Federal Home Loan Bank of Des Moines 10-Q 10 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Federal Home Loan Bank of Des Moines
Entity Central Index Key	1,325,814
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		56,603,795

Statements of Condition

Statements of Condition - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 201	$ 503
Interest-bearing deposits	1	1
Securities purchased under agreements to resell	4,900	4,600
Federal funds sold	4,435	4,250
Investment securities
Trading securities (Note 3)	937	1,177
Available-for-sale securities (Note 4)	19,451	20,796
Held-to-maturity securities (fair value of $3,325 and $3,686) (Note 5)	3,295	3,628
Total investment securities	23,683	25,601
Advances (includes $15 and $0 at fair value under the fair value option) (Note 7)	109,963	102,613
Mortgage loans held for portfolio, net
Mortgage loans held for portfolio, net of allowance for credit losses of $1 and $2 (Notes 8 and 9)	7,310	7,096
Accrued interest receivable	305	223
Derivative assets, net (Note 10)	83	100
Other assets	100	112
TOTAL ASSETS	150,981	145,099
Deposits
Interest-bearing	914	1,013
Non-interest-bearing	114	94
Total deposits	1,028	1,107
Consolidated obligations (Note 11)
Discount notes	43,122	36,682
Bonds	98,468	98,893
Total consolidated obligations	141,590	135,575
Loans from Other Federal Home Loan Banks	0	600
Mandatorily redeemable capital stock (Note 12)	373	385
Accrued interest payable	238	210
Affordable Housing Program payable	155	142
Derivative liabilities, net (Note 10)	2	6
Other liabilities	56	53
TOTAL LIABILITIES	143,442	138,078
Commitments and contingencies (Note 14)
CAPITAL (Note 12)
Capital stock - Class B putable ($100 par value); 54 and 51 issued and outstanding shares	5,420	5,068
Retained earnings
Unrestricted	1,593	1,504
Restricted	384	335
Total retained earnings	1,977	1,839
Accumulated other comprehensive income (loss)	142	114
TOTAL CAPITAL	7,539	7,021
TOTAL LIABILITIES AND CAPITAL	$ 150,981	$ 145,099

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Millions, $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Held-to-Maturity Securities, Fair Value	$ 3,325	$ 3,686
Advances, Fair Value Disclosure	15	0
Loans and Leases Receivable, Allowance	$ 1	$ 2
Capital Stock - Class B Putable, Par Value	$ 100	$ 100
Common Class B [Member]
Capital Stock - Class B Putable, Par Value	$ 100	$ 100
Capital Stock - Class B Putable, Issued Shares	54	51
Capital Stock - Class B Putable, Outstanding Shares	54	51

Statements of Income

Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
INTEREST INCOME
Advances	$ 626	$ 381	$ 1,128	$ 714
Interest-bearing deposits	1	1	1	1
Securities purchased under agreements to resell	16	8	28	16
Federal funds sold	22	15	45	27
Trading securities	8	12	16	23
Available-for-sale securities	122	89	232	168
Held-to-maturity securities	22	20	43	40
Mortgage loans held for portfolio	61	59	121	117
Total interest income	878	585	1,614	1,106
INTEREST EXPENSE
Consolidated obligations - Discount notes	170	124	294	233
Consolidated obligations - Bonds	534	286	982	539
Deposits	2	1	5	2
Mandatorily redeemable capital stock	5	4	9	9
Total interest expense	711	415	1,290	783
NET INTEREST INCOME	167	170	324	323
OTHER INCOME (LOSS)
Trading Securities, Change in Unrealized Holding Gain (Loss)	(8)	4	(24)	9
Net gains (losses) on derivatives and hedging activities	14	(3)	34	3
Gains on litigation settlements, net	0	0	0	21
Other, net	2	5	6	8
Total other income (loss)	8	6	16	41
OTHER EXPENSE
Compensation and benefits	14	14	31	27
Contractual services	3	3	6	6
Professional fees	4	5	7	10
Other operating expenses	6	5	11	10
Federal Housing Finance Agency	3	2	5	5
Office of Finance	1	2	3	4
Other, net	1	0	2	1
Total other expense	32	31	65	63
NET INCOME BEFORE ASSESSMENTS	143	145	275	301
Affordable Housing Program assessments	14	15	28	31
NET INCOME	$ 129	$ 130	$ 247	$ 270

Statements of Comprehensive Inc

Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 129	$ 130	$ 247	$ 270
Other comprehensive income (loss)
Unrealized gains (losses)	(17)	41	28	105
Pension and postretirement benefits	0	1	0	2
Total other comprehensive income (loss)	(17)	42	28	107
TOTAL COMPREHENSIVE INCOME (LOSS)	$ 112	$ 172	$ 275	$ 377

Statements of Capital

Statements of Capital - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 7,021	$ 7,401
Proceeds from issuance of capital stock			4,015	2,905
Repurchases/redemptions of capital stock			(3,624)	(3,171)
Net shares reclassified (to) from mandatorily redeemable capital stock	$ (36)	$ (18)	(39)	(28)
Total Comprehensive Income	112	172	275	377
Cash dividends on capital stock			(109)	(88)
Ending Balance	7,539	7,396	7,539	7,396
Additional Capital from Merger [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			0	52
Cash dividends on capital stock				(52)
Ending Balance	0	0	0	0
Retained Earnings, Unrestricted [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			1,504	1,219
Total Comprehensive Income			198	216
Cash dividends on capital stock			(109)	(36)
Ending Balance	1,593	1,399	1,593	1,399
Retained Earnings, Restricted [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			335	231
Total Comprehensive Income			49	54
Ending Balance	384	285	384	285
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			1,839	1,450
Total Comprehensive Income			247	270
Cash dividends on capital stock			(109)	(36)
Ending Balance	1,977	1,684	1,977	1,684
Accumulated Other Comprehensive Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	159	47	114	(18)
Total Comprehensive Income			28	107
Ending Balance	142	89	142	89
Common Class B [Member] | Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 5,068	$ 5,917
BALANCE (shares)			51	59
Proceeds from issuance of capital stock			$ 4,015	$ 2,905
Proceeds from issuance of capital stock (shares)			40	29
Repurchases/redemptions of capital stock			$ 3,624	$ (3,171)
Repurchases/redemptions of capital stock (shares)			(37)	(32)
Net shares reclassified (to) from mandatorily redeemable capital stock			$ (39)	$ (28)
Net shares reclassified (to) from mandatorily redeemable capital stock (shares)			0	0
Ending Balance	$ 5,420	$ 5,623	$ 5,420	$ 5,623
BALANCE (shares)	54	56	54	56

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net Income	$ 247	$ 270
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation and amortization	18	16
Net (gains) losses on trading securities	24	(9)
Net change in derivatives and hedging activities	87	(1)
Other adjustments	1	(1)
Net change in:
Accrued interest receivable	(121)	(36)
Other assets	2	(4)
Accrued interest payable	27	29
Other liabilities	15	(15)
Total adjustments	53	(21)
Net Cash Provided by (Used in) Operating Activities	300	249
Net change in:
Interest-bearing deposits	63	17
Securities purchased under agreements to resell	(300)	2,425
Federal funds sold	(185)	(5)
Premises, software, and equipment	(11)	(21)
Increase (Decrease) in Loans to Federal Home Loan Banks	0	200
Trading securities
Proceeds from maturities of long-term	215	13
Available-for-sale securities
Proceeds from sales and maturities of long-term	1,703	1,002
Purchases of long-term	(497)	(402)
Held-to-maturity securities
Proceeds from sales and maturities of long-term	344	457
Advances
Principal collected	149,512	142,862
Originated	(157,016)	(130,163)
Mortgage loans held for portfolio
Principal collected	445	516
Originated or purchased	(669)	(566)
Proceeds from sales of foreclosed assets	3	4
Net Cash Provided by (Used in) Investing Activities	(6,393)	16,339
FINANCING ACTIVITIES
Net change in deposits	(11)	(150)
Increase (Decrease) in Loans from Federal Home Loan Banks	(600)	0
Net payments on derivative contracts with financing elements	0	(2)
Net proceeds from issuance of consolidated obligations
Discount notes	91,697	118,084
Bonds	21,052	26,848
Payments for maturing and retiring consolidated obligations
Discount notes	(85,275)	(132,486)
Bonds	(21,303)	(27,575)
Proceeds from issuance of capital stock	4,015	2,905
Payments for repurchases/redemptions of capital stock	(3,624)	(3,171)
Net payments for repurchases/redemptions of mandatorily redeemable capital stock	(51)	(212)
Cash dividends paid	(109)	(88)
Net cash provided by (used in) financing activities	5,791	(15,847)
Net increase (decrease) in cash and due from banks	(302)	741
Cash and due from banks at the beginning of the period	503	223
cash and due from banks at the end of the period	201	964
SUPPLEMENTAL DISCLOSURES
Interest paid	1,249	769
Affordable Housing Program payments	16	15
Noncash Investing and Financing Items [Abstract]
Capitalized interest on reverse mortgage securities	39	27
Mortgage loan charge-offs	0	1
Transfers of mortgage loans to real estate owned	3	3
Capital stock reclassified to (from) mandatorily redeemable capital stock, net	$ 39	$ 28

Background Information

Background Information	6 Months Ended
	Jun. 30, 2018
Background Information [Abstract]
Nature of Operations [Text Block]	Background Information The Federal Home Loan Bank of Des Moines (the Bank) is a federally chartered corporation organized on October 31, 1932, that is exempt from all federal, state, and local taxation (except real property taxes) and is one of 11 district Federal Home Loan Banks (FHLBanks). The FHLBanks were created under the authority of the Federal Home Loan Bank Act of 1932 (FHLBank Act). With the passage of the Housing and Economic Recovery Act of 2008 (Housing Act), the Federal Housing Finance Agency (Finance Agency) was established and became the new independent federal regulator of Federal National Mortgage Association (Fannie Mae) and Federal Home Loan Mortgage Corporation (Freddie Mac) (collectively, Enterprises), as well as the FHLBanks and FHLBanks’ Office of Finance, effective July 30, 2008. The Finance Agency’s mission is to ensure that the Enterprises and FHLBanks operate in a safe and sound manner so that they serve as a reliable source of liquidity and funding for housing finance and community investment. The Finance Agency establishes policies and regulations governing the operations of the Enterprises and FHLBanks. Each FHLBank operates as a separate entity with its own management, employees, and board of directors. The FHLBanks are government-sponsored enterprises (GSEs) that serve the public by enhancing the availability of funds for residential mortgages and targeted community development. The Bank provides a readily available source of funding and liquidity to its member institutions and eligible housing associates in Alaska, Hawaii, Idaho, Iowa, Minnesota, Missouri, Montana, North Dakota, Oregon, South Dakota, Utah, Washington, Wyoming, and the U.S. Pacific territories of American Samoa, Guam, and the Commonwealth of the Northern Mariana Islands. Commercial banks, savings institutions, credit unions, insurance companies, and community development financial institutions (CDFIs) may apply for membership. State and local housing associates that meet certain statutory criteria may also borrow from the Bank; while eligible to borrow, housing associates are not members of the Bank and, as such, are not permitted to hold capital stock. The Bank is a cooperative. This means the Bank is owned by its customers, whom the Bank calls members. As a condition of membership in the Bank, all members must purchase and maintain membership capital stock based on a percentage of their total assets, subject to a minimum and maximum amount, as of the preceding December 31 st . Each member is also required to purchase and maintain activity-based capital stock to support certain business activities with the Bank. The Bank’s current and former members own all of the outstanding capital stock of the Bank. Former members own capital stock (included in mandatorily redeemable capital stock) to support business transactions still carried on the Bank’s Statements of Condition. All stockholders, including current and former members, may receive dividends on their capital stock investment to the extent declared by the Bank’s Board of Directors.

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation [Text Block]	Basis of Presentation The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information. Accordingly, they do not include all of the disclosures required by GAAP for annual financial statements and should be read in conjunction with the audited financial statements for the year ended December 31, 2017 , which are contained in the Bank’s 2017 Annual Report on Form 10-K filed with the SEC on March 12, 2018 ( 2017 Form 10-K). In the opinion of management, the unaudited financial information is complete and reflects all adjustments, consisting of normal recurring adjustments, necessary for a fair statement of results for the interim periods. The preparation of financial statements in accordance with GAAP requires management to make assumptions and estimates that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates. The results of operations for interim periods are not necessarily indicative of the results to be expected for the full year ending December 31, 2018. Reclassifications Certain amounts in the Bank’s 2017 financial statements and footnotes have been reclassified to conform to the presentation as of June 30, 2018 . In particular, due to the change in current presentation, variation margin on cleared derivatives has been allocated to the individual derivative instruments. Previously, this amount was included as a component of netting adjustments and cash collateral. For additional details regarding this reclassification, refer to “Note 10 — Derivatives and Hedging Activities.” SIGNIFICANT ACCOUNTING POLICIES There have been no material changes to the Bank’s significant accounting policies during the six months ended June 30, 2018 . Descriptions of all significant accounting policies are included in “Note 1 — Summary of Significant Accounting Policies” in the 2017 Form 10-K.

Recently Adopted and Issued Acc

Recently Adopted and Issued Accounting Guidance	6 Months Ended
	Jun. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Adopted and Issued Accounting Guidance [Text Block]	Recently Adopted and Issued Accounting Guidance ADOPTED ACCOUNTING GUIDANCE Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (ASU 2017-07) On March 10, 2017, the FASB issued amended guidance that requires an employer to disaggregate the service cost component from the other components of net periodic pension cost and net periodic postretirement benefit cost (net benefit cost). The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018 and was adopted retrospectively. The adoption of this guidance resulted in a reclassification of other net benefit costs from “Compensation and Benefits” to “Other Expense, Net” in the Bank’s Statements of Income. The adoption of this guidance did not have a material effect on the Bank’s financial condition, result of operations, or cash flows. Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15) On August 26, 2016, the FASB issued amendments to clarify guidance on the classification of certain cash receipts and payments in the statement of cash flows. This guidance is intended to reduce existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018 and was adopted retrospectively. The adoption of this guidance did not have a direct effect on the Bank’s financial condition, results of operations, or cash flows. However, the Bank did revise its previously reported supplemental interest paid disclosure to align with the clarified accounting guidance. Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) On January 5, 2016, the FASB issued amended guidance on certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. This guidance includes, but is not limited to, the following: • Requires equity investments (with certain exceptions) to be measured at fair value with changes in fair value recognized in income. • Requires an entity to present separately in other comprehensive income (OCI) the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. • Requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the statements of condition or the accompanying notes to the financial statements. • Eliminates the requirement for public entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the statements of condition. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018 and was adopted using the modified retrospective approach. The adoption of this guidance affected the Bank’s fair value disclosures. However, the guidance did not have any effect on the Bank’s financial condition, results of operations, or cash flows. Revenue from Contracts with Customers (ASU 2014-09) On May 28, 2014, the FASB issued guidance on revenue from contracts with customers. This guidance outlines a single comprehensive model for recognizing revenue arising from contracts with customers and supersedes most current revenue recognition guidance. In addition, this guidance amends the existing requirements for the recognition of a gain or loss on the transfer of non-financial assets that are not in a contract with a customer. This guidance applies to all contracts with customers except those that are within the scope of certain other standards, such as financial instruments, certain guarantees, insurance contracts, and lease contracts. The guidance provides entities with the option of using either of the following adoption methods: a full retrospective method, retrospectively to each prior reporting period presented; or a modified retrospective method, retrospectively with the cumulative effect of initially applying this guidance recognized at the date of initial application. On August 12, 2015, the FASB issued an amendment to defer the effective date of this guidance issued in May 2014 by one year. In 2016, the FASB issued additional amendments to clarify certain aspects of the new revenue guidance. However, these amendments did not change the core principle in the new revenue standard. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018, and was adopted retrospectively. Given that the majority of the Bank’s financial instruments and other contractual rights that generate revenue are covered by other U.S. GAAP, the adoption of this guidance did not have a material effect on the Bank’s financial condition, results of operations, and cash flows. ISSUED ACCOUNTING GUIDANCE Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12) On August 28, 2017, the FASB issued amended guidance to improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. This guidance requires that, for fair value hedges, the entire change in the fair value of the hedging instrument included in the assessment of hedge effectiveness be presented in the same income statement line that is used to present the earnings effect of the hedged item. For cash flow hedges, the entire change in the fair value of the hedging instrument included in the assessment of hedge effectiveness must be recorded in OCI. In addition, the amendments include certain targeted improvements to the assessment of hedge effectiveness and permit, among other things, the following: • Measurement of the change in fair value of the hedged item on the basis of the benchmark rate component of the contractual coupon cash flows determined at hedge inception. • Measurement of the hedged item in a partial-term fair value hedge of interest-rate risk by assuming the hedged item has a term that reflects only the designated cash flows being hedged. • Consideration only of how changes in the benchmark interest rate affect a decision to settle a prepayable instrument before its scheduled maturity in calculating the change in the fair value of the hedged item attributable to interest-rate risk. • For a cash flow hedge of interest-rate risk of a variable-rate financial instrument, an entity could designate as the hedged risk the variability in cash flows attributable to the contractually specified interest-rate. This guidance becomes effective for the Bank for the interim and annual periods beginning on January 1, 2019, and early adoption is permitted. For all cash flow hedges existing on the date of adoption, this guidance should be applied through a cumulative-effect adjustment to accumulated other comprehensive income (AOCI) with a corresponding adjustment to retained earnings as of the beginning of the year of adoption. The amended presentation and disclosure guidance is required only prospectively. The Bank does not intend to adopt this guidance early. The Bank is in the process of evaluating this guidance, and its effect on the Bank’s financial condition, results of operations, and cash flows has not yet been determined. Premium Amortization on Purchased Callable Debt Securities (ASU 2017-08) On March 30, 2017, the FASB issued guidance to shorten the amortization period for certain purchased callable debt securities held at a premium. Specifically, this guidance requires the premium to be amortized to the earliest call date. This guidance does not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. This guidance is effective for the Bank for the interim and annual periods beginning on January 1, 2019, and early adoption is permitted. This guidance should be applied using a modified retrospective method through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Bank does not intend to adopt this guidance early. The Bank has evaluated this guidance and its effect on the Bank’s financial condition, results of operations, and cash flows is not expected to be material. Measurement of Credit Losses on Financial Instruments (ASU 2016-13) On June 16, 2016, the FASB issued amended guidance for the accounting of credit losses on financial instruments. The amendments require entities to measure expected credit losses based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. The new guidance requires a financial asset, or a group of financial assets, measured at amortized cost to be presented at the net amount expected to be collected. The guidance also requires, among other things, the following: • The statement of income to reflect the measurement of credit losses for newly recognized financial assets, as well as the expected increases or decreases of expected credit losses that have taken place during the period. • Entities to determine the allowance for credit losses for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination (PCD) that are measured at amortized cost in a similar manner to other financial assets measured at amortized cost. The initial allowance for credit losses is required to be added to the purchase price of the assets acquired. • Entities to record credit losses relating to available-for-sale (AFS) debt securities through an allowance for credit losses. The amendments limit the allowance for credit losses to the amount by which fair value is below amortized cost. • Public entities to further disaggregate the current disclosure of credit quality indicators in relation to the amortized cost of financing receivables by the year of origination (i.e., vintage). This guidance is effective for the Bank for the interim and annual periods beginning on January 1, 2020. Early application is permitted as of the interim and annual reporting periods beginning after December 15, 2018. This guidance should be applied using a modified-retrospective approach, through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. In addition, entities are required to use a prospective transition approach for PCD assets upon adoption and for debt securities for which an other-than-temporary impairment had been recognized before the effective date. The Bank does not intend to adopt the new guidance early. While the Bank is in the process of evaluating this guidance, the Bank expects the adoption of the guidance may result in an increase in the allowance for credit losses and corresponding expense, including an allowance for debt securities, given the requirement to assess losses for the entire estimated life of the financial asset. The effect on the Bank’s financial condition, results of operations, and cash flows will depend upon the composition of financial assets held by the Bank at the adoption date as well as the economic conditions and forecasts at that time. Leases (ASU 2016-02) On February 25, 2016, the FASB issued guidance which requires recognition of lease assets and lease liabilities on the statement of condition and disclosure of key information about leasing arrangements. Specifically, this guidance requires a lessee, of operating or finance leases, to recognize on the statement of condition a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election not to recognize lease assets and lease liabilities. Under previous GAAP, a lessee was not required to recognize lease assets and lease liabilities arising from operating leases on the statement of condition. While this guidance does not fundamentally change lessor accounting, some changes have been made to align that guidance with the lessee guidance and other areas within GAAP. This guidance becomes effective for the Bank for the interim and annual periods beginning on January 1, 2019, and early application is permitted. In July 2018, the FASB issued amendments that, among other things, provide entities with an additional transition method to adopt the guidance. The new transition method allows entities an option to recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Bank does not intend to adopt this new guidance early. Upon adoption, the Bank expects to report higher assets and liabilities as a result of recording right-of-use assets and lease liabilities on its statements of condition. The Bank is in the process of evaluating this guidance, and its effect on the Bank’s financial condition, results of operations, and cash flows has not yet been determined.

Trading Securities

Trading Securities	6 Months Ended
	Jun. 30, 2018
Trading Securities [Member]
Investment Holdings [Line Items]
Investments in Debt and Marketable Equity Securities (and certain trading assets) [Text Block]	Trading Securities MAJOR SECURITY TYPES Trading securities were as follows (dollars in millions): June 30, December 31, Non-mortgage-backed securities U.S. obligations 1 $ 182 $ 197 GSE and Tennessee Valley Authority obligations 57 260 Other 2 265 272 Total non-mortgage-backed securities 504 729 Mortgage-backed securities GSE multifamily 433 448 Total fair value $ 937 $ 1,177 1 Represents investment securities backed by the full faith and credit of the U.S. Government. 2 Consists of taxable municipal bonds. NET GAINS (LOSSES) ON TRADING SECURITIES The Bank did not sell any trading securities during the three and six months ended June 30, 2018 and 2017 . During the three and six months ended June 30, 2018 , the Bank recorded net holding losses of $8 million and $24 million on its trading securities compared to net holding gains of $4 million and $9 million for the same periods in 2017 .

Available-for-Sale Securities

Available-for-Sale Securities	6 Months Ended
	Jun. 30, 2018
Available-for-sale Securities [Member]
Investment Holdings [Line Items]
Investments in Debt and Marketable Equity Securities (and certain trading assets) [Text Block]	Available-for-Sale Securities MAJOR SECURITY TYPES AFS securities we re as follows (dollars in millions): June 30, 2018 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities U.S. obligations 2 $ 2,808 $ 13 $ (1 ) $ 2,820 GSE and Tennessee Valley Authority obligations 1,001 38 — 1,039 State or local housing agency obligations 908 — (2 ) 906 Other 3 260 12 — 272 Total non-mortgage-backed securities 4,977 63 (3 ) 5,037 Mortgage-backed securities U.S. obligations single-family 2 4,065 33 (1 ) 4,097 GSE single-family 883 7 (5 ) 885 GSE multifamily 9,380 59 (7 ) 9,432 Total mortgage-backed securities 14,328 99 (13 ) 14,414 Total $ 19,305 $ 162 $ (16 ) $ 19,451 December 31, 2017 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities U.S. obligations 2 $ 3,096 $ 8 $ (5 ) $ 3,099 GSE and Tennessee Valley Authority obligations 1,197 39 — 1,236 State or local housing agency obligations 935 — (1 ) 934 Other 3 269 9 — 278 Total non-mortgage-backed securities 5,497 56 (6 ) 5,547 Mortgage-backed securities U.S. obligations single-family 2 3,716 11 (1 ) 3,726 GSE single-family 983 7 (2 ) 988 GSE multifamily 10,482 57 (4 ) 10,535 Total mortgage-backed securities 15,181 75 (7 ) 15,249 Total $ 20,678 $ 131 $ (13 ) $ 20,796 1 Amortized cost includes adjustments made to the cost basis of an investment for accretion, amortization, and/or fair value hedge accounting adjustments. 2 Represents investment securities backed by the full faith and credit of the U.S. Government. 3 Consists of taxable municipal bonds and/or Private Export Funding Corporation (PEFCO) bonds. UNREALIZED LOSSES The following tables summarize AFS securities with unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in millions). In cases where the gross unrealized losses for an investment category are less than $1 million, the losses are not reported. June 30, 2018 Less than 12 Months 12 Months or More Total Fair Unrealized Losses Fair Unrealized Losses Fair Unrealized Losses Non-mortgage-backed securities U.S. obligations 1 $ 316 $ — $ 338 $ (1 ) $ 654 $ (1 ) State or local housing agency obligations 13 — 594 (2 ) 607 (2 ) Total non-mortgage-backed securities 329 — 932 (3 ) 1,261 (3 ) Mortgage-backed securities U.S. obligations single-family 1 497 (1 ) — — 497 (1 ) GSE single-family 297 (5 ) 48 — 345 (5 ) GSE multifamily 2,653 (4 ) 859 (3 ) 3,512 (7 ) Total mortgage-backed securities 3,447 (10 ) 907 (3 ) 4,354 (13 ) Total $ 3,776 $ (10 ) $ 1,839 $ (6 ) $ 5,615 $ (16 ) December 31, 2017 Less than 12 Months 12 Months or More Total Fair Unrealized Losses Fair Unrealized Losses Fair Unrealized Losses Non-mortgage-backed securities U.S. obligations 1 $ 29 $ — $ 1,783 $ (5 ) $ 1,812 $ (5 ) State or local housing agency obligations 6 — 655 (1 ) 661 (1 ) Total non-mortgage-backed securities 35 — 2,438 (6 ) 2,473 (6 ) Mortgage-backed securities U.S. obligations single-family 1 111 — 887 (1 ) 998 (1 ) GSE single-family 222 (2 ) 53 — 275 (2 ) GSE multifamily 224 (1 ) 1,756 (3 ) 1,980 (4 ) Total mortgage-backed securities 557 (3 ) 2,696 (4 ) 3,253 (7 ) Total $ 592 $ (3 ) $ 5,134 $ (10 ) $ 5,726 $ (13 ) 1 Represents investment securities backed by the full faith and credit of the U.S. Government. CONTRACTUAL MATURITY The following table summarizes AFS securities by contractual maturity. Expected maturities of some securities may differ from contractual maturities as borrowers may have the right to call or prepay obligations with or without call or prepayment fees (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amortized Fair Value Amortized Fair Value Non-mortgage-backed securities Due in one year or less $ 26 $ 26 $ 158 $ 159 Due after one year through five years 969 976 750 755 Due after five years through ten years 3,160 3,181 3,574 3,583 Due after ten years 822 854 1,015 1,050 Total non-mortgage-backed securities 4,977 5,037 5,497 5,547 Mortgage-backed securities 14,328 14,414 15,181 15,249 Total $ 19,305 $ 19,451 $ 20,678 $ 20,796

Held-to-Maturity Securities

Held-to-Maturity Securities	6 Months Ended
	Jun. 30, 2018
Held-to-maturity Securities [Member]
Investment Holdings [Line Items]
Investments in Debt and Marketable Equity Securities (and certain trading assets) [Text Block]	Held-to-Maturity Securities MAJOR SECURITY TYPES Held-to-maturity (HTM) securities wer e as follows (dollars in millions): June 30, 2018 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities GSE and Tennessee Valley Authority obligations $ 391 $ 49 $ (2 ) $ 438 State or local housing agency obligations 427 1 (2 ) 426 Total non-mortgage-backed securities 818 50 (4 ) 864 Mortgage-backed securities U.S. obligations single-family 2 11 — — 11 U.S. obligations commercial 2 2 — — 2 GSE single-family 2,453 8 (24 ) 2,437 Private-label residential 11 — — 11 Total mortgage-backed securities 2,477 8 (24 ) 2,461 Total $ 3,295 $ 58 $ (28 ) $ 3,325 December 31, 2017 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities GSE and Tennessee Valley Authority obligations $ 393 $ 65 $ — $ 458 State or local housing agency obligations 454 2 (2 ) 454 Total non-mortgage-backed securities 847 67 (2 ) 912 Mortgage-backed securities U.S. obligations single-family 2 15 — — 15 U.S. obligations commercial 2 2 — — 2 GSE single-family 2,752 7 (14 ) 2,745 Private-label residential 12 — — 12 Total mortgage-backed securities 2,781 7 (14 ) 2,774 Total $ 3,628 $ 74 $ (16 ) $ 3,686 1 Amortized cost includes adjustments made to the cost basis of an investment for accretion or amortization. 2 Represents investment securities backed by the full faith and credit of the U.S. Government. UNREALIZED LOSSES The following tables summarize HTM securities with unrealized losses by major security type and the length of time that individual securities have been in a continuous unrealized loss position (dollars in millions). In cases where the gross unrealized losses for an investment category are less than $1 million, the losses are not reported. June 30, 2018 Less than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Non-mortgage-backed securities GSE and Tennessee Valley Authority obligations $ 90 $ (2 ) $ — $ — $ 90 $ (2 ) State or local housing agency obligations $ 17 $ — $ 162 $ (2 ) $ 179 $ (2 ) Total non-mortgage-backed securities 107 (2 ) 162 (2 ) 269 (4 ) Mortgage-backed securities U.S. obligations single-family 1 — — 5 — 5 — U.S. obligations commercial 1 1 — 1 — 2 — GSE single-family 12 — 1,200 (24 ) 1,212 (24 ) Private-label residential — — 7 — 7 — Total mortgage-backed securities 13 — 1,213 (24 ) 1,226 (24 ) Total $ 120 $ (2 ) $ 1,375 $ (26 ) $ 1,495 $ (28 ) December 31, 2017 Less than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Non-mortgage-backed securities State or local housing agency obligations $ 2 $ — $ 168 $ (2 ) $ 170 $ (2 ) Total non-mortgage-backed securities 2 — 168 (2 ) 170 (2 ) Mortgage-backed securities U.S. obligations single-family 1 7 — 1 — 8 — U.S. obligations commercial 1 1 — 1 — 2 — GSE single-family 42 — 1,427 (14 ) 1,469 (14 ) Private-label residential — — 8 — 8 — Total mortgage-backed securities 50 — 1,437 (14 ) 1,487 (14 ) Total $ 52 $ — $ 1,605 $ (16 ) $ 1,657 $ (16 ) 1 Represents investment securities backed by the full faith and credit of the U.S. Government. CONTRACTUAL MATURITY The following table summarizes HTM securities by contractual maturity. Expected maturities of some securities may differ from contractual maturities as borrowers may have the right to call or prepay obligations with or without call or prepayment fees (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amortized Fair Value Amortized Fair Value Non-mortgage-backed securities Due in one year or less $ 14 $ 14 $ 20 $ 20 Due after one year through five years 71 71 72 72 Due after five years through ten years 340 362 344 376 Due after ten years 393 417 411 444 Total non-mortgage-backed securities 818 864 847 912 Mortgage-backed securities 2,477 2,461 2,781 2,774 Total $ 3,295 $ 3,325 $ 3,628 $ 3,686

Other-Than-Temporary Impairment

Other-Than-Temporary Impairment	6 Months Ended
	Jun. 30, 2018
Other than Temporary Impairment Losses, Investments [Abstract]
Other-Than-Temporary Impairment [Text Block]	Other-Than-Temporary Impairment The Bank evaluates its individual AFS and HTM securities in an unrealized loss position for other-than-temporary impairment (OTTI) on a quarterly basis. As part of its evaluation of securities for OTTI, the Bank considers its intent to sell each debt security and whether it is more likely than not that it will be required to sell the security before its anticipated recovery. If either of these conditions is met, the Bank will recognize an OTTI charge to earnings equal to the entire difference between the security’s amortized cost basis and its fair value at the reporting date. For securities in an unrealized loss position that meet neither of these conditions, the Bank performs analyses to determine if any of these securities are other-than-temporarily impaired. The analysis of the Bank’s AFS and HTM investment securities in an unrealized loss position at June 30, 2018 is discussed below: • U.S. obligations and GSE and Tennessee Valley Authority obligations. The unrealized losses were due primarily to changes in interest rates and not to a significant deterioration in the fundamental credit quality of the obligations. The strength of the issuers’ guarantees through direct obligations or support from the U.S. Government was sufficient to protect the Bank from losses based on current expectations. The Bank expects to recover the amortized cost bases on these securities and neither intends to sell these securities nor considers it more likely than not that it will be required to sell these securities before recovery of their amortized cost bases. As such, the Bank did not consider these securities to be other-than-temporarily impaired at June 30, 2018 . • State or local housing agency obligations . The unrealized losses were due to changes in interest rates and illiquidity in the credit markets, and not to a significant deterioration in the fundamental credit quality of the obligations. The creditworthiness of the issuers and the strength of the underlying collateral and credit enhancements were sufficient to protect the Bank from losses based on current expectations. The Bank does not intend to sell these securities nor is it more likely than not that it will be required to sell these securities before recovery of their amortized cost bases. As such, the Bank did not consider these securities to be other-than-temporarily impaired at June 30, 2018 . • Private-label residential mortgage-backed securities. On a quarterly basis, the Bank engages other designated FHLBanks to perform cash flow analyses on its private-label mortgage-backed securities (private-label MBS). As of June 30, 2018 , the Bank compared the present value of cash flows expected to be collected with respect to its private-label MBS to the amortized cost bases of the securities to determine whether a credit loss existed. At June 30, 2018 , the Bank’s cash flow analyses for private-label MBS did not project any credit losses. The Bank does not intend to sell its private-label MBS nor is it more likely than not that the Bank will be required to sell its private-label MBS before recovery of their amortized cost bases. As a result, the Bank did not consider any of its private-label MBS to be other-than-temporarily impaired at June 30, 2018 .

Advances

Advances	6 Months Ended
	Jun. 30, 2018
Advances [Abstract]
Advances [Text Block]	Advances CONTRACTUAL MATURITY The following table summarizes the Bank’s advances outstanding by contractual maturity (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Amount Weighted Overdrawn demand deposit accounts $ 34 3.10 % $ 1 3.63 % Due in one year or less 52,016 2.16 45,310 1.62 Due after one year through two years 18,954 2.25 17,094 1.79 Due after two years through three years 20,620 2.31 14,222 1.64 Due after three years through four years 10,543 2.51 17,561 1.79 Due after four years through five years 3,918 2.51 3,089 1.91 Thereafter 4,097 2.83 5,401 2.28 Total par value 110,182 2.28 % 102,678 1.73 % Premiums 44 53 Discounts (10 ) (12 ) Fair value hedging adjustments (253 ) (106 ) Total $ 109,963 $ 102,613 The following table summarizes all advances by year of contractual maturity or next call date for callable advances, and by year of contractual maturity or next put date for putable advances (dollars in millions): Year of Contractual Maturity Year of Contractual Maturity or Next Put Date June 30, 2018 December 31, 2017 June 30, 2018 December 31, 2017 Overdrawn demand deposit accounts $ 34 $ 1 $ 34 $ 1 Due in one year or less 83,073 69,971 52,075 45,372 Due after one year through two years 11,161 16,539 18,954 17,094 Due after two years through three years 3,458 3,809 20,595 14,222 Due after three years through four years 7,746 8,511 10,533 17,520 Due after four years through five years 1,895 1,276 3,909 3,073 Thereafter 2,815 2,571 4,082 5,396 Total par value $ 110,182 $ 102,678 $ 110,182 $ 102,678 The Bank offers advances to members and eligible housing associates that may be prepaid on pertinent dates (call dates) prior to maturity without incurring prepayment fees (callable advances). Other advances may require a prepayment fee or credit that makes the Bank financially indifferent to the prepayment of the advance. At June 30, 2018 and December 31, 2017 , the Bank had callable advances outstanding totaling $39.6 billion and $27.0 billion . The Bank also offers putable advances. With a putable advance, the Bank has the right to terminate the advance from the borrower on the predetermined exercise dates. Generally, these put options are exercised when interest rates increase relative to contractual rates. At June 30, 2018 and December 31, 2017 , t he Bank had putable advances outstanding totaling $89 million and $405 million . PREPAYMENT FEES The Bank generally charges a prepayment fee for advances that a borrower elects to terminate prior to the stated maturity or outside of a predetermined call or put date. The fees charged are priced to make the Bank financially indifferent to the prepayment of the advance. For certain advances with symmetrical prepayment features, the Bank may charge the borrower a prepayment fee or pay the borrower a prepayment credit, depending on certain circumstances, such as movements in interest rates, when the advance is prepaid. Prepayment fees and credits are recorded net of fair value hedging adjustments in advance income in the Statements of Income. During the three and six months ended June 30, 2018 , the Bank recorded prepayment fees on advances, net of $1 million and $6 million compared to $1 million for both of the same periods in 2017 . CREDIT RISK EXPOSURE AND SECURITY TERMS The Bank’s potential credit risk from advances is concentrated in commercial banks, savings institutions, and insurance companies. At June 30, 2018 and December 31, 2017 , the Bank had outstanding advances of $51.0 billion and $45.8 billion to one member that individually held 10 percent or more of the Bank’s advances, which represents 46 percent and 45 percent of total outstanding advances. For information related to the Bank’s credit risk exposure on advances, refer to “Note 9 — Allowance for Credit Losses.”

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	6 Months Ended
	Jun. 30, 2018
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portfolio [Text Block]	Mortgage Loans Held for Portfolio Mortgage loans held for portfolio includes conventional mortgage loans or government-guaranteed or -insured mortgage loans obtained through the Mortgage Partnership Finance (MPF) program (Mortgage Partnership Finance and MPF are registered trademarks of the FHLBank of Chicago) or Mortgage Purchase Program (MPP). The MPF program, which represents 96 percent of the Bank’s mortgage loans held for portfolio, involves investment by the Bank in single-family mortgage loans held for portfolio that are either purchased from participating financial institutions (PFIs) or funded by the Bank through PFIs. MPF loans may also be acquired through participations in pools of eligible mortgage loans purchased from other FHLBanks. The Bank’s MPF PFIs generally originate, service, and credit enhance mortgage loans that are sold to the Bank. MPF PFIs participating in the servicing release program do not service the loans owned by the Bank. The servicing on these loans is sold concurrently by the MPF PFI to a designated mortgage service provider. Under the MPP, the Bank acquired single-family mortgage loans that were purchased directly from MPP PFIs. Similar to the MPF program, MPP PFIs generally originated, serviced, and credit enhanced the mortgage loans sold to the Bank. The MPP program represents four percent of the Bank’s mortgage loans held for portfolio. The Bank does not currently purchase mortgage loans under this program. All loans in this portfolio were originated prior to 2006. The following table presents information on the Bank’s mortgage loans held for portfolio (dollars in millions): June 30, 2018 December 31, 2017 Fixed rate, long-term single-family mortgage loans $ 6,281 $ 5,998 Fixed rate, medium-term 1 single-family mortgage loans 934 1,003 Total unpaid principal balance 7,215 7,001 Premiums 99 98 Discounts (6 ) (6 ) Basis adjustments from mortgage loan commitments 3 5 Total mortgage loans held for portfolio 7,311 7,098 Allowance for credit losses (1 ) (2 ) Total mortgage loans held for portfolio, net $ 7,310 $ 7,096 1 Medium-term is defined as a term of 15 years or less. The following table presents the Bank’s mortgage loans held for portfolio by collateral or guarantee type (dollars in millions): June 30, 2018 December 31, 2017 Conventional mortgage loans $ 6,699 $ 6,472 Government-insured mortgage loans 516 529 Total unpaid principal balance $ 7,215 $ 7,001 For information related to the Bank’s credit risk exposure on mortgage loans held for portfolio, refer to “Note 9 — Allowance for Credit Losses.”

Allowance for Credit Losses

Allowance for Credit Losses	6 Months Ended
	Jun. 30, 2018
Allowance for Credit Losses [Abstract]
Allowance for Credit Losses [Text Block]	Allowance for Credit Losses The Bank has established an allowance for credit losses methodology for each of its financing receivable portfolio segments: advances, standby letters of credit, and other extensions of credit to borrowers (collectively, credit products), government-insured mortgage loans held for portfolio, MPF and MPP conventional mortgage loans held for portfolio, and term securities purchased under agreements to resell. CREDIT PRODUCTS The Bank manages its credit exposure to credit products through an approach that includes establishing a credit limit for each borrower. This approach includes an ongoing review of each borrower’s financial condition in conjunction with the Bank’s collateral and lending policies to limit risk of loss while balancing borrowers’ needs for a reliable source of funding. In addition, the Bank lends to eligible borrowers in accordance with the FHLBank Act, Finance Agency regulations, and other applicable laws. The Bank is required by regulation to obtain sufficient collateral to fully secure credit products. The estimated value of the collateral required to secure each borrower’s credit products is calculated by applying collateral discounts, or haircuts, to the unpaid principal balance or market value, if available, of the collateral. Eligible collateral includes (i) fully disbursed whole first mortgages on improved residential real property or securities representing a whole interest in such mortgages, (ii) loans and securities issued, insured, or guaranteed by the U.S. Government or any agency thereof, including mortgage-backed securities (MBS) issued or guaranteed by Fannie Mae, Freddie Mac, or Government National Mortgage Association and Federal Family Education Loan Program guaranteed student loans, (iii) cash deposited with the Bank, and (iv) other real estate-related collateral acceptable to the Bank, such as second lien mortgages, home equity lines of credit, tax-exempt municipal securities, and commercial real estate mortgages, provided such collateral has a readily ascertainable value and the Bank can perfect a security interest in such property. In addition, community financial institutions may also pledge collateral consisting of secured small business, small agri-business, or small farm loans. As additional security, the FHLBank Act provides that the Bank has a lien on each member’s capital stock investment; however, capital stock cannot be pledged as collateral to secure credit exposures. Collateral arrangements may vary depending upon borrower credit quality, financial condition and performance, borrowing capacity, and overall credit exposure to the borrower. The Bank can also require additional or substitute collateral to protect its security interest. The Bank periodically evaluates and makes changes to its collateral guidelines and collateral haircuts. Borrowers may pledge collateral to the Bank by executing a blanket pledge agreement, specifically assigning collateral, or placing physical possession of collateral with the Bank or its custodians. The Bank perfects its security interest in all pledged collateral by filing Uniform Commercial Code financing statements or by taking possession or control of the collateral. Under the FHLBank Act, any security interest granted to the Bank by its members, or any affiliates of its members, has priority over the claims and rights of any party (including any receiver, conservator, trustee, or similar party having rights of a lien creditor), unless those claims and rights would be entitled to priority under otherwise applicable law and are held by actual purchasers or by parties that have perfected security interests. Under a blanket pledge agreement, the Bank is granted a security interest in all financial assets of the borrower to fully secure the borrower’s obligation. Other than securities and cash deposits, the Bank does not initially take delivery of collateral from blanket agreement borrowers. In the event of deterioration in the financial condition of a blanket pledge agreement, the Bank has the ability to require delivery of pledged collateral sufficient to secure the borrower’s obligation. With respect to non-blanket pledge agreement borrowers that are federally insured, the Bank generally requires collateral to be specifically assigned. With respect to non-blanket pledge agreement borrowers that are not federally insured (typically insurance companies, CDFIs, and housing associates), the Bank generally takes control of collateral through the delivery of cash, securities, or loans to the Bank or its custodians. Using a risk-based approach and taking into consideration each borrower’s financial strength, the Bank considers the types and level of collateral to be the primary indicator of credit quality on its credit products. At June 30, 2018 and December 31, 2017 , the Bank had rights to collateral on a borrower-by-borrower basis with an unpaid principal balance or market value, if available, in excess of its outstanding extensions of credit. At June 30, 2018 and December 31, 2017 , none of the Bank’s credit products were past due, on non-accrual status, or considered impaired. In addition, there were no troubled debt restructurings (TDRs) related to credit products during the six months ended June 30, 2018 and 2017 . The Bank has never experienced a credit loss on its credit products. Based upon the Bank’s collateral and lending policies, the collateral held as security, and the repayment history on credit products, management has determined that there were no probable credit losses on its credit products as of June 30, 2018 and December 31, 2017 . Accordingly, the Bank has not recorded any allowance for credit losses for its credit products. GOVERNMENT-INSURED MORTGAGE LOANS The Bank invests in government-insured fixed rate mortgage loans in both the MPF and MPP portfolios that are insured or guaranteed by the Federal Housing Administration, the Department of Veterans Affairs, and/or the Rural Housing Service of the Department of Agriculture. The servicer or PFI obtains and maintains insurance or a guaranty from the applicable government agency. The servicer or PFI is responsible for compliance with all government agency requirements and for obtaining the benefit of the applicable guarantee or insurance with respect to defaulted government-insured mortgage loans. Any losses incurred on these loans that are not recovered from the insurer/guarantor are absorbed by the servicers. As such, the Bank only has credit risk for these loans if the servicer or PFI fails to pay for losses not covered by the guarantee or insurance. Management views this risk as remote and has never experienced a credit loss on its government-insured mortgage loans. As a result, the Bank did not establish an allowance for credit losses for its government-insured mortgage loans at June 30, 2018 and December 31, 2017 . Furthermore, none of these mortgage loans have been placed on non-accrual status because of the U.S. Government guarantee or insurance on these loans and the contractual obligation of the loan servicer to repurchase the loans when certain criteria are met. CONVENTIONAL MORTGAGE LOANS The Bank’s management of credit risk in the MPF and MPP programs involves several layers of legal loss protection that are defined in agreements among the Bank and its participating PFIs. These loss layers may vary depending on the product alternatives selected and credit profile of the loans. The Bank’s loss protection consists of the following loss layers, in order of priority: • Homeowner Equity. • Primary Mortgage Insurance (PMI). At the time of origination, PMI is required on all loans with homeowner equity of less than 20 percent of the original purchase price or appraised value, whichever is less and as applicable to the specific loan. • First Loss Account (FLA). For each MPF master commitment, the Bank’s potential loss exposure prior to the PFI’s credit enhancement obligation is estimated and tracked in a memorandum account called the FLA. • Credit Enhancement Obligation of PFI. PFIs have a credit enhancement obligation at the time an MPF mortgage loan is purchased to absorb certain losses in excess of the FLA in order to limit the Bank’s loss exposure to that of an investor in an investment grade MBS. PFIs pledge collateral to secure this obligation. Allowance Methodology The Bank utilizes an allowance for credit losses to reserve for estimated losses in its conventional MPF and MPP mortgage loan portfolios at the balance sheet date. The measurement of the Bank’s MPF and MPP allowance for credit losses is determined by the following: • reviewing similar conventional mortgage loans for impairment on a collective basis. This evaluation is primarily based on the following factors: (i) current loan delinquencies, (ii) loans migrating to collateral-dependent status, and (iii) actual historical loss severities; • reviewing conventional mortgage loans for impairment on an individual basis; and • estimating additional credit losses in the conventional mortgage loan portfolio. These losses result from other factors that may not be captured in the methodology previously described at the balance sheet date, which include but are not limited to certain quantifiable economic factors, such as unemployment rates and home prices impacting housing markets. The following table summarizes the allowance for credit losses and the recorded investment of the Bank’s conventional mortgage loan portfolio by impairment methodology (dollars in millions): June 30, 2018 December 31, 2017 Allowance for credit losses Collectively evaluated for impairment $ 1 $ 2 Recorded investment 1 Collectively evaluated for impairment $ 6,759 $ 6,530 Individually evaluated for impairment, without a related allowance 59 61 Total recorded investment $ 6,818 $ 6,591 1 Represents the unpaid principal balance adjusted for accrued interest, unamortized premiums, discounts, basis adjustments, and direct write-downs. CREDIT QUALITY INDICATORS Key credit quality indicators for mortgage loans include the migration of past due loans, loans in process of foreclosure, and non-accrual loans. The tables below summarize the Bank’s key credit quality indicators for mortgage loans (dollars in millions): June 30, 2018 Conventional MPF/MPP Government-Guaranteed or -Insured 6 Total Past due 30 - 59 days $ 44 $ 18 $ 62 Past due 60 - 89 days 13 6 19 Past due 90 - 179 days 10 3 13 Past due 180 days or more 16 4 20 Total past due mortgage loans 83 31 114 Total current mortgage loans 6,735 499 7,234 Total recorded investment of mortgage loans 1 $ 6,818 $ 530 $ 7,348 In process of foreclosure (included above) 2 $ 11 $ 2 $ 13 Serious delinquency rate 3 — % 1 % — % Past due 90 days or more and still accruing interest 4 — $ 7 $ 7 Non-accrual mortgage loans 5 $ 40 $ — $ 40 1 Represents the unpaid principal balance adjusted for accrued interest, unamortized premiums, discounts, basis adjustments, and direct write-downs. 2 Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu has been reported. Loans in process of foreclosure are included in past due or current loans depending on their payment status. 3 Represents mortgage loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the total recorded investment. 4 Represents government-insured mortgage loans that are 90 days or more past due. 5 Represents conventional mortgage loans that are 90 days or more past due and TDRs. 6 The Bank did not record any allowance for credit losses on government-guaranteed or -insured mortgage loans at June 30, 2018 and December 31, 2017 . December 31, 2017 Conventional MPF/MPP Government- Guaranteed or -Insured 6 Total Past due 30 - 59 days $ 58 $ 19 $ 77 Past due 60 - 89 days 16 6 22 Past due 90 - 179 days 15 5 20 Past due 180 days or more 21 6 27 Total past due mortgage loans 110 36 146 Total current mortgage loans 6,481 507 6,988 Total recorded investment of mortgage loans 1 $ 6,591 $ 543 $ 7,134 In process of foreclosure (included above) 2 $ 12 $ 2 $ 14 Serious delinquency rate 3 1 % 2 % 1 % Past due 90 days or more and still accruing interest 4 $ — $ 11 $ 11 Non-accrual mortgage loans 5 $ 48 $ — $ 48 1 Represents the unpaid principal balance adjusted for accrued interest, unamortized premiums, discounts, basis adjustments, and direct write-downs. 2 Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu has been reported. Loans in process of foreclosure are included in past due or current loans depending on their payment status. 3 Represents mortgage loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the total recorded investment. 4 Represents government-insured mortgage loans that are 90 days or more past due. 5 Represents conventional mortgage loans that are 90 days or more past due and TDRs. 6 The Bank did not record any allowance for credit losses on government-guaranteed or -insured mortgage loans at June 30, 2018 and December 31, 2017 . INDIVIDUALLY EVALUATED IMPAIRED LOANS As previously described, the Bank evaluates certain conventional mortgage loans for impairment individually. A loan is considered impaired when, based on current information and events, it is probable that the Bank will be unable to collect all amounts due according to the contractual terms of the loan agreement. The Bank did no t recognize any interest income on impaired loans during the three and six months ended June 30, 2018 and 2017 . During both the three and six months ended June 30, 2018 , the average recorded investment of conventional impaired loans without an allowance was $60 million as compared to $68 million and $69 million for the same periods in 2017 . TERM SECURITIES PURCHASED UNDER AGREEMENTS TO RESELL Term securities purchased under agreements to resell are considered collateralized financing agreements and represent short-term investments. The terms of these investments are structured such that if the market value of the underlying securities decreases below the market value required as collateral, the counterparty must place an equivalent amount of additional securities as collateral or remit an equivalent amount of cash. Otherwise, the dollar value of the resale agreement will decrease accordingly. If an agreement to resell is deemed to be impaired, the difference between the fair value of the collateral and the amortized cost of the agreement will be charged to earnings to establish an allowance for credit losses. Based upon the collateral held as security, the Bank determined that no allowance for credit losses was needed for its term securities purchased under agreements to resell at June 30, 2018 and December 31, 2017 . OFF-BALANCE SHEET CREDIT EXPOSURES At June 30, 2018 and December 31, 2017 , the Bank did not record a liability to reflect an allowance for credit losses for off-balance sheet credit exposures. For additional information on the Bank’s off-balance sheet credit exposures, see “Note 14 — Commitments and Contingencies.”

Derivatives and Hedging Activit

Derivatives and Hedging Activities	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities NATURE OF BUSINESS ACTIVITY The Bank is exposed to interest rate risk primarily from the effect of interest rate changes on its interest-earning assets and its related funding sources. The goal of the Bank’s interest rate risk management strategy is not to eliminate interest rate risk, but to manage it within appropriate limits. To mitigate the risk of loss, the Bank has established policies and procedures, which include guidelines on the amount of exposure to interest rate changes it is willing to accept. The Bank enters into derivative contracts to manage the interest rate risk exposures inherent in its otherwise unhedged assets and funding positions. Finance Agency regulations and the Bank’s Enterprise Risk Management Policy (ERMP) establish guidelines for derivatives, prohibit trading in or the speculative use of derivatives, and limit credit risk arising from derivatives. Derivative financial instruments are used by the Bank to achieve its financial and risk management objectives. The Bank reevaluates its hedging strategies from time to time and may change the hedging techniques it uses or may adopt new strategies. The most common ways in which the Bank uses derivatives are to: • reduce the interest rate sensitivity and repricing gaps of assets and liabilities; • preserve an interest rate spread between the yield of an asset and the cost of the related liability. Without the use of derivatives, this interest rate spread could be reduced or eliminated when a change in the interest rate on the asset does not match a change in the interest rate on the liability; • mitigate the adverse earnings effects of the shortening or extension of certain assets and liabilities; • manage embedded options in assets and liabilities; and • reduce funding costs by combining a derivative with a consolidated obligation, as the cost of a combined funding structure can be lower than the cost of a comparable consolidated obligation. APPLICATION OF DERIVATIVES The Bank transacts most of its derivative transactions with large banks and major broker-dealers. Over-the-counter derivative transactions may be either executed directly with a counterparty (uncleared derivatives) or cleared through a Futures Commission Merchant (i.e., clearings agent) with a Derivative Clearinghouse Organization (cleared derivatives). Once a derivative transaction has been accepted for clearing by the Derivative Clearinghouse Organization (Clearinghouse), the derivative transaction is novated and the executing counterparty is replaced with the Clearinghouse. The Bank is not a derivative dealer and does not trade derivatives for a short-term profit. TYPES OF DERIVATIVES The Bank may use the following derivative instruments: • interest rate swaps; • options; • swaptions; • interest rate caps and floors; and • futures/forwards contracts. The Bank may have the following types of hedged items: • investment securities; • advances; • mortgage loans; • consolidated obligations; and • firm commitments. For additional information on the Bank’s derivative and hedging accounting policy, see “Note 1 — Summary of Significant Accounting Policies” in the 2017 Form 10-K. FINANCIAL STATEMENT EFFECT AND ADDITIONAL FINANCIAL INFORMATION The notional amount of derivatives serves as a factor in determining periodic interest payments and cash flows received and paid. However, the notional amount of derivatives represents neither the actual amounts exchanged nor the overall exposure of the Bank to credit and market risk. The risks of derivatives can be measured meaningfully on a portfolio basis that takes into account the counterparties, the types of derivatives, the items being hedged, and any offsets between the derivatives and the items being hedged. The following table summarizes the Bank’s notional amount and fair value of derivative instruments and total derivative assets and liabilities. Total derivative assets and liabilities include the effect of netting adjustments and cash collateral. For purposes of this disclosure, the derivative values include the fair value of derivatives and the related accrued interest (dollars in millions): June 30, 2018 December 31, 2017 1 Notional Amount Derivative Assets Derivative Liabilities Notional Amount Derivative Assets Derivative Liabilities Derivatives designated as hedging instruments (fair value hedges) Interest rate swaps $ 46,828 $ 125 $ 105 $ 52,120 $ 77 $ 151 Derivatives not designated as hedging instruments (economic hedges) Interest rate swaps 1,372 29 21 1,407 20 37 Forward settlement agreements (TBAs) 167 — 1 66 — — Mortgage delivery commitments 172 — — 72 — — Total derivatives not designated as hedging instruments 1,711 29 22 1,545 20 37 Total derivatives before netting and collateral adjustments $ 48,539 154 127 $ 53,665 97 188 Netting adjustments and cash collateral 2 (71 ) (125 ) 3 (182 ) Total derivative assets and derivative liabilities $ 83 $ 2 $ 100 $ 6 1 To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017. Previously, this amount was included with netting adjustments and cash collateral. 2 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. At June 30, 2018 and December 31, 2017 , cash collateral posted by the Bank (including accrued interest) was $128 million and $191 million . At June 30, 2018 and December 31, 2017 , the Bank received cash collateral (including accrued interest) from clearing agents and/or counterparties of $73 million and $6 million . The following table summarizes the components of “Net gains (losses) on derivatives and hedging activities” as presented in the Statements of Income (dollars in millions): For the Three Months Ended For the Six Months Ended June 30, June 30, 2018 2017 2018 2017 Derivatives designated as hedging instruments (fair value hedges) Interest rate swaps $ 7 $ 6 $ 7 $ 10 Derivatives not designated as hedging instruments (economic hedges) Interest rate swaps 7 (6 ) 28 (1 ) Forward settlement agreements (TBAs) 1 — 2 (1 ) Mortgage delivery commitments — — (1 ) 1 Net interest settlements (1 ) (3 ) (3 ) (7 ) Total net gains (losses) related to derivatives not designated as hedging instruments 7 (9 ) 26 (8 ) Other 1 — — 1 1 Net gains (losses) on derivatives and hedging activities $ 14 $ (3 ) $ 34 $ 3 1 Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settled contract. The following tables summarize, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair value hedging relationships, the net fair value hedge ineffectiveness, and the effect of those derivatives on the Bank’s net interest income (dollars in millions): For the Three Months Ended June 30, 2018 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ 55 $ (48 ) $ 7 $ (6 ) Advances 2 31 (29 ) 2 13 Consolidated obligation bonds — (2 ) (2 ) (62 ) Total $ 86 $ (79 ) $ 7 $ (55 ) For the Three Months Ended June 30, 2017 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ (41 ) $ 49 $ 8 $ (24 ) Advances 2 (25 ) 26 1 (21 ) Consolidated obligation bonds 72 (75 ) (3 ) 7 Total $ 6 $ — $ 6 $ (38 ) 1 Represents the net interest settlements on derivatives in fair value hedge relationships and the amortization of the financing element of off-market derivatives, both of which are included in the interest income or interest expense line item of the respective hedged item type. During the three months ended June 30, 2018 and 2017 , the amortization for off-market derivatives totaled less than $1 million and $4 million. 2 Includes net gains (losses) on fair value hedge firm commitments of forward starting advances. The following tables summarize, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair value hedging relationships, the net fair value hedge ineffectiveness, and the effect of those derivatives on the Bank’s net interest income (dollars in millions): For the Six Months Ended June 30, 2018 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ 207 $ (203 ) $ 4 $ (19 ) Advances 2 156 (154 ) 2 12 Consolidated obligation bonds (154 ) 155 1 (94 ) Total $ 209 $ (202 ) $ 7 $ (101 ) For the Six Months Ended June 30, 2017 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ (4 ) $ 18 $ 14 $ (53 ) Advances 2 8 (6 ) 2 (45 ) Consolidated obligation bonds 22 (28 ) (6 ) 26 Total $ 26 $ (16 ) $ 10 $ (72 ) 1 Represents the net interest settlements on derivatives in fair value hedge relationships and the amortization of the financing element of off-market derivatives, both of which are included in the interest income or interest expense line item of the respective hedged item type. During the six months ended June 30, 2018 and 2017, the amortization for off-market derivatives totaled less than $1 million and $9 million. 2 Includes net gains (losses) on fair value hedge firm commitments of forward starting advances. MANAGING CREDIT RISK ON DERIVATIVES The Bank is subject to credit risk due to the risk of nonperformance by counterparties to its derivative contracts. The Bank manages credit risk through credit analyses, collateral requirements, and adherence to the requirements set forth in the Bank’s policies, U.S. Commodity Futures Trading Commission regulations, and Finance Agency regulations. For uncleared derivatives, the degree of credit risk depends on the extent to which master netting arrangements are included in these contracts to mitigate the risk. The Bank requires collateral agreements on its uncleared derivatives. Certain of the Bank’s uncleared derivative instruments contain provisions that require the Bank to post additional collateral with its counterparties if there is deterioration in the Bank’s credit rating. If the Bank’s credit rating is lowered by a nationally recognized statistical rating organization (NRSRO), the Bank may be required to deliver additional collateral on uncleared derivative instruments in net liability positions, unless the collateral delivery threshold is set to zero. The aggregate fair value of all uncleared derivative instruments with credit-risk related contingent features that were in a net liability position (before cash collateral and related accrued interest) at June 30, 2018 was $1 million , for which the Bank was not required to post collateral in the normal course of business. If the Bank’s credit rating had been lowered from its current rating to the next lower rating, the Bank would not have been required to deliver additional collateral to its uncleared derivative counterparties at June 30, 2018 . For cleared derivatives, the Clearinghouse is the Bank’s counterparty. The Clearinghouse notifies the clearing agent of the required initial and variation margin and the clearing agent in turn notifies the Bank. The Bank utilizes one Clearinghouse for all cleared derivative transactions, CME Clearing. Variation margin payments with CME Clearing are legally characterized as daily settlement payments, rather than collateral. Initial margin is considered cash collateral. The requirement that the Bank post initial and variation margin through the clearing agent, to the Clearinghouse, exposes the Bank to institutional credit risk if the clearing agent or the Clearinghouse fails to meet its obligations. The use of cleared derivatives is intended to mitigate credit risk exposure because a central counterparty is substituted for individual counterparties and collateral/payments for changes in the fair value of cleared derivatives is posted daily through a clearing agent. The Clearinghouse determines initial margin requirements and generally credit ratings are not factored into the initial margin. However, clearing agents may require additional initial margin to be posted based on credit considerations, including, but not limited to, credit rating downgrades. The Bank was not required to post additional initial margin by its clearing agents, based on credit considerations at June 30, 2018 . OFFSETTING OF DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES The Bank presents derivative instruments, related cash collateral, including initial margin, received or pledged, and associated accrued interest on a net basis by clearing agent and/or by counterparty when it has met the netting requirements. Additional information regarding these agreements is provided in “Note 1 — Summary of Significant Accounting Policies” in the 2017 Form 10-K. The Bank has analyzed the enforceability of offsetting rights incorporated in its cleared derivative transactions and has determined that the exercise of those offsetting rights by a non-defaulting party under these transactions should be upheld under applicable law upon an event of default, including a bankruptcy, insolvency, or similar proceeding involving the Clearinghouse or the clearing agent, or both. Based on this analysis, the Bank presents a net derivative receivable or payable for all of its transactions through a particular clearing agent with a particular Clearinghouse. The following table presents the fair value of derivative instruments meeting or not meeting the netting requirements and the related collateral received from or pledged to counterparties (dollars in millions): June 30, 2018 Derivative Instruments Meeting Netting Requirements Amount Recognized Gross Amount of Netting Adjustments and Cash Collateral Total Derivative Assets and Total Derivative Liabilities Derivative Assets Uncleared derivatives $ 151 $ (150 ) $ 1 Cleared derivatives 3 79 82 Total $ 154 $ (71 ) $ 83 Derivative Liabilities Uncleared derivatives $ 120 $ (118 ) $ 2 Cleared derivatives 7 (7 ) — Total $ 127 $ (125 ) $ 2 December 31, 2017 Derivative Instruments Meeting Netting Requirements Amount Recognized 1 Gross Amount of Netting Adjustments and Cash Collateral Total Derivative Assets and Total Derivative Liabilities Derivative Assets Uncleared derivatives $ 88 $ (87 ) $ 1 Cleared derivatives 9 90 99 Total $ 97 $ 3 $ 100 Derivative Liabilities Uncleared derivatives $ 170 $ (164 ) $ 6 Cleared derivatives 18 (18 ) — Total $ 188 $ (182 ) $ 6 1 To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with gross amount of netting adjustments and cash collateral.

Consolidated Obligations

Consolidated Obligations	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Consolidated Obligations [Text Block]	Consolidated Obligations Consolidated obligations consist of bonds and discount notes. The FHLBanks issue consolidated obligations through the Office of Finance as their agent. Bonds are issued primarily to raise intermediate- and long-term funds for the Bank and are not subject to any statutory or regulatory limits on their maturity. Discount notes are issued primarily to raise short-term funds for the Bank and have original maturities of up to one year. Discount notes sell at or below their face amount and are redeemed at par value when they mature. Although the Bank is primarily liable for the portion of consolidated obligations issued on its behalf, it is also jointly and severally liable with the other FHLBanks for the payment of principal and interest on all FHLBank System consolidated obligations. The Finance Agency, at its discretion, may require any FHLBank to make principal and/or interest payments due on any consolidated obligation, whether or not the primary obligor FHLBank has defaulted on the payment of that consolidated obligation. The Finance Agency has never exercised this discretionary authority. At June 30, 2018 and December 31, 2017 , the total par value of outstanding consolidated obligations of the FHLBanks was $1,059.9 billion and $1,034.2 billion . DISCOUNT NOTES The following table summarizes the Bank’s discount notes (dollars in millions): June 30, 2018 December 31, 2017 Amount Weighted Average Interest Rate Amount Weighted Average Interest Rate Par value $ 43,241 1.87 % $ 36,740 1.20 % Discounts and concessions 1 (119 ) (58 ) Total $ 43,122 $ 36,682 1 Concessions represent fees paid to dealers in connections with the issuance of certain consolidated obligation discount notes. BONDS The following table summarizes the Bank’s bonds outstanding by contractual maturity (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Average Interest Rate Amount Weighted Average Interest Rate Due in one year or less $ 57,307 1.87 % $ 50,077 1.32 % Due after one year through two years 24,341 1.90 32,249 1.43 Due after two years through three years 3,034 2.59 3,177 2.84 Due after three years through four years 7,207 1.71 7,422 1.69 Due after four years through five years 2,124 2.31 1,507 2.42 Thereafter 4,917 3.37 4,752 3.10 Total par value 98,930 1.97 % 99,184 1.54 % Premiums 168 193 Discounts and concessions 1 (52 ) (60 ) Fair value hedging adjustments (578 ) (424 ) Total $ 98,468 $ 98,893 1 Concessions represent fees paid to dealers in connections with the issuance of certain consolidated obligation bonds. The following table summarizes the Bank’s bonds outstanding by call features (dollars in millions): June 30, December 31, Non-callable or non-putable $ 94,742 $ 97,196 Callable 4,188 1,988 Total par value $ 98,930 $ 99,184

Capital

Capital	6 Months Ended
	Jun. 30, 2018
Capital [Abstract]
Capital [Text Block]	Capital CAPITAL STOCK The Bank’s capital stock has a par value of $100 per share, and all shares are issued, redeemed, and repurchased only at the stated par value. The Bank generally issues a single class of capital stock (Class B stock) and has two subclasses of capital stock: membership and activity-based. Each member must purchase and hold membership capital stock in an amount equal to 0.12 percent of its total assets as of the preceding December 31 st , subject to a cap of $10 million and a floor of $10,000 . Each member is also required to purchase activity-based capital stock equal to 4.00 percent of its advances and mortgage loans outstanding in the Bank’s Statements of Condition. All capital stock issued is subject to a five year notice of redemption period. The capital stock requirements established in the Bank’s Capital Plan are designed so that the Bank can remain adequately capitalized as member activity changes. The Bank’s Board of Directors may make adjustments to the capital stock requirements within ranges established in the Capital Plan. EXCESS STOCK Capital stock owned by members in excess of their investment requirement is deemed excess capital stock. Under its Capital Plan, the Bank, at its discretion and upon 15 days’ written notice, may repurchase excess membership capital stock. The Bank, at its discretion, may also repurchase excess activity-based capital stock to the extent that (i) the excess capital stock balance exceeds an operational threshold set forth in the Capital Plan, which is currently set at zero, or (ii) a member submits a notice to redeem all or a portion of the excess activity-based capital stock. At June 30, 2018 and December 31, 2017 , the Bank’s excess capital stock outstanding was less than $1 million. MANDATORILY REDEEMABLE CAPITAL STOCK The Bank reclassifies capital stock subject to redemption from equity to a liability (mandatorily redeemable capital stock) at the time shares meet the definition of a mandatorily redeemable financial instrument. This occurs after a member provides written notice of intention to withdraw from membership, becomes ineligible for continuing membership, or attains non-member status by merger or consolidation, charter termination, or other involuntary termination from membership. Dividends on mandatorily redeemable capital stock are classified as interest expense in the Statements of Income. As a result of the final rule on membership issued by the Finance Agency effective February 19, 2016, the eligibility requirements for FHLBank members were changed rendering captive insurance companies ineligible for FHLBank membership. On the effective date of the final rule, the Bank reclassified the total outstanding capital stock held by all of the Bank’s captive insurance companies, to mandatorily redeemable capital stock. In accordance with the final rule, on February 17, 2017, the Bank terminated the membership of all captive insurance company members that were admitted as members after September 12, 2014 (the date the Finance Agency proposed this rule) and repurchased outstanding capital stock to these captive insurance company members in the amount of $148 million . Captive insurance company members that were admitted as members prior to September 12, 2014 will also have their memberships terminated no later than February 19, 2021. At June 30, 2018 and December 31, 2017 , the Bank’s mandatorily redeemable capital stock totaled $373 million and $385 million . During the three and six months ended June 30, 2018 , interest expense on mandatorily redeemable capital stock was $5 million and $9 million . Interest expense on mandatorily redeemable capital stock was $4 million and $9 million for the three and six months ended June 30, 2017 . The following table summarizes changes in mandatorily redeemable capital stock (dollars in millions): For the Three Months Ended June 30, 2018 2017 Balance, beginning of period $ 356 $ 494 Capital stock reclassified to (from) mandatorily redeemable capital stock, net 36 18 Net payments for repurchases/redemptions of mandatorily redeemable capital stock (19 ) (32 ) Balance, end of period $ 373 $ 480 The following table summarizes changes in mandatorily redeemable capital stock (dollars in millions): For the Six Months Ended June 30, 2018 2017 Balance, beginning of period $ 385 $ 664 Capital stock reclassified to (from) mandatorily redeemable capital stock, net 39 28 Net payments for repurchases/redemptions of mandatorily redeemable capital stock (51 ) (212 ) Balance, end of period $ 373 $ 480 The following table summarizes the Bank’s mandatorily redeemable capital stock by year of contractual redemption (dollars in millions): Year of Contractual Redemption 1 June 30, 2018 December 31, 2017 Due in one year or less $ — $ 4 Due after one year through two years 2 2 Due after two years through three years 1 — Due after three years through four years 11 1 Due after four years through five years 26 22 Thereafter 2 317 341 Past contractual redemption date due to outstanding activity with the Bank 16 15 Total $ 373 $ 385 1 At the Bank’s election, the mandatorily redeemable capital stock may be redeemed prior to the expiration of the five year redemption period that commences on the date of the notice of redemption, or in the case of captive insurance company members, on the date of the membership termination. 2 Represents mandatorily redeemable capital stock resulting from the Finance Agency rule previously discussed that makes captive insurance companies ineligible for FHLBank membership. The related mandatorily redeemable capital stock is not required to be redeemed until five years after the member's termination. RESTRICTED RETAINED EARNINGS The Bank entered into a Joint Capital Enhancement Agreement (JCE Agreement) with all of the other FHLBanks in February 2011. The JCE Agreement, as amended, is intended to enhance the capital position of the Bank over time. It requires the Bank to allocate 20 percent of its quarterly net income to a separate restricted retained earnings account until the balance of that account equals at least one percent of its average balance of outstanding consolidated obligations for the previous quarter. The restricted retained earnings are not available to pay dividends. At June 30, 2018 and December 31, 2017 , the Bank’s restricted retained earnings account totaled $384 million and $335 million . ACCUMULATED OTHER COMPREHENSIVE INCOME The following table summarizes changes in AOCI (dollars in millions): Net unrealized gains (losses) on AFS securities (Note 4) Pension and postretirement benefits Total AOCI Balance, March 31, 2017 $ 50 $ (3 ) $ 47 Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities 41 — 41 Reclassifications from AOCI to net income Amortization - pension and postretirement — 1 1 Net current period other comprehensive income (loss) 41 1 42 Balance, June 30, 2017 $ 91 $ (2 ) $ 89 Balance, March 31, 2018 $ 163 $ (4 ) $ 159 Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities (17 ) — (17 ) Net current period other comprehensive income (loss) (17 ) — (17 ) Balance, June 30, 2018 $ 146 $ (4 ) $ 142 Balance, December 31, 2016 $ (14 ) $ (4 ) $ (18 ) Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities 105 — 105 Reclassifications from AOCI to net income Amortization - pension and postretirement — 2 2 Net current period other comprehensive income (loss) 105 2 107 Balance, June 30, 2017 $ 91 $ (2 ) $ 89 Balance, December 31, 2017 $ 118 $ (4 ) $ 114 Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities 28 — 28 Net current period other comprehensive income (loss) 28 — 28 Balance, June 30, 2018 $ 146 $ (4 ) $ 142 REGULATORY CAPITAL REQUIREMENTS The Bank is subject to three regulatory capital requirements: • Risk-based capital . The Bank must maintain at all times permanent capital greater than or equal to the sum of its credit, market, and operations risk capital requirements, all calculated in accordance with Finance Agency regulations. Only permanent capital, defined as Class B stock (including mandatorily redeemable capital stock), and retained earnings can satisfy this risk-based capital requirement. • Regulatory capital . The Bank is required to maintain a minimum four percent capital-to-asset ratio, which is defined as total regulatory capital divided by total assets. Total regulatory capital includes Class B stock (including mandatorily redeemable capital stock) and retained earnings. It does not include AOCI. • Leverage capital . The Bank is required to maintain a minimum five percent leverage ratio, which is defined as the sum of permanent capital weighted 1.5 times and nonpermanent capital weighted 1.0 times, divided by total assets. The Bank did not hold any nonpermanent capital at June 30, 2018 and December 31, 2017 . If the Bank’s capital falls below the required levels, the Finance Agency has authority to take actions necessary to return it to levels that it deems to be consistent with safe and sound business operations. The following table shows the Bank’s compliance with the Finance Agency’s regulatory capital requirements (dollars in millions): June 30, 2018 December 31, 2017 Required Actual Required Actual Regulatory capital requirements Risk-based capital $ 1,178 $ 7,770 $ 1,041 $ 7,292 Regulatory capital $ 6,039 $ 7,770 $ 5,804 $ 7,292 Leverage capital $ 7,549 $ 11,656 $ 7,255 $ 10,937 Capital-to-assets ratio 4.00 % 5.15 % 4.00 % 5.03 % Leverage ratio 5.00 % 7.72 % 5.00 % 7.54 %

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value [Text Block]	Fair Value Fair value amounts are determined by the Bank using available market information and reflect the Bank’s best judgment of appropriate valuation methods. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (i.e., and exit price). The fair value hierarchy requires an entity to maximize the use of significant observable inputs and minimize the use of significant unobservable inputs when measuring fair value. The inputs are evaluated and an overall level for the fair value measurement is determined. This overall level is an indication of market observability of the fair value measurement for the asset or liability. The fair value hierarchy prioritizes the inputs used to measure fair value into three broad levels: • Level 1 Inputs. Quoted prices (unadjusted) for identical assets or liabilities in an active market that the Bank can access on the measurement date. • Level 2 Inputs. Inputs other than quoted prices within Level 1 that are observable inputs for the asset or liability, either directly or indirectly. If the asset or liability has a specified (contractual) term, a Level 2 input must be observable for substantially the full term of the asset or liability. Level 2 inputs include the following: (i) quoted prices for similar assets or liabilities in active markets, (ii) quoted prices for identical or similar assets or liabilities in markets that are not active, (iii) inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates and yield curves that are observable at commonly quoted intervals and implied volatilities, and (iv) market-corroborated inputs. • Level 3 Inputs. Unobservable inputs for the asset or liability. The Bank reviews its fair value hierarchy classifications on a quarterly basis. Changes in the observability of the valuation inputs may result in a reclassification of certain assets or liabilities. These reclassifications are reported as transfers in/out as of the beginning of the quarter in which the changes occur. There were no such transfers during the six months ended June 30, 2018 and 2017 . The following table summarizes the carrying value, fair value, and fair value hierarchy of the Bank’s financial instruments at June 30, 2018 (dollars in millions). The Bank records trading securities, AFS securities, derivative assets, derivative liabilities, certain advances, and certain other assets at fair value on a recurring basis, and on occasion certain mortgage loans held for portfolio on a non-recurring basis. The Bank records all other financial assets and liabilities at amortized cost. The fair values do not represent an estimate of the overall market value of the Bank as a going concern, which would take into account future business opportunities and the net profitability of assets and liabilities. Fair Value Financial Instruments Carrying Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Cash and due from banks $ 201 $ 201 $ — $ — $ — $ 201 Interest-bearing deposits 1 — 1 — — 1 Securities purchased under agreements to resell 4,900 — 4,900 — — 4,900 Federal funds sold 4,435 — 4,435 — — 4,435 Trading securities 937 — 937 — — 937 Available-for-sale securities 19,451 — 19,451 — — 19,451 Held-to-maturity securities 3,295 — 3,314 11 — 3,325 Advances 109,963 — 110,031 — — 110,031 Mortgage loans held for portfolio, net 7,310 — 7,189 63 — 7,252 Accrued interest receivable 305 — 305 — — 305 Derivative assets, net 83 — 154 — (71 ) 83 Other assets 29 29 — — — 29 Liabilities Deposits (1,028 ) — (1,028 ) — — (1,028 ) Consolidated obligations Discount notes (43,122 ) — (43,119 ) — — (43,119 ) Bonds (98,468 ) — (98,539 ) — — (98,539 ) Total consolidated obligations (141,590 ) — (141,658 ) — — (141,658 ) Mandatorily redeemable capital stock (373 ) (373 ) — — — (373 ) Accrued interest payable (238 ) — (238 ) — — (238 ) Derivative liabilities, net (2 ) — (127 ) — 125 (2 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. The following table summarizes the carrying value, fair value, and fair value hierarchy of the Bank’s financial instruments at December 31, 2017 (dollars in millions): Fair Value Financial Instruments Carrying Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Cash and due from banks $ 503 $ 503 $ — $ — $ — $ 503 Interest-bearing deposits 1 — 1 — — 1 Securities purchased under agreements to resell 4,600 — 4,600 — — 4,600 Federal funds sold 4,250 — 4,250 — — 4,250 Trading securities 1,177 — 1,177 — — 1,177 Available-for-sale securities 20,796 — 20,796 — — 20,796 Held-to-maturity securities 3,628 — 3,674 12 — 3,686 Advances 102,613 — 102,708 — — 102,708 Mortgage loans held for portfolio, net 7,096 — 7,124 64 — 7,188 Accrued interest receivable 223 — 223 — — 223 Derivative assets, net 100 — 97 — 3 100 Other assets 28 28 — — — 28 Liabilities Deposits (1,107 ) — (1,107 ) — — (1,107 ) Borrowings from other FHLBanks (600 ) — (600 ) — — (600 ) Consolidated obligations Discount notes (36,682 ) — (36,674 ) — — (36,674 ) Bonds (98,893 ) — (99,150 ) — — (99,150 ) Total consolidated obligations (135,575 ) — (135,824 ) — — (135,824 ) Mandatorily redeemable capital stock (385 ) (385 ) — — — (385 ) Accrued interest payable (210 ) — (210 ) — — (210 ) Derivative liabilities, net (6 ) — (188 ) — 182 (6 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. To conform with current presentation $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with netting adjustments and cash collateral. SUMMARY OF VALUATION TECHNIQUES AND PRIMARY INPUTS The valuation techniques and primary inputs used to develop the measurement of fair value for assets and liabilities that are measured at fair value on a recurring or non-recurring basis in the Statements of Condition are outlined below. Trading and AFS Investment Securities. The Bank’s valuation technique incorporates prices from multiple designated third-party pricing vendors, when available. The pricing vendors generally use various proprietary models to price investment securities. The inputs to those models are derived from various sources including, but not limited to, benchmark securities and yields, reported trades, dealer estimates, issuer spreads, bids, offers, and other market-related data. Since many investment securities do not trade on a daily basis, the pricing vendors use available information, as applicable, such as benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing to determine the prices for individual securities. Each pricing vendor has an established process in place to challenge investment valuations, which facilitates resolution of questionable prices identified by the Bank. Annually, the Bank conducts reviews of its pricing vendors to confirm and further augment its understanding of the vendors’ pricing processes, methodologies, and control procedures for investment securities. The Bank’s valuation technique for estimating the fair values of its investment securities first requires the establishment of a median price for each security. All prices that are within a specified tolerance threshold of the median price are included in the cluster of prices that are averaged to compute a default price. All prices that are outside the threshold (outliers) are subject to further analysis (including, but not limited to, comparison to prices provided by an additional third-party valuation service, prices for similar securities, and/or non-binding dealer estimates) to determine if an outlier is a better estimate of fair value. If an outlier (or some other price identified in the analysis) is determined to be a better estimate of fair value, then the outlier (or the other price as appropriate) is used as the final price rather than the default price. Alternatively, if the analysis confirms that an outlier (or outliers) is (are) in fact not representative of fair value and the default price is the best estimate, then the default price is used as the final price. In all cases, the final price is used to determine the fair value of the security. In limited instances, when no prices are available from one of the designated pricing services, the Bank obtains prices from dealers. As of June 30, 2018 and December 31, 2017 , multiple prices were received for the majority of the Bank’s trading and AFS investment securities. Based on the Bank’s review of the pricing methods and controls employed by the third-party pricing vendors and the relative lack of dispersion among the vendor prices, the Bank believes its final prices are representative of the prices that would have been received if the assets had been sold at the measurement date (i.e., exit prices) and further, that the fair value measurements are classified appropriately in the fair value hierarchy. Advances Recorded under the Fair Value Option. The fair value of advances recorded under the fair value option is determined by calculating the present value of the expected future cash flows and includes accrued interest receivable. The discount rates used in these calculations are equivalent to the replacement advance rates for advances with similar terms. In accordance with Finance Agency regulations, advances generally require a prepayment fee sufficient to make the Bank financially indifferent to a borrower’s decision to prepay the advances. Therefore, the fair value of advances assumes no prepayment risk. The Bank uses the following inputs for measuring the fair value of advances: • Consolidated Obligation Curve (CO Curve) . The Office of Finance constructs a curve, referred to as the CO Curve, using the U.S. Treasury Curve as a base curve which is then adjusted by adding indicative spreads obtained from market-observable sources. These market indications are generally derived from pricing indications from dealers, historical pricing relationships, recent GSE trades, and secondary market activity. The Bank utilizes the CO Curve as its input to fair value for advances because it represents the Bank’s cost of funds and is used to price advances. • Volatility assumption . Market-based expectations of future interest rate volatility implied from current market prices for similar options. • Spread assumption . Represents a spread adjustment to the CO Curve. Impaired Mortgage Loans Held for Portfolio. The fair value of impaired mortgage loans held for portfolio is estimated by obtaining property values from an external pricing vendor. This vendor utilizes multiple pricing models that generally factor in market observable inputs, including actual sales transactions and home price indices. The Bank applies an adjustment to these values to capture certain limitations in the estimation process and takes into consideration estimated selling costs and expected PMI proceeds. In limited instances, the Bank may estimate the fair value of an impaired mortgage loan by calculating the present value of expected future cash flows discounted at the loan’s effective interest rate. Derivative Assets and Liabilities. The fair value of derivatives is generally estimated using standard valuation techniques such as discounted cash flow analyses and comparisons to similar instruments, and includes variation margin payments for daily settled contracts. In limited instances, fair value estimates for interest-rate related derivatives may be obtained using an external pricing model that utilizes observable market data. The Bank is subject to credit risk in derivatives transactions due to the potential nonperformance of its derivatives counterparties. The use of cleared derivatives is intended to mitigate credit risk exposure because a central counterparty is substituted for individual counterparties and collateral/payments is posted daily, through a clearing agent, for changes in the fair value of cleared derivatives. To mitigate credit risk on uncleared derivatives, the Bank enters into master netting agreements with its counterparties as well as collateral agreements that provide for the delivery of collateral at specified levels tied to those counterparties’ credit ratings. The Bank has evaluated the potential for the fair value of its derivatives to be affected by counterparty credit risk and its own credit risk and has determined that no adjustments were significant to the overall fair value measurements. The fair values of the Bank’s derivative assets and derivative liabilities include accrued interest receivable/payable and cash collateral remitted to/received from counterparties. The estimated fair values of the accrued interest receivable/payable and cash collateral approximate their carrying values due to their short-term nature. The fair values of derivatives are netted by clearing agent and/or counterparty if the netting requirements are met. If these netted amounts are positive, they are classified as an asset and, if negative, they are classified as a liability. The Bank’s discounted cash flow model utilizes market-observable inputs (inputs that are actively quoted and can be validated to external sources). The Bank uses the following inputs for measuring the fair value of interest-related derivatives: • Discount rate assumption . The Bank utilizes the Overnight-Index Swap (OIS) curve. • Forward interest rate assumption . The Bank utilizes the London Interbank Offered Rate (LIBOR) swap curve. • Volatility assumption . Market-based expectations of future interest rate volatility implied from current market prices for similar options. For forward settlement agreements (TBAs), the Bank utilizes TBA securities prices that are determined by coupon class and expected term until settlement. For mortgage delivery commitments, the Bank utilizes TBA securities prices adjusted for factors such as credit risk and servicing spreads. Other Assets . These represent grantor trust assets, which are carried at estimated fair value based on quoted market prices as of the last business day of the reporting period. Subjectivity of Estimates . Estimates of the fair value of financial assets and liabilities using the methods previously described are highly subjective and require judgments regarding significant matters, such as the amount and timing of future cash flows, prepayment speed assumptions, expected interest rate volatility, possible distributions of future interest rates used to value options, and the selection of discount rates that appropriately reflect market and credit risks. The use of different assumptions could have a material effect on the fair value estimates. FAIR VALUE ON A RECURRING BASIS The following table summarizes, for each hierarchy level, the Bank’s assets and liabilities that are measured at fair value in the Statements of Condition a t June 30, 2018 (dollar s in millions): Recurring Fair Value Measurements Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Trading securities U.S. obligations $ — $ 182 $ — $ — $ 182 GSE and Tennessee Valley Authority obligations — 57 — — 57 Other non-MBS — 265 — — 265 GSE multifamily MBS — 433 — — 433 Total trading securities — 937 — — 937 Available-for-sale securities U.S. obligations — 2,820 — — 2,820 GSE and Tennessee Valley Authority obligations — 1,039 — — 1,039 State or local housing agency obligations — 906 — — 906 Other non-MBS — 272 — — 272 U.S. obligations single-family MBS — 4,097 — — 4,097 GSE single-family MBS — 885 — — 885 GSE multifamily MBS — 9,432 — — 9,432 Total available-for-sale securities — 19,451 — — 19,451 Advances 2 — 15 — — 15 Derivative assets, net Interest-rate related — 154 — (71 ) 83 Other assets 29 — — — 29 Total recurring assets at fair value $ 29 $ 20,557 $ — $ (71 ) $ 20,515 Liabilities Derivative liabilities, net Interest-rate related — (126 ) — 125 (1 ) Forward settlement agreements (TBAs) — (1 ) — — (1 ) Total recurring liabilities at fair value $ — $ (127 ) $ — $ 125 $ (2 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. 2 Represents financial instruments recorded under the fair value option. The following table summarizes, for each hierarchy level, the Bank’s assets and liabilities that are measured at fair value in the Statements of Condition at December 31, 2017 (dollars in millions): Recurring Fair Value Measurements Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Trading securities U.S. obligations $ — $ 197 $ — $ — $ 197 GSE and Tennessee Valley Authority obligations — 260 — — 260 Other non-MBS — 272 — — 272 GSE multifamily MBS — 448 — — 448 Total trading securities — 1,177 — — 1,177 Available-for-sale securities U.S. obligations — 3,099 — — 3,099 GSE and Tennessee Valley Authority obligations — 1,236 — — 1,236 State or local housing agency obligations — 934 — — 934 Other non-MBS — 278 — — 278 U.S. obligations single-family MBS — 3,726 — — 3,726 GSE single-family MBS — 988 — — 988 GSE multifamily MBS — 10,535 — — 10,535 Total available-for-sale securities — 20,796 — — 20,796 Derivative assets, net Interest-rate related — 97 — 3 100 Other assets 28 — — — 28 Total recurring assets at fair value $ 28 $ 22,070 $ — $ 3 $ 22,101 Liabilities Derivative liabilities, net Interest-rate related — (188 ) — 182 (6 ) Total recurring liabilities at fair value $ — $ (188 ) $ — $ 182 $ (6 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with netting adjustments and cash collateral. FAIR VALUE ON A NON-RECURRING BASIS The Bank measures certain impaired mortgage loans held for portfolio at level 3 fair value on a non-recurring basis. These assets are subject to fair value adjustments in certain circumstances. At June 30, 2018 and December 31, 2017 , impaired mortgage loans held for portfolio recorded at fair value as a result of a non-recurring change in fair value were $1 million and $7 million . These fair values were as of the date the fair value adjustment was recorded during the six months ended June 30, 2018 and year-ended December 31, 2017 . FAIR VALUE OPTION The fair value option provides an irrevocable option to elect fair value as an alternative measurement for selected financial assets, financial liabilities, unrecognized firm commitments, and written loan commitments not previously carried at fair value. It require entities to display the fair value of those assets and liabilities for which it has chosen to use fair value on the face of the Statements of Condition. Fair value is used for both the initial and subsequent measurement of the designated assets, liabilities, and commitments, with the changes in fair value recognized in income. The Bank elects the fair value option for certain financial instruments when a hedge relationship does not qualify for hedge accounting. These fair value elections are made primarily in an effort to mitigate the potential income statement volatility that can arise when an economic derivative is adjusted for changes in fair value but the related hedged item is not. For financial instruments recorded under the fair value option, the related contractual interest income and interest expense are recorded as part of net interest income in the Statements of Income. The remaining changes are recorded as “Net gains (losses) on financial instruments held at fair value” in the Statements of Income. For the three and six months ended June 30, 2018 and 2017, net gains on financial instruments held at fair value were less than $1 million. At June 30, 2018 and December 31, 2017 , the Bank determined no credit risk adjustments for nonperformance were necessary to the instruments recorded under the fair value option. At December 31, 2017, advances recorded under the fair value option were less than $1 million. The following table summarizes the difference between the unpaid principal balance and fair value of outstanding instruments for which the fair value option was elected at June 30, 2018 (dollars in million): June 30, 2018 Unpaid Principal Balance Fair Value Fair Value Over (Under) Unpaid Principal Advances 1 $ 15 $ 15 $ — 1 At June 30, 2018 none of the advances were 90 days or more past due or had been placed on non-accrual status.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies Joint and Several Liability . The FHLBanks have joint and several liability for all consolidated obligations issued. Accordingly, if an FHLBank were unable to repay any consolidated obligation for which it is the primary obligor, each of the other FHLBanks could be called upon by the Finance Agency to repay all or part of such obligations. No FHLBank has ever been asked or required to repay the principal or interest on any consolidated obligation on behalf of another FHLBank. A t June 30, 2018 and December 31, 2017 , the total par value of outstanding consolidated obligations issued on behalf of other FHLBanks for which the Bank is jointly and severally liable was approximately $917.7 billion and $898.3 billion . The following table summarizes additional off-balance sheet commitments for the Bank (dollars in millions): June 30, 2018 December 31, 2017 Expire within one year Expire after one year Total Total Standby letters of credit 1 $ 9,111 $ 166 $ 9,277 $ 8,594 Standby bond purchase agreements 117 587 704 755 Commitments to purchase mortgage loans 172 — 172 72 Commitments to issue bonds 264 — 264 — Commitments to fund advances 779 1 780 1,138 1 Excludes commitments to issue standby letters of credit of $53 million and $7 million at June 30, 2018 and December 31, 2017 . Standby Letters of Credit . The Bank issues standby letters of credit on behalf of its members to support certain obligations of the members to third-party beneficiaries. These standby letters of credit are subject to the same collateralization and borrowing limits that are applicable to advances. Standby letters of credit may be offered to assist members in facilitating residential housing finance, community lending, and asset-liability management, and to provide liquidity. In particular, members often use standby letters of credit as collateral for deposits from federal and state government agencies. Standby letters of credit are executed with members for a fee. If the Bank is required to make payment for a beneficiary’s draw, the member either reimburses the Bank for the amount drawn or, subject to the Bank’s discretion, the amount drawn may be converted into a collateralized advance to the member. The original terms of standby letters of credit range from less than one month to 13 years, currently no later than 2025 . The carrying value of guarantees related to standby letters of credit are recorded in “Other liabilities” in the Statements of Condition and amounted to $2 million and $3 million at June 30, 2018 and December 31, 2017 . The Bank monitors the creditworthiness of its standby letters of credit based on an evaluation of its borrowers. The Bank has established parameters for the measurement, review, classification, and monitoring of credit risk related to these standby letters of credit. Based on management’s credit analyses and collateral requirements, the Bank does not deem it necessary to have any provision for credit losses on these standby letters of credit. All standby letters of credit are subject to the same collateralization and borrowing limits that apply to advances and are fully collateralized at the time of issuance. Standby Bond Purchase Agreements . The Bank has entered into standby bond purchase agreements with state housing associates within its district whereby, for a fee, it agrees to serve as a standby liquidity provider if required, to purchase and hold the housing associate’s bonds until the designated marketing agent can find a suitable investor or the housing associate repurchases the bonds according to a schedule established by the agreement. Each standby bond purchase agreement includes the provisions under which the Bank would be required to purchase the bonds. At June 30, 2018 , the Bank had standby bond purchase agreements with seven housing associates. The standby bond purchase commitments entered into by the Bank have original expiration periods of up to seven years, currently no later than 2024 . During both the six months ended June 30, 2018 and 2017 , the Bank was not required to purchase any bonds under these agreements. Commitments to Purchase Mortgage Loans . The Bank enters into commitments that unconditionally obligate it to purchase mortgage loans from its members. Commitments are generally for periods not to exceed 45 days. These commitments are considered derivatives and their estimated fair value at June 30, 2018 and December 31, 2017 is reported in “Note 10 — Derivatives and Hedging Activities” as mortgage delivery commitments. Commitments to Issue Bonds . At June 30, 2018 , the Bank had commitments to issue $264 million of consolidated obligation bonds. At December 31, 2017 , the Bank had no commitments to issue consolidated obligation bonds. Commitments to Fund Advances. The Bank enters into commitments that legally bind it to fund additional advances up to 24 months in the future. At June 30, 2018 and December 31, 2017 , the Bank had commitments to fund advances of $0.8 billion and $1.1 billion . Other Commitments. For each MPF master commitment, the Bank’s potential loss exposure prior to the PFI’s credit enhancement obligation is estimated and tracked in a memorandum account called the FLA. For absorbing certain losses in excess of the FLA, PFIs are paid a credit enhancement fee, a portion of which may be performance-based. To the extent the Bank experiences losses under the FLA, it may be able to recapture performance-based credit enhancement fees paid to the PFI to offset these losses. The FLA balance for all MPF master commitments with a PFI credit enhancement obligation was $108 million and $104 million at June 30, 2018 and December 31, 2017 . Legal Proceedings . As a result of the merger with the Federal Home Loan Bank of Seattle (Merger), the Bank has been involved in a number of legal proceedings initiated by the Seattle Bank against various entities relating to its purchases and subsequent impairment of certain private-label MBS. Of the 11 cases initially filed, one has been dismissed, two have been settled in part and dismissed in part, and eight have been settled. The Bank appealed the one complete dismissal and two partial dismissals covering the claims related to five certificates across three different cases. The appellate court affirmed the dismissal of the claims related to four certificates in December 2017 and affirmed the dismissal of the remaining certificate in May 2018. In January 2018, the Bank filed petitions for discretionary review of the appellate court’s rulings in December related to four of the certificates with the Washington Supreme Court. On May 3, 2018, the Court granted those petitions. The aggregate consideration paid for these four certificates is $567 million. Oral arguments have been scheduled for October 9, 2018. In June 2018, the Bank filed a petition for discretionary review of the appellate court’s ruling in May on the fifth certificate. The aggregate consideration paid for that one certificate is $200 million. The Washington Supreme Court has not yet acted on that petition. Other than the private-label MBS litigation, the Bank does not believe any legal proceedings to which it is a party could have a material impact on its financial condition, results of operations, or cash flows. Litigation settlement gains are considered realized and recorded when the Bank receives cash or assets that are readily convertible to known amounts of cash or claims to cash. In addition, litigation settlement gains are considered realizable and recorded when the Bank enters into a signed agreement that is not subject to appeal, where the counterparty has the ability to pay, and the amount to be received can be reasonably estimated. Prior to being realized or realizable, the Bank considers potential litigation settlement gains to be gain contingencies, and therefore they are not recorded in the Statements of Income. The Bank records legal expenses related to litigation settlements as incurred in other expenses in the Statements of Income with the exception of certain legal expenses related to litigation settlement awards that are contingent based fees for the attorneys representing the Bank. The Bank incurs and recognizes these contingent based legal fees only when litigation settlement awards are realized, at which time these fees are netted against the gains recognized on the litigation settlement. During the three months ended June 30, 2018 and 2017 , and during the six months ended June 30, 2018 , the Bank did not recognize net gains on private-label MBS litigation settlements. During the six months ended June 30, 2017 , the Bank recognized $21 million in net gains on litigation settlements through other income (loss), due to the settlement of one of the Bank’s private-label MBS claims.

Activities with Stockholders

Activities with Stockholders	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Activities with Stockholders [Text Block]	Activities with Stockholders The Bank is a cooperative. This means the Bank is owned by its customers, whom the Bank calls members. As a condition of membership in the Bank, all members must purchase and maintain membership capital stock based on a percentage of their total assets, subject to a minimum and maximum amount, as of the preceding December 31 st . Each member is also required to purchase and maintain activity-based capital stock to support certain business activities with the Bank. TRANSACTIONS WITH DIRECTORS’ FINANCIAL INSTITUTIONS In the normal course of business, the Bank extends credit to its members whose directors and officers serve as Bank directors (Directors’ Financial Institutions). Finance Agency regulations require that transactions with Directors’ Financial Institutions be made on the same terms and conditions as those with any other member. The following table summarizes the Bank’s outstanding transactions with Directors’ Financial Institutions (dollars in millions): June 30, 2018 December 31, 2017 Amount % of Total Amount % of Total Advances $ 5,134 5 $ 6,036 6 Mortgage loans 86 1 68 1 Deposits 11 1 39 4 Capital stock 256 4 297 5 BUSINESS CONCENTRATIONS The Bank considers itself to have business concentrations with stockholders owning 10 percent or more of its total capital stock outstanding (including mandatorily redeemable capital stock). At June 30, 2018 , the Bank had the following business concentrations with stockholders (dollars in millions): Capital Stock Mortgage Interest Stockholder Amount % of Total 1 Advances Loans 4 Income 2 Wells Fargo Bank, N.A. $ 2,052 35 $ 51,025 $ 27 $ 550 Superior Guaranty Insurance Company 3 19 — — 463 — Total $ 2,071 35 $ 51,025 $ 490 $ 550 1 Pursuant to applicable Finance Agency regulations, the Bank’s voting structure limits the voting rights of these stockholders and other members holding a significant amount of the Bank’s capital stock. 2 Represents interest income earned on advances during the six months ended June 30, 2018 . Interest income on mortgage loans is excluded from this table as this interest relates to the borrower, not to the stockholder. 3 Superior Guaranty Insurance Company is an affiliate of Wells Fargo Bank, N.A. 4 PFI rights and obligations associated with MPP mortgage loans of $27 million were transferred from Wells Fargo Trust Company, N.A. (formerly Wells Fargo Bank Northwest N.A.) to Wells Fargo Bank, N.A. during the three months ended June 30, 2018. At December 31, 2017 , the Bank had the following business concentrations with stockholders (dollars in millions): Capital Stock Mortgage Interest Stockholder Amount % of Total 1 Advances Loans Income 2 Wells Fargo Bank, N.A. $ 1,843 34 $ 45,825 $ — $ 834 Superior Guaranty Insurance Company 3 22 — — 520 — Wells Fargo Bank Northwest N.A. 3 1 — — 30 — Total $ 1,866 34 $ 45,825 $ 550 $ 834 1 Pursuant to applicable Finance Agency regulations, the Bank’s voting structure limits the voting rights of these stockholders and other members holding a significant amount of the Bank’s capital stock. 2 Represents interest income earned on advances during the year ended December 31, 2017 . Interest income on mortgage loans is excluded from this table as this interest relates to the borrower, not to the stockholder. 3 Superior Guaranty Insurance Company and Wells Fargo Bank Northwest, N.A. were affiliates of Wells Fargo Bank, N.A at December 31, 2017.

Activities with Other FHLBanks

Activities with Other FHLBanks	6 Months Ended
	Jun. 30, 2018
Activities with Other FHLBanks [Abstract]
Activities with Other FHLBanks [Text Block]	Activities with Other FHLBanks Overnight Funds . The Bank may lend or borrow unsecured overnight funds to or from other FHLBanks. All such transactions are at current market rates. The following table summarizes loan activity to other FHLBanks during the six months ended June 30, 2018 and 2017 (dollars in millions): Other FHLBank Beginning Balance Loans Principal Repayment Ending Balance 2018 Boston $ — $ 800 $ (800 ) $ — San Francisco — 300 (300 ) — Dallas — 500 (500 ) — $ — $ 1,600 $ (1,600 ) $ — 2017 San Francisco $ 200 $ — $ (200 ) $ — During the six months ended June 30, 2017, the Bank did not borrow funds from other FHLBanks. The following table summarizes borrowing activity from other FHLBanks during the six months ended June 30, 2018 (dollars in millions): Other FHLBank Beginning Balance Borrowing Principal Payment Ending Balance 2018 Atlanta $ 200 $ — $ (200 ) $ — Boston 400 — (400 ) — $ 600 $ — $ (600 ) $ — At June 30, 2018 and 2017 , none of the previous transactions were outstanding on the Bank’s Statements of Condition. The interest income and expense related to this activity were immaterial. Advance Transfers. The Bank may purchase or sell advances from/to other FHLBanks. These transfers are accounted for in the same manner as an advances origination with a member bank. During the six months ended June 30, 2017, a member of the Federal Home Loan Bank of Chicago (Chicago Bank) re-designated its charter, and concurrently transferred its Federal Home Loan Bank membership from the Chicago Bank to the Des Moines Bank. In conjunction with this transfer and at request of the member, the Bank purchased $37 million of par value advances outstanding to this member from the Chicago Bank and recognized related premiums of $1 million . There were no advance transfers during the six months ended June 30, 2018 .

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Subsequent events have been evaluated from July 1, 2018 , through the time of the Form 10-Q filing with the Securities and Exchange Commission. No material subsequent events requiring disclosure were identified.

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted and Issued Accounting Guidance ADOPTED ACCOUNTING GUIDANCE Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (ASU 2017-07) On March 10, 2017, the FASB issued amended guidance that requires an employer to disaggregate the service cost component from the other components of net periodic pension cost and net periodic postretirement benefit cost (net benefit cost). The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018 and was adopted retrospectively. The adoption of this guidance resulted in a reclassification of other net benefit costs from “Compensation and Benefits” to “Other Expense, Net” in the Bank’s Statements of Income. The adoption of this guidance did not have a material effect on the Bank’s financial condition, result of operations, or cash flows. Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15) On August 26, 2016, the FASB issued amendments to clarify guidance on the classification of certain cash receipts and payments in the statement of cash flows. This guidance is intended to reduce existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018 and was adopted retrospectively. The adoption of this guidance did not have a direct effect on the Bank’s financial condition, results of operations, or cash flows. However, the Bank did revise its previously reported supplemental interest paid disclosure to align with the clarified accounting guidance. Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) On January 5, 2016, the FASB issued amended guidance on certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. This guidance includes, but is not limited to, the following: • Requires equity investments (with certain exceptions) to be measured at fair value with changes in fair value recognized in income. • Requires an entity to present separately in other comprehensive income (OCI) the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. • Requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the statements of condition or the accompanying notes to the financial statements. • Eliminates the requirement for public entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the statements of condition. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018 and was adopted using the modified retrospective approach. The adoption of this guidance affected the Bank’s fair value disclosures. However, the guidance did not have any effect on the Bank’s financial condition, results of operations, or cash flows. Revenue from Contracts with Customers (ASU 2014-09) On May 28, 2014, the FASB issued guidance on revenue from contracts with customers. This guidance outlines a single comprehensive model for recognizing revenue arising from contracts with customers and supersedes most current revenue recognition guidance. In addition, this guidance amends the existing requirements for the recognition of a gain or loss on the transfer of non-financial assets that are not in a contract with a customer. This guidance applies to all contracts with customers except those that are within the scope of certain other standards, such as financial instruments, certain guarantees, insurance contracts, and lease contracts. The guidance provides entities with the option of using either of the following adoption methods: a full retrospective method, retrospectively to each prior reporting period presented; or a modified retrospective method, retrospectively with the cumulative effect of initially applying this guidance recognized at the date of initial application. On August 12, 2015, the FASB issued an amendment to defer the effective date of this guidance issued in May 2014 by one year. In 2016, the FASB issued additional amendments to clarify certain aspects of the new revenue guidance. However, these amendments did not change the core principle in the new revenue standard. This guidance became effective for the Bank for the interim and annual periods beginning on January 1, 2018, and was adopted retrospectively. Given that the majority of the Bank’s financial instruments and other contractual rights that generate revenue are covered by other U.S. GAAP, the adoption of this guidance did not have a material effect on the Bank’s financial condition, results of operations, and cash flows. ISSUED ACCOUNTING GUIDANCE Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12) On August 28, 2017, the FASB issued amended guidance to improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. This guidance requires that, for fair value hedges, the entire change in the fair value of the hedging instrument included in the assessment of hedge effectiveness be presented in the same income statement line that is used to present the earnings effect of the hedged item. For cash flow hedges, the entire change in the fair value of the hedging instrument included in the assessment of hedge effectiveness must be recorded in OCI. In addition, the amendments include certain targeted improvements to the assessment of hedge effectiveness and permit, among other things, the following: • Measurement of the change in fair value of the hedged item on the basis of the benchmark rate component of the contractual coupon cash flows determined at hedge inception. • Measurement of the hedged item in a partial-term fair value hedge of interest-rate risk by assuming the hedged item has a term that reflects only the designated cash flows being hedged. • Consideration only of how changes in the benchmark interest rate affect a decision to settle a prepayable instrument before its scheduled maturity in calculating the change in the fair value of the hedged item attributable to interest-rate risk. • For a cash flow hedge of interest-rate risk of a variable-rate financial instrument, an entity could designate as the hedged risk the variability in cash flows attributable to the contractually specified interest-rate. This guidance becomes effective for the Bank for the interim and annual periods beginning on January 1, 2019, and early adoption is permitted. For all cash flow hedges existing on the date of adoption, this guidance should be applied through a cumulative-effect adjustment to accumulated other comprehensive income (AOCI) with a corresponding adjustment to retained earnings as of the beginning of the year of adoption. The amended presentation and disclosure guidance is required only prospectively. The Bank does not intend to adopt this guidance early. The Bank is in the process of evaluating this guidance, and its effect on the Bank’s financial condition, results of operations, and cash flows has not yet been determined. Premium Amortization on Purchased Callable Debt Securities (ASU 2017-08) On March 30, 2017, the FASB issued guidance to shorten the amortization period for certain purchased callable debt securities held at a premium. Specifically, this guidance requires the premium to be amortized to the earliest call date. This guidance does not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. This guidance is effective for the Bank for the interim and annual periods beginning on January 1, 2019, and early adoption is permitted. This guidance should be applied using a modified retrospective method through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Bank does not intend to adopt this guidance early. The Bank has evaluated this guidance and its effect on the Bank’s financial condition, results of operations, and cash flows is not expected to be material. Measurement of Credit Losses on Financial Instruments (ASU 2016-13) On June 16, 2016, the FASB issued amended guidance for the accounting of credit losses on financial instruments. The amendments require entities to measure expected credit losses based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. The new guidance requires a financial asset, or a group of financial assets, measured at amortized cost to be presented at the net amount expected to be collected. The guidance also requires, among other things, the following: • The statement of income to reflect the measurement of credit losses for newly recognized financial assets, as well as the expected increases or decreases of expected credit losses that have taken place during the period. • Entities to determine the allowance for credit losses for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination (PCD) that are measured at amortized cost in a similar manner to other financial assets measured at amortized cost. The initial allowance for credit losses is required to be added to the purchase price of the assets acquired. • Entities to record credit losses relating to available-for-sale (AFS) debt securities through an allowance for credit losses. The amendments limit the allowance for credit losses to the amount by which fair value is below amortized cost. • Public entities to further disaggregate the current disclosure of credit quality indicators in relation to the amortized cost of financing receivables by the year of origination (i.e., vintage). This guidance is effective for the Bank for the interim and annual periods beginning on January 1, 2020. Early application is permitted as of the interim and annual reporting periods beginning after December 15, 2018. This guidance should be applied using a modified-retrospective approach, through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. In addition, entities are required to use a prospective transition approach for PCD assets upon adoption and for debt securities for which an other-than-temporary impairment had been recognized before the effective date. The Bank does not intend to adopt the new guidance early. While the Bank is in the process of evaluating this guidance, the Bank expects the adoption of the guidance may result in an increase in the allowance for credit losses and corresponding expense, including an allowance for debt securities, given the requirement to assess losses for the entire estimated life of the financial asset. The effect on the Bank’s financial condition, results of operations, and cash flows will depend upon the composition of financial assets held by the Bank at the adoption date as well as the economic conditions and forecasts at that time. Leases (ASU 2016-02) On February 25, 2016, the FASB issued guidance which requires recognition of lease assets and lease liabilities on the statement of condition and disclosure of key information about leasing arrangements. Specifically, this guidance requires a lessee, of operating or finance leases, to recognize on the statement of condition a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election not to recognize lease assets and lease liabilities. Under previous GAAP, a lessee was not required to recognize lease assets and lease liabilities arising from operating leases on the statement of condition. While this guidance does not fundamentally change lessor accounting, some changes have been made to align that guidance with the lessee guidance and other areas within GAAP. This guidance becomes effective for the Bank for the interim and annual periods beginning on January 1, 2019, and early application is permitted. In July 2018, the FASB issued amendments that, among other things, provide entities with an additional transition method to adopt the guidance. The new transition method allows entities an option to recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Bank does not intend to adopt this new guidance early. Upon adoption, the Bank expects to report higher assets and liabilities as a result of recording right-of-use assets and lease liabilities on its statements of condition. The Bank is in the process of evaluating this guidance, and its effect on the Bank’s financial condition, results of operations, and cash flows has not yet been determined.
Other Than Temporary Impairment, Policy [Policy Text Block]	The Bank evaluates its individual AFS and HTM securities in an unrealized loss position for other-than-temporary impairment (OTTI) on a quarterly basis. As part of its evaluation of securities for OTTI, the Bank considers its intent to sell each debt security and whether it is more likely than not that it will be required to sell the security before its anticipated recovery. If either of these conditions is met, the Bank will recognize an OTTI charge to earnings equal to the entire difference between the security’s amortized cost basis and its fair value at the reporting date. For securities in an unrealized loss position that meet neither of these conditions, the Bank performs analyses to determine if any of these securities are other-than-temporarily impaired.
Advance Prepayment Fees, Policy [Policy Text Block]	The Bank generally charges a prepayment fee for advances that a borrower elects to terminate prior to the stated maturity or outside of a predetermined call or put date. The fees charged are priced to make the Bank financially indifferent to the prepayment of the advance. For certain advances with symmetrical prepayment features, the Bank may charge the borrower a prepayment fee or pay the borrower a prepayment credit, depending on certain circumstances, such as movements in interest rates, when the advance is prepaid. Prepayment fees and credits are recorded net of fair value hedging adjustments in advance income in the Statements of Income.
Loan and leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]	The Bank utilizes an allowance for credit losses to reserve for estimated losses in its conventional MPF and MPP mortgage loan portfolios at the balance sheet date. The measurement of the Bank’s MPF and MPP allowance for credit losses is determined by the following: • reviewing similar conventional mortgage loans for impairment on a collective basis. This evaluation is primarily based on the following factors: (i) current loan delinquencies, (ii) loans migrating to collateral-dependent status, and (iii) actual historical loss severities; • reviewing conventional mortgage loans for impairment on an individual basis; and • estimating additional credit losses in the conventional mortgage loan portfolio. These losses result from other factors that may not be captured in the methodology previously described at the balance sheet date, which include but are not limited to certain quantifiable economic factors, such as unemployment rates and home prices impacting housing markets.
Impairment Financing Receivable, Policy [Policy Text Block]	As previously described, the Bank evaluates certain conventional mortgage loans for impairment individually. A loan is considered impaired when, based on current information and events, it is probable that the Bank will be unable to collect all amounts due according to the contractual terms of the loan agreement.
Derivatives, Offsetting Fair Value Amounts, Policy [Policy Text Block]	The Bank presents derivative instruments, related cash collateral, including initial margin, received or pledged, and associated accrued interest on a net basis by clearing agent and/or by counterparty when it has met the netting requirements. Additional information regarding these agreements is provided in “Note 1 — Summary of Significant Accounting Policies” in the 2017 Form 10-K. The Bank has analyzed the enforceability of offsetting rights incorporated in its cleared derivative transactions and has determined that the exercise of those offsetting rights by a non-defaulting party under these transactions should be upheld under applicable law upon an event of default, including a bankruptcy, insolvency, or similar proceeding involving the Clearinghouse or the clearing agent, or both. Based on this analysis, the Bank presents a net derivative receivable or payable for all of its transactions through a particular clearing agent with a particular Clearinghouse.
Shares Subject to Mandatory Redemption, Changes in Redemption Value, Policy [Policy Text Block]	The Bank reclassifies capital stock subject to redemption from equity to a liability (mandatorily redeemable capital stock) at the time shares meet the definition of a mandatorily redeemable financial instrument. This occurs after a member provides written notice of intention to withdraw from membership, becomes ineligible for continuing membership, or attains non-member status by merger or consolidation, charter termination, or other involuntary termination from membership. Dividends on mandatorily redeemable capital stock are classified as interest expense in the Statements of Income.
Restricted Retained Earnings, Policy [Policy Text Block]	The Bank entered into a Joint Capital Enhancement Agreement (JCE Agreement) with all of the other FHLBanks in February 2011. The JCE Agreement, as amended, is intended to enhance the capital position of the Bank over time. It requires the Bank to allocate 20 percent of its quarterly net income to a separate restricted retained earnings account until the balance of that account equals at least one percent of its average balance of outstanding consolidated obligations for the previous quarter. The restricted retained earnings are not available to pay dividends.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair value amounts are determined by the Bank using available market information and reflect the Bank’s best judgment of appropriate valuation methods. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (i.e., and exit price). The fair value hierarchy requires an entity to maximize the use of significant observable inputs and minimize the use of significant unobservable inputs when measuring fair value. The inputs are evaluated and an overall level for the fair value measurement is determined. This overall level is an indication of market observability of the fair value measurement for the asset or liability. The fair value hierarchy prioritizes the inputs used to measure fair value into three broad levels: • Level 1 Inputs. Quoted prices (unadjusted) for identical assets or liabilities in an active market that the Bank can access on the measurement date. • Level 2 Inputs. Inputs other than quoted prices within Level 1 that are observable inputs for the asset or liability, either directly or indirectly. If the asset or liability has a specified (contractual) term, a Level 2 input must be observable for substantially the full term of the asset or liability. Level 2 inputs include the following: (i) quoted prices for similar assets or liabilities in active markets, (ii) quoted prices for identical or similar assets or liabilities in markets that are not active, (iii) inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates and yield curves that are observable at commonly quoted intervals and implied volatilities, and (iv) market-corroborated inputs. • Level 3 Inputs. Unobservable inputs for the asset or liability. The Bank reviews its fair value hierarchy classifications on a quarterly basis. Changes in the observability of the valuation inputs may result in a reclassification of certain assets or liabilities. These reclassifications are reported as transfers in/out as of the beginning of the quarter in which the changes occur.
Commitments and Contingencies, Policy [Policy Text Block]	Litigation settlement gains are considered realized and recorded when the Bank receives cash or assets that are readily convertible to known amounts of cash or claims to cash. In addition, litigation settlement gains are considered realizable and recorded when the Bank enters into a signed agreement that is not subject to appeal, where the counterparty has the ability to pay, and the amount to be received can be reasonably estimated. Prior to being realized or realizable, the Bank considers potential litigation settlement gains to be gain contingencies, and therefore they are not recorded in the Statements of Income. The Bank records legal expenses related to litigation settlements as incurred in other expenses in the Statements of Income with the exception of certain legal expenses related to litigation settlement awards that are contingent based fees for the attorneys representing the Bank. The Bank incurs and recognizes these contingent based legal fees only when litigation settlement awards are realized, at which time these fees are netted against the gains recognized on the litigation settlement.
Reclassification, Policy [Policy Text Block]	Reclassifications Certain amounts in the Bank’s 2017 financial statements and footnotes have been reclassified to conform to the presentation as of June 30, 2018 . In particular, due to the change in current presentation, variation margin on cleared derivatives has been allocated to the individual derivative instruments. Previously, this amount was included as a component of netting adjustments and cash collateral.

Trading Securities (Tables)

Trading Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities [Table Text Block]	Trading securities were as follows (dollars in millions): June 30, December 31, Non-mortgage-backed securities U.S. obligations 1 $ 182 $ 197 GSE and Tennessee Valley Authority obligations 57 260 Other 2 265 272 Total non-mortgage-backed securities 504 729 Mortgage-backed securities GSE multifamily 433 448 Total fair value $ 937 $ 1,177 1 Represents investment securities backed by the full faith and credit of the U.S. Government. 2 Consists of taxable municipal bonds.

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Schedule of Available-for-sale Securities [Line Items]
Schedule of Available-for-Sale Securities Reconciliation [Table Text Block]	AFS securities we re as follows (dollars in millions): June 30, 2018 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities U.S. obligations 2 $ 2,808 $ 13 $ (1 ) $ 2,820 GSE and Tennessee Valley Authority obligations 1,001 38 — 1,039 State or local housing agency obligations 908 — (2 ) 906 Other 3 260 12 — 272 Total non-mortgage-backed securities 4,977 63 (3 ) 5,037 Mortgage-backed securities U.S. obligations single-family 2 4,065 33 (1 ) 4,097 GSE single-family 883 7 (5 ) 885 GSE multifamily 9,380 59 (7 ) 9,432 Total mortgage-backed securities 14,328 99 (13 ) 14,414 Total $ 19,305 $ 162 $ (16 ) $ 19,451 December 31, 2017 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities U.S. obligations 2 $ 3,096 $ 8 $ (5 ) $ 3,099 GSE and Tennessee Valley Authority obligations 1,197 39 — 1,236 State or local housing agency obligations 935 — (1 ) 934 Other 3 269 9 — 278 Total non-mortgage-backed securities 5,497 56 (6 ) 5,547 Mortgage-backed securities U.S. obligations single-family 2 3,716 11 (1 ) 3,726 GSE single-family 983 7 (2 ) 988 GSE multifamily 10,482 57 (4 ) 10,535 Total mortgage-backed securities 15,181 75 (7 ) 15,249 Total $ 20,678 $ 131 $ (13 ) $ 20,796 1 Amortized cost includes adjustments made to the cost basis of an investment for accretion, amortization, and/or fair value hedge accounting adjustments. 2 Represents investment securities backed by the full faith and credit of the U.S. Government. 3 Consists of taxable municipal bonds and/or Private Export Funding Corporation (PEFCO) bonds.
Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Schedule of Unrealized Loss on Investments [ Table Text Block]	The following tables summarize AFS securities with unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in millions). In cases where the gross unrealized losses for an investment category are less than $1 million, the losses are not reported. June 30, 2018 Less than 12 Months 12 Months or More Total Fair Unrealized Losses Fair Unrealized Losses Fair Unrealized Losses Non-mortgage-backed securities U.S. obligations 1 $ 316 $ — $ 338 $ (1 ) $ 654 $ (1 ) State or local housing agency obligations 13 — 594 (2 ) 607 (2 ) Total non-mortgage-backed securities 329 — 932 (3 ) 1,261 (3 ) Mortgage-backed securities U.S. obligations single-family 1 497 (1 ) — — 497 (1 ) GSE single-family 297 (5 ) 48 — 345 (5 ) GSE multifamily 2,653 (4 ) 859 (3 ) 3,512 (7 ) Total mortgage-backed securities 3,447 (10 ) 907 (3 ) 4,354 (13 ) Total $ 3,776 $ (10 ) $ 1,839 $ (6 ) $ 5,615 $ (16 ) December 31, 2017 Less than 12 Months 12 Months or More Total Fair Unrealized Losses Fair Unrealized Losses Fair Unrealized Losses Non-mortgage-backed securities U.S. obligations 1 $ 29 $ — $ 1,783 $ (5 ) $ 1,812 $ (5 ) State or local housing agency obligations 6 — 655 (1 ) 661 (1 ) Total non-mortgage-backed securities 35 — 2,438 (6 ) 2,473 (6 ) Mortgage-backed securities U.S. obligations single-family 1 111 — 887 (1 ) 998 (1 ) GSE single-family 222 (2 ) 53 — 275 (2 ) GSE multifamily 224 (1 ) 1,756 (3 ) 1,980 (4 ) Total mortgage-backed securities 557 (3 ) 2,696 (4 ) 3,253 (7 ) Total $ 592 $ (3 ) $ 5,134 $ (10 ) $ 5,726 $ (13 ) 1 Represents investment securities backed by the full faith and credit of the U.S. Government.
Investments Classified by Contractual Maturity Date [Table Text Block]	The following table summarizes AFS securities by contractual maturity. Expected maturities of some securities may differ from contractual maturities as borrowers may have the right to call or prepay obligations with or without call or prepayment fees (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amortized Fair Value Amortized Fair Value Non-mortgage-backed securities Due in one year or less $ 26 $ 26 $ 158 $ 159 Due after one year through five years 969 976 750 755 Due after five years through ten years 3,160 3,181 3,574 3,583 Due after ten years 822 854 1,015 1,050 Total non-mortgage-backed securities 4,977 5,037 5,497 5,547 Mortgage-backed securities 14,328 14,414 15,181 15,249 Total $ 19,305 $ 19,451 $ 20,678 $ 20,796

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities [Table Text Block]	Held-to-maturity (HTM) securities wer e as follows (dollars in millions): June 30, 2018 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities GSE and Tennessee Valley Authority obligations $ 391 $ 49 $ (2 ) $ 438 State or local housing agency obligations 427 1 (2 ) 426 Total non-mortgage-backed securities 818 50 (4 ) 864 Mortgage-backed securities U.S. obligations single-family 2 11 — — 11 U.S. obligations commercial 2 2 — — 2 GSE single-family 2,453 8 (24 ) 2,437 Private-label residential 11 — — 11 Total mortgage-backed securities 2,477 8 (24 ) 2,461 Total $ 3,295 $ 58 $ (28 ) $ 3,325 December 31, 2017 Amortized 1 Gross Gross Fair Value Non-mortgage-backed securities GSE and Tennessee Valley Authority obligations $ 393 $ 65 $ — $ 458 State or local housing agency obligations 454 2 (2 ) 454 Total non-mortgage-backed securities 847 67 (2 ) 912 Mortgage-backed securities U.S. obligations single-family 2 15 — — 15 U.S. obligations commercial 2 2 — — 2 GSE single-family 2,752 7 (14 ) 2,745 Private-label residential 12 — — 12 Total mortgage-backed securities 2,781 7 (14 ) 2,774 Total $ 3,628 $ 74 $ (16 ) $ 3,686 1 Amortized cost includes adjustments made to the cost basis of an investment for accretion or amortization. 2 Represents investment securities backed by the full faith and credit of the U.S. Government.
Held-to-maturity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Schedule of Unrealized Loss on Investments [ Table Text Block]	The following tables summarize HTM securities with unrealized losses by major security type and the length of time that individual securities have been in a continuous unrealized loss position (dollars in millions). In cases where the gross unrealized losses for an investment category are less than $1 million, the losses are not reported. June 30, 2018 Less than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Non-mortgage-backed securities GSE and Tennessee Valley Authority obligations $ 90 $ (2 ) $ — $ — $ 90 $ (2 ) State or local housing agency obligations $ 17 $ — $ 162 $ (2 ) $ 179 $ (2 ) Total non-mortgage-backed securities 107 (2 ) 162 (2 ) 269 (4 ) Mortgage-backed securities U.S. obligations single-family 1 — — 5 — 5 — U.S. obligations commercial 1 1 — 1 — 2 — GSE single-family 12 — 1,200 (24 ) 1,212 (24 ) Private-label residential — — 7 — 7 — Total mortgage-backed securities 13 — 1,213 (24 ) 1,226 (24 ) Total $ 120 $ (2 ) $ 1,375 $ (26 ) $ 1,495 $ (28 ) December 31, 2017 Less than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Non-mortgage-backed securities State or local housing agency obligations $ 2 $ — $ 168 $ (2 ) $ 170 $ (2 ) Total non-mortgage-backed securities 2 — 168 (2 ) 170 (2 ) Mortgage-backed securities U.S. obligations single-family 1 7 — 1 — 8 — U.S. obligations commercial 1 1 — 1 — 2 — GSE single-family 42 — 1,427 (14 ) 1,469 (14 ) Private-label residential — — 8 — 8 — Total mortgage-backed securities 50 — 1,437 (14 ) 1,487 (14 ) Total $ 52 $ — $ 1,605 $ (16 ) $ 1,657 $ (16 ) 1 Represents investment securities backed by the full faith and credit of the U.S. Government.
Investments Classified by Contractual Maturity Date [Table Text Block]	The following table summarizes HTM securities by contractual maturity. Expected maturities of some securities may differ from contractual maturities as borrowers may have the right to call or prepay obligations with or without call or prepayment fees (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amortized Fair Value Amortized Fair Value Non-mortgage-backed securities Due in one year or less $ 14 $ 14 $ 20 $ 20 Due after one year through five years 71 71 72 72 Due after five years through ten years 340 362 344 376 Due after ten years 393 417 411 444 Total non-mortgage-backed securities 818 864 847 912 Mortgage-backed securities 2,477 2,461 2,781 2,774 Total $ 3,295 $ 3,325 $ 3,628 $ 3,686

Advances (Tables)

Advances (Tables)	6 Months Ended
	Jun. 30, 2018
Advances [Abstract]
Schedule of Federal Home Loan Bank Advances by Year of Contractual Maturity [Table Text Block]	The following table summarizes the Bank’s advances outstanding by contractual maturity (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Amount Weighted Overdrawn demand deposit accounts $ 34 3.10 % $ 1 3.63 % Due in one year or less 52,016 2.16 45,310 1.62 Due after one year through two years 18,954 2.25 17,094 1.79 Due after two years through three years 20,620 2.31 14,222 1.64 Due after three years through four years 10,543 2.51 17,561 1.79 Due after four years through five years 3,918 2.51 3,089 1.91 Thereafter 4,097 2.83 5,401 2.28 Total par value 110,182 2.28 % 102,678 1.73 % Premiums 44 53 Discounts (10 ) (12 ) Fair value hedging adjustments (253 ) (106 ) Total $ 109,963 $ 102,613 The following table summarizes all advances by year of contractual maturity or next call date for callable advances, and by year of contractual maturity or next put date for putable advances (dollars in millions): Year of Contractual Maturity Year of Contractual Maturity or Next Put Date June 30, 2018 December 31, 2017 June 30, 2018 December 31, 2017 Overdrawn demand deposit accounts $ 34 $ 1 $ 34 $ 1 Due in one year or less 83,073 69,971 52,075 45,372 Due after one year through two years 11,161 16,539 18,954 17,094 Due after two years through three years 3,458 3,809 20,595 14,222 Due after three years through four years 7,746 8,511 10,533 17,520 Due after four years through five years 1,895 1,276 3,909 3,073 Thereafter 2,815 2,571 4,082 5,396 Total par value $ 110,182 $ 102,678 $ 110,182 $ 102,678

Mortgage Loans Held for Portf31

Mortgage Loans Held for Portfolio (Tables)	6 Months Ended
	Jun. 30, 2018
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	The following table presents information on the Bank’s mortgage loans held for portfolio (dollars in millions): June 30, 2018 December 31, 2017 Fixed rate, long-term single-family mortgage loans $ 6,281 $ 5,998 Fixed rate, medium-term 1 single-family mortgage loans 934 1,003 Total unpaid principal balance 7,215 7,001 Premiums 99 98 Discounts (6 ) (6 ) Basis adjustments from mortgage loan commitments 3 5 Total mortgage loans held for portfolio 7,311 7,098 Allowance for credit losses (1 ) (2 ) Total mortgage loans held for portfolio, net $ 7,310 $ 7,096 1 Medium-term is defined as a term of 15 years or less. The following table presents the Bank’s mortgage loans held for portfolio by collateral or guarantee type (dollars in millions): June 30, 2018 December 31, 2017 Conventional mortgage loans $ 6,699 $ 6,472 Government-insured mortgage loans 516 529 Total unpaid principal balance $ 7,215 $ 7,001

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2018
Allowance for Credit Losses [Abstract]
Allowance for Credit Losses by Impairment Methodology [Table Text Block]	The following table summarizes the allowance for credit losses and the recorded investment of the Bank’s conventional mortgage loan portfolio by impairment methodology (dollars in millions): June 30, 2018 December 31, 2017 Allowance for credit losses Collectively evaluated for impairment $ 1 $ 2 Recorded investment 1 Collectively evaluated for impairment $ 6,759 $ 6,530 Individually evaluated for impairment, without a related allowance 59 61 Total recorded investment $ 6,818 $ 6,591 1 Represents the unpaid principal balance adjusted for accrued interest, unamortized premiums, discounts, basis adjustments, and direct write-downs.
Past Due Financing Receivables [Table Text Block]	The tables below summarize the Bank’s key credit quality indicators for mortgage loans (dollars in millions): June 30, 2018 Conventional MPF/MPP Government-Guaranteed or -Insured 6 Total Past due 30 - 59 days $ 44 $ 18 $ 62 Past due 60 - 89 days 13 6 19 Past due 90 - 179 days 10 3 13 Past due 180 days or more 16 4 20 Total past due mortgage loans 83 31 114 Total current mortgage loans 6,735 499 7,234 Total recorded investment of mortgage loans 1 $ 6,818 $ 530 $ 7,348 In process of foreclosure (included above) 2 $ 11 $ 2 $ 13 Serious delinquency rate 3 — % 1 % — % Past due 90 days or more and still accruing interest 4 — $ 7 $ 7 Non-accrual mortgage loans 5 $ 40 $ — $ 40 1 Represents the unpaid principal balance adjusted for accrued interest, unamortized premiums, discounts, basis adjustments, and direct write-downs. 2 Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu has been reported. Loans in process of foreclosure are included in past due or current loans depending on their payment status. 3 Represents mortgage loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the total recorded investment. 4 Represents government-insured mortgage loans that are 90 days or more past due. 5 Represents conventional mortgage loans that are 90 days or more past due and TDRs. 6 The Bank did not record any allowance for credit losses on government-guaranteed or -insured mortgage loans at June 30, 2018 and December 31, 2017 . December 31, 2017 Conventional MPF/MPP Government- Guaranteed or -Insured 6 Total Past due 30 - 59 days $ 58 $ 19 $ 77 Past due 60 - 89 days 16 6 22 Past due 90 - 179 days 15 5 20 Past due 180 days or more 21 6 27 Total past due mortgage loans 110 36 146 Total current mortgage loans 6,481 507 6,988 Total recorded investment of mortgage loans 1 $ 6,591 $ 543 $ 7,134 In process of foreclosure (included above) 2 $ 12 $ 2 $ 14 Serious delinquency rate 3 1 % 2 % 1 % Past due 90 days or more and still accruing interest 4 $ — $ 11 $ 11 Non-accrual mortgage loans 5 $ 48 $ — $ 48 1 Represents the unpaid principal balance adjusted for accrued interest, unamortized premiums, discounts, basis adjustments, and direct write-downs. 2 Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu has been reported. Loans in process of foreclosure are included in past due or current loans depending on their payment status. 3 Represents mortgage loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the total recorded investment. 4 Represents government-insured mortgage loans that are 90 days or more past due. 5 Represents conventional mortgage loans that are 90 days or more past due and TDRs.

Derivatives and Hedging Activ33

Derivatives and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Offsetting Assets [Table Text Block]	The following table presents the fair value of derivative instruments meeting or not meeting the netting requirements and the related collateral received from or pledged to counterparties (dollars in millions): June 30, 2018 Derivative Instruments Meeting Netting Requirements Amount Recognized Gross Amount of Netting Adjustments and Cash Collateral Total Derivative Assets and Total Derivative Liabilities Derivative Assets Uncleared derivatives $ 151 $ (150 ) $ 1 Cleared derivatives 3 79 82 Total $ 154 $ (71 ) $ 83 Derivative Liabilities Uncleared derivatives $ 120 $ (118 ) $ 2 Cleared derivatives 7 (7 ) — Total $ 127 $ (125 ) $ 2 December 31, 2017 Derivative Instruments Meeting Netting Requirements Amount Recognized 1 Gross Amount of Netting Adjustments and Cash Collateral Total Derivative Assets and Total Derivative Liabilities Derivative Assets Uncleared derivatives $ 88 $ (87 ) $ 1 Cleared derivatives 9 90 99 Total $ 97 $ 3 $ 100 Derivative Liabilities Uncleared derivatives $ 170 $ (164 ) $ 6 Cleared derivatives 18 (18 ) — Total $ 188 $ (182 ) $ 6 1 To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with gross amount of netting adjustments and cash collateral.
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table summarizes the Bank’s notional amount and fair value of derivative instruments and total derivative assets and liabilities. Total derivative assets and liabilities include the effect of netting adjustments and cash collateral. For purposes of this disclosure, the derivative values include the fair value of derivatives and the related accrued interest (dollars in millions): June 30, 2018 December 31, 2017 1 Notional Amount Derivative Assets Derivative Liabilities Notional Amount Derivative Assets Derivative Liabilities Derivatives designated as hedging instruments (fair value hedges) Interest rate swaps $ 46,828 $ 125 $ 105 $ 52,120 $ 77 $ 151 Derivatives not designated as hedging instruments (economic hedges) Interest rate swaps 1,372 29 21 1,407 20 37 Forward settlement agreements (TBAs) 167 — 1 66 — — Mortgage delivery commitments 172 — — 72 — — Total derivatives not designated as hedging instruments 1,711 29 22 1,545 20 37 Total derivatives before netting and collateral adjustments $ 48,539 154 127 $ 53,665 97 188 Netting adjustments and cash collateral 2 (71 ) (125 ) 3 (182 ) Total derivative assets and derivative liabilities $ 83 $ 2 $ 100 $ 6 1 To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017. Previously, this amount was included with netting adjustments and cash collateral. 2 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. At June 30, 2018 and December 31, 2017 , cash collateral posted by the Bank (including accrued interest) was $128 million and $191 million . At June 30, 2018 and December 31, 2017 , the Bank received cash collateral (including accrued interest) from clearing agents and/or counterparties of $73 million and $6 million .
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	The following table summarizes the components of “Net gains (losses) on derivatives and hedging activities” as presented in the Statements of Income (dollars in millions): For the Three Months Ended For the Six Months Ended June 30, June 30, 2018 2017 2018 2017 Derivatives designated as hedging instruments (fair value hedges) Interest rate swaps $ 7 $ 6 $ 7 $ 10 Derivatives not designated as hedging instruments (economic hedges) Interest rate swaps 7 (6 ) 28 (1 ) Forward settlement agreements (TBAs) 1 — 2 (1 ) Mortgage delivery commitments — — (1 ) 1 Net interest settlements (1 ) (3 ) (3 ) (7 ) Total net gains (losses) related to derivatives not designated as hedging instruments 7 (9 ) 26 (8 ) Other 1 — — 1 1 Net gains (losses) on derivatives and hedging activities $ 14 $ (3 ) $ 34 $ 3 1 Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settled contract.
Schedule of Derivative Instruments By Type, Gain (Loss) in Statement of Financial Performance [Table Text Block]	The following tables summarize, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair value hedging relationships, the net fair value hedge ineffectiveness, and the effect of those derivatives on the Bank’s net interest income (dollars in millions): For the Three Months Ended June 30, 2018 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ 55 $ (48 ) $ 7 $ (6 ) Advances 2 31 (29 ) 2 13 Consolidated obligation bonds — (2 ) (2 ) (62 ) Total $ 86 $ (79 ) $ 7 $ (55 ) For the Three Months Ended June 30, 2017 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ (41 ) $ 49 $ 8 $ (24 ) Advances 2 (25 ) 26 1 (21 ) Consolidated obligation bonds 72 (75 ) (3 ) 7 Total $ 6 $ — $ 6 $ (38 ) 1 Represents the net interest settlements on derivatives in fair value hedge relationships and the amortization of the financing element of off-market derivatives, both of which are included in the interest income or interest expense line item of the respective hedged item type. During the three months ended June 30, 2018 and 2017 , the amortization for off-market derivatives totaled less than $1 million and $4 million. 2 Includes net gains (losses) on fair value hedge firm commitments of forward starting advances. The following tables summarize, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair value hedging relationships, the net fair value hedge ineffectiveness, and the effect of those derivatives on the Bank’s net interest income (dollars in millions): For the Six Months Ended June 30, 2018 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ 207 $ (203 ) $ 4 $ (19 ) Advances 2 156 (154 ) 2 12 Consolidated obligation bonds (154 ) 155 1 (94 ) Total $ 209 $ (202 ) $ 7 $ (101 ) For the Six Months Ended June 30, 2017 Hedged Item Type Net Gains (Losses) on Derivatives Net Gains (Losses) on Hedged Items Net Fair Value Hedge Ineffectiveness Effect on Net Interest Income 1 Available-for-sale investments $ (4 ) $ 18 $ 14 $ (53 ) Advances 2 8 (6 ) 2 (45 ) Consolidated obligation bonds 22 (28 ) (6 ) 26 Total $ 26 $ (16 ) $ 10 $ (72 ) 1 Represents the net interest settlements on derivatives in fair value hedge relationships and the amortization of the financing element of off-market derivatives, both of which are included in the interest income or interest expense line item of the respective hedged item type. During the six months ended June 30, 2018 and 2017, the amortization for off-market derivatives totaled less than $1 million and $9 million. 2 Includes net gains (losses) on fair value hedge firm commitments of forward starting advances.
Offsetting Assets and Liabilities [Table Text Block]	The following table presents the fair value of derivative instruments meeting or not meeting the netting requirements and the related collateral received from or pledged to counterparties (dollars in millions): June 30, 2018 Derivative Instruments Meeting Netting Requirements Amount Recognized Gross Amount of Netting Adjustments and Cash Collateral Total Derivative Assets and Total Derivative Liabilities Derivative Assets Uncleared derivatives $ 151 $ (150 ) $ 1 Cleared derivatives 3 79 82 Total $ 154 $ (71 ) $ 83 Derivative Liabilities Uncleared derivatives $ 120 $ (118 ) $ 2 Cleared derivatives 7 (7 ) — Total $ 127 $ (125 ) $ 2 December 31, 2017 Derivative Instruments Meeting Netting Requirements Amount Recognized 1 Gross Amount of Netting Adjustments and Cash Collateral Total Derivative Assets and Total Derivative Liabilities Derivative Assets Uncleared derivatives $ 88 $ (87 ) $ 1 Cleared derivatives 9 90 99 Total $ 97 $ 3 $ 100 Derivative Liabilities Uncleared derivatives $ 170 $ (164 ) $ 6 Cleared derivatives 18 (18 ) — Total $ 188 $ (182 ) $ 6 1 To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with gross amount of netting adjustments and cash collateral.

Consolidated Obligations (Table

Consolidated Obligations (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Short-term Debt [Table Text Block]	The following table summarizes the Bank’s discount notes (dollars in millions): June 30, 2018 December 31, 2017 Amount Weighted Average Interest Rate Amount Weighted Average Interest Rate Par value $ 43,241 1.87 % $ 36,740 1.20 % Discounts and concessions 1 (119 ) (58 ) Total $ 43,122 $ 36,682 1 Concessions represent fees paid to dealers in connections with the issuance of certain consolidated obligation discount notes.
Schedule of Maturities of Long-term Debt [Table Text Block]	The following table summarizes the Bank’s bonds outstanding by contractual maturity (dollars in millions): June 30, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Average Interest Rate Amount Weighted Average Interest Rate Due in one year or less $ 57,307 1.87 % $ 50,077 1.32 % Due after one year through two years 24,341 1.90 32,249 1.43 Due after two years through three years 3,034 2.59 3,177 2.84 Due after three years through four years 7,207 1.71 7,422 1.69 Due after four years through five years 2,124 2.31 1,507 2.42 Thereafter 4,917 3.37 4,752 3.10 Total par value 98,930 1.97 % 99,184 1.54 % Premiums 168 193 Discounts and concessions 1 (52 ) (60 ) Fair value hedging adjustments (578 ) (424 ) Total $ 98,468 $ 98,893 1 Concessions represent fees paid to dealers in connections with the issuance of certain consolidated obligation bonds.
Schedule of Long-term Debt by Call Feature [Table Text Block]	The following table summarizes the Bank’s bonds outstanding by call features (dollars in millions): June 30, December 31, Non-callable or non-putable $ 94,742 $ 97,196 Callable 4,188 1,988 Total par value $ 98,930 $ 99,184

Capital (Tables)

Capital (Tables)	6 Months Ended
	Jun. 30, 2018
Capital [Abstract]
Mandatorily Redeemable Capital Stock [Table Text Block]	The following table summarizes changes in mandatorily redeemable capital stock (dollars in millions): For the Three Months Ended June 30, 2018 2017 Balance, beginning of period $ 356 $ 494 Capital stock reclassified to (from) mandatorily redeemable capital stock, net 36 18 Net payments for repurchases/redemptions of mandatorily redeemable capital stock (19 ) (32 ) Balance, end of period $ 373 $ 480 The following table summarizes changes in mandatorily redeemable capital stock (dollars in millions): For the Six Months Ended June 30, 2018 2017 Balance, beginning of period $ 385 $ 664 Capital stock reclassified to (from) mandatorily redeemable capital stock, net 39 28 Net payments for repurchases/redemptions of mandatorily redeemable capital stock (51 ) (212 ) Balance, end of period $ 373 $ 480 The following table summarizes the Bank’s mandatorily redeemable capital stock by year of contractual redemption (dollars in millions): Year of Contractual Redemption 1 June 30, 2018 December 31, 2017 Due in one year or less $ — $ 4 Due after one year through two years 2 2 Due after two years through three years 1 — Due after three years through four years 11 1 Due after four years through five years 26 22 Thereafter 2 317 341 Past contractual redemption date due to outstanding activity with the Bank 16 15 Total $ 373 $ 385 1 At the Bank’s election, the mandatorily redeemable capital stock may be redeemed prior to the expiration of the five year redemption period that commences on the date of the notice of redemption, or in the case of captive insurance company members, on the date of the membership termination. 2 Represents mandatorily redeemable capital stock resulting from the Finance Agency rule previously discussed that makes captive insurance companies ineligible for FHLBank membership. The related mandatorily redeemable capital stock is not required to be redeemed until five years after the member's termination.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table summarizes changes in AOCI (dollars in millions): Net unrealized gains (losses) on AFS securities (Note 4) Pension and postretirement benefits Total AOCI Balance, March 31, 2017 $ 50 $ (3 ) $ 47 Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities 41 — 41 Reclassifications from AOCI to net income Amortization - pension and postretirement — 1 1 Net current period other comprehensive income (loss) 41 1 42 Balance, June 30, 2017 $ 91 $ (2 ) $ 89 Balance, March 31, 2018 $ 163 $ (4 ) $ 159 Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities (17 ) — (17 ) Net current period other comprehensive income (loss) (17 ) — (17 ) Balance, June 30, 2018 $ 146 $ (4 ) $ 142 Balance, December 31, 2016 $ (14 ) $ (4 ) $ (18 ) Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities 105 — 105 Reclassifications from AOCI to net income Amortization - pension and postretirement — 2 2 Net current period other comprehensive income (loss) 105 2 107 Balance, June 30, 2017 $ 91 $ (2 ) $ 89 Balance, December 31, 2017 $ 118 $ (4 ) $ 114 Other comprehensive income (loss) before reclassifications Net unrealized gains (losses) on AFS securities 28 — 28 Net current period other comprehensive income (loss) 28 — 28 Balance, June 30, 2018 $ 146 $ (4 ) $ 142
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]	The following table shows the Bank’s compliance with the Finance Agency’s regulatory capital requirements (dollars in millions): June 30, 2018 December 31, 2017 Required Actual Required Actual Regulatory capital requirements Risk-based capital $ 1,178 $ 7,770 $ 1,041 $ 7,292 Regulatory capital $ 6,039 $ 7,770 $ 5,804 $ 7,292 Leverage capital $ 7,549 $ 11,656 $ 7,255 $ 10,937 Capital-to-assets ratio 4.00 % 5.15 % 4.00 % 5.03 % Leverage ratio 5.00 % 7.72 % 5.00 % 7.54 %

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value, Option, Quantitative Disclosures [Table Text Block]	The following table summarizes the difference between the unpaid principal balance and fair value of outstanding instruments for which the fair value option was elected at June 30, 2018 (dollars in million): June 30, 2018 Unpaid Principal Balance Fair Value Fair Value Over (Under) Unpaid Principal Advances 1 $ 15 $ 15 $ — 1 At June 30, 2018 none of the advances were 90 days or more past due or had been placed on non-accrual status.
Fair Value, by Balance Sheet Grouping [Table Text Block]	The following table summarizes the carrying value, fair value, and fair value hierarchy of the Bank’s financial instruments at June 30, 2018 (dollars in millions). The Bank records trading securities, AFS securities, derivative assets, derivative liabilities, certain advances, and certain other assets at fair value on a recurring basis, and on occasion certain mortgage loans held for portfolio on a non-recurring basis. The Bank records all other financial assets and liabilities at amortized cost. The fair values do not represent an estimate of the overall market value of the Bank as a going concern, which would take into account future business opportunities and the net profitability of assets and liabilities. Fair Value Financial Instruments Carrying Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Cash and due from banks $ 201 $ 201 $ — $ — $ — $ 201 Interest-bearing deposits 1 — 1 — — 1 Securities purchased under agreements to resell 4,900 — 4,900 — — 4,900 Federal funds sold 4,435 — 4,435 — — 4,435 Trading securities 937 — 937 — — 937 Available-for-sale securities 19,451 — 19,451 — — 19,451 Held-to-maturity securities 3,295 — 3,314 11 — 3,325 Advances 109,963 — 110,031 — — 110,031 Mortgage loans held for portfolio, net 7,310 — 7,189 63 — 7,252 Accrued interest receivable 305 — 305 — — 305 Derivative assets, net 83 — 154 — (71 ) 83 Other assets 29 29 — — — 29 Liabilities Deposits (1,028 ) — (1,028 ) — — (1,028 ) Consolidated obligations Discount notes (43,122 ) — (43,119 ) — — (43,119 ) Bonds (98,468 ) — (98,539 ) — — (98,539 ) Total consolidated obligations (141,590 ) — (141,658 ) — — (141,658 ) Mandatorily redeemable capital stock (373 ) (373 ) — — — (373 ) Accrued interest payable (238 ) — (238 ) — — (238 ) Derivative liabilities, net (2 ) — (127 ) — 125 (2 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. The following table summarizes the carrying value, fair value, and fair value hierarchy of the Bank’s financial instruments at December 31, 2017 (dollars in millions): Fair Value Financial Instruments Carrying Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Cash and due from banks $ 503 $ 503 $ — $ — $ — $ 503 Interest-bearing deposits 1 — 1 — — 1 Securities purchased under agreements to resell 4,600 — 4,600 — — 4,600 Federal funds sold 4,250 — 4,250 — — 4,250 Trading securities 1,177 — 1,177 — — 1,177 Available-for-sale securities 20,796 — 20,796 — — 20,796 Held-to-maturity securities 3,628 — 3,674 12 — 3,686 Advances 102,613 — 102,708 — — 102,708 Mortgage loans held for portfolio, net 7,096 — 7,124 64 — 7,188 Accrued interest receivable 223 — 223 — — 223 Derivative assets, net 100 — 97 — 3 100 Other assets 28 28 — — — 28 Liabilities Deposits (1,107 ) — (1,107 ) — — (1,107 ) Borrowings from other FHLBanks (600 ) — (600 ) — — (600 ) Consolidated obligations Discount notes (36,682 ) — (36,674 ) — — (36,674 ) Bonds (98,893 ) — (99,150 ) — — (99,150 ) Total consolidated obligations (135,575 ) — (135,824 ) — — (135,824 ) Mandatorily redeemable capital stock (385 ) (385 ) — — — (385 ) Accrued interest payable (210 ) — (210 ) — — (210 ) Derivative liabilities, net (6 ) — (188 ) — 182 (6 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. To conform with current presentation $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with netting adjustments and cash collateral.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	The following table summarizes, for each hierarchy level, the Bank’s assets and liabilities that are measured at fair value in the Statements of Condition a t June 30, 2018 (dollar s in millions): Recurring Fair Value Measurements Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Trading securities U.S. obligations $ — $ 182 $ — $ — $ 182 GSE and Tennessee Valley Authority obligations — 57 — — 57 Other non-MBS — 265 — — 265 GSE multifamily MBS — 433 — — 433 Total trading securities — 937 — — 937 Available-for-sale securities U.S. obligations — 2,820 — — 2,820 GSE and Tennessee Valley Authority obligations — 1,039 — — 1,039 State or local housing agency obligations — 906 — — 906 Other non-MBS — 272 — — 272 U.S. obligations single-family MBS — 4,097 — — 4,097 GSE single-family MBS — 885 — — 885 GSE multifamily MBS — 9,432 — — 9,432 Total available-for-sale securities — 19,451 — — 19,451 Advances 2 — 15 — — 15 Derivative assets, net Interest-rate related — 154 — (71 ) 83 Other assets 29 — — — 29 Total recurring assets at fair value $ 29 $ 20,557 $ — $ (71 ) $ 20,515 Liabilities Derivative liabilities, net Interest-rate related — (126 ) — 125 (1 ) Forward settlement agreements (TBAs) — (1 ) — — (1 ) Total recurring liabilities at fair value $ — $ (127 ) $ — $ 125 $ (2 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. 2 Represents financial instruments recorded under the fair value option. The following table summarizes, for each hierarchy level, the Bank’s assets and liabilities that are measured at fair value in the Statements of Condition at December 31, 2017 (dollars in millions): Recurring Fair Value Measurements Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral 1 Total Assets Trading securities U.S. obligations $ — $ 197 $ — $ — $ 197 GSE and Tennessee Valley Authority obligations — 260 — — 260 Other non-MBS — 272 — — 272 GSE multifamily MBS — 448 — — 448 Total trading securities — 1,177 — — 1,177 Available-for-sale securities U.S. obligations — 3,099 — — 3,099 GSE and Tennessee Valley Authority obligations — 1,236 — — 1,236 State or local housing agency obligations — 934 — — 934 Other non-MBS — 278 — — 278 U.S. obligations single-family MBS — 3,726 — — 3,726 GSE single-family MBS — 988 — — 988 GSE multifamily MBS — 10,535 — — 10,535 Total available-for-sale securities — 20,796 — — 20,796 Derivative assets, net Interest-rate related — 97 — 3 100 Other assets 28 — — — 28 Total recurring assets at fair value $ 28 $ 22,070 $ — $ 3 $ 22,101 Liabilities Derivative liabilities, net Interest-rate related — (188 ) — 182 (6 ) Total recurring liabilities at fair value $ — $ (188 ) $ — $ 182 $ (6 ) 1 Amounts represent the application of the netting requirements that allow the Bank to net settle positive and negative positions and also cash collateral and the related accrued interest held or placed with the same clearing agent and/or counterparty. To conform with current presentation, $313 million in variation margin has been allocated to the individual derivative instruments as of December 31, 2017 . Previously, this amount was included with netting adjustments and cash collateral.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	The following table summarizes additional off-balance sheet commitments for the Bank (dollars in millions): June 30, 2018 December 31, 2017 Expire within one year Expire after one year Total Total Standby letters of credit 1 $ 9,111 $ 166 $ 9,277 $ 8,594 Standby bond purchase agreements 117 587 704 755 Commitments to purchase mortgage loans 172 — 172 72 Commitments to issue bonds 264 — 264 — Commitments to fund advances 779 1 780 1,138 1 Excludes commitments to issue standby letters of credit of $53 million and $7 million at June 30, 2018 and December 31, 2017 .

Activities with Stockholders (T

Activities with Stockholders (Tables)	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions by Balance Sheet Grouping [Table Text Block]	The following table summarizes the Bank’s outstanding transactions with Directors’ Financial Institutions (dollars in millions): June 30, 2018 December 31, 2017 Amount % of Total Amount % of Total Advances $ 5,134 5 $ 6,036 6 Mortgage loans 86 1 68 1 Deposits 11 1 39 4 Capital stock 256 4 297 5
Schedule Of Related Party Transactions By Related Party [Tables Text Block]	At June 30, 2018 , the Bank had the following business concentrations with stockholders (dollars in millions): Capital Stock Mortgage Interest Stockholder Amount % of Total 1 Advances Loans 4 Income 2 Wells Fargo Bank, N.A. $ 2,052 35 $ 51,025 $ 27 $ 550 Superior Guaranty Insurance Company 3 19 — — 463 — Total $ 2,071 35 $ 51,025 $ 490 $ 550 1 Pursuant to applicable Finance Agency regulations, the Bank’s voting structure limits the voting rights of these stockholders and other members holding a significant amount of the Bank’s capital stock. 2 Represents interest income earned on advances during the six months ended June 30, 2018 . Interest income on mortgage loans is excluded from this table as this interest relates to the borrower, not to the stockholder. 3 Superior Guaranty Insurance Company is an affiliate of Wells Fargo Bank, N.A. 4 PFI rights and obligations associated with MPP mortgage loans of $27 million were transferred from Wells Fargo Trust Company, N.A. (formerly Wells Fargo Bank Northwest N.A.) to Wells Fargo Bank, N.A. during the three months ended June 30, 2018. At December 31, 2017 , the Bank had the following business concentrations with stockholders (dollars in millions): Capital Stock Mortgage Interest Stockholder Amount % of Total 1 Advances Loans Income 2 Wells Fargo Bank, N.A. $ 1,843 34 $ 45,825 $ — $ 834 Superior Guaranty Insurance Company 3 22 — — 520 — Wells Fargo Bank Northwest N.A. 3 1 — — 30 — Total $ 1,866 34 $ 45,825 $ 550 $ 834 1 Pursuant to applicable Finance Agency regulations, the Bank’s voting structure limits the voting rights of these stockholders and other members holding a significant amount of the Bank’s capital stock. 2 Represents interest income earned on advances during the year ended December 31, 2017 . Interest income on mortgage loans is excluded from this table as this interest relates to the borrower, not to the stockholder. 3 Superior Guaranty Insurance Company and Wells Fargo Bank Northwest, N.A. were affiliates of Wells Fargo Bank, N.A at December 31, 2017.

Activities with Other FHLBanks

Activities with Other FHLBanks (Tables)	6 Months Ended
	Jun. 30, 2018
Activities with Other FHLBanks [Abstract]
Schedule of Loans to Other Federal Home Loan Banks [Table Text Block]	The following table summarizes loan activity to other FHLBanks during the six months ended June 30, 2018 and 2017 (dollars in millions): Other FHLBank Beginning Balance Loans Principal Repayment Ending Balance 2018 Boston $ — $ 800 $ (800 ) $ — San Francisco — 300 (300 ) — Dallas — 500 (500 ) — $ — $ 1,600 $ (1,600 ) $ — 2017 San Francisco $ 200 $ — $ (200 ) $ —
Schedule of Loans From Other Federal Home Loan Banks [Table Text Block]	The following table summarizes borrowing activity from other FHLBanks during the six months ended June 30, 2018 (dollars in millions): Other FHLBank Beginning Balance Borrowing Principal Payment Ending Balance 2018 Atlanta $ 200 $ — $ (200 ) $ — Boston 400 — (400 ) — $ 600 $ — $ (600 ) $ —

Background Information (Details

Background Information (Details)	Jun. 30, 2018bank
Background Information [Abstract]
Number of Federal Home Loan Banks	11

Trading Securities (Major Secur

Trading Securities (Major Security Types) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 937	$ 1,177
Other U.S. obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	182	197
GSE obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	57	260
Other [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	265	272
Non-mortgage-backed securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	504	729
Multifamily [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 433	$ 448

Trading Securities (Net Gains (

Trading Securities (Net Gains (Losses) on Trading Securities) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Trading Securities [Abstract]
Trading Securities, Change in Unrealized Holding Gain (Loss)	$ (8)	$ 4	$ (24)	$ 9

Available-for-Sale Securities43

Available-for-Sale Securities (Major Security Types) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 19,305	$ 20,678
Gross Unrealized Gains	162	131
Gross Unrealized Losses	(16)	(13)
Fair Value	19,451	20,796
Other U.S. obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,808	3,096
Gross Unrealized Gains	13	8
Gross Unrealized Losses	(1)	(5)
Fair Value	2,820	3,099
GSE obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,001	1,197
Gross Unrealized Gains	38	39
Gross Unrealized Losses	0	0
Fair Value	1,039	1,236
State or local housing agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	908	935
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(1)
Fair Value	906	934
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	260	269
Gross Unrealized Gains	12	9
Gross Unrealized Losses	0	0
Fair Value	272	278
Non-mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,977	5,497
Gross Unrealized Gains	63	56
Gross Unrealized Losses	(3)	(6)
Fair Value	5,037	5,547
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,328	15,181
Gross Unrealized Gains	99	75
Gross Unrealized Losses	(13)	(7)
Fair Value	14,414	15,249
Single Family [Member] | Other U.S. obligations MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,065	3,716
Gross Unrealized Gains	33	11
Gross Unrealized Losses	(1)	(1)
Fair Value	4,097	3,726
Single Family [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	883	983
Gross Unrealized Gains	7	7
Gross Unrealized Losses	(5)	(2)
Fair Value	885	988
Multifamily [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,380	10,482
Gross Unrealized Gains	59	57
Gross Unrealized Losses	(7)	(4)
Fair Value	$ 9,432	$ 10,535

Available-for-Sale Securities44

Available-for-Sale Securities (Unrealized Losses) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 3,776	$ 592
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(10)	(3)
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,839	5,134
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(6)	(10)
Continuous Unrealized Loss Position, Fair Value	5,615	5,726
Continuous Unrealized Loss Position, Unrealized Losses	(16)	(13)
Other U.S. obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	316	29
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	338	1,783
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(1)	(5)
Continuous Unrealized Loss Position, Fair Value	654	1,812
Continuous Unrealized Loss Position, Unrealized Losses	(1)	(5)
State or local housing agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	13	6
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	594	655
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(2)	(1)
Continuous Unrealized Loss Position, Fair Value	607	661
Continuous Unrealized Loss Position, Unrealized Losses	(2)	(1)
Non-mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	329	35
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	932	2,438
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(3)	(6)
Continuous Unrealized Loss Position, Fair Value	1,261	2,473
Continuous Unrealized Loss Position, Unrealized Losses	(3)	(6)
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	3,447	557
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(10)	(3)
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	907	2,696
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(3)	(4)
Continuous Unrealized Loss Position, Fair Value	4,354	3,253
Continuous Unrealized Loss Position, Unrealized Losses	(13)	(7)
Multifamily [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	2,653	224
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(4)	(1)
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	859	1,756
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(3)	(3)
Continuous Unrealized Loss Position, Fair Value	3,512	1,980
Continuous Unrealized Loss Position, Unrealized Losses	(7)	(4)
Single Family [Member] | Other U.S. obligations MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	497	111
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1)	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	0	887
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	0	(1)
Continuous Unrealized Loss Position, Fair Value	497	998
Continuous Unrealized Loss Position, Unrealized Losses	(1)	(1)
Single Family [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Available-for-sale Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	297	222
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(5)	(2)
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	48	53
Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	0	0
Continuous Unrealized Loss Position, Fair Value	345	275
Continuous Unrealized Loss Position, Unrealized Losses	$ (5)	$ (2)

Available-for-Sale Securities45

Available-for-Sale Securities (Contractual Maturity) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 19,305	$ 20,678
Fair Value	19,451	20,796
Non-mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturities, Due in one year or less, Amortized Cost	26	158
Contractual Maturities, Due in one year or less, Fair Value	26	159
Contractual Maturities, Due after one year through five years, Amortized Cost	969	750
Contractual Maturities, Due after one year through five years, Fair Value	976	755
Contractual Maturities, Due after five years through ten years, Amortized Cost	3,160	3,574
Contractual Maturities, Due after five years through ten years, Fair Value	3,181	3,583
Contractual Maturities, Due after ten years, Amortized Cost	822	1,015
Contractual Maturities, Due after ten years, Fair Value	854	1,050
Amortized Cost	4,977	5,497
Fair Value	5,037	5,547
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,328	15,181
Fair Value	$ 14,414	$ 15,249

Held-to-Maturity Securities (Ma

Held-to-Maturity Securities (Major Security Types) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 3,295	$ 3,628
Accumulated Unrecognized Holding Gain	58	74
Accumulated Unrecognized Holding Loss	(28)	(16)
Fair Value	3,325	3,686
GSE obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	391	393
Accumulated Unrecognized Holding Gain	49	65
Accumulated Unrecognized Holding Loss	(2)	0
Fair Value	438	458
State or local housing agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	427	454
Accumulated Unrecognized Holding Gain	1	2
Accumulated Unrecognized Holding Loss	(2)	(2)
Fair Value	426	454
Non-mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	818	847
Accumulated Unrecognized Holding Gain	50	67
Accumulated Unrecognized Holding Loss	(4)	(2)
Fair Value	864	912
Mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,477	2,781
Accumulated Unrecognized Holding Gain	8	7
Accumulated Unrecognized Holding Loss	(24)	(14)
Fair Value	2,461	2,774
Single Family [Member] | Other U.S. obligations MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	11	15
Accumulated Unrecognized Holding Gain	0	0
Accumulated Unrecognized Holding Loss	0	0
Fair Value	11	15
Single Family [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,453	2,752
Accumulated Unrecognized Holding Gain	8	7
Accumulated Unrecognized Holding Loss	(24)	(14)
Fair Value	2,437	2,745
Commercial Mortgage Backed Securities [Member] | Other U.S. obligations MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2	2
Accumulated Unrecognized Holding Gain	0	0
Accumulated Unrecognized Holding Loss	0	0
Fair Value	2	2
Residential Mortgage Backed Securities [Member] | Mortgage-backed securities, Private-label [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	11	12
Accumulated Unrecognized Holding Gain	0	0
Accumulated Unrecognized Holding Loss	0	0
Fair Value	$ 11	$ 12

Held-to-Maturity Securities (Un

Held-to-Maturity Securities (Unrealized Losses) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 120	$ 52
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2)	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,375	1,605
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(26)	(16)
Continuous Unrealized Loss Position, Fair Value	1,495	1,657
Continuous Unrealized Loss Position, Unrealized Losses	(28)	(16)
GSE obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	90
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2)
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Continuous Unrealized Loss Position, Fair Value	90
Continuous Unrealized Loss Position, Unrealized Losses	(2)
State or local housing agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	17	2
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	162	168
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(2)
Continuous Unrealized Loss Position, Fair Value	179	170
Continuous Unrealized Loss Position, Unrealized Losses	(2)	(2)
Non-mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	107	2
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2)	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	162	168
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(2)
Continuous Unrealized Loss Position, Fair Value	269	170
Continuous Unrealized Loss Position, Unrealized Losses	(4)	(2)
Mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	13	50
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,213	1,437
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(24)	(14)
Continuous Unrealized Loss Position, Fair Value	1,226	1,487
Continuous Unrealized Loss Position, Unrealized Losses	(24)	(14)
Commercial Mortgage Backed Securities [Member] | Other U.S. obligations MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	1	1
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1	1
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Continuous Unrealized Loss Position, Fair Value	2	2
Continuous Unrealized Loss Position, Unrealized Losses	0	0
Single Family [Member] | Other U.S. obligations MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	7
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	5	1
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Continuous Unrealized Loss Position, Fair Value	5	8
Continuous Unrealized Loss Position, Unrealized Losses	0	0
Single Family [Member] | Mortgage-backed securities, GSE [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	12	42
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,200	1,427
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(24)	(14)
Continuous Unrealized Loss Position, Fair Value	1,212	1,469
Continuous Unrealized Loss Position, Unrealized Losses	(24)	(14)
Residential Mortgage Backed Securities [Member] | Mortgage-backed securities, Private-label [Member]
Schedule of Held-to-maturity Securities [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	0
Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	7	8
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Continuous Unrealized Loss Position, Fair Value	7	8
Continuous Unrealized Loss Position, Unrealized Losses	$ 0	$ 0

Held-to-Maturity Securities (Co

Held-to-Maturity Securities (Contractual Maturity) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 3,295	$ 3,628
Fair Value	3,325	3,686
Non-mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost	14	20
Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value	14	20
Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost	71	72
Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value	71	72
Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost	340	344
Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value	362	376
Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Amortized Cost	393	411
Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Fair Value	417	444
Amortized Cost	818	847
Fair Value	864	912
Mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,477	2,781
Fair Value	$ 2,461	$ 2,774

Advances (Narrative) (Details)

Advances (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances [Line Items]
Advances	$ 109,963	$ 102,613
Federal Home Loan Bank, Advances, Par Value	110,182	102,678
Federal Home Loan Bank, Advances, Callable Option [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank, Advances, Par Value	39,600	27,000
Federal Home Loan Bank, Advances, Putable Option [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank, Advances, Par Value	89	405
Wells Fargo Bank N.A. [Member]
Federal Home Loan Bank, Advances [Line Items]
Advances	$ 51,025	$ 45,825
Federal Home Loan Bank Advances, Percent	46.00%	45.00%

Advances (Redemption Terms) (De

Advances (Redemption Terms) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Advances [Abstract]
Overdrawn demand deposit accounts	$ 34	$ 1
Weighted Average Interest Rate on Overdrawn Demand Deposit	3.10%	3.63%
Due in one year or less	$ 52,016	$ 45,310
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Next Twelve Rolling Months	2.16%	1.62%
Due after one year through two years	$ 18,954	$ 17,094
Federal Home Loan Bank Advances, Weighted Average Interest Rate, Maturing in Rolling Year Two	2.25%	1.79%
Due after two years through three years	$ 20,620	$ 14,222
Federal Home Loan Bank Advances, Weighted Average Interest Rate, Maturing in Rolling Year Three	2.31%	1.64%
Due after three years through four years	$ 10,543	$ 17,561
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Four	2.51%	1.79%
Due after four years through five years	$ 3,918	$ 3,089
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Five	2.51%	1.91%
Thereafter	$ 4,097	$ 5,401
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing after Rolling Year Five	2.83%	2.28%
Federal Home Loan Bank, Advances, Par Value	$ 110,182	$ 102,678
Federal Home Loan Bank, Advances, Weighted Average Interest Rate	2.28%	1.73%
Premiums	$ 44	$ 53
Discounts	(10)	(12)
Fair value hedging adjustments	(253)	(106)
Total	109,963	102,613
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Next Rolling Twelve Months	83,073	69,971
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Next Rolling Twelve Months	52,075	45,372
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Two	11,161	16,539
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Two	18,954	17,094
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Three	3,458	3,809
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Three	20,595	14,222
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Four	7,746	8,511
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Four	10,533	17,520
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Five	1,895	1,276
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Five	3,909	3,073
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, after Rolling Year Five	2,815	2,571
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, after Rolling Year Five	$ 4,082	$ 5,396

Advances (Prepayment Fees) (Det

Advances (Prepayment Fees) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Advances [Abstract]
Prepayment fees on advances, net	$ 1	$ 1	$ 6	$ 1

Mortgage Loans Held for Portf52

Mortgage Loans Held for Portfolio (Mortgage Loans Held for Portfolio) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Mortgage Loans on Real Estate [Line Items]
Unpaid principal balance	$ 7,215	$ 7,001
Premiums	99	98
Discounts	(6)	(6)
Basis adjustments from mortgage loan commitments	3	5
Total mortgage loans held for portfolio	7,311	7,098
Allowance for credit losses	(1)	(2)
Total mortgage loans held for portfolio, net	7,310	7,096
Single Family [Member] | Fixed rate, long-term single family mortgages [Member]
Mortgage Loans on Real Estate [Line Items]
Unpaid principal balance	6,281	5,998
Single Family [Member] | Fixed rate, medium-term single family mortgages [Member]
Mortgage Loans on Real Estate [Line Items]
Unpaid principal balance	$ 934	$ 1,003

Mortgage Loans Held for Portf53

Mortgage Loans Held for Portfolio (Mortgage Loans Held for Portfolio by Collateral or Guarantee Type) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Mortgage Loans on Real Estate [Line Items]
Unpaid principal balance	$ 7,215	$ 7,001
Conventional Mortgage Loan [Member]
Mortgage Loans on Real Estate [Line Items]
Unpaid principal balance	6,699	6,472
Loans Insured or Guaranteed by US Government Authorities [Member]
Mortgage Loans on Real Estate [Line Items]
Unpaid principal balance	$ 516	$ 529

Allowance for Credit Losses (Al

Allowance for Credit Losses (Allowance and Recorded Investment by Impairment Methodology) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Gross	$ 7,348	$ 7,134
Conventional Mortgage Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1	2
Financing Receivable, Collectively Evaluated for Impairment	6,759	6,530
Financing Receivable, Individually Evaluated for Impairment	59	61
Financing Receivable, Gross	$ 6,818	$ 6,591

Allowance for Credit Losses (Cr

Allowance for Credit Losses (Credit Quality Indicators) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	$ 114	$ 146
Total current loans	7,234	6,988
Total recorded investment	7,348	7,134
In process of foreclosure	$ 13	$ 14
Serious delinquency rate	0.00%	1.00%
Past due 90 days or more and still accruing interest	$ 7	$ 11
Non-accrual mortgage loans	40	48
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	62	77
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	19	22
Financing Receivables, 90 to 179 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	13	20
Financing Receivables, Greater than 180 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	20	27
Conventional Mortgage Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	83	110
Total current loans	6,735	6,481
Total recorded investment	6,818	6,591
In process of foreclosure	$ 11	$ 12
Serious delinquency rate	0.00%	1.00%
Past due 90 days or more and still accruing interest	$ 0	$ 0
Non-accrual mortgage loans	40	48
Conventional Mortgage Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	44	58
Conventional Mortgage Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	13	16
Conventional Mortgage Loan [Member] | Financing Receivables, 90 to 179 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	10	15
Conventional Mortgage Loan [Member] | Financing Receivables, Greater than 180 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	16	21
Loans Insured or Guaranteed by US Government Authorities [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	31	36
Total current loans	499	507
Total recorded investment	530	543
In process of foreclosure	$ 2	$ 2
Serious delinquency rate	1.00%	2.00%
Past due 90 days or more and still accruing interest	$ 7	$ 11
Non-accrual mortgage loans	0	0
Loans Insured or Guaranteed by US Government Authorities [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	18	19
Loans Insured or Guaranteed by US Government Authorities [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	6	6
Loans Insured or Guaranteed by US Government Authorities [Member] | Financing Receivables, 90 to 179 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	3	5
Loans Insured or Guaranteed by US Government Authorities [Member] | Financing Receivables, Greater than 180 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	$ 4	$ 6

Allowance for Credit Losses (In

Allowance for Credit Losses (Individually Evaluated Impaired Loans) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0	$ 0	$ 0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	$ 60	$ 68	$ 60	$ 69

Derivatives and Hedging Activ57

Derivatives and Hedging Activities (Derivatives in Statement of Condition) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	$ 48,539	$ 53,665
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	154	97
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	127	188
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(71)	3
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(125)	(182)
Derivative assets, net	83	100
Derivative liabilities, net	2	6
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	128	191
Derivative Asset, Collateral, Obligation to Return Cash, Offset	73	6
Variation Margin for Daily Settled Contracts		313
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	46,828	52,120
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	125	77
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	105	151
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	1,711	1,545
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	29	20
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	22	37
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	1,372	1,407
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	29	20
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	21	37
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Collateralized Mortgage Backed Securities [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	167	66
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	1	0
Mortgages [Member] | Not Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	172	72
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ 0	$ 0

Derivatives and Hedging Activ58

Derivatives and Hedging Activities (Derivatives in Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Designated as Hedging Instruments, Gain (Loss), Net	$ 7	$ 6	$ 7	$ 10
Derivatives Not Designated as Hedging Instruments, Gain (Loss), Net	7	(9)	26	(8)
Derivative Instruments, Other Gain (Loss)	0	0	1	1
Net gains (losses) on derivatives and hedging activities	14	(3)	34	3
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Designated as Hedging Instruments, Gain (Loss), Net	7	6	7	10
Net Interest Settlements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Not Designated as Hedging Instruments, Gain (Loss), Net	(1)	(3)	(3)	(7)
Mortgages [Member] | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Not Designated as Hedging Instruments, Gain (Loss), Net	0	0	(1)	1
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Not Designated as Hedging Instruments, Gain (Loss), Net	7	(6)	28	(1)
Collateralized Mortgage Backed Securities [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member] | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Not Designated as Hedging Instruments, Gain (Loss), Net	$ 1	$ 0	$ 2	$ (1)

Derivatives and Hedging Activ59

Derivatives and Hedging Activities (Derivatives in Statement of Income and Impact on Interest) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	$ 86	$ 6	$ 209	$ 26
Net Fair Value Hedge Ineffectiveness	7	6	7	10
Effect on Net Interest Income	(55)	(38)	(101)	(72)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(79)	0	(202)	(16)
Amortization and Accretion of Off-Market Derivatives	1	4	1	9
Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	55	(41)	207	(4)
Net Fair Value Hedge Ineffectiveness	7	8	4	14
Effect on Net Interest Income	(6)	(24)	(19)	(53)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(48)	49	(203)	18
Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	31	(25)	156	8
Net Fair Value Hedge Ineffectiveness	2	1	2	2
Effect on Net Interest Income	13	(21)	12	(45)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(29)	26	(154)	(6)
Consolidated Obligation Bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	0	72	(154)	22
Net Fair Value Hedge Ineffectiveness	(2)	(3)	1	(6)
Effect on Net Interest Income	(62)	7	(94)	26
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	$ (2)	$ (75)	$ 155	$ (28)

Derivatives and Hedging Activ60

Derivatives and Hedging Activities (Credit Risk Exposure) (Details) $ in Millions	Jun. 30, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Collateral Already Posted, Aggregate Fair Value	$ 0
Derivative, Net Liability Position, Aggregate Fair Value	$ 1

Derivatives and Hedging Activ61

Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Offsetting Assets and Liabilities [Line Items]
variation margin for daily settled contracts		$ 313
Derivative Asset, Fair Value, Gross Asset	$ 154	97
Derivative Liability, Fair Value, Gross Liability	127	188
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(71)	3
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(125)	(182)
Derivative assets, net	83	100
Derivative liabilities, net	2	6
Over the Counter [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	151	88
Derivative Liability, Fair Value, Gross Liability	120	170
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(150)	(87)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(118)	(164)
Exchange Cleared [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	3	9
Derivative Liability, Fair Value, Gross Liability	7	18
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	79	90
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(7)	(18)
Exchange Cleared [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative assets, net	82	99
Derivative liabilities, net	0	0
Over the Counter [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative assets, net	1	1
Derivative liabilities, net	$ 2	$ 6

Consolidated Obligations Narrat

Consolidated Obligations Narrative (Details) - USD ($) $ in Billions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Short-term and Long-term Debt [Line Items]
Obligation with Joint and Several Liability Arrangement, Amount Outstanding	$ 917.7	$ 898.3
FHLBanks [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Obligation with Joint and Several Liability Arrangement, Amount Outstanding	$ 1,059.9	$ 1,034.2

Consolidated Obligations Discou

Consolidated Obligations Discount Notes (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Total	$ 43,122	$ 36,682
Consolidated Obligation Discount Notes [Member]
Short-term Debt [Line Items]
Par value	$ 43,241	$ 36,740
Par Value, Weighted Average Interest Rate	1.87%	1.20%
Discounts and concessions	$ (119)	$ (58)

Consolidated Obligations Bonds

Consolidated Obligations Bonds (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total	$ 98,468	$ 98,893
Consolidated Obligation Bonds [Member]
Debt Instrument [Line Items]
Due in one year or less	$ 57,307	$ 50,077
Due in one year or less, Weighted Average Interest Rate	1.87%	1.32%
Due after one year through two years, Weighted Average Interest Rate	1.90%	1.43%
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	$ 24,341	$ 32,249
Due after two years through three years	$ 3,034	$ 3,177
Due after two years through three years, Weighted Average Interest Rate	2.59%	2.84%
Due after three years through four years	$ 7,207	$ 7,422
Due after three years through four years, Weighted Average Interest Rate	1.71%	1.69%
Due after four years through five years	$ 2,124	$ 1,507
Due after four years through five years, Weighted Average Interest Rate	2.31%	2.42%
Thereafter	$ 4,917	$ 4,752
Thereafter, Weighted Average Interest Rate	3.37%	3.10%
Total par value	$ 98,930	$ 99,184
Total par value, Weighted Average Interest Rate	1.97%	1.54%
Premiums	$ 168	$ 193
Discounts and concessions	(52)	(60)
Fair value hedging adjustments	(578)	(424)
Total	$ 98,468	$ 98,893

Consolidated Obligations Bond65

Consolidated Obligations Bonds by Call Features (Details) - Consolidated Obligation Bonds [Member] - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total par value	$ 98,930	$ 99,184
Noncallable or Nonputable [Member]
Debt Instrument [Line Items]
Total par value	94,742	97,196
Callable [Member]
Debt Instrument [Line Items]
Total par value	$ 4,188	$ 1,988

Capital (Narrative) (Details)

Capital (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Stock, Par or Stated Value Per Share	$ 100		$ 100		$ 100
Number of Subclasses of Capital Stock	2		2
Redemption Period Under FHLBank Capital Plan			5 years
Written Notice Period Required to Repurchase Excess Membership Capital Stock			15 days
Net payments for repurchases/redemptions of mandatorily redeemable capital stock	$ (19,000,000)	$ (32,000,000)	$ (51,000,000)	$ (212,000,000)
Net Shares Reclassified to Mandatorily Redeemable Capital Stock, Value	36,000,000	$ 18,000,000	39,000,000	$ 28,000,000
Excess Capital	$ 0		$ 0		$ 0
Minimum Capital Stock Required to be Held by Members as a Percent of Total Assets at Preceeding Fiscal Year End, Subject to Cap and Floor	0.12%		0.12%
Activity Based Capital Stock Required by Members as a Percent of Total Advances and Mortgage Loans Oustanding as Disclosed in the Statement of Condition	4.00%		4.00%
Maximum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Federal Home Loan Banks, Membership Requirements, Capital Stock	$ 10,000,000		$ 10,000,000
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Federal Home Loan Banks, Membership Requirements, Capital Stock	$ 10,000		10,000
Captive Insurance Companies [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Net payments for repurchases/redemptions of mandatorily redeemable capital stock			$ (148,000,000)

Capital (Rollforward of MRCS) (

Capital (Rollforward of MRCS) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
MRCS [Abstract]
Beginning Balance	$ 356	$ 494	$ 385	$ 664
Net Shares Reclassified to Mandatorily Redeemable Capital Stock, Value	36	18	39	28
Financial Instruments Subject To Mandatory Redemption Repurchases	(19)	(32)	(51)	(212)
Ending Balance	$ 373	$ 480	$ 373	$ 480

Capital (Mandatorily Redeemable

Capital (Mandatorily Redeemable Capital Stock) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
MRCS [Abstract]
Financial Instruments Subject to Mandatory Redemption, Redeemable within One year	$ 0		$ 0			$ 4
Financial Instruments Subject to Mandatory Redemption, Redeemable in Year Two	2		2			2
Financial Instruments Subject to Mandatory Redemption, Redeemable in Year Three	1		1			0
Financial Instruments Subject to Mandatory Redemption, Redeemable in Year Four	11		11			1
Financial Instruments Subject to Mandatory Redemption, Redeemable in Year Five	26		26			22
Financial Instruments Subject to Mandatory Redemption, Redeemable After Year Five	317		317			341
Financial Instruments Subject to Mandatory Redemption, Past Contractual Redemption Date, Due to Outstanding Activity	16		16			15
Mandatorily redeemable capital stock	373	$ 480	373	$ 480	$ 356	$ 385	$ 494	$ 664
Interest Expense, Capital Securities	$ 5	$ 4	$ 9	$ 9

Capital (Accumulated Other Comp

Capital (Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 7,021	$ 7,401
Other comprehensive income (loss) before reclassifications, Net unrealized losses	$ (17)	$ 41	28	105
Total other comprehensive income (loss)	(17)	42	28	107
Ending Balance	7,539	7,396	7,539	7,396
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	163	50	118	(14)
Other comprehensive income (loss) before reclassifications, Net unrealized losses	(17)	41	28	105
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax		0		0
Total other comprehensive income (loss)	(17)	41	28	105
Ending Balance	146	91	146	91
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(4)	(3)	(4)	(4)
Other comprehensive income (loss) before reclassifications, Net unrealized losses	0	0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax		1		2
Total other comprehensive income (loss)	0	1	0	2
Ending Balance	(4)	(2)	(4)	(2)
Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	159	47	114	(18)
Other comprehensive income (loss) before reclassifications, Net unrealized losses	(17)	41	28	105
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax		1		2
Total other comprehensive income (loss)	(17)	42	28	107
Ending Balance	$ 142	$ 89	$ 142	$ 89

Capital (Regulatory Capital Req

Capital (Regulatory Capital Requirements) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Capital [Abstract]
Number of Finance Agency Regulatory Capital Requirements	3
Federal Home Loan Bank, Risk-Based Capital, Required	$ 1,178	$ 1,041
Federal Home Loan Bank, Risk-Based Capital, Actual	7,770	7,292
Federal Home Loan Bank, Regulatory Capital, Required	6,039	5,804
Federal Home Loan Bank, Regulatory Capital, Actual	7,770	7,292
Federal Home Loan Bank, Leverage Capital, Required	7,549	7,255
Federal Home Loan Bank, Leverage Capital, Actual	$ 11,656	$ 10,937
Regulatory Capital Ratio, Required	4.00%	4.00%
Federal Home Loan Bank, Regulatory Capital Ratio, Actual	5.15%	5.03%
Leverage Ratio, Required	5.00%	5.00%
Federal Home Loan Bank, Leverage Ratio, Actual	7.72%	7.54%
Weight Applied to Permanent Capital in Computing Leverage Ratio	1.5
Weight Applied to Nonpermanent Capital in Computing Leverage Ratio	1

Capital Retained Earnings (Deta

Capital Retained Earnings (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Capital [Abstract]
Quarterly Net Income Allocated to Restricted Retained Earnings	20.00%
Percent of Average Balance of Outstanding Consolidated Obligations Prescribed per the Joint Capital Enhancement Agreement For Each Previous Quarter	1.00%
Retained Earnings, Appropriated	$ 384	$ 335

Fair Value (Carrying Value and

Fair Value (Carrying Value and Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
variation margin for daily settled contracts			$ 313
Assets
Cash and due from banks	$ 201		503
Trading securities	937		1,177
Available-for-sale securities	19,451		20,796
Held-to-maturity securities	3,295		3,628
Held-to-Maturity Securities, Fair Value	3,325		3,686
Loans to Other Federal Home Loan Banks	0		0
Accrued interest receivable	305		223
Derivative assets, net	83		100
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(71)		3
Liabilities
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	125		182
Mandatorily redeemable capital stock	(373)	$ (356)	(385)	$ (480)	$ (494)	$ (664)
Accrued interest payable	(238)		(210)
Derivative liabilities, net	(2)		(6)
Reported Value Measurement [Member]
Assets
Cash and due from banks	201		503
Interest-bearing deposits	1		1
Securities purchased under agreements to resell	4,900		4,600
Federal funds sold	4,435		4,250
Trading securities	937		1,177
Available-for-sale securities	19,451		20,796
Held-to-maturity securities	3,295		3,628
Advances	109,963		102,613
Mortgage loans held for portfolio, net	7,310		7,096
Accrued interest receivable	305		223
Derivative assets, net	83		100
Other assets	29		28
Liabilities
Deposits	(1,028)		(1,107)
Federal Home Loan Bank Borrowings, Fair Value Disclosure			(600)
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	(141,590)		(135,575)
Mandatorily redeemable capital stock	(373)		(385)
Accrued interest payable	(238)		(210)
Derivative liabilities, net	(2)		(6)
Fair Value [Member]
Assets
Cash and due from banks	201		503
Interest-bearing deposits	1		1
Securities purchased under agreements to resell	4,900		4,600
Federal funds sold	4,435		4,250
Trading securities	937		1,177
Available-for-sale securities	19,451		20,796
Held-to-Maturity Securities, Fair Value	3,325		3,686
Advances	110,031		102,708
Mortgage loans held for portfolio, net	7,252		7,188
Accrued interest receivable	305		223
Derivative assets, net	83		100
Other assets	29		28
Liabilities
Deposits	(1,028)		(1,107)
Federal Home Loan Bank Borrowings, Fair Value Disclosure			(600)
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	(141,658)		(135,824)
Mandatorily redeemable capital stock	(373)		(385)
Accrued interest payable	(238)		(210)
Derivative liabilities, net	(2)		(6)
Fair Value, Level 1 [Member]
Assets
Cash and due from banks	201		503
Interest-bearing deposits	0		0
Securities purchased under agreements to resell	0		0
Federal funds sold	0		0
Trading securities	0		0
Available-for-sale securities	0		0
Held-to-Maturity Securities, Fair Value	0		0
Advances	0		0
Mortgage loans held for portfolio, net	0		0
Accrued interest receivable	0		0
Derivative assets, net	0		0
Other assets	29		28
Liabilities
Deposits	0		0
Federal Home Loan Bank Borrowings, Fair Value Disclosure			0
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	0		0
Mandatorily redeemable capital stock	(373)		(385)
Accrued interest payable	0		0
Derivative liabilities, net	0		0
Fair Value, Level 2 [Member]
Assets
Cash and due from banks	0		0
Interest-bearing deposits	1		1
Securities purchased under agreements to resell	4,900		4,600
Federal funds sold	4,435		4,250
Trading securities	937		1,177
Available-for-sale securities	19,451		20,796
Held-to-Maturity Securities, Fair Value	3,314		3,674
Advances	110,031		102,708
Mortgage loans held for portfolio, net	7,189		7,124
Accrued interest receivable	305		223
Derivative assets, net	154		97
Other assets	0		0
Liabilities
Deposits	(1,028)		(1,107)
Federal Home Loan Bank Borrowings, Fair Value Disclosure			(600)
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	(141,658)		(135,824)
Mandatorily redeemable capital stock	0		0
Accrued interest payable	(238)		(210)
Derivative liabilities, net	(127)		(188)
Fair Value, Level 3 [Member]
Assets
Cash and due from banks	0		0
Interest-bearing deposits	0		0
Securities purchased under agreements to resell	0		0
Federal funds sold	0		0
Trading securities	0		0
Available-for-sale securities	0		0
Held-to-Maturity Securities, Fair Value	11		12
Advances	0		0
Mortgage loans held for portfolio, net	63		64
Accrued interest receivable	0		0
Derivative assets, net	0		0
Other assets	0		0
Liabilities
Deposits	0		0
Federal Home Loan Bank Borrowings, Fair Value Disclosure			0
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	0		0
Mandatorily redeemable capital stock	0		0
Accrued interest payable	0		0
Derivative liabilities, net	0		0
Consolidated Obligation Discount Notes [Member] | Reported Value Measurement [Member]
Liabilities
Discount notes	(43,122)		(36,682)
Consolidated Obligation Discount Notes [Member] | Fair Value [Member]
Liabilities
Discount notes	(43,119)		(36,674)
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 1 [Member]
Liabilities
Discount notes	0		0
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 2 [Member]
Liabilities
Discount notes	(43,119)		(36,674)
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 3 [Member]
Liabilities
Discount notes	0		0
Consolidated Obligation Bonds [Member] | Reported Value Measurement [Member]
Liabilities
Bonds, Fair Value	(98,468)		(98,893)
Consolidated Obligation Bonds [Member] | Fair Value [Member]
Liabilities
Bonds, Fair Value	(98,539)		(99,150)
Consolidated Obligation Bonds [Member] | Fair Value, Level 1 [Member]
Liabilities
Bonds, Fair Value	0		0
Consolidated Obligation Bonds [Member] | Fair Value, Level 2 [Member]
Liabilities
Bonds, Fair Value	(98,539)		(99,150)
Consolidated Obligation Bonds [Member] | Fair Value, Level 3 [Member]
Liabilities
Bonds, Fair Value	$ 0		$ 0

Fair Value (Fair Value on a Rec

Fair Value (Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
variation margin for daily settled contracts		$ 313
Trading securities	$ 937	1,177
Available-for-sale securities	19,451	20,796
Advances, Fair Value Disclosure	15	0
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(71)	3
Derivative assets, net	83	100
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	125	182
Derivative liabilities, net	(2)	(6)
Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Derivative assets, net	0	0
Other assets	29	28
Derivative liabilities, net	0	0
Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	937	1,177
Available-for-sale securities	19,451	20,796
Derivative assets, net	154	97
Other assets	0	0
Derivative liabilities, net	(127)	(188)
Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Derivative assets, net	0	0
Other assets	0	0
Derivative liabilities, net	0	0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(71)	3
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	125	182
Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Advances, Fair Value Disclosure	0
Other assets	29	28
Total recurring assets	29	28
Total recurring liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	937	1,177
Available-for-sale securities	19,451	20,796
Advances, Fair Value Disclosure	15
Other assets	0	0
Total recurring assets	20,557	22,070
Total recurring liabilities	(127)	(188)
Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Advances, Fair Value Disclosure	0
Other assets	0	0
Total recurring assets	0	0
Total recurring liabilities	0	0
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(71)	3
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	125	182
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	0	0
Derivative liabilities, net	0	0
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	154	97
Derivative liabilities, net	126	(188)
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	0	0
Derivative liabilities, net	0	0
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	0
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	1
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	0
Other U.S. obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	182	197
Available-for-sale securities	2,820	3,099
Other U.S. obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Other U.S. obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	182	197
Available-for-sale securities	2,820	3,099
Other U.S. obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
GSE obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	57	260
Available-for-sale securities	1,039	1,236
GSE obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
GSE obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	57	260
Available-for-sale securities	1,039	1,236
GSE obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
State or local housing agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	906	934
State or local housing agency obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
State or local housing agency obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	906	934
State or local housing agency obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Other non-MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	265	272
Available-for-sale securities	272	278
Other non-MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Other non-MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	265	272
Available-for-sale securities	272	278
Other non-MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	937	1,177
Available-for-sale securities	19,451	20,796
Derivative assets, net	83	100
Other assets	29	28
Derivative liabilities, net	(2)	(6)
Fair Value [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	937	1,177
Available-for-sale securities	19,451	20,796
Advances, Fair Value Disclosure	15
Other assets	29	28
Total recurring assets	20,515	22,101
Total recurring liabilities	(2)	(6)
Fair Value [Member] | Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	83	100
Derivative liabilities, net	(1)	(6)
Fair Value [Member] | Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	1
Fair Value [Member] | Other U.S. obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	182	197
Available-for-sale securities	2,820	3,099
Fair Value [Member] | GSE obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	57	260
Available-for-sale securities	1,039	1,236
Fair Value [Member] | State or local housing agency obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	906	934
Fair Value [Member] | Other non-MBS [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	265	272
Available-for-sale securities	272	278
Single Family [Member] | Other U.S. obligations MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,097	3,726
Single Family [Member] | Other U.S. obligations MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Single Family [Member] | Other U.S. obligations MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,097	3,726
Single Family [Member] | Other U.S. obligations MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Single Family [Member] | GSE MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	885	988
Single Family [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Single Family [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	885	988
Single Family [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Single Family [Member] | Fair Value [Member] | Other U.S. obligations MBS [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,097	3,726
Single Family [Member] | Fair Value [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	885	988
Multifamily [Member] | GSE MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	433	448
Available-for-sale securities	9,432	10,535
Multifamily [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Multifamily [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	433	448
Available-for-sale securities	9,432	10,535
Multifamily [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Multifamily [Member] | Fair Value [Member] | GSE MBS [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	433	448
Available-for-sale securities	$ 9,432	$ 10,535

Fair Value (Fair Value on a Non

Fair Value (Fair Value on a Non-Recurring Basis) (Details) - Fair Value, Level 3 [Member] - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired mortgage loans held for portfolio	$ 63	$ 64
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired mortgage loans held for portfolio	$ 1	$ 7

Fair Value (Fair Value Differen

Fair Value (Fair Value Difference Between Fair Value and Remaining Contractual Principal Balance Outstanding) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Option, Quantitative Disclosures [Line Items]
Federal Home Loan Bank, Advances, Par Value	$ 110,182	$ 102,678
Advances, Fair Value Disclosure	15	$ 0
Federal Home Loan Bank, Advances, Valuation Adjustments under Fair Value Option	0
Reported Value Measurement [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Federal Home Loan Bank, Advances, Par Value	$ 15

Commitments and Contingencies76

Commitments and Contingencies (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)Institutions	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Institutions	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Obligation with Joint and Several Liability Arrangement, Amount Outstanding	$ 917,700		$ 917,700		$ 898,300
Other liabilities	56		56		53
FLA Balance For All Master Commitments	108		108		104
Gain (Loss) Related to Litigation Settlement	0	$ 0	0	$ 21
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring Within One Year	9,111		9,111
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring After One Year	166		166
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	9,277		$ 9,277		8,594
Standby Letters Of Credit Original Terms			P13Y
Other liabilities	2		$ 2		3
Financial Standby Letter of Credit [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring Within One Year	117		117
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring After One Year	587		587
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 704		$ 704		755
Original Expiration Periods Up To			7 years
Number of Housing Authorities For Which the Bank Has Standby Bond Purchase Agreements | Institutions	7		7
Fees Generated From Guarantees Related to Standby Bond Purchase Agreements	$ 0	$ 0	$ 1	$ 1
Commitments to Issue Bonds [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring Within One Year	264		264		0
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring After One Year	0		0
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	264		264		0
Loan Origination Commitments [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring Within One Year	779		779
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring After One Year	1		1
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	780		780		1,138
Mortgages [Member] | Forward Contracts [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring Within One Year	172		172
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Expiring After One Year	0		0
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	172		$ 172		72
Period of Delivery Commitments			45 days
standby letters of credit issuance commitments [Domain]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 53		$ 53		$ 7

Activities with Stockholders 77

Activities with Stockholders (Transactions with Directors' Financial Institutions) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Advances	$ 109,963	$ 102,613
Mortgage Loans	7,311	7,098
Deposits, Domestic	1,028	1,107
Capital Stock	5,420	5,068
Director [Member]
Related Party Transaction [Line Items]
Advances	$ 5,134	$ 6,036
Advances, Percent	5.00%	6.00%
Mortgage Loans	$ 86	$ 68
Mortgage Loans, Percent	1.00%	1.00%
Deposits, Domestic	$ 11	$ 39
Deposits, Percent	1.00%	4.00%
Capital Stock	$ 256	$ 297
Capital Stock, Percent	4.00%	5.00%

Activities with Stockholders (B

Activities with Stockholders (Business Concentrations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Advances	$ 109,963		$ 109,963		$ 102,613
Mortgage Loans	7,311		7,311		7,098
Interest Income on Advances	626	$ 381	1,128	$ 714
Wells Fargo Bank N.A. [Member]
Related Party Transaction [Line Items]
Transfer of PFI Rights and Obligations	27
Capital Stock	$ 2,052		$ 2,052		$ 1,843
Capital Stock Percentage	35.00%		35.00%		34.00%
Advances	$ 51,025		$ 51,025		$ 45,825
Mortgage Loans	27		27		0
Interest Income on Advances			550		834
Superior Guaranty Insurance Company [Member]
Related Party Transaction [Line Items]
Capital Stock	$ 19		$ 19		$ 22
Capital Stock Percentage	0.00%		0.00%		0.00%
Advances	$ 0		$ 0		$ 0
Mortgage Loans	463		463		520
Interest Income on Advances			0		0
Wells Fargo Northwest NA [Member] [Member]
Related Party Transaction [Line Items]
Capital Stock					$ 1
Capital Stock Percentage					0.00%
Advances					$ 0
Mortgage Loans					30
Interest Income on Advances					0
Principal Owner [Member]
Related Party Transaction [Line Items]
Capital Stock	$ 2,071		$ 2,071		$ 1,866
Capital Stock Percentage	35.00%		35.00%		34.00%
Advances	$ 51,025		$ 51,025		$ 45,825
Mortgage Loans	$ 490		490		550
Interest Income on Advances			$ 550		$ 834
Stockholders' Equity, Total [Member] | Stockholders' Capital Stock Outstanding Concenetration Risk [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Business Concentration Percentage			10.00%

Activities with Other FHLBank79

Activities with Other FHLBanks (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Schedule of Other Transactions [Line Items]
Loans from Other Federal Home Loan Banks	$ 0	$ 0	$ 600	$ 600
Payments for Federal Home Loan Bank Advances	157,016	130,163
Payments for Federal Home Loan Bank Advances	1,600
Proceeds from Federal Home Loan Bank Loans	(1,600)
Loans to Other Federal Home Loan Banks	0		0
Federal Home Loan Bank, Advances, Premium	44		53
Proceeds from Federal Home Loan Bank Borrowings		0
Repayments of Federal Home Loan Bank Borrowings		(600)
Federal Home Loan Bank of Atlanta [Member]
Schedule of Other Transactions [Line Items]
Loans from Other Federal Home Loan Banks	0		200
Proceeds from Federal Home Loan Bank Borrowings	0
Repayments of Federal Home Loan Bank Borrowings	(200)
Federal Home Loan Bank of Boston [Member]
Schedule of Other Transactions [Line Items]
Loans from Other Federal Home Loan Banks	0		400
Payments for Federal Home Loan Bank Advances	800
Proceeds from Federal Home Loan Bank Loans	(800)
Loans to Other Federal Home Loan Banks	0		0
Proceeds from Federal Home Loan Bank Borrowings	0
Repayments of Federal Home Loan Bank Borrowings	(400)
Federal Home Loan Bank of San Francisco [Member]
Schedule of Other Transactions [Line Items]
Payments for Federal Home Loan Bank Advances	300	0
Proceeds from Federal Home Loan Bank Loans	(300)	(200)
Loans to Other Federal Home Loan Banks	0	$ 0	0	$ 200
Federal Home Loan Bank of Dallas [Member]
Schedule of Other Transactions [Line Items]
Payments for Federal Home Loan Bank Advances	500
Proceeds from Federal Home Loan Bank Loans	(500)
Loans to Other Federal Home Loan Banks	0		$ 0
Federal Home Loan Bank of Chicago [Member]
Schedule of Other Transactions [Line Items]
Payments for Federal Home Loan Bank Advances	37
Federal Home Loan Bank, Advances, Premium	$ 1