluated for impairment	0	12
Homogeneous pools of loans and collectively evaluated for impairment	4	3
Allowance for credit losses on conventional MPF Loans	4	15	24	29
Individually evaluated for impairment	144	160
Collectively evaluated for impairment	4,252	4,538
Total recorded investment	$4,396	$4,698

Allowance_for_Credit_Losses_Cr

Allowance for Credit Losses (Credit Quality Indicators - MPF Loans) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Recorded Investment, Past Due [Line Items]
Total past due	$420	$493
Total current	5,341	5,610
Total recorded investment	5,761	6,103
Also in process of foreclosure	80	88
Serious delinquency rate	3.04%	3.25%
Past due 90 days or more still accruing interest	53	69
On nonaccrual status	144	163
Conventional
Recorded Investment, Past Due [Line Items]
Total past due	284	334
Total current	4,112	4,364
Total recorded investment	4,396	4,698
Also in process of foreclosure	66	77
Serious delinquency rate	3.04%	3.28%
Past due 90 days or more still accruing interest	11	25
On nonaccrual status	144	163
Government
Recorded Investment, Past Due [Line Items]
Total past due	136	159
Total current	1,229	1,246
Total recorded investment	1,365	1,405
Also in process of foreclosure	14	11
Serious delinquency rate	3.06%	3.15%
Past due 90 days or more still accruing interest	42	44
On nonaccrual status	0	0
Past due 30-59 days
Recorded Investment, Past Due [Line Items]
Total past due	188	230
Past due 30-59 days | Conventional
Recorded Investment, Past Due [Line Items]
Total past due	114	138
Past due 30-59 days | Government
Recorded Investment, Past Due [Line Items]
Total past due	74	92
Past due 60-89 days
Recorded Investment, Past Due [Line Items]
Total past due	57	66
Past due 60-89 days | Conventional
Recorded Investment, Past Due [Line Items]
Total past due	37	43
Past due 60-89 days | Government
Recorded Investment, Past Due [Line Items]
Total past due	20	23
Past due 90 days or more
Recorded Investment, Past Due [Line Items]
Total past due	175	197
Past due 90 days or more | Conventional
Recorded Investment, Past Due [Line Items]
Total past due	133	153
Past due 90 days or more | Government
Recorded Investment, Past Due [Line Items]
Total past due	$42	$44

Allowance_for_Credit_Losses_Tr

Allowance for Credit Losses (Troubled debt restructurings outstanding balances) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Troubled debt restructurings outstanding [Abstract]
Financing Receivable, Modifications, Recorded Investment	$68	$73

Allowance_for_Credit_Losses_Im

Allowance for Credit Losses (Impaired MPF Loans at period ends) (Details) (Conventional, USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Conventional
Financing Receivable, Impaired [Line Items]
Recorded investment with an allowance	$0	$160
Recorded investment without an allowance	144	0
Unpaid principal balance with an allowance	0	158
Unpaid principal balance without an allowance	152	0
Related allowance	$0	$12

Allowance_for_Credit_Losses_Im1

Allowance for Credit Losses (Impaired MPF Loans during the periods) (Details) (Conventional, USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Conventional
Financing Receivable, Impaired [Line Items]
Average recorded investment with an allowance	$0	$204
Average recorded investment without an allowance	$148	$0

Derivatives_and_Hedging_Activi2

Derivatives and Hedging Activities (Narrative) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Additional collateral due to derivatives counterparties if credit rating was lowered one level	$32
Financial Instruments, Owned and Pledged as Collateral, at Fair Value	76	71
Financial Instruments Owned and Pledged as Collateral, Amount Eligible to be Repledged by Counterparty	$76

Derivatives_and_Hedging_Activi3

Derivatives and Hedging Activities (Derivatives in statements of condition) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]
Notional Amount	$60,335		$53,400
Derivatives on statements of condition	8		29
Derivatives on statements of condition	45		55
Cash collateral posted	-1,000		-978
Cash collateral received	-55		-29
Derivatives in hedge accounting relationships- | Interest rate swaps
Derivatives, Fair Value [Line Items]
Notional Amount	31,559		30,940
Derivatives not in hedge accounting relationships-
Derivatives, Fair Value [Line Items]
Notional Amount	28,776		22,460
Derivatives not in hedge accounting relationships- | Interest rate swaps
Derivatives, Fair Value [Line Items]
Notional Amount	25,297		19,159
Derivatives not in hedge accounting relationships- | Interest rate swaptions
Derivatives, Fair Value [Line Items]
Notional Amount	1,810		1,850
Derivatives not in hedge accounting relationships- | Interest rate caps or floors
Derivatives, Fair Value [Line Items]
Notional Amount	1,164		1,164
Derivatives not in hedge accounting relationships- | Interest rate futures
Derivatives, Fair Value [Line Items]
Notional Amount	1		3
Derivatives not in hedge accounting relationships- | Mortgage delivery commitments
Derivatives, Fair Value [Line Items]
Notional Amount	501		284
Derivatives not in hedge accounting relationships- | Other
Derivatives, Fair Value [Line Items]
Notional Amount	3		0
Derivative Assets
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	794		704
Netting adjustments and cash collateral	-786	[1]	-675	[1]
Derivatives on statements of condition	8		29
Derivative Assets | Derivatives in hedge accounting relationships- | Interest rate swaps
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	71		53
Derivative Assets | Derivatives not in hedge accounting relationships-
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	723		651
Derivative Assets | Derivatives not in hedge accounting relationships- | Interest rate swaps
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	547		487
Derivative Assets | Derivatives not in hedge accounting relationships- | Interest rate swaptions
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	66		56
Derivative Assets | Derivatives not in hedge accounting relationships- | Interest rate caps or floors
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	104		105
Derivative Assets | Derivatives not in hedge accounting relationships- | Interest rate futures
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	0		0
Derivative Assets | Derivatives not in hedge accounting relationships- | Mortgage delivery commitments
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	6		3
Derivative Assets | Derivatives not in hedge accounting relationships- | Other
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	0		0
Derivative Liabilities
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	1,807		1,680
Netting adjustments and cash collateral	-1,762	[1]	-1,625	[1]
Derivatives on statements of condition	45		55
Derivative Liabilities | Derivatives in hedge accounting relationships- | Interest rate swaps
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	1,394		1,348
Derivative Liabilities | Derivatives not in hedge accounting relationships-
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	413		332
Derivative Liabilities | Derivatives not in hedge accounting relationships- | Interest rate swaps
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	407		329
Derivative Liabilities | Derivatives not in hedge accounting relationships- | Interest rate swaptions
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	0		0
Derivative Liabilities | Derivatives not in hedge accounting relationships- | Interest rate caps or floors
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	0		0
Derivative Liabilities | Derivatives not in hedge accounting relationships- | Interest rate futures
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	0		0
Derivative Liabilities | Derivatives not in hedge accounting relationships- | Mortgage delivery commitments
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	6		3
Derivative Liabilities | Derivatives not in hedge accounting relationships- | Other
Derivatives, Fair Value [Line Items]
Gross derivative amount before adjustments	$0		$0
[1]	Amounts represent the application of the netting requirements that allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed by us with the same clearing agent and/or counterparty. Cash collateral posted was $1.0 billion at March 31, 2015, and $978 million at December 31, 2014. Cash collateral received was $55 million at March 31, 2015, and $29 million at December 31, 2014.

Derivatives_and_Hedging_Activi4

Derivatives and Hedging Activities (Derivative instruments with legal right of offset) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Derivatives with legal right of offset -
Derivatives on statements of condition	$8		$29
Derivatives on statements of condition	45		55
Credit Exposure On Overcollateralized Pledged Securities Exceeding Derivative Liability	74		4
Derivative Assets
Derivatives with legal right of offset -
Gross recognized amount	788		701
Netting adjustments and cash collateral	-786	[1]	-675	[1]
Derivatives with legal right of offset - net	2		26
Derivatives without legal right of offset	6		3
Derivatives on statements of condition	8		29
Noncash collateral received (pledged) and cannot be sold or repledged	1		23
Net amount	7		6
Derivative Assets | Bilateral
Derivatives with legal right of offset -
Gross recognized amount	707		656
Netting adjustments and cash collateral	-705		-632
Derivatives with legal right of offset - net	2		24
Derivatives without legal right of offset	6		3
Derivatives on statements of condition	8		27
Noncash collateral received (pledged) and cannot be sold or repledged	1		23
Net amount	7		4
Derivative Assets | Cleared
Derivatives with legal right of offset -
Gross recognized amount	81		45
Netting adjustments and cash collateral	-81		-43
Derivatives with legal right of offset - net	0		2
Derivatives without legal right of offset	0		0
Derivatives on statements of condition	0		2
Noncash collateral received (pledged) and cannot be sold or repledged	0		0
Net amount	0		2
Derivative Liabilities
Derivatives with legal right of offset -
Gross recognized amount	1,801		1,677
Netting adjustments and cash collateral	-1,762	[1]	-1,625	[1]
Derivatives with legal right of offset - net	39		52
Derivatives without legal right of offset	6		3
Derivatives on statements of condition	45		55
Noncash collateral received (pledged) and cannot be sold or repledged	3		0
Net amount	42		55
Derivative Liabilities | Bilateral
Derivatives with legal right of offset -
Gross recognized amount	1,491		1,466
Netting adjustments and cash collateral	-1,455		-1,414
Derivatives with legal right of offset - net	36		52
Derivatives without legal right of offset	6		3
Derivatives on statements of condition	42		55
Noncash collateral received (pledged) and cannot be sold or repledged	0		0
Net amount	42		55
Derivative Liabilities | Cleared
Derivatives with legal right of offset -
Gross recognized amount	310		211
Netting adjustments and cash collateral	-307		-211
Derivatives with legal right of offset - net	3		0
Derivatives without legal right of offset	0		0
Derivatives on statements of condition	3		0
Noncash collateral received (pledged) and cannot be sold or repledged	3		0
Net amount	$0		$0
[1]	Amounts represent the application of the netting requirements that allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed by us with the same clearing agent and/or counterparty. Cash collateral posted was $1.0 billion at March 31, 2015, and $978 million at December 31, 2014. Cash collateral received was $55 million at March 31, 2015, and $29 million at December 31, 2014.

Derivatives_and_Hedging_Activi5

Derivatives and Hedging Activities (Derivatives in Statement of Income) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedges	$0	$1
Economic hedges	8	-9
Gains (losses) on derivatives and hedging activities	-11	-14
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Fair value hedges	-19	-6
Economic hedges	-23	1
Interest rate swaptions
Derivative Instruments, Gain (Loss) [Line Items]
Economic hedges	8	-15
Interest rate caps or floors
Derivative Instruments, Gain (Loss) [Line Items]
Economic hedges	-1	-10
Net interest settlements
Derivative Instruments, Gain (Loss) [Line Items]
Economic hedges	$24	$15

Derivatives_and_Hedging_Activi6

Derivatives and Hedging Activities (Fair Value Hedges) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Net Interest Settlements Recorded in Net Interest Income	$130		$127
Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
On Derivative	-23		101
On Hedged Item	4		-107
Total Ineffectiveness Recognized in Derivatives and Hedging Activities	-19		-6
Net Interest Settlements Recorded in Net Interest Income	4	[1]	6	[1]
Closed Hedge Adjustments Amortized into Net Interest Income	-13	[2]	-11	[2]
Fair Value Hedging [Member] | Available-for-sale securities
Derivative Instruments, Gain (Loss) [Line Items]
On Derivative	-36		-2
On Hedged Item	31		1
Total Ineffectiveness Recognized in Derivatives and Hedging Activities	-5		-1
Net Interest Settlements Recorded in Net Interest Income	-34	[1]	-35	[1]
Closed Hedge Adjustments Amortized into Net Interest Income	-10	[2]	0	[2]
Fair Value Hedging [Member] | Advances
Derivative Instruments, Gain (Loss) [Line Items]
On Derivative	-61		-30
On Hedged Item	57		32
Total Ineffectiveness Recognized in Derivatives and Hedging Activities	-4		2
Net Interest Settlements Recorded in Net Interest Income	-20	[1]	-20	[1]
Closed Hedge Adjustments Amortized into Net Interest Income	1	[2]	-1	[2]
Fair Value Hedging [Member] | MPF Loans held for portfolio
Derivative Instruments, Gain (Loss) [Line Items]
On Derivative	0		0
On Hedged Item	0		0
Total Ineffectiveness Recognized in Derivatives and Hedging Activities	0		0
Net Interest Settlements Recorded in Net Interest Income	0	[1]	0	[1]
Closed Hedge Adjustments Amortized into Net Interest Income	-4	[2]	-5	[2]
Fair Value Hedging [Member] | Consolidated obligation bonds
Derivative Instruments, Gain (Loss) [Line Items]
On Derivative	74		133
On Hedged Item	-84		-140
Total Ineffectiveness Recognized in Derivatives and Hedging Activities	-10		-7
Net Interest Settlements Recorded in Net Interest Income	58	[1]	61	[1]
Closed Hedge Adjustments Amortized into Net Interest Income	$0	[2]	($5)	[2]
[1]	Represents the effect of net interest settlements attributable to open derivative hedging instruments on net interest income. The effect of derivatives on net interest income is included in the interest income/expense line item of the respective hedged item type.
[2]	Amortization of hedge adjustments is included in the interest income/expense line item of the respective hedged item type.

Derivatives_and_Hedging_Activi7

Derivatives and Hedging Activities (Cash Flow Hedges) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities	$0		$1
Net Interest Settlements Classified in Net Interest Income	-130		-127
Cash Flow Hedge Gain (Loss) to be Reclassified Next 12 Months, Net	-1
Maximum Hedging Period For Forecasted Cash Flows	5 years
Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Amortization of Effective Portion Reclassified From AOCI to Interest	1		2
Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities	0		1
Total Reclassified From AOCI to Statements of Income	1		3
Net Change in Other Comprehensive Income	-28		21
Effective Portion Recorded in AOCI	-27		24
Net Interest Settlements Classified in Net Interest Income	-62	[1]	-61	[1]
Advances | Cash Flow Hedges | Interest rate floors
Derivative Instruments, Gain (Loss) [Line Items]
Amortization of Effective Portion Reclassified From AOCI to Interest	3		3
Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities	0		0
Total Reclassified From AOCI to Statements of Income	3		3
Net Change in Other Comprehensive Income	-3		-3
Effective Portion Recorded in AOCI	0		0
Net Interest Settlements Classified in Net Interest Income	0		0
Discount Notes | Cash Flow Hedges | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amortization of Effective Portion Reclassified From AOCI to Interest	-1		-1
Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities	0		1
Total Reclassified From AOCI to Statements of Income	-1		0
Net Change in Other Comprehensive Income	-26		24
Effective Portion Recorded in AOCI	-27		24
Net Interest Settlements Classified in Net Interest Income	-62	[1]	-61	[1]
Consolidated obligation bonds | Cash Flow Hedges | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amortization of Effective Portion Reclassified From AOCI to Interest	-1
Ineffective Portion Reclassified From AOCI to Derivatives and Hedging Activities	0
Total Reclassified From AOCI to Statements of Income	-1
Net Change in Other Comprehensive Income	1
Effective Portion Recorded in AOCI	0
Net Interest Settlements Classified in Net Interest Income	$0
[1]	Represents the effect of net interest settlements attributable to open derivative hedging instruments on net interest income. The effect of derivatives on net interest income is included in the interest income/expense line item of the respective hedged item type.

Consolidated_Obligations_Bonds

Consolidated Obligations (Bonds by maturity date) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Consolidated obligation bonds
Contractual Maturity
Due in one year or less	2,190
One to two years	3,795
Two to three years	8,074
Three to four years	3,907
Four to five years	6,599
Thereafter	8,540
Total par value	33,105	34,401
Weighted Average Interest Rate
Due in one year or less	3.00%
One to two years	2.44%
Two to three years	1.94%
Three to four years	1.17%
Four to five years	1.56%
Thereafter	2.49%
Total par value	2.04%
Consolidated obligation bonds | By Next Maturity or Call Date
Contractual Maturity
Due in one year or less	23,807
One to two years	2,898
Two to three years	2,834
Three to four years	980
Four to five years	1,374
Thereafter	1,212
Total par value	33,105
Minimum [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Term	1 year
Maximum [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Term	20 years

Consolidated_Obligations_Short

Consolidated Obligations (Short term discount notes) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Short-term Debt [Line Items]
Carrying Amount	$30,474	$31,054
Discount Notes
Short-term Debt [Line Items]
Carrying Amount	30,474	31,054
Par Value	$30,486	$31,060
Weighted Average Interest Rate	0.11%	0.09%

Consolidated_Obligations_Bonds1

Consolidated Obligations (Bonds by callable feature) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Total consolidated obligation bonds	$33,043	$34,251
Consolidated obligation bonds
Debt Instrument [Line Items]
Par Value	33,105	34,401
Bond premiums (discounts), net	15	17
Hedging adjustments	-93	-177
Fair value option adjustments	16	10
Total consolidated obligation bonds	33,043	34,251
Noncallable | Consolidated obligation bonds
Debt Instrument [Line Items]
Par Value	10,763	11,046
Callable | Consolidated obligation bonds
Debt Instrument [Line Items]
Par Value	$22,342	$23,355

Consolidated_Obligations_Syste

Consolidated Obligations (Systemwide joint & several liability) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Consolidated obligation bonds
Obligation with Joint and Several Liability Arrangement [Line Items]
FHLB System total consolidated obligations	$459,021	$484,812
FHLB Chicago as primary obligor	33,105	34,401
As a percent of the FHLB System	7.00%	7.00%
Discount Notes
Obligation with Joint and Several Liability Arrangement [Line Items]
FHLB System total consolidated obligations	353,175	362,363
FHLB Chicago as primary obligor	30,486	31,060
As a percent of the FHLB System	9.00%	9.00%
Total
Obligation with Joint and Several Liability Arrangement [Line Items]
FHLB System total consolidated obligations	812,196	847,175
FHLB Chicago as primary obligor	$63,591	$65,461
As a percent of the FHLB System	8.00%	8.00%

Capital_and_Mandatorily_Redeem2

Capital and Mandatorily Redeemable Capital Stock (Capital rules) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Banking and Thrift [Abstract]
Capital stock par value	$100	$100
Capital Stock, redemption, period of written notice	5 years

Capital_and_Mandatorily_Redeem3

Capital and Mandatorily Redeemable Capital Stock (Regulatory capital requirements) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Federal Home Loan Banks [Abstract]
Risk Based Capital, Requirement	$1,135	$1,127
Risk Based Capital, Actual	4,416	4,317
Regulatory Capital, Requirement	2,806	2,874
Regulatory Capital, Actual	4,416	4,317
Regulatory Capital Ratio, Requirement	4.00%	4.00%
Regulatory Capital Ratio, Actual	6.29%	6.01%
Leverage Capital, Requirement	3,507	3,592
Leverage Capital, Actual	$6,623	$6,475
Leverage Ratio, Requirement	5.00%	5.00%
Leverage Ratio, Actual	9.44%	9.01%

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Total AOCI
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$217	$67
Change in the period before reclassifications to net income	-44	93
Amounts reclassified in period to:
Net interest income	-1	-2
Non-interest gain (loss)		-1
Non-interest expense		1
Net change in the period	-45	91
Ending balance	172	158
Net Unrealized Gain (Loss) | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,060	1,052
Change in the period before reclassifications to net income	-22	55
Amounts reclassified in period to:
Net interest income	0	0
Non-interest gain (loss)		0
Non-interest expense		0
Net change in the period	-22	55
Ending balance	1,038	1,107
Non-credit OTTI | Held-to-maturity Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	-264	-320
Change in the period before reclassifications to net income	13	14
Amounts reclassified in period to:
Net interest income	0	0
Non-interest gain (loss)		0
Non-interest expense		0
Net change in the period	13	14
Ending balance	-251	-306
Net Unrealized on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	-580	-665
Change in the period before reclassifications to net income	-27	24
Amounts reclassified in period to:
Net interest income	-1	-2
Non-interest gain (loss)		-1
Non-interest expense		0
Net change in the period	-28	21
Ending balance	-608	-644
Post-Retirement Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1	0
Change in the period before reclassifications to net income	-8	0
Amounts reclassified in period to:
Net interest income	0	0
Non-interest gain (loss)		0
Non-interest expense		1
Net change in the period	-8	1
Ending balance	($7)	$1

Fair_Value_Accounting_Carrying

Fair Value Accounting (Carrying Value and Fair Value of Financial Instruments) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Financial Assets -
Held-to-maturity securities	$6,932		$7,824
Advances	85		83
Financial Liabilities -
Consolidated obligation discount notes	-7,655		-1,799
Consolidated obligation bonds	-2,903		-2,785
Carrying Amount
Financial Assets -
Cash and due from banks	1,458		342
Interest bearing deposits	560		560
Federal Funds sold	3,022		1,525
Securities purchased under agreements to resell	1,400		3,400
Held-to-maturity securities	6,223		7,118
Advances	31,941		32,485
MPF Loans held in portfolio, net	5,728		6,057
Financial Liabilities -
Deposits	-646		-666
Consolidated obligation discount notes	-30,474		-31,054
Consolidated obligation bonds	-33,043		-34,251
Subordinated notes	-944		-944
Fair Value
Financial Assets -
Cash and due from banks	1,458		342
Interest bearing deposits	560		560
Federal Funds sold	3,022		1,525
Securities purchased under agreements to resell	1,400		3,400
Held-to-maturity securities	6,932		7,824
Advances	31,995		32,546
MPF Loans held in portfolio, net	6,266		6,585
Financial Liabilities -
Deposits	-646		-666
Consolidated obligation discount notes	-30,473		-31,055
Consolidated obligation bonds	-33,672		-34,831
Subordinated notes	-1,002		-1,013
Level 1
Financial Assets -
Cash and due from banks	1,458		342
Interest bearing deposits	560		560
Federal Funds sold	0		0
Securities purchased under agreements to resell	0		0
Held-to-maturity securities	0		0
Advances	0		0
MPF Loans held in portfolio, net			0
Financial Liabilities -
Deposits	0		0
Consolidated obligation discount notes	0		0
Consolidated obligation bonds	0		0
Subordinated notes	0		0
Level 2
Financial Assets -
Cash and due from banks	0		0
Interest bearing deposits	0		0
Federal Funds sold	3,022		1,525
Securities purchased under agreements to resell	1,400		3,400
Held-to-maturity securities	5,514		6,356
Advances	31,995		32,546
MPF Loans held in portfolio, net	6,111		6,435
Financial Liabilities -
Deposits	-646		-666
Consolidated obligation discount notes	-30,473		-31,055
Consolidated obligation bonds	-33,613		-34,768
Subordinated notes	-1,002		-1,013
Level 3
Financial Assets -
Cash and due from banks	0		0
Interest bearing deposits	0		0
Federal Funds sold	0		0
Securities purchased under agreements to resell	0		0
Held-to-maturity securities	1,418		1,468
Advances	0		0
MPF Loans held in portfolio, net	155		150
Financial Liabilities -
Deposits	0		0
Consolidated obligation discount notes	0		0
Consolidated obligation bonds	-59	[1]	-63	[1]
Subordinated notes	$0		$0
[1]	Amount represents debt carried at fair value under a full fair value hedge strategy, not at fair value under the fair value option.

Fair_Value_Accounting_Fair_Val

Fair Value Accounting (Fair Value Measured on Recurring Basis) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Financial Assets -
Trading securities	$162		$167
Available-for-sale	19,449		19,975
Advances	85		83
Derivative assets	8		29
Financial Liabilities -
Consolidated obligation discount notes	-7,655		-1,799
Consolidated obligation bonds	-2,903		-2,785
Derivative liabilities	-45		-55
Recurring
Financial Assets -
Trading securities	162		167
Available-for-sale	19,449		19,975
Advances	85		83
Derivative assets	8		29
Netting	-786	[1]	-675	[1]
Total financial assets at fair value	19,704		20,254
Financial Liabilities -
Consolidated obligation discount notes	-7,655		-1,799
Consolidated obligation bonds	-2,962		-2,848
Derivative liabilities	-45		-55
Netting	1,762	[1]	1,625	[1]
Total financial liabilities at fair value	-10,662		-4,702
U.S. Government & other government related | Recurring
Financial Assets -
Trading securities	101		102
Available-for-sale	479		508
State or local housing agency | Recurring
Financial Assets -
Available-for-sale	4		3
FFELP ABS | Recurring
Financial Assets -
Available-for-sale	5,994		6,221
Residential MBS: | GSE | Recurring
Financial Assets -
Trading securities	59		63
Available-for-sale	10,648		10,827
Residential MBS: | Government-guaranteed | Recurring
Financial Assets -
Trading securities	2		2
Available-for-sale	2,255		2,345
Residential MBS: | Private-label | Recurring
Financial Assets -
Available-for-sale	69		71
Level 1
Financial Assets -
Advances	0		0
Financial Liabilities -
Consolidated obligation discount notes	0		0
Consolidated obligation bonds	0		0
Level 2
Financial Assets -
Advances	31,995		32,546
Financial Liabilities -
Consolidated obligation discount notes	-30,473		-31,055
Consolidated obligation bonds	-33,613		-34,768
Level 2 | Recurring
Financial Assets -
Trading securities	162		167
Available-for-sale	19,380		19,904
Advances	85		83
Derivative assets	785		691
Total financial assets at fair value	20,412		20,845
Financial Liabilities -
Consolidated obligation discount notes	-7,655		-1,799
Consolidated obligation bonds	-2,903		-2,785
Derivative liabilities	-1,807		-1,680
Total financial liabilities at fair value	-12,365		-6,264
Level 2 | U.S. Government & other government related | Recurring
Financial Assets -
Trading securities	101		102
Available-for-sale	479		508
Level 2 | State or local housing agency | Recurring
Financial Assets -
Available-for-sale	4		3
Level 2 | FFELP ABS | Recurring
Financial Assets -
Available-for-sale	5,994		6,221
Level 2 | Residential MBS: | GSE | Recurring
Financial Assets -
Trading securities	59		63
Available-for-sale	10,648		10,827
Level 2 | Residential MBS: | Government-guaranteed | Recurring
Financial Assets -
Trading securities	2		2
Available-for-sale	2,255		2,345
Level 2 | Residential MBS: | Private-label | Recurring
Financial Assets -
Available-for-sale	0		0
Level 3
Financial Assets -
Advances	0		0
Financial Liabilities -
Consolidated obligation discount notes	0		0
Consolidated obligation bonds	-59	[2]	-63	[2]
Level 3 | Recurring
Financial Assets -
Trading securities	0		0
Available-for-sale	69		71
Advances	0		0
Derivative assets	9		13
Total financial assets at fair value	78		84
Level 3 as a percent of total assets at fair value	0.40%		0.40%
Financial Liabilities -
Consolidated obligation discount notes	0		0
Consolidated obligation bonds	-59	[2]	-63	[2]
Derivative liabilities	0		0
Total financial liabilities at fair value	-59		-63
Level 3 as a percent of total liabilities at fair value	0.60%		1.30%
Level 3 | U.S. Government & other government related | Recurring
Financial Assets -
Trading securities	0		0
Available-for-sale	0		0
Level 3 | State or local housing agency | Recurring
Financial Assets -
Available-for-sale	0		0
Level 3 | FFELP ABS | Recurring
Financial Assets -
Available-for-sale	0		0
Level 3 | Residential MBS: | GSE | Recurring
Financial Assets -
Trading securities	0		0
Available-for-sale	0		0
Level 3 | Residential MBS: | Government-guaranteed | Recurring
Financial Assets -
Trading securities	0		0
Available-for-sale	0		0
Level 3 | Residential MBS: | Private-label | Recurring
Financial Assets -
Available-for-sale	$69		$71
[1]	The netting adjustment amount includes cash collateral (either received or paid by us) and related accrued interest in cases where we have a legal right of setoff, by contract (e.g., master netting agreement) or otherwise, to discharge all or a portion of the debt owed to our counterparty by applying against the debt an amount that our counterparty owes to us. See Note 9 - Derivatives and Hedging Activities for further details.
[2]	Amount represents debt carried at fair value under a full fair value hedge strategy, not at fair value under the fair value option.

Fair_Value_Accounting_Fair_Val1

Fair Value Accounting (Fair Value Measured on a Nonrecurring Basis) (Details) (Non-recurring, Level 3, USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Non-recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired conventional MPF Loans held in portfolio	$155	$150
REO (recorded in Other Assets)	$31	$9

Fair_Value_Accounting_Fair_Val2

Fair Value Accounting (Fair Value Option) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Option, Quantitative Disclosures [Roll Forward]
Balance beginning of period	$83
Balance beginning of period	-2,785
Balance beginning of period	-1,799
Net gain (loss) on instruments held at fair value	3	4
Balance end of period	85
Balance end of period	-2,903
Balance end of period	-7,655
Advances
Fair Value, Option, Quantitative Disclosures [Roll Forward]
Balance beginning of period	83	30
New transactions elected for fair value option	0	0
Maturities and extinguishments (if any)	0	0
Net gain (loss) on instruments held at fair value	1	0
Change in accrued interest and other	1	0
Balance end of period	85	30
Consolidated obligation bonds
Fair Value, Option, Quantitative Disclosures [Roll Forward]
Balance beginning of period	-2,785	-1,021
New transactions elected for fair value option	-628	-2,660
Maturities and extinguishments (if any)	515	270
Net gain (loss) on instruments held at fair value	2	4
Change in accrued interest and other	-7	-1
Balance end of period	-2,903	-3,408
Discount Notes
Fair Value, Option, Quantitative Disclosures [Roll Forward]
Balance beginning of period	-1,799	-75
New transactions elected for fair value option	-5,855	0
Maturities and extinguishments (if any)	0	75
Net gain (loss) on instruments held at fair value	0	0
Change in accrued interest and other	-1	0
Balance end of period	($7,655)	$0

Fair_Value_Accounting_Fair_Val3

Fair Value Accounting (Fair Value Option Difference Between Fair Value and Unpaid Principal Balance) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value	$85	$83
Fair Value	2,903	2,785
Fair Value	7,655	1,799
Advances
Fair Value, Option, Quantitative Disclosures [Line Items]
Unpaid Principal Balance	81	80
Fair Value Over (Under) UPB	4	3
Fair Value	85	83	30	30
Consolidated obligation bonds
Fair Value, Option, Quantitative Disclosures [Line Items]
Unpaid Principal Balance	2,887	2,775
Fair Value Over (Under) UPB	16	10
Fair Value	2,903	2,785	3,408	1,021
Discount Notes
Fair Value, Option, Quantitative Disclosures [Line Items]
Unpaid Principal Balance	7,656	1,800
Fair Value Over (Under) UPB	-1	-1
Fair Value	$7,655	$1,799	$0	$75

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Commitments
Expire within one year	$4,641		$7,025
Expire after one year	1,942		1,573
Total	6,583		8,598
Unsettled consolidated obligation bonds
Commitments
Expire within one year	610		91
Expire after one year	0		0
Total	610		91
Member standby letters of credit
Commitments
Expire within one year	3,615		2,410
Expire after one year	1,398	[1]	1,207	[1]
Total	5,013		3,617
Portion of expire after one year that are also renewable annually	981		974
Housing authority standby bond purchase agreements
Commitments
Expire within one year	17		155
Expire after one year	436		262
Total	453		417
Committed unused member lines of credit
Commitments
Expire within one year	0		4,000
Expire after one year	0		0
Total	0		4,000
Advance commitments
Commitments
Expire within one year	85		158
Expire after one year	108		104
Total	193		262
Other commitments
Commitments
Expire within one year	314		211
Expire after one year	0		0
Total	$314		$211
[1]	Contains $981 million and $974 million of member standby letters of credit at MarchB 31, 2015, and DecemberB 31, 2014, which were renewable annually.

Transactions_with_Members_and_2

Transactions with Members and Other FHLBs (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Accounts With Related Party Transactions [Line Items]
Assets - Interest bearing deposits	$560	$560
Assets - Advances	31,941	32,485
Liabilities - Deposits	646	666
Equity - Capital Stock	1,923	1,902
Transactions with members
Accounts With Related Party Transactions [Line Items]
Assets - Interest bearing deposits	560	560
Assets - Advances	11,170	11,159
Assets - Advance Interest Receivable	3	2
Liabilities - Deposits	20	26
Equity - Capital Stock	$268	$267