Federal Home Loan Bank of Boston 10-K 20 Mar 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Feb. 29, 2020	Jun. 30, 2019
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	000-51402
Entity Registrant Name	FEDERAL HOME LOAN BANK OF BOSTON
Entity Tax Identification Number	04-6002575
Entity Address, Address Line One	800 Boylston Street,
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
City Area Code	(617)
Local Phone Number	292-9600
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Amendment Flag	false
Entity Central Index Key	0001331463
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Address, Postal Zip Code	02199
Entity Public Float			$ 0
Entity Incorporation, State or Country Code	X1
Common Class A [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		0
Common Class B [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		20,758,802

Statements of Condition

Statements of Condition - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks		$ 69,416	$ 10,431
Interest-bearing deposits		1,253,873	593,199
Securities purchased under agreements to resell		3,500,000	6,499,000
Federal funds sold		860,000	1,500,000
Investment securities:
Trading securities		2,250,264	163,038
Available-for-sale securities - includes $3,025 pledged as collateral at December 31, 2018, that may be repledged		7,409,000	5,849,944
Held-to-maturity securities - includes $92 and $3,456 pledged as collateral at December 31, 2019 and 2018, respectively that may be repledged	[1],[2]	871,107	1,295,023
Total investment securities		10,530,371	7,308,005
Advances		34,595,363	43,192,222
Mortgage loans held for portfolio, net of allowance for credit losses of $500 at December 31, 2019 and 2018		4,501,251	4,299,402
Accrued interest receivable		112,163	112,751
Derivative assets, net		159,731	22,403
Other assets		80,643	55,904
Total Assets		55,662,811	63,593,317
Deposits
Interest-bearing		616,532	448,247
Non-interest-bearing		57,777	26,631
Total deposits		674,309	474,878
Consolidated obligations (COs):
Bonds		23,888,493	25,912,684
Discount notes		27,681,169	33,065,822
Total consolidated obligations		51,569,662	58,978,506
Mandatorily redeemable capital stock		5,806	31,868
Accrued interest payable		104,477	112,043
Affordable Housing Program (AHP) payable		86,131	83,965
Derivative liabilities, net		10,271	255,800
Other liabilities		66,843	48,898
Total liabilities		52,517,499	59,985,958
Commitments and contingencies (Note 20)
Capital
Capital stock – Class B – putable ($100 par value), 18,691 shares and 25,289 shares issued and outstanding at December 31, 2019 and 2018, respectively		1,869,130	2,528,854
Retained earnings:
Unrestricted		1,114,337	1,084,342
Restricted		348,817	310,670
Total retained earnings		1,463,154	1,395,012
Accumulated other comprehensive loss		(186,972)	(316,507)
Total capital		3,145,312	3,607,359
Total Liabilities and Capital		$ 55,662,811	$ 63,593,317
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,035,410 and $1,528,929 at December 31, 2019 and 2018 , respectively.

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Available-for-sale securities pledged as collateral that may be repledged	$ 0	$ 3,025
Held-to-maturity securities - pledged as collateral that may be repledged (a)	92	3,456
Allowance for credit losses	500	500
Fair value of held-to-maturity securities	$ 1,035,410	$ 1,528,929
Common Class B [Member]
Common Stock, Class B, putable shares issued	18,691	25,289
Common Stock, Class B, putable par value per share	$ 100	$ 100
Common Stock, Class B, putable shares outstanding	18,691	25,289

Statements of Operations

Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INTEREST INCOME
Advances		$ 854,599	$ 867,215	$ 514,176
Prepayment fees on advances, net		35,011	216	898
Interest-bearing deposits		22,390	5,433	2,045
Securities purchased under agreements to resell		123,438	77,718	27,486
Federal funds sold		58,015	108,144	58,642
Investment securities:
Trading securities		22,037	8,789	10,604
Available-for-sale securities		115,942	143,952	118,270
Held-to-maturity securities		65,758	77,892	79,723
Total investment securities		203,737	230,633	208,597
Mortgage loans held for portfolio		147,885	136,672	125,002
Other		25	22	43
Total interest income		1,445,100	1,426,053	936,889
Consolidated obligations:
Bonds		598,585	545,228	421,622
Discount notes		569,896	561,443	233,081
Total consolidated obligations		1,168,481	1,106,671	654,703
Deposits		6,582	5,311	3,615
Mandatorily redeemable capital stock		974	1,923	1,558
Other borrowings		37	38	10
Total interest expense		1,176,074	1,113,943	659,886
NET INTEREST INCOME		269,026	312,110	277,003
Provision for (reduction of ) credit losses		85	(34)	(96)
NET INTEREST INCOME AFTER PROVISION FOR (REDUCTION OF) CREDIT LOSSES		268,941	312,144	277,099
OTHER INCOME (LOSS)
Net other-than-temporary impairment losses on investment securities, credit portion		(1,212)	(532)	(1,454)
Litigation settlements		29,361	12,769	20,761
Loss on early extinguishment of debt		(15,238)	0	0
Service fees		12,987	10,268	8,697
Net unrealized gains (losses) on trading securities		1,287	(4,515)	(6,078)
Net gains on derivatives and hedging activities		1,419
Net gains on derivatives and hedging activities			2,336	551
Realized net gain from sale of held-to-maturity securities	[1]	12,031	0	0
Other		349	500	435
Total other income		40,984	20,826	22,912
OTHER EXPENSE
Compensation and benefits		47,263	47,681	46,799
Other operating expenses		25,017	24,243	24,342
Federal Housing Finance Agency (the FHFA)		3,914	3,582	3,800
Office of Finance		3,468	3,526	3,260
Other		18,222	12,870	10,300
Total other expense		97,884	91,902	88,501
INCOME BEFORE ASSESSMENTS		212,041	241,068	211,510
AHP assessments		21,302	24,299	21,307
NET INCOME		$ 190,739	$ 216,769	$ 190,203
[1]	The securities sold had less than 15 percent of the acquired principal outstanding at the time of the sale. Such sales are treated as maturities for the purposes of security classification. The sale does not impact our ability and intent to hold the remaining investments classified as held-to-maturity through their stated maturity dates.

Statements of Comprehensive Inc

Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 190,739	$ 216,769	$ 190,203
Other comprehensive income:
Net unrealized gains (losses) on available-for-sale securities	79,036	(30,627)	14,478
Net noncredit portion of other-than-temporary impairment gains on held-to-maturity securities	53,118	29,064	34,161
Net unrealized (losses) gains relating to hedging activities	(913)
Net unrealized (losses) gains relating to hedging activities		11,317	7,751
Pension and postretirement benefits	(1,531)	679	184
Total other comprehensive income	129,710	10,433	56,574
Comprehensive income	$ 320,449	$ 227,202	$ 246,777

Statements of Capital

Statements of Capital - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	$ 3,607,359	$ 3,265,130	$ 3,244,778
Comprehensive income	320,449	227,202	246,777
Proceeds from sale of capital stock	1,854,487	1,800,880	1,067,674
Repurchase of capital stock	(2,514,211)	(1,555,438)	(1,186,589)
Shares reclassified to mandatorily redeemable capital stock	0	(309)	(8,670)
Cash dividends on capital stock	(122,772)	(130,106)	(98,840)
Period end	3,145,312	3,607,359	3,265,130
Retained Earnings, Unrestricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,084,342	1,041,033	987,711
Cumulative effect of change in accounting principle	175
Comprehensive income	152,592	173,415	152,162
Cash dividends on capital stock	(122,772)	(130,106)	(98,840)
Period end	1,114,337	1,084,342	1,041,033
Retained Earnings, Restricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	310,670	267,316	229,275
Comprehensive income	38,147	43,354	38,041
Period end	348,817	310,670	267,316
Retained Earnings, Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,395,012	1,308,349	1,216,986
Cumulative effect of change in accounting principle	175
Comprehensive income	190,739	216,769	190,203
Cash dividends on capital stock	(122,772)	(130,106)	(98,840)
Period end	1,463,154	1,395,012	1,308,349
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	(316,507)	(326,940)	(383,514)
Cumulative effect of change in accounting principle	(175)
Comprehensive income	129,710	10,433	56,574
Period end	$ (186,972)	$ (316,507)	$ (326,940)
Common Class B [Member] | Capital Stock Class B - Putable
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period, shares	25,289	22,837	24,113
Beginning of period	$ 2,528,854	$ 2,283,721	$ 2,411,306
Proceeds from sale of capital stock, shares	18,544	18,009	10,677
Proceeds from sale of capital stock	$ 1,854,487	$ 1,800,880	$ 1,067,674
Repurchase of capital stock, shares	(25,142)	(15,554)	(11,866)
Repurchase of capital stock	$ (2,514,211)	$ (1,555,438)	$ (1,186,589)
Shares reclassified to mandatorily redeemable capital stock, shares		(3)	(87)
Shares reclassified to mandatorily redeemable capital stock		$ (309)	$ (8,670)
Period end, shares	18,691	25,289	22,837
Period end	$ 1,869,130	$ 2,528,854	$ 2,283,721

Statements of Cash Flows

Statements of Cash Flows - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
OPERATING ACTIVITIES
Net Income		$ 190,739,000	$ 216,769,000	$ 190,203,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		(19,937,000)	(1,192,000)	(12,892,000)
Provision for (reduction of ) credit losses		85,000	(34,000)	(96,000)
Change in net fair-value adjustments on derivatives and hedging activities		(284,002,000)	36,176,000	8,554,000
Net other-than-temporary impairment losses on investment securities, credit portion		1,212,000	532,000	1,454,000
Loss on early extinguishment of debt		15,238,000	0	0
Other adjustments		9,182,000	6,335,000	4,637,000
Realized net gain from sale of held-to-maturity securities	[1]	(12,031,000)	0	0
Net change in:
Market value of trading securities		(1,287,000)	4,515,000	6,078,000
Accrued interest receivable		588,000	(18,651,000)	(9,452,000)
Other assets		(7,510,000)	(2,627,000)	(3,147,000)
Accrued interest payable		(7,566,000)	21,417,000	9,804,000
Other liabilities		6,927,000	7,170,000	5,883,000
Total adjustments		(299,101,000)	53,641,000	10,823,000
Net cash (used in) provided by operating activities		(108,362,000)	270,410,000	201,026,000
INVESTING ACTIVITIES
Interest-bearing deposits		(776,421,000)	(629,887,000)	52,274,000
Securities purchased under agreements to resell		2,999,000,000	(1,150,000,000)	650,000,000
Federal funds sold		640,000,000	1,950,000,000	(750,000,000)
Loans to other FHLBanks		0	400,000,000	(400,000,000)
Trading securities:
Proceeds		177,340,000	779,652,000	1,032,652,000
Purchases		(2,263,279,000)	(749,072,000)	(618,051,000)
Available-for-sale securities:
Proceeds		1,714,800,000	1,409,776,000	1,462,091,000
Purchases		(3,206,255,000)	(12,800,000)	(2,222,738,000)
Held-to-maturity securities:
Proceeds		510,590,000	385,610,000	568,279,000
Advances to members:
Repaid		474,957,725,000	652,931,105,000	487,707,464,000
Originated		(466,272,505,000)	(658,551,866,000)	(486,239,305,000)
Mortgage loans held for portfolio:
Proceeds		590,161,000	414,690,000	472,636,000
Purchases		(803,765,000)	(719,845,000)	(794,914,000)
Other investing activities, net		(430,000)	1,454,000	748,000
Net Cash provided by (used in) investing activities		8,266,961,000	(3,541,183,000)	921,136,000
FINANCING ACTIVITIES
Net change in deposits		199,521,000	(2,071,000)	(5,594,000)
Net payments on derivatives with a financing element		(48,642,000)	0	(4,101,000)
Net proceeds from issuance of consolidated obligations:
Discount notes		144,030,097,000	198,660,164,000	170,645,541,000
Bonds		10,851,335,000	10,188,427,000	10,655,859,000
Payments for maturing and retiring consolidated obligations:
Discount notes		(149,400,564,000)	(193,351,448,000)	(172,999,084,000)
Bonds		(12,909,970,000)	(12,586,510,000)	(9,449,955,000)
Bonds transferred to other FHLBanks		(12,697,000)	0	0
Repayment of financing lease		(136,000)	0	0
Proceeds from issuance of capital stock		1,854,487,000	1,800,880,000	1,067,674,000
Payments for repurchase of capital stock		(2,514,211,000)	(1,555,438,000)	(1,186,589,000)
Payments for redemption of mandatorily redeemable capital stock		(26,062,000)	(4,364,000)	(5,434,000)
Cash dividends paid		(122,772,000)	(130,109,000)	(98,837,000)
Net cash (used in) provided by financing activities		(8,099,614,000)	3,019,531,000	(1,380,520,000)
Net increase (decrease) in cash and due from banks		58,985,000	(251,242,000)	(258,358,000)
Cash and due from banks at beginning of the year		10,431,000	261,673,000	520,031,000
Cash and due from banks at end of the year		69,416,000	10,431,000	261,673,000
Supplemental disclosures:
Interest paid		1,224,032,000	1,084,131,000	667,629,000
AHP payments		15,723,000	17,729,000	18,628,000
Noncash receipt of trading securities		0	6,624,000	0
Noncash transfers of mortgage loans held for portfolio to other assets		2,020,000	1,438,000	2,618,000
Lease liabilities arising from obtaining right-of-use assets		$ 12,572,000	$ 0	$ 0
[1]	The securities sold had less than 15 percent of the acquired principal outstanding at the time of the sale. Such sales are treated as maturities for the purposes of security classification. The sale does not impact our ability and intent to hold the remaining investments classified as held-to-maturity through their stated maturity dates.

Background Information

Background Information	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations [Text Block]	Background Information We are a federally chartered corporation and one of 11 district Federal Home Loan Banks (the FHLBanks or the FHLBank System). The FHLBanks are government-sponsored enterprises (GSEs) that were organized under the Federal Home Loan Bank Act of 1932, as amended (FHLBank Act), to serve the public by enhancing the availability of credit for residential mortgages, targeted community development and economic growth. Each FHLBank operates in a specifically defined geographic territory, or district. We provide a readily available, competitively priced source of funds to our members and certain nonmember institutions located within the six New England states, which are Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. Certain regulated financial institutions, including community development financial institutions (CDFIs) and insurance companies with their principal places of business in New England and engaged in residential housing finance, may apply for membership. Additionally, certain nonmember institutions (referred to as housing associates) that meet applicable legal criteria may also borrow from us. While eligible to borrow, housing associates are not eligible to become members and, therefore, are not allowed to hold capital stock. As we are a cooperative, current and former members own all of our outstanding capital stock and may receive dividends on their investment. We do not have any wholly or partially owned subsidiaries, and we do not have an equity position in any partnerships, corporations, or off-balance-sheet special-purpose entities. All members must purchase our stock as a condition of membership and as a condition of engaging in certain business activities with us. The FHFA, our primary regulator, is the independent federal regulator of the FHLBanks, Federal Home Loan Mortgage Corporation (Freddie Mac), and Federal National Mortgage Association (Fannie Mae). A purpose of the FHFA is to ensure that the FHLBanks operate in a safe and sound manner, including maintenance of adequate capital and internal controls. In addition, the FHFA is responsible for ensuring that 1) the operations and activities of each FHLBank foster liquid, efficient, competitive, and resilient national housing finance markets, 2) each FHLBank complies with the title and the rules, regulations, guidelines, and orders issued under the Housing and Economic Recovery Act (HERA) and the authorizing statutes, 3) each FHLBank carries out its statutory mission through only activities that are authorized under and consistent with HERA and the authorizing statutes, and 4) the activities of each FHLBank and the manner in which such FHLBank is operated is consistent with the public interest. Each FHLBank is a separate legal entity with its own management, employees, and board of directors. The Office of Finance is the FHLBanks' fiscal agent and is a joint office of the FHLBanks established to facilitate the issuance and servicing of the FHLBanks' COs and to prepare the combined quarterly and annual financial reports of all the FHLBanks. As provided by the FHLBank Act, and applicable regulations, COs are backed only by the financial resources of all the FHLBanks and are our primary source of funds. Deposits, other borrowings, and the issuance of capital stock, which is principally held by our current and former members, provide other funds. We primarily use these funds to provide loans, called advances, to invest in single-family mortgage loans under the Mortgage Partnership Finance ® (MPF ® ) program, and also to fund other investments. In addition, we offer correspondent services, such as wire-transfer, securities-safekeeping, and settlement services. "Mortgage Partnership Finance", "MPF" and "MPF Xtra" are registered trademarks of the FHLBank of Chicago.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies Use of Estimates These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). The preparation of financial statements in accordance with GAAP requires management to make subjective assumptions and estimates that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported amounts of income and expenses. The most significant of these estimates include but are not limited to, accounting for derivatives and hedging activities, estimation of fair values, and amortization of premiums and discounts associated with prepayable mortgage-backed securities. Actual results could differ from these estimates. Fair Value We determine the fair-value amounts recorded on the statement of condition and in the note disclosures for the periods presented by using available market and other pertinent information, and reflect our best judgment of appropriate valuation methods. Although we use our best judgment in estimating the fair value of these financial instruments, there are inherent limitations in any valuation technique. Therefore, these fair values may not be indicative of the amounts that would have been realized in market transactions at the reporting dates. See Note 19 — Fair Values for more information. Financial Instruments Meeting Netting Requirements We present certain financial instruments on a net basis when they are subject to a legal right of offset and all other requirements for netting are met (collectively referred to as the netting requirements). For these financial instruments, we have elected to offset our asset and liability positions, as well as cash collateral received or pledged, when we have met the netting requirements. The net exposure for these financial instruments can change on a daily basis; therefore, there may be a delay between the time this exposure change is identified and additional collateral is requested, and the time when this collateral is received or pledged. Likewise, there may be a delay for excess collateral to be returned. For derivative instruments that meet the requirements for netting, any excess cash collateral received or pledged is recognized as a derivative liability or derivative asset. See Note 12 — Derivatives and Hedging Activities for additional information regarding these agreements. Based on the fair value of the related collateral held, the securities purchased under agreements to resell were fully collateralized for the periods presented. At December 31, 2019 and 2018 , we had $3.5 billion and $6.5 billion in securities purchased under agreements to resell. There were no offsetting amounts related to these securities at December 31, 2019 and 2018 . Interest-Bearing Deposits, Securities Purchased Under Agreements to Resell, and Federal Funds Sold Interest-bearing deposits, securities purchased under agreements to resell, and federal funds sold provide short-term liquidity and are carried at cost. Federal funds sold consist of short-term, unsecured loans transacted with counterparties that we consider to be of investment quality. Securities purchased under agreements to resell are treated as short-term collateralized loans that are classified as assets in the statement of condition. If the fair value of the underlying securities decreases below the fair value required as collateral, the counterparty has the option to provide additional securities in safekeeping in our name in an amount equal to the decrease or remit cash in such amount. If the counterparty defaults on this obligation, we will decrease the dollar value of the resale agreement accordingly. We have not sold or repledged the collateral received on securities purchased under agreements to resell. Securities purchased under agreements to resell averaged $5.5 billion during 2019 and $4.0 billion during 2018 , and the maximum amount outstanding at any month-end during 2019 and 2018 was $7.0 billion and $6.5 billion , respectively. Investment Securities We classify investments as trading, available-for-sale, or held-to-maturity at the date of acquisition. Purchases and sales of securities are recorded on a trade date basis. Trading. Securities classified as trading are held for liquidity purposes and carried at fair value. We record changes in the fair value of these investments through other income as net unrealized gains (losses) on trading securities. FHFA regulations prohibit trading in or the speculative use of these instruments and limit the credit risks we have from these instruments. Available-for-sale. We classify certain investments that are not classified as held-to-maturity or trading as available-for-sale and carry them at fair value. Changes in fair value of available-for-sale securities not being hedged by derivatives, or in an economic hedging relationship, are recorded in other comprehensive income (loss) as net unrealized gains (losses) on available-for-sale securities. For available-for-sale securities that have been hedged under fair-value hedge designations, we record the portion of the change in the fair value of the investment related to the risk being hedged in available-for-sale interest income together with the related change in the fair value of the derivative. Prior to January 1, 2019, this amount was recorded in other income as net gains (losses) on derivatives and hedging activities. The remainder of the change in the fair value of the investment is recorded in other comprehensive income (loss) as net unrealized gains (losses) on available-for-sale securities. Held-to-Maturity. Certain investments for which we have both the ability and intent to hold to maturity are classified as held-to-maturity and are carried at cost, adjusted for periodic principal repayments, amortization of premiums and accretion of discounts using the level-yield method, other-than-temporary impairment, and accretion of the noncredit portion of other-than-temporary impairment recognized in other comprehensive income (loss). Premiums and Discounts. We amortize premiums and accrete discounts on mortgage-backed securities (MBS) using the level-yield method over the estimated lives of the securities. This method requires a retrospective adjustment of the effective yield each time we change the estimated life, based on actual prepayments received and changes in expected prepayments, as if the new estimate had been known since the original acquisition date of the securities. We estimate prepayment speeds on each individual security using the most recent three months of historical constant prepayment rates, as available, or may subscribe to third-party data services that provide estimates of future cash flows, from which we determine expected asset lives. We amortize premiums and accrete discounts on other investments using the level-yield method to the contractual maturity of the securities. Investment Securities – Other-than-Temporary Impairment We evaluate our individual available-for-sale and held-to-maturity securities in an unrealized loss position for other-than-temporary impairment each quarter. An investment is considered impaired when its fair value is less than its amortized cost. We consider other-than-temporary impairment to have occurred if we: • have an intent to sell the investment; • believe it is more likely than not that we will be required to sell the investment before the recovery of its amortized cost based on available evidence; or • do not expect to recover the entire amortized cost of the debt security. Recognition of Other-than-Temporary Impairment. If either of the first two conditions above is met, we recognize an other-than-temporary impairment charge in earnings equal to the entire difference between the security's amortized cost and its fair value as of the statement of condition date. For securities in an unrealized loss position that meet neither of the first two conditions (excluding agency MBS) and for each of our private-label MBS, we perform an analysis to determine if we will recover the entire amortized cost of each of these securities. The present value of the cash flows expected to be collected is compared with the amortized cost of the debt security to determine whether a credit loss exists. If the present value of the cash flows expected to be collected is less than the amortized cost of the debt security, the security is deemed to be other-than-temporarily impaired and the carrying value of the debt security is adjusted to its fair value. However, rather than recognizing the entire difference between the amortized cost and fair value in earnings, only the amount of the impairment representing the credit loss (that is, the credit component) is recognized in earnings, while the amount related to all other factors (that is, the noncredit component) is recognized in other comprehensive income (loss). For a security that is determined to be other-than-temporarily impaired, in the event that the present value of the cash flows expected to be collected is less than the fair value of the security, the credit loss on the security is limited to the amount of that security's unrealized losses. In performing a detailed cash-flow analysis, we estimate the cash flows expected to be collected. If this estimate results in a present value of expected cash flows (discounted at the security's effective yield) that is less than the amortized cost basis of a security (that is, a credit loss exists), other-than-temporary impairment is considered to have occurred. For determining the present value of variable-rate and hybrid private-label residential MBS, we use the effective interest rate derived from a variable-rate index, such as one-month London Interbank Offered Rate (LIBOR), plus the contractual spread, plus or minus a fixed-spread adjustment when there is an existing discount or premium on the security. Because the implied forward yield curve of a selected variable-rate index changes over time, the effective interest rates derived from that index will also change over time and would therefore impact the present value of the subject security. Interest Income Recognition. Upon subsequent evaluation of a debt security when there is no additional other-than-temporary impairment, we adjust the accretable yield on a prospective basis if there is a significant increase in the security's expected future cash flows. This adjusted yield is used to calculate the amount to be recognized into income over the remaining life of the security so as to match the amount and timing of future cash flows expected to be collected. Subsequent changes in estimated cash flows that are deemed significant will change the accretable yield on a prospective basis. For debt securities classified as held-to-maturity, the other-than-temporary impairment recognized in other comprehensive income (loss) is accreted to the carrying value of each security on a prospective basis, based on the amount and timing of future estimated cash flows. The estimated cash flows and accretable yield are re-evaluated each quarter. Advances We report advances at amortized cost. Advances carried at amortized cost are reported net of premiums/discounts and any hedging adjustments, as discussed in Note 9 — Advances . We generally record our advances at par. However, we may record premiums or discounts on advances in the following cases: • Advances may be acquired from another FHLBank when one of our members acquires a member of another FHLBank. In these cases, we may purchase the advances from the other FHLBank at a price that results in a fair market yield for the acquired advance. • When the prepayment of an advance is followed by disbursement of a new advance and the transactions effectively represent a modification of the previous advance, the prepayment fee received is deferred, recorded as a discount to the modified advance, and accreted over the life of the new advance. • When an advance is modified under our advance restructuring program and our analysis of the restructuring concludes that the transaction is an extinguishment of the prior advance rather than a modification, the deferred prepayment fee is recognized into income immediately, recorded as premium on the new advance, and amortized over the life of the new advance. • When we make an AHP advance, the present value of the variation in the cash flow caused by the difference in the interest rate between the AHP advance rate and our related cost of funds for comparable maturity funding is charged against the AHP liability and recorded as a discount on the AHP advance. • Advances issued under our Jobs for New England (JNE) and Helping to House New England (HHNE) programs have an interest rate at a significant discount to market rates. Due to the below market interest rate, we record a discount on the advance and an interest rate subsidy expense at the time that we transact the advance. The subsidy expense is recorded in other expense in the statement of operations. We amortize the premiums and accrete the discounts on advances to interest income using the level-yield method. We record interest on advances to interest income as earned. Prepayment Fees. We charge borrowers a prepayment fee when they prepay certain advances before the original maturity. We record prepayment fees net of hedging fair-value adjustments included in the carrying value of the advance as advances interest income on the statement of operations. Advance Modifications. In cases in which we fund a new advance concurrently with or within a short period of time of the prepayment of an existing advance by the same member, we evaluate whether the new advance meets the accounting criteria to qualify as a modification of the existing advance or whether it constitutes a new advance. We compare the present value of cash flows on the new advance with the present value of cash flows remaining on the existing advance. If there is at least a 10 percent difference in the present value of cash flows or if we conclude the difference between the advances is more than minor based on a qualitative assessment of the modifications made to the advance's original contractual terms, the advance is accounted for as a new advance. In all other instances, the new advance is accounted for as a modification. If a new advance qualifies as a modification of the existing advance, the net prepayment fee on the prepaid advance is deferred, recorded in the basis of the modified advance, and amortized to interest income over the life of the modified advance using the level-yield method. This amortization is recorded in advance-interest income. If the modified advance is hedged, changes in fair value are recorded after the amortization of the basis adjustment in advance interest income. Prior to January 1, 2019, this amortization resulted in offsetting amounts being recorded in net interest income and net gains (losses) on derivatives and hedging activities in other income. For prepaid advances that were hedged and meet the hedge-accounting requirements, we terminate the hedging relationship upon prepayment and record the prepayment fee net of the hedging fair-value adjustment in the basis of the advance as advance-interest income. If we fund a new advance to a member concurrent with or within a short period of time after the prepayment of a previous advance to that member, we evaluate whether the new advance qualifies as a modification of the original hedged advance. If the new advance qualifies as a modification of the original hedged advance, the hedging fair-value adjustment and the prepayment fee are included in the carrying amount of the modified advance and are amortized in interest income over the life of the modified advance using the level-yield method. If the modified advance is also hedged and the hedge meets the hedging criteria, the modified advance is marked to fair value after the modification, and subsequent fair-value changes are recorded in advance interest income. Prior to January 1, 2019, subsequent fair value changes were recorded in other income as net gains (losses) on derivatives and hedging activities. If a new advance does not qualify as a modification of an existing advance, prepayment of the existing advance is treated as an advance termination and any prepayment fee, net of hedging adjustments, is recorded to advance-interest income in the statement of operations. Commitment Fees We record commitment fees for standby letters of credit to members as deferred fee income when received, and amortize these fees on a straight-line basis to service-fees income in other income over the term of the standby letter of credit. Based upon past experience, we believe the likelihood of standby letters of credit being drawn upon is remote. Mortgage Loans Held for Portfolio We participate in the MPF program through which we invest in conventional, residential, fixed-rate mortgage loans (conventional mortgage loans) and government-insured or -guaranteed residential fixed-rate mortgage loans (government mortgage loans) that are purchased from participating financial institutions (see Note 10 — Mortgage Loans Held for Portfolio ). We classify our investments in mortgage loans for which we have the intent and ability to hold for the foreseeable future or until maturity or payoff as held for portfolio. As of December 31, 2019 , all our investments in mortgage loans are held for portfolio. Accordingly, these investments are reported at their principal amount outstanding net of unamortized premiums, discounts, unrealized gains and losses from investments initially classified as mortgage loan commitments, direct write-downs, and the allowance for credit losses on mortgage loans. Premiums and Discounts. We compute the amortization of mortgage-loan-origination fees (premiums and discounts) as interest income using the level-yield method over the contractual term to maturity of each individual loan, which results in income recognition in a manner that is effectively proportionate to the actual repayment behavior of the underlying assets and reflects the contractual terms of the assets without regard to changes in estimated prepayments based on assumptions about future borrower behavior. Credit-Enhancement Fees. For conventional mortgage loans, participating financial institutions retain a portion of the credit risk on the loans in which we invest by providing credit-enhancement protection either through a direct liability to pay credit losses up to a specified amount or through a contractual obligation to provide supplemental mortgage insurance. Participating financial institutions are paid a credit-enhancement fee for assuming credit risk and in some instances all or a portion of the credit-enhancement fee may be performance-based. Credit-enhancement fees are paid monthly and are determined based on the remaining unpaid principal balance of the pertinent MPF loans. The required credit-enhancement amount varies depending on the MPF product. Credit-enhancement fees are recorded as an offset to mortgage-loan-interest income. To the extent that losses in the current month exceed performance-based credit-enhancement fees accrued, the remaining losses may be recovered from future performance-based credit-enhancement fees payable to the participating financial institution. Other Fees. We record other nonorigination fees in connection with our MPF program activities in other income. Such fees include delivery-commitment-extension fees, pair-off fees, price-adjustment fees, and counterparty fees in connection with MPF products under which we facilitate third party investment in loans (non-investment MPF products) such as with the MPF Xtra ® product. Delivery-commitment-extension fees are charged when a participating financial institution requests to extend the period of the delivery commitment beyond the original stated expiration. Pair-off fees represent a make-whole provision; they are received when the amount funded under a delivery commitment is less than a certain threshold (under-delivery) of the delivery-commitment amount. Price-adjustment fees are received when the amount funded is greater than a certain threshold (over-delivery) of the delivery-commitment amount. To the extent that pair-off fees relate to under-deliveries of loans, they are recorded in service fee income. Fees related to over-deliveries represent purchase-price adjustments to the related loans acquired and are recorded as part of the carrying value of the loan. The FHLBank of Chicago pays us a counterparty fee for the costs and expenses of marketing activities for loans originated for sale under non-investment MPF products. Mortgage-Loan Participations. We may purchase and sell participations in MPF loans from other FHLBanks from time to time. References to our investments in mortgage loans throughout this report include any participation interests we own. Allowance for Credit Losses An allowance for credit losses is a valuation allowance separately established for each identified portfolio segment, if necessary, to provide for probable losses inherent in our portfolio as of the statement of condition date and the amount of loss can be reasonably estimated. A loan is considered impaired when, based on current information and events, it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. To the extent necessary, an allowance for credit losses for off-balance-sheet credit exposure is recorded as a liability. Portfolio Segments. A portfolio segment is defined as the level at which an entity develops and documents a systematic methodology for determining its allowance for credit losses. We have established an allowance methodology for each of our portfolio segments. See Note 11 – Allowance for Credit Losses for additional information. Nonaccrual Loans. We place conventional mortgage loans on nonaccrual status when the collection of the contractual principal or interest is 90 days or more past due. When a conventional mortgage loan is placed on nonaccrual status, accrued but uncollected interest is reversed against interest income in the current period. We generally record cash payments received on nonaccrual loans first as interest income and then as a reduction of principal as specified in the contractual agreement, unless we consider the collection of the remaining principal amount due to be doubtful. If we consider the collection of the remaining principal amount to be doubtful, cash payments received are applied first solely to principal until the remaining principal amount due is expected to be collected and then as a recovery of any charge-off, if applicable, followed by recording interest income. A loan on nonaccrual status may be restored to accrual status when the collection of the contractual principal and interest is less than 90 days past due. We do not place government mortgage loans on nonaccrual status when the collection of the contractual principal or interest is 90 days or more past due because of the U.S. government guarantee of the loan and the contractual obligations of each related servicer, as more fully discussed in Note 11 – Allowance for Credit Losses . Collateral-dependent Loans. An impaired loan is considered collateral-dependent if repayment is expected to be provided solely by the sale of the underlying property; that is, there is no other available and reliable source of repayment. A loan that is considered collateral-dependent is measured for impairment based on the fair value of the underlying property less estimated selling costs, with any shortfall recognized as an allowance for loan loss or charged-off. Interest income on impaired loans is recognized in the same manner as non-accrual loans. Charge-Off Policy. A charge-off is recorded if it is estimated that the recorded investment in a loan will not be recovered. We evaluate whether to record a charge-off on a conventional mortgage loan upon the occurrence of a confirming event. Confirming events include, but are not limited to, the occurrence of foreclosure or notification of a claim against any of the credit-enhancements. We charge off the portion of outstanding conventional mortgage loan balances in excess of fair value of the underlying property, less cost to sell and adjusted for any available credit-enhancements for loans that are 180 or more days past due, when the borrower has filed for bankruptcy protection and the loan is at least 30 days past due, or when there is evidence of fraud. Troubled Debt Restructurings We consider a troubled debt restructuring of a financing receivable to have occurred when we grant a concession to a borrower that we would not otherwise consider for economic or legal reasons related to the borrower's financial difficulties. We place conventional mortgage loans that are deemed to be troubled debt restructurings as a result of our modification program on nonaccrual when payments are 60 days or more past due. Real Estate Owned Real-estate-owned property (REO) includes assets that have been received in satisfaction of debt or as a result of actual foreclosures. REO is recorded as other assets in the statement of condition and is carried at the lower of cost or fair value less estimated selling costs. At December 31, 2019 and 2018 , we had $1.3 million and $818 thousand , respectively, in assets classified as REO. Fair value is derived from third-party valuations of the property. If the fair value of the REO less estimated selling costs is less than the recorded investment in the MPF loan at the date of transfer, we recognize a charge-off to the allowance for credit losses. Subsequent realized gains and realized or unrealized losses are included in other income (loss) in the statement of operations. Derivatives and Hedging Activities All derivatives are recognized on the statement of condition at fair value and are reported as either derivative assets or derivative liabilities, net of cash collateral and accrued interest received from or pledged to clearing members and/or counterparties. We offset fair-value amounts recognized for derivatives and fair-value amounts recognized for the right to reclaim cash collateral (a receivable) or the obligation to return cash collateral (a payable) arising from derivatives recognized at fair value executed with the same clearing member and/or counterparty when the netting requirements have been met. If these netted amounts are positive, they are classified as an asset and, if negative, they are classified as a liability. Derivative assets and derivative liabilities reported on the statement of condition also include net accrued interest. Cash flows associated with derivatives are reflected as cash flows from operating activities in the statement of cash flows unless the derivative meets the criteria to be a financing derivative. Each derivative is designated as one of the following: • a qualifying hedge of the change in fair value of a recognized asset or liability or an unrecognized firm commitment (a fair value hedge); • a qualifying hedge of a forecasted transaction (a cash-flow hedge); or • a nonqualifying hedge of an asset or liability (an economic hedge) for asset-liability-management purposes. We utilize two derivatives clearing organizations (DCOs), for all cleared derivative transactions, Chicago Mercantile Exchange, Inc. (CME Inc.) and LCH Limited (LCH Ltd.). At both DCOs, variation margin is characterized as daily settlement payments and initial margin is considered collateral. Accounting for Fair-Value and Cash-Flow Hedges. If hedging relationships meet certain criteria, including, but not limited to, formal documentation of the hedging relationship and an expectation to be highly effective, they qualify for fair-value or cash-flow hedge accounting. For cash-flow hedges, we measure effectiveness using the hypothetical derivative method, which compares the cumulative change in fair value of the actual derivative designated as the hedging instrument to the cumulative change in fair value of a hypothetical derivative having terms that identically match the critical terms of the hedged forecasted transaction. Derivatives that are used in fair-value hedges are typically executed at the same time as the hedged items, and we designate the hedged item in a qualifying hedge relationship as of the trade date. We then record the changes in fair value of the derivative and the hedged item beginning on the trade date. Beginning January 1, 2019, we adopted new hedge accounting guidance which, among other things, impacts the presentation of gains (losses) on derivatives and hedging activities for qualifying hedges as follows: • Changes in the fair value of a derivative that is designated and qualifies as a fair-value hedge, along with changes in the fair value of the hedged asset or liability that are attributable to the hedged risk, are recorded in net interest income in the same line as the earnings effect of the hedged item. • Changes in the fair value of a derivative that is designated and qualifies as a cash-flow hedge are recorded in other comprehensive income (loss), a component of capital, until the hedged transaction affects earnings. Prior to January 1, 2019, for both fair-value and cash-flow hedges, any hedge ineffectiveness (which represented the amount by which the change in the fair value of the derivative differed from the change in the fair value of the hedged item or the variability in the cash flows of the forecasted transaction attributable to the hedged risk) was recorded in non-interest income as net gains (losses) on derivatives and hedging activities. Accounting for Economic Hedges. An economic hedge is defined as a derivative hedging specific or nonspecific assets, liabilities, or firm commitments that does not qualify or was not designated for fair-value or cash-flow hedge accounting, but is an acceptable hedging strategy under our risk-management policy. These economic hedging strategies also comply with FHFA regulatory requirements prohibiting speculative derivative transactions. An economic hedge introduces the potential for earnings variability caused by the changes in fair value of the derivatives that are recorded in income but not offset by corresponding changes in the fair value of the economically hedged assets, liabilities, or firm commitments. As a result, we recognize only the net interest and the change in fair value of these derivatives in other income (loss) as net gains (losses) on derivatives and hedging activities with no offsetting fair-value adjustments for the economically hedged assets, liabilities, or firm commitments. Accrued Interest Receivable and Payable. The differential between accrual of interest receivable and payable on derivatives designated as a fair-value hedge or as a cash-flow hedge is recognized through adjustments to the interest income or interest expense of the designated hedged investment securities, advances, COs, or other financial instruments. The differential between accrual of interest receivable and payable on economic hedges is recognized in other income (loss), along with changes in fair value of these derivatives, as net gains (losses) on derivatives and hedging activities. Discontinuance of Hedge Accounting. We may discontinue hedge accounting prospectively when: • we determine that the derivative is no longer effective in offsetting changes in the fair value or cash flows of a hedged item attributable to the hedged risk (including hedged items such as firm commitments or forecasted transactions); • the derivative and/or the hedged item expires or is sold, terminated, or exercised; • it is no longer probable that the forecasted transaction in a cash-flow hedge will occur in the originally expected period or within the following two months; • a hedged firm commitment in a fair-value hedge no longer meets the definition of a firm commitment; or • we determine that designating the derivative as a hedging instrument is no longer appropriate. If hedge accounting is discontinued because we determine that the derivative no longer qualifies as an effective fair-value hedge of an existing hedged item, we either terminate the derivative or continue to carry the derivative on the statement of condition at its fair value and cease to adjust the hedged asset or liability for changes in fair value. We will then begin to amortize the cumulative basis adjustment on the hedged item into earnings over the remaining life of the hedged item

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	12 Months Ended
	Dec. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Recently Issued and Adopted Accounting Guidance Effective January 1, 2019 Inclusion of the Overnight Indexed Swap Rate Based on the Secured Overnight Financing Rate (SOFR) as a Benchmark Interest Rate for Hedge Accounting Purposes. On October 25, 2018, the FASB issued amended guidance to permit use of the overnight-index swap (OIS) rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes. This guidance became effective for us on January 1, 2019. Upon adoption, SOFR became an eligible benchmark interest rate which we may elect to apply to future hedge relationships. Targeted Improvements to Accounting for Hedging Activities. 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 other comprehensive income. 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 of how changes in the benchmark interest rate alone 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; • For a closed portfolio of prepayable financial assets or one or more beneficial interests secured by a portfolio of prepayable financial instruments, an entity can designate an amount that is not expected to be affected by prepayments, defaults, and other events affecting the timing and amount of cash flows (the “last-of-layer” method) into a hedging relationship; and • An entity can perform subsequent assessments of hedge effectiveness qualitatively in instances where initial quantitative testing is required. We adopted this guidance effective January 1, 2019. For all cash-flow hedges existing on the date of adoption, this guidance was applied through a cumulative-effect adjustment to accumulated other comprehensive income with a corresponding adjustment to retained earnings as of the beginning of the year of adoption. The amended presentation and disclosure guidance were applied prospectively; prior period comparative financial information has not been reclassified to conform to current presentation. The adoption of this guidance did not have a material effect on our financial condition, results of operations, or cash flows. See Note 2 — Summary of Significant Accounting Policies and Note 12 — Derivatives and Hedging Activities for additional information. Leases. On February 25, 2016, the FASB issued guidance that requires recognition of lease assets and lease liabilities on the statement of condition and disclosure of key information about leasing arrangements. In particular, 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. However, 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. The guidance became effective for us on January 1, 2019. Upon adoption of the new guidance, we recognized right-of-use assets and lease liabilities for our operating leases of approximately $11.9 million and $12.5 million , respectively, on the statement of condition. See Note 2 — Summary of Significant Accounting Policies for additional information. Effective January 1, 2020 Facilitation of the Effects of Reference Rate Reform on Financial Reporting . On March 12, 2020, the Financial Accounting Standards Board released temporary optional guidance that provides transition relief for reference rate reform. The guidance contains optional expedients and exceptions for applying generally accepted accounting principles to contract modifications, hedging relationships, and other transactions that reference LIBOR or a reference rate that is expected to be discontinued as a result of reference rate reform if certain criteria are met. In addition to the optional expedients for contract modifications and hedging relationships, this update provides a one-time election to sell, transfer, or both sell and transfer debt securities classified as held-to-maturity that reference a rate affected by reference rate reform and that are classified as held-to-maturity before January 1, 2020. This standard is effective upon issuance and the provisions generally can be applied prospectively as of January 1, 2020 through December 31, 2022. We are in the process of evaluating this guidance, and its anticipated effect on our financial condition, results of operations, and cash flows has not yet been determined. Financial Instruments - Credit Losses. 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 over the contractual term of the financial asset(s). The guidance also requires, among other things, that we: • Reflect in the statement of operations 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. • Determine the allowance for credit losses for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination 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. • Record credit losses relating to available-for-sale 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. • Further disaggregate the current disclosure of credit quality indicators in relation to the amortized cost of financing receivables by the year of origination. This guidance is effective for us for interim and annual periods beginning on January 1, 2020. This guidance is required to 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 purchased financial assets with a more-than-insignificant amount of credit deterioration since origination and for debt securities for which an other-than-temporary impairment had been recognized before the effective date. The adoption of this guidance did not have a material effect on our financial condition, results of operations, or cash flows.

Cash and Due From Banks

Cash and Due From Banks	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents Disclosure [Text Block]	Cash and Due from Banks Cash and due from banks includes cash on hand, cash items in the process of collection, compensating balances, and amounts due from correspondent banks and the Federal Reserve Bank of Boston. Compensating Balances. We maintain collected cash balances with a commercial bank in return for certain services. The related agreement contains no legal restrictions on the withdrawal of funds. The average collected cash balance was $19.3 million and $16.3 million for the years ended December 31, 2019 and 2018 , respectively.

Trading Securities

Trading Securities	12 Months Ended
	Dec. 31, 2019
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Trading Securities (and Certain Trading Assets) Disclosure [Text Block]	Trading Securities Table 5.1 - Trading Securities by Major Security Type (dollars in thousands) December 31, 2019 December 31, 2018 Corporate bonds $ 5,896 $ 6,102 U.S. Treasury obligations 2,240,236 — 2,246,132 6,102 MBS U.S. government-guaranteed – single-family 4,047 5,344 GSE – single-family 85 148 GSE – multifamily — 151,444 4,132 156,936 Total $ 2,250,264 $ 163,038 Table 5.2 - Unrealized and Realized Gains (Losses) on Trading Securities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Net unrealized gains (losses) on trading securities held at year end $ 1,379 $ (4,515 ) $ (6,145 ) Net unrealized and realized gains on trading securities sold or matured during the year (92 ) — 67 Net unrealized gains (losses) on trading securities $ 1,287 $ (4,515 ) $ (6,078 ) We do not participate in speculative trading practices and typically hold these investments over a longer time horizon.

Available-for-Sale Securities

Available-for-Sale Securities	12 Months Ended
	Dec. 31, 2019
Debt Securities, Available-for-sale [Abstract]
Available-for-Sale Securities Disclosure [Text Block]	Available-for-Sale Securities Table 6.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) December 31, 2019 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value State housing-finance-agency obligations (HFA securities) $ 69,320 $ — $ (4,668 ) $ 64,652 Supranational institutions 429,354 — (12,925 ) 416,429 U.S. government-owned corporations 323,192 — (26,431 ) 296,761 GSE 130,935 — (7,149 ) 123,786 952,801 — (51,173 ) 901,628 MBS U.S. government guaranteed – single-family 60,003 — (2,289 ) 57,714 U.S. government guaranteed – multifamily 283,674 — (1,057 ) 282,617 GSE – single-family 2,598,325 5,323 (13,377 ) 2,590,271 GSE – multifamily 3,588,119 3,109 (14,458 ) 3,576,770 6,530,121 8,432 (31,181 ) 6,507,372 Total $ 7,482,922 $ 8,432 $ (82,354 ) $ 7,409,000 December 31, 2018 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 55,500 $ — $ (5,899 ) $ 49,601 Supranational institutions 419,222 — (14,067 ) 405,155 U.S. government-owned corporations 297,729 — (24,560 ) 273,169 GSE 122,423 — (6,796 ) 115,627 894,874 — (51,322 ) 843,552 MBS U.S. government guaranteed – single-family 79,075 20 (3,437 ) 75,658 U.S. government guaranteed – multifamily 368,103 — (6,969 ) 361,134 GSE – single-family 3,649,964 681 (88,486 ) 3,562,159 GSE – multifamily 1,010,886 168 (3,613 ) 1,007,441 5,108,028 869 (102,505 ) 5,006,392 Total $ 6,002,902 $ 869 $ (153,827 ) $ 5,849,944 _______________________ (1) Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments. Table 6.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position (dollars in thousands) December 31, 2019 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 12,229 $ (1,591 ) $ 52,423 $ (3,077 ) $ 64,652 $ (4,668 ) Supranational institutions — — 416,429 (12,925 ) 416,429 (12,925 ) U.S. government-owned corporations — — 296,761 (26,431 ) 296,761 (26,431 ) GSE — — 123,786 (7,149 ) 123,786 (7,149 ) 12,229 (1,591 ) 889,399 (49,582 ) 901,628 (51,173 ) MBS U.S. government guaranteed – single-family 10,885 (1 ) 45,490 (2,288 ) 56,375 (2,289 ) U.S. government guaranteed – multifamily — — 282,617 (1,057 ) 282,617 (1,057 ) GSE – single-family 189,402 (968 ) 1,423,927 (12,409 ) 1,613,329 (13,377 ) GSE – multifamily 1,800,586 (13,242 ) 405,778 (1,216 ) 2,206,364 (14,458 ) 2,000,873 (14,211 ) 2,157,812 (16,970 ) 4,158,685 (31,181 ) Total temporarily impaired $ 2,013,102 $ (15,802 ) $ 3,047,211 $ (66,552 ) $ 5,060,313 $ (82,354 ) December 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 11,118 $ (1,682 ) $ 38,483 $ (4,217 ) $ 49,601 $ (5,899 ) Supranational institutions — — 405,155 (14,067 ) 405,155 (14,067 ) U.S. government-owned corporations — — 273,169 (24,560 ) 273,169 (24,560 ) GSE — — 115,627 (6,796 ) 115,627 (6,796 ) 11,118 (1,682 ) 832,434 (49,640 ) 843,552 (51,322 ) MBS U.S. government guaranteed – single-family — — 57,679 (3,437 ) 57,679 (3,437 ) U.S. government guaranteed – multifamily — — 361,134 (6,969 ) 361,134 (6,969 ) GSE – single-family 53,122 (388 ) 3,417,076 (88,098 ) 3,470,198 (88,486 ) GSE – multifamily 902,850 (3,613 ) — — 902,850 (3,613 ) 955,972 (4,001 ) 3,835,889 (98,504 ) 4,791,861 (102,505 ) Total temporarily impaired $ 967,090 $ (5,683 ) $ 4,668,323 $ (148,144 ) $ 5,635,413 $ (153,827 ) Table 6.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 7,600 $ 7,563 $ — $ — Due after one year through five years 61,720 57,089 55,500 49,601 Due after five years through 10 years 477,232 463,465 465,248 450,102 Due after 10 years 406,249 373,511 374,126 343,849 952,801 901,628 894,874 843,552 MBS (1) 6,530,121 6,507,372 5,108,028 5,006,392 Total $ 7,482,922 $ 7,409,000 $ 6,002,902 $ 5,849,944 _______________________ (1) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities

Held-to-Maturity Securities	12 Months Ended
	Dec. 31, 2019
Debt Securities, Held-to-maturity [Abstract]
Held-to-maturity Securities Disclosure [Text Block]	Held-to-Maturity Securities Table 7.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) December 31, 2019 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value HFA securities $ 87,250 $ — $ 87,250 $ — $ (3,845 ) $ 83,405 MBS U.S. government guaranteed – single-family 6,987 — 6,987 129 — 7,116 GSE – single-family 303,604 — 303,604 5,197 (246 ) 308,555 GSE – multifamily 140,661 — 140,661 612 (2 ) 141,271 Private-label 408,640 (76,035 ) 332,605 162,904 (446 ) 495,063 859,892 (76,035 ) 783,857 168,842 (694 ) 952,005 Total $ 947,142 $ (76,035 ) $ 871,107 $ 168,842 $ (4,539 ) $ 1,035,410 December 31, 2018 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value U.S. agency obligations $ 208 $ — $ 208 $ — $ — $ 208 HFA securities 104,465 — 104,465 4 (4,612 ) 99,857 104,673 — 104,673 4 (4,612 ) 100,065 MBS U.S. government guaranteed – single-family 8,173 — 8,173 158 — 8,331 GSE – single-family 412,639 — 412,639 6,861 (1,389 ) 418,111 GSE – multifamily 209,786 — 209,786 1,728 — 211,514 Private-label 688,905 (129,153 ) 559,752 234,083 (2,927 ) 790,908 1,319,503 (129,153 ) 1,190,350 242,830 (4,316 ) 1,428,864 Total $ 1,424,176 $ (129,153 ) $ 1,295,023 $ 242,834 $ (8,928 ) $ 1,528,929 Table 7.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position (dollars in thousands) December 31, 2019 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 3,089 $ (1 ) $ 80,316 $ (3,844 ) $ 83,405 $ (3,845 ) MBS GSE – single-family 32,335 (101 ) 16,465 (145 ) 48,800 (246 ) GSEs – multifamily 949 (2 ) — — 949 (2 ) Private-label 913 (9 ) 23,999 (574 ) 24,912 (583 ) 34,197 (112 ) 40,464 (719 ) 74,661 (831 ) Total $ 37,286 $ (113 ) $ 120,780 $ (4,563 ) $ 158,066 $ (4,676 ) December 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 6,196 $ (9 ) $ 92,822 $ (4,603 ) $ 99,018 $ (4,612 ) MBS GSE – single-family 69,377 (580 ) 52,237 (809 ) 121,614 (1,389 ) Private-label 25,680 (331 ) 114,937 (4,587 ) 140,617 (4,918 ) 95,057 (911 ) 167,174 (5,396 ) 262,231 (6,307 ) Total $ 101,253 $ (920 ) $ 259,996 $ (9,999 ) $ 361,249 $ (10,919 ) Table 7.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 3,090 $ 3,090 $ 3,089 $ 1,043 $ 1,043 $ 1,047 Due after one year through five years — — — 6,205 6,205 6,196 Due after five years through 10 years 15,405 15,405 15,270 16,865 16,865 16,639 Due after 10 years 68,755 68,755 65,046 80,560 80,560 76,183 87,250 87,250 83,405 104,673 104,673 100,065 MBS (2) 859,892 783,857 952,005 1,319,503 1,190,350 1,428,864 Total $ 947,142 $ 871,107 $ 1,035,410 $ 1,424,176 $ 1,295,023 $ 1,528,929 _______________________ (1) Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss. (2) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees. Table 7.4 - Proceeds from Sale and Gains and Losses on Held-to-Maturity Securities (1) (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Proceeds from sale of held-to-maturity securities $ 185,177 $ — $ — Amortized cost of held-to-maturity securities 173,146 — — Realized net gain from sale of held-to-maturity securities $ 12,031 $ — $ — _______________________ (1) The securities sold had less than 15 percent of the acquired principal outstanding at the time of the sale. Such sales are treated as maturities for the purposes of security classification. The sale does not impact our ability and intent to hold the remaining investments classified as held-to-maturity through their stated maturity dates.

Other-Than-Temporary Impairment

Other-Than-Temporary Impairment	12 Months Ended
	Dec. 31, 2019
Other than Temporary Impairment Losses, Investments [Abstract]
Other-than-Temporary Impairment [Text Block]	Other-Than-Temporary Impairment We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter. Available-for-Sale Securities We determined that none of our available-for-sale securities were other-than-temporarily impaired at December 31, 2019 . At December 31, 2019 , we held certain available-for-sale securities in an unrealized loss position. We consider these unrealized losses temporary because we expect to recover the entire amortized cost basis on these available-for-sale securities in an unrealized loss position and neither intend to sell these securities nor is it more likely than not that we will be required to sell these securities before the anticipated recovery of each security's remaining amortized cost basis. Additionally, there have been no shortfalls of principal or interest on any available-for-sale security. Held-to-Maturity Securities HFA Securities and Agency MBS. We have reviewed our investments in HFA securities and agency MBS and have determined that all unrealized losses are temporary. We do not intend to sell the investments nor is it more likely than not that we will be required to sell the investments before recovery of the amortized cost basis, and we do not consider these investments to be other-than-temporarily impaired at December 31, 2019 . Private-Label Residential MBS. To ensure consistency in determination of the other-than-temporary impairment for private-label residential MBS among all FHLBanks, the FHLBanks use an FHLBank System governance committee (the OTTI Governance Committee) and a formal process to ensure consistency in key other-than-temporary impairment modeling assumptions used for purposes of their cash-flow analyses for the majority of these securities. We use the FHLBanks' uniform framework and approved assumptions for purposes of our other-than-temporary impairment cash-flow analyses of our private-label residential MBS. We are responsible for making our own determination of impairment and the reasonableness of assumptions, inputs, and methodologies used and for performing the required present value calculations using appropriate historical cost bases and yields. Our evaluation includes estimating the projected cash flows that we are likely to collect based on an assessment of available information, including the structure of the applicable security and certain assumptions to determine whether we will recover the entire amortized cost basis of the security, such as: • the remaining payment terms for the security; • prepayment speeds; • default rates; • loss severity on the collateral supporting each security based on underlying loan-level borrower and loan characteristics; • expected housing price changes, with projections ranging from a decrease of 4.0 percent to an increase of 8.0 percent over the 12-month period beginning October 1, 2019. For the vast majority of markets, the projected short-term housing price changes range from an increase of 2.0 percent to an increase of 6.0 percent . Thereafter, we have projected a unique long-term forecast for each relevant geographic area based on an internally developed framework derived from historical data; and • interest-rate assumptions. To assess whether the entire amortized cost basis of private-label residential MBS will be recovered, cash-flow analyses for each of our private-label residential MBS were performed. For those securities for which a credit loss was recognized during the year ended December 31, 2019 , Table 8.1 presents a summary of the average projected values over the remaining lives of the securities for the significant inputs used to measure the amount of the credit loss recognized in earnings, as well as related current credit-enhancement. Credit-enhancement is defined as the percentage of subordinated tranches, over-collateralization, and other credit-enhancement, if any, in a security structure that will generally absorb losses before we will experience a credit loss on the security. The calculated averages represent the dollar-weighted average of Alt-A other-than-temporarily impaired private-label residential MBS. Table 8.1 - Significant Inputs and Current Credit Enhancement for Securities with a Credit Loss in 2019 (dollars in thousands) Weighted Average of Significant Inputs Weighted Average Current Credit Enhancement Private-label MBS by Classification Par Value Projected Prepayment Rates Projected Default Rates Projected Loss Severities Private-label residential MBS - Alt-A (1) $ 39,989 12.3 % 22.9 % 55.1 % 5.7 % _______________________ (1) Securities are classified based upon the current performance characteristics of the underlying loan pool and therefore the manner in which the loan pool backing the security has been modeled (as prime, Alt-A, or subprime), rather than their classification of the security at the time of issuance. Table 8.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) December 31, 2019 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 3,796 $ 3,474 $ 2,510 $ 3,590 Private-label residential MBS – Alt-A 561,825 383,439 308,368 470,192 Total other-than-temporarily impaired securities $ 565,621 $ 386,913 $ 310,878 $ 473,782 _______________________ (1) Securities are classified based on the classifications of their underlying loan composition at the time of issuance. We instituted and are continuing litigation related to certain of the private-label MBS in which we invested. Our complaint asserts, among others, claims for untrue or misleading statements in the sale of securities. It is possible that classifications of private-label MBS as provided herein when based on classification at the time of issuance as disclosed by those securities' issuance documents, as well as other statements about the securities, are inaccurate. Table 8.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Balance at beginning of year $ 422,035 $ 452,523 $ 490,404 Additions: Credit losses for which other-than-temporary impairment was not previously recognized 128 — — Additional credit losses for which an other-than-temporary impairment charge was previously recognized 1,084 532 1,454 Reductions: Securities sold or matured during the year (56,710 ) — (5,600 ) Portion of increase in cash flows expected to be collected over the remaining life of the security that are recognized in the current period as interest income (26,907 ) (31,020 ) (33,735 ) Balance at end of year $ 339,630 $ 422,035 $ 452,523

Advances

Advances	12 Months Ended
	Dec. 31, 2019
Advances [Abstract]
Federal Home Loan Bank, Advances [Text Block]	Advances General Terms. We offer a wide range of fixed- and variable-rate advance products with different maturities, interest rates, payment characteristics, and optionality. Advances have maturities ranging from one day to 30 years or longer with the approval of our credit committee. At December 31, 2019 and 2018 , we had advances outstanding with interest rates ranging from (0.35) percent to 7.72 percent and 0.00 percent to 7.72 percent . Advances with negative interest rates contain embedded interest-rate features that have met the requirements to be separated from the host contract and are recorded as stand-alone derivatives, and which we economically hedge with derivatives containing offsetting interest-rate features. Table 9.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 5,101 2.05 % $ 12,332 2.88 % Due in one year or less 18,972,466 1.96 24,029,592 2.48 Due after one year through two years 8,600,922 2.16 11,413,640 2.55 Due after two years through three years 2,200,019 2.16 2,832,290 2.47 Due after three years through four years 1,766,314 2.71 1,648,076 2.37 Due after four years through five years 1,726,754 2.15 1,980,468 2.24 Thereafter 1,312,311 2.68 1,351,987 2.99 Total par value 34,583,887 2.10 % 43,268,385 2.50 % Premiums 3,397 3,935 Discounts (41,744 ) (36,528 ) Fair value of bifurcated derivatives (1) 29,983 13,051 Hedging adjustments 19,840 (56,621 ) Total $ 34,595,363 $ 43,192,222 _________________________ (1) At December 31, 2019 and 2018 , we had certain advances with embedded features that met the requirements to be separated from the host contract and designated as stand-alone derivatives. We offer advances to members and eligible nonmembers that provide the borrower the right, based upon predetermined option exercise dates, to repay the advance prior to maturity without incurring prepayment or termination fees (callable advances). We also offer certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees. Other advances may only be prepaid by paying a fee (prepayment fee) that makes us financially indifferent to the prepayment of the advance. Table 9.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (dollars in thousands) December 31, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 5,101 $ 12,332 Due in one year or less 25,116,961 32,748,467 Due after one year through two years 3,450,922 3,913,640 Due after two years through three years 1,949,499 2,672,290 Due after three years through four years 1,461,314 1,261,176 Due after four years through five years 1,309,679 1,362,468 Thereafter 1,290,411 1,298,012 Total par value $ 34,583,887 $ 43,268,385 We offer putable advances that provide us with the right to require repayment prior to maturity of the advance (and thereby extinguish the advance) on predetermined exercise dates (put dates). Generally, we would exercise the put options when interest rates increase relative to contractual rates. Table 9.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value December 31, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 5,101 $ 12,332 Due in one year or less 20,240,466 25,199,892 Due after one year through two years 8,603,422 11,652,840 Due after two years through three years 2,001,019 2,834,790 Due after three years through four years 965,814 1,367,576 Due after four years through five years 1,598,254 1,152,468 Thereafter 1,169,811 1,048,487 Total par value $ 34,583,887 $ 43,268,385 Table 9.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances December 31, 2019 December 31, 2018 Fixed-rate Due in one year or less $ 18,733,966 $ 23,822,091 Due after one year 9,372,625 9,748,187 Total fixed-rate 28,106,591 33,570,278 Variable-rate Due in one year or less 243,601 219,832 Due after one year 6,233,695 9,478,275 Total variable-rate 6,477,296 9,698,107 Total par value $ 34,583,887 $ 43,268,385 Advance Concentrations . Our advances are principally concentrated in commercial banks, insurance companies, savings institutions, and credit unions. At December 31, 2019 and 2018 , we had $12.3 billion and $16.4 billion , respectively, of advances issued to members with at least $1.0 billion of advances outstanding. These advances were made to five borrowers and six borrowers at December 31, 2019 and 2018 , representing 35.6 percent and 37.9 percent , respectively, of total par value of outstanding advances. For information related to our credit risk on advances and allowance for credit losses, see Note 11 — Allowance for Credit Losses . Prepayment Fees. We record prepayment fees received from borrowers on certain prepaid advances net of any associated basis adjustments related to hedging activities on those advances and net of deferred prepayment fees on advance prepayments considered to be loan modifications. Additionally, for certain advances products, the prepayment-fee provisions of the advance agreement could result in either a payment from the borrower or to the borrower when such an advance is prepaid, based upon market conditions at the time of prepayment (referred to as a symmetrical prepayment fee). Advances with a symmetrical prepayment fee provision are hedged with derivatives containing offsetting terms, so that we are financially indifferent to the borrower's decision to prepay such advances. The net amount of prepayment fees is reflected as interest income in the statement of operations. We also offer an advance restructuring program under which the prepayment fee on prepaid advances may be satisfied by the borrower's agreement to pay an interest rate on a new advance sufficient to amortize the prepayment fee by the maturity date of the new advance, rather than paying the fee in immediately available funds to us. If we conclude an advance restructuring is an extinguishment of the prior loan rather than a modification, the deferred prepayment fee is recognized into income immediately. Table 9.5 - Advances Prepayment Fees (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Prepayment fees received from borrowers $ 33,809 $ 409 $ 1,568 Hedging fair-value adjustments on prepaid advances 1,923 264 (218 ) Net discounts (premiums) associated with prepaid advances 157 (159 ) (137 ) Deferred recognition of prepayment fees received from borrowers on advance prepayments deemed to be loan modifications (1,793 ) (298 ) (315 ) Prepayment fees recognized in income on advance restructurings deemed to be extinguishments 915 — — Advance prepayment fees recognized in income, net $ 35,011 $ 216 $ 898

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Mortgage Loans Held for Portofolio [Text Block]	Mortgage Loans Held for Portfolio We invest in mortgage loans through the MPF program. These mortgage loans are either guaranteed or insured by federal agencies, as is the case with government mortgage loans, or are credit-enhanced, directly or indirectly, by the related entity that sold the loan (a participating financial institution), as is the case with conventional mortgage loans. All such investments are held for portfolio. The mortgage loans are typically originated and credit-enhanced by the related participating financial institution. The majority of these loans are serviced by the originating institution or an affiliate thereof. However, a portion of these loans are sold servicing-released by the participating financial institution and serviced by a third-party servicer. Table 10.1 - Mortgage Loans Held for Portfolio (dollars in thousands) December 31, 2019 December 31, 2018 Real estate Fixed-rate 15-year single-family mortgages $ 339,042 $ 392,128 Fixed-rate 20- and 30-year single-family mortgages 4,093,416 3,839,078 Premiums 66,776 67,671 Discounts (1,607 ) (1,800 ) Deferred derivative gains, net 4,124 2,825 Total mortgage loans held for portfolio 4,501,751 4,299,902 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,501,251 $ 4,299,402 Table 10.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) December 31, 2019 December 31, 2018 Conventional mortgage loans $ 4,140,255 $ 3,902,555 Government mortgage loans 292,203 328,651 Total par value $ 4,432,458 $ 4,231,206 See Note 11 — Allowance for Credit Losses for information related to our credit risk from our investments in mortgage loans and allowance for credit losses based on these investments.

Allowance for Credit Losses

Allowance for Credit Losses	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Allowance for Credit Losses [Text Block]	Allowance for Credit Losses An allowance for credit losses is a valuation allowance separately established for each identified portfolio segment, if necessary, to provide for probable losses inherent in our portfolio as of the statement of condition date. To the extent necessary, an allowance for credit losses for off-balance-sheet credit exposure is recorded as a liability. Portfolio Segments. We have established an allowance methodology for each of our portfolio segments. A portfolio segment is defined as the level at which an entity develops and documents a systematic method for determining its allowance for credit losses. We have developed and documented a systematic methodology for determining an allowance for credit losses for our: • secured member credit products, such as our advances and letters of credit; • investments in government mortgage loans held for portfolio; • investments in conventional mortgage loans held for portfolio; • investments via term securities purchased under agreements to resell; and • investments via term federal funds sold. Classes of Financing Receivables. Classes of financing receivables generally are a disaggregation of a portfolio segment to the extent that is needed to understand the exposure to credit risk arising from these financing receivables. We determined that no further disaggregation of portfolio segments identified above is needed as we assessed and measured the credit risk arising from these financing receivables at the portfolio segment level. Secured Member Credit Products We manage our credit exposure to secured member credit products through an integrated approach that generally includes establishing a credit limit for each borrower. This approach includes an ongoing review of each borrower's financial condition, and collateral and lending policies that are intended to limit risk of loss while balancing borrowers' needs for a reliable source of funding. In addition, we lend to eligible borrowers in accordance with the FHLBank Act, FHFA regulations, and other applicable laws and guidance. We are required to obtain sufficient collateral to secure our credit products. The estimated value of the collateral pledged to secure each borrower's credit products is calculated by applying collateral discounts, or haircuts, to the market value or unpaid principal balance of the collateral, as applicable. We accept certain investment securities, residential mortgage loans, deposits, and other assets as collateral. We require all borrowers that pledge securities collateral to place physical possession of such securities collateral with our safekeeping agent, the borrower's approved designated agent, or the borrower's securities corporation, subject to a control agreement giving us appropriate control over such collateral. In addition, community financial institutions are eligible to use expanded statutory collateral provisions for small-business and agriculture loans. Members also pledge their Bank capital stock as collateral. Collateral arrangements may vary depending upon borrower credit quality, financial condition, performance, borrowing capacity, and our overall credit exposure to the borrower. We can call for additional or substitute collateral to further safeguard our security interest. We either allow the borrower to retain possession of loan collateral pledged to us while agreeing to hold such collateral for our benefit or require the borrower to specifically assign or place physical possession of such loan collateral with us or a third-party custodian that we approve. We are provided an additional safeguard for our security interests by Section 10(e) of the FHLBank Act, which generally affords any security interest granted by a borrower to the Bank priority over the claims and rights of any other party. The exceptions to this prioritization are limited to claims that would be entitled to priority under otherwise applicable law and are held by bona fide purchasers for value or by secured parties with higher priority perfected security interests. The priority granted to our security interests under Section 10(e) of the FHLBank Act may not apply when lending to insurance company members. This is due to the anti-preemption provision contained in the McCarran-Ferguson Act, which provides that federal law does not preempt state insurance law unless the federal law expressly regulates the business of insurance. Thus, if state law conflicts with Section 10(e) of the FHLBank Act, the protection afforded by this provision may not be available to us. However, we perfect our security interests in the collateral pledged by our members, including insurance company members, by filing Uniform Commercial Code (UCC)-1 financing statements, taking possession or control of such collateral, or taking other appropriate steps. Using a risk-based approach and taking into consideration each borrower's financial strength, we consider the types and level of collateral to be the primary indicator of credit quality on our credit products. At December 31, 2019 , and 2018 , we had rights to collateral, on a borrower-by-borrower basis, with an estimated value in excess of our outstanding extensions of credit. We continue to evaluate and make changes to our collateral guidelines based on market conditions. At December 31, 2019 , and 2018 , none of our secured member credit products outstanding were past due, on nonaccrual status, or considered impaired. In addition, there were no troubled debt restructurings related to credit products during the years ended December 31, 2019 , and 2018 . Based upon the collateral held as security, our credit extension and collateral policies, management's credit analysis, and the repayment history on secured member credit products, we have not recorded any allowance for credit losses on our secured member credit products at December 31, 2019 and 2018 . At December 31, 2019 and 2018 , no liability to reflect an allowance for credit losses for off-balance-sheet credit exposures was recorded. See Note 20 — Commitments and Contingencies for additional information on our off-balance-sheet credit exposure. Government Mortgage Loans Held for Portfolio We invest in government mortgage loans secured by one- to four-family residential properties. Government mortgage loans are mortgage loans insured or guaranteed by the Federal Housing Administration (the FHA), the U.S. Department of Veterans Affairs (the VA), the Rural Housing Service of the U.S. Department of Agriculture (RHS), or by the U.S. Department of Housing and Urban Development (HUD). The servicer provides and maintains insurance or a guarantee from the applicable government agency. The servicer is responsible for compliance with all government agency requirements and for obtaining the benefit of the applicable insurance or guaranty with respect to defaulted government-guaranteed mortgage loans. Any losses incurred on these loans that are not recovered from the insurer or guarantor are absorbed by the related servicer. Therefore, we only have credit risk for these loans if the servicer fails to pay for losses not covered by insurance or guarantees. Due to government guarantees or insurance on our government loans, there is no allowance for credit losses for the government mortgage loan portfolio as of December 31, 2019 and 2018 . Additionally, these mortgage loans are not placed on nonaccrual status due to the government guarantee or insurance on these loans and the contractual obligation of the loan servicers to repurchase their related loans when certain criteria are met. Conventional Mortgage Loans Held for Portfolio Our methodology for determining our loan loss reserve consists of estimating loan loss severity using a third-party model incorporating delinquency to default transition performance of the loans, relevant market conditions affecting the performance of the loans, and portfolio level credit protection, particularly credit-enhancements, as discussed below under — Credit-Enhancements. Our inputs to the third-party model consist of loan-related characteristics, such as credit scores, occupancy statuses, loan-to-value ratios, property types, and locations. We update our view of the loan transition performance and market conditions quarterly and periodically adjust our methodology to reflect the changes in the loans’ performances and the market. Individually Evaluated Mortgage Loans. Certain conventional mortgage loans, primarily impaired mortgage loans that are considered collateral-dependent, may be specifically identified for purposes of calculating the allowance for credit losses. A mortgage loan is considered collateral-dependent if repayment is expected to be provided by the sale of the underlying property, that is, if it is considered likely that the borrower will default. The estimated credit losses on impaired collateral-dependent loans may be separately determined because sufficient information exists to make a reasonable estimate of the inherent loss on these loans on an individual loan basis. Loans that are considered collateral-dependent are measured for impairment based on the fair value of the underlying property less estimated selling costs. The incurred loss of an individually evaluated mortgage loan is equal to the difference between the carrying value of the loan and the estimated fair value of the collateral, less estimated selling costs, and may include expected proceeds from primary mortgage insurance and other applicable credit-enhancements. Additionally, for our investments in loans modified under our temporary loan modification plan, on the effective date of a loan modification we measure the present value of expected future cash flows discounted at the loan's effective interest rate and reduce the carrying value of the loan accordingly. Collectively Evaluated Mortgage Loans. We evaluate the credit risk of our investments in conventional mortgage loans for impairment on a collective basis that considers loan-pool-specific attribute data at the master commitment pool level (including historical delinquency migration), applies estimated loss severities, and incorporates available credit-enhancements to establish our best estimate of probable incurred losses at the reporting date. Migration analysis is a methodology for estimating the rate of default experienced on pools of similar loans based on our historical experience. We apply migration analysis to conventional loans that are currently not past due, loans that are 30 to 59 days past due, 60 to 89 days past due, and 90 to 179 days past due. We then estimate the dollar amount of loans in these categories that we believe are likely to migrate to a realized loss position and apply a loss severity factor to estimate losses that would be incurred at the statement of condition date. The losses are then reduced by the probable cash flows resulting from available credit-enhancement. Credit-enhancement cash flows that are projected and assessed as not probable of receipt are not considered in reducing estimated losses. Estimating a Margin of Imprecision. We also assess a factor for the margin of imprecision to the estimation of credit losses for the homogeneous population. The margin of imprecision is a factor in the allowance for credit losses that recognizes the imprecise nature of the measurement process and is included as part of the mortgage loan allowance for credit loss. This amount represents a subjective management judgment based on facts and circumstances that exist as of the reporting date that is unallocated to any specific measurable economic or credit event and is intended to cover other inherent losses that may not be captured in our methodology. The actual loss that may occur on homogeneous populations of mortgage loans may differ from the estimated loss. Credit Quality Indicator and Other Delinquency Statistics. The key credit quality indicator for mortgage loans is payment status. Table 11.1 sets forth the payment status for our investments in mortgage loans based on recorded investment as well as other delinquency statistics at December 31, 2019 and 2018 : Table 11.1 - Credit Quality Indicator and Other Delinquency Statistics (dollars in thousands) December 31, 2019 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 36,336 $ 11,630 $ 47,966 Past due 60-89 days delinquent 6,911 3,471 10,382 Past due 90 days or more delinquent 10,696 5,570 16,266 Total past due 53,943 20,671 74,614 Total current loans 4,171,676 278,924 4,450,600 Total mortgage loans $ 4,225,619 $ 299,595 $ 4,525,214 Other delinquency statistics In process of foreclosure, included above (1) $ 2,813 $ 2,222 $ 5,035 Serious delinquency rate (2) 0.26 % 1.86 % 0.36 % Past due 90 days or more still accruing interest $ — $ 5,570 $ 5,570 Loans on nonaccrual status (3) $ 11,510 $ — $ 11,510 December 31, 2018 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 23,045 $ 10,884 $ 33,929 Past due 60-89 days delinquent 7,019 3,344 10,363 Past due 90 days or more delinquent 7,384 6,670 14,054 Total past due 37,448 20,898 58,346 Total current loans 3,947,096 316,285 4,263,381 Total mortgage loans $ 3,984,544 $ 337,183 $ 4,321,727 Other delinquency statistics In process of foreclosure, included above (1) $ 3,467 $ 2,086 $ 5,553 Serious delinquency rate (2) 0.20 % 1.98 % 0.34 % Past due 90 days or more still accruing interest $ — $ 6,670 $ 6,670 Loans on nonaccrual status (3) $ 7,975 $ — $ 7,975 _______________________ (1) Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported. (2) Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class. (3) Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan. Credit-Enhancements. Our allowance for credit losses factors in the credit-enhancements associated with conventional mortgage loans under the MPF program. These credit-enhancements apply after the homeowner's equity is exhausted and can include primary and/or supplemental mortgage insurance or other kinds of credit-enhancement. The credit risk analysis of our conventional loans is performed at the individual master commitment level to determine the credit-enhancements available to recover losses on loans under each individual master commitment. The credit-enhancement amounts estimated to protect us against credit losses are determined through the use of a model. Any incurred losses that would be recovered from the credit-enhancements are not reserved as part of our allowance for loan losses. In such cases, a receivable is generally established to reflect the expected recovery from credit-enhancement arrangements. The FHFA final rule on acquired member assets (AMA) went into effect on January 18, 2017, allowing each FHLBank to utilize its own model to determine the credit-enhancement for AMA loan assets and pool loans in lieu of a nationally recognized statistical ratings organization (NRSRO) ratings model. Upon effectiveness of the final AMA rule, we determined that assets delivered to us must be credit enhanced at our determined “AMA investment grade” of a double-A rated MBS. In March 2017, we determined that assets delivered to us must be credit enhanced at our revised determination of “AMA investment grade” of a single-A-minus rated MBS. This revision had no impact on the allowance for credit losses. We share the risk of credit losses on our investments in mortgage loans with the related participating financial institution by structuring potential losses on these investments into layers with respect to each master commitment. We analyze the risk characteristics of our mortgage loans using a third-party model to determine the credit-enhancement amount at the time of purchase. This credit-enhancement amount is broken into two parts: the Bank's first-loss account and the participating financial institution's credit-enhancement obligation, which may be calculated based on the risk analysis to equal the difference between the amounts needed for the master commitment to have a rating equivalent to a single-A-minus rated MBS and our initial first-loss account exposure. The first-loss account represents the first layer or portion of credit losses that we absorb with respect to our investments in mortgage loans after considering the borrower's equity and primary mortgage insurance. The participating financial institution is required to cover the next layer of losses up to an agreed-upon credit-enhancement obligation amount, which may consist of a direct liability of the participating financial institution to pay credit losses up to a specified amount, a contractual obligation of a participating financial institution to provide supplemental mortgage insurance, or a combination of both. We absorb any remaining unallocated losses. The aggregate amount of the first-loss account is documented and tracked but is neither recorded nor reported as an allowance for loan losses in our financial statements. As credit and special hazard losses are realized that are not covered by the liquidation value of the real property or primary mortgage insurance, they are first charged to us, with a corresponding reduction of the first-loss account for that master commitment up to the amount in the first-loss account at that time. Over time, the first-loss account may cover the expected credit losses on a master commitment, although losses that are greater than expected or that occur early in the life of a master commitment could exceed the amount in the first-loss account. In that case, the excess losses would be charged to the participating financial institution's credit-enhancement amount, then to us after the participating financial institution's credit-enhancement amount has been exhausted. For loans in which we buy or sell participations from or to other FHLBanks that participate in the MPF program (MPF Banks), the amount of the first-loss account remaining to absorb losses for loans that we own is partly dependent on the percentage of our participation in such loans. Assuming losses occur on a proportional basis between loans that we own and loans owned by other MPF Banks, at December 31, 2019 and 2018 , the amount of first-loss account remaining for losses allocable to us was $28.5 million and $25.3 million , respectively. Participating financial institutions are paid a credit-enhancement fee for assuming credit risk and in some instances all or a portion of the credit-enhancement fee may be performance based. For certain MPF products, our losses incurred under the first-loss account can be mitigated by withholding future performance-based credit-enhancement fees that would otherwise be payable to the participating financial institutions. We record credit-enhancement fees paid to participating financial institutions as a reduction to mortgage-loan-interest income. Withheld performance-based credit-enhancement fees can mitigate losses from our investments in mortgage loans and therefore we consider our expectations for each master commitment for such withheld fees in determining the allowance for loan losses. More specifically, we determine the amount of credit-enhancement fees available to mitigate losses as follows: accrued credit-enhancement fees to be paid to participating financial institutions; plus projected credit-enhancement fees to be paid to the participating financial institutions using the weighted average life of the loans within each relevant master commitment; minus any losses incurred or expected to be incurred. Allowance for Credit Losses on Mortgage Loans. Table 11.2 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the years ended December 31, 2019 , 2018 , and 2017 , as well as the recorded investment in mortgage loans by impairment methodology at December 31, 2019 , 2018 , and 2017 . The recorded investment in a loan is the par amount of the loan, adjusted for accrued interest, unamortized premiums or discounts, deferred derivative gains and losses, and direct write-downs. The recorded investment is net of any valuation allowance. Table 11.2 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) 2019 2018 2017 Allowance for credit losses Balance, beginning of year $ 500 $ 500 $ 650 (Charge-offs) recoveries (85 ) 34 (54 ) Provision for (reduction of) credit losses 85 (34 ) (96 ) Balance, end of year $ 500 $ 500 $ 500 Ending balance, individually evaluated for impairment $ — $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 500 $ 500 Recorded investment, end of year (1) Individually evaluated for impairment $ 13,395 $ 15,402 $ 17,668 Collectively evaluated for impairment $ 4,212,224 $ 3,969,142 $ 3,632,833 _________________________ (1) These amounts exclude government mortgage loans because we make no allowance for credit losses based on our investments in government mortgage loans, as discussed above under — Government Mortgage Loans Held for Portfolio. Troubled Debt Restructurings. We consider a troubled debt restructuring of a financing receivable to have occurred when we grant a concession to a borrower that we would not otherwise consider for economic or legal reasons related to the borrower's financial difficulties. We have granted a concession when we do not expect to collect all amounts due to us under the original contract as a result of the restructuring. A mortgage loan considered to be a troubled debt restructuring is individually evaluated for impairment when determining its related allowance for credit losses. When a loan first becomes a troubled debt restructuring, we compare the carrying value of the loan at the time of modification with the present value of the revised cash flows discounted at the original effective yield on the loan. Credit losses are measured by estimating the loss severity rate incurred as of the reporting date as well as the economic loss attributable to delaying the original contractual principal and interest due dates, if applicable. At December 31, 2019 and 2018 , the recorded investment of mortgage loans classified as troubled debt restructurings were $7.2 million and $8.5 million , respectively. Federal Funds Sold and Securities Purchased Under Agreements to Resell. Term federal funds sold and term securities purchased under agreements to resell are all short term (less than three months), and they are generally transacted with counterparties that we consider to be of investment quality. We invest in federal funds sold on an unsecured basis and we evaluate these investments for purposes of an allowance for credit losses only if the investment is not paid when due. All investments in federal funds sold as of December 31, 2019 and 2018 , were repaid according to their contractual terms. Securities purchased under agreements to resell are considered collateralized financing arrangements and effectively represent short-term loans. The terms of these loans are structured such that if the market value of the underlying securities decreases below the market value required as collateral, the counterparty must provide additional securities as collateral in an amount equal to the decrease or remit cash in such amount. If we determine that an agreement to resell is impaired, the difference between the fair value of the collateral and the amortized cost of the agreement is charged to earnings. Based upon the collateral held as security, we determined that no allowance for credit losses was needed for the securities purchased under agreements to resell at December 31, 2019 and 2018 .

Derivatives and Hedging Activit

Derivatives and Hedging Activities	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities Nature of Business Activity We are exposed to interest-rate risk primarily from the effects of interest-rate changes on interest-earning assets and interest-bearing liabilities that finance these assets. The goal of our interest-rate risk-management strategy is to manage interest-rate risk within appropriate limits. As part of our effort to mitigate the risk of loss, we have established policies and procedures, which include guidelines on the amount of exposure to interest-rate changes we will accept. In addition, we monitor the risk to our interest income, net interest margin, and average maturity of interest-earning assets and interest-bearing liabilities. Consistent with FHFA regulations, we enter into derivatives to manage the interest-rate-risk exposures inherent in otherwise unhedged assets and liabilities and achieve our risk-management objectives. FHFA regulation prohibits us from the speculative use of these derivative instruments. The use of derivatives is an integral part of our financial and risk management strategy. We may enter into derivatives that do not necessarily qualify for hedge accounting. We reevaluate our hedging strategies periodically and may change the hedging techniques we use or may adopt new strategies. The most common ways in which we use derivatives are to: • effectively change the coupon repricing characteristics of assets and liabilities from fixed-rate to floating-rate; • hedge the mark-to-market sensitivity of existing assets or liabilities; • offset or neutralize embedded options in assets and liabilities; and • hedge the potential yield variability of anticipated asset or liability transactions. Application of Derivatives We formally document at inception all relationships between derivatives designated as hedging instruments and hedged items, as well as our risk-management objectives and strategies for undertaking various hedge transactions and our method of assessing hedge effectiveness. This process includes linking all derivatives that are designated as fair-value or cash-flow hedges to specific assets or liabilities on the statement of condition, firm commitments, or forecasted transactions. We may use derivatives to adjust the effective maturity, repricing frequency, or option characteristics of our financial instruments, including our advances products, investments, and COs to achieve risk-management objectives. Derivative instruments are designated by us as: • a qualifying fair-value hedge of a non-derivative financial instrument or a cash-flow hedge of a forecasted transaction; and • a non-qualifying economic hedge in general asset-liability management where derivatives serve a documented risk-mitigation purpose but do not qualify for hedge accounting. These hedges are primarily used to manage certain mismatches between the coupon features of our assets and liabilities. We transact all of our derivatives with counterparties who are major banks or, in a few instances, with their affiliates with unconditional guarantees provided by the respective major banks. Some of these derivative counterparties and their affiliates buy, sell, and distribute COs, and may be affiliates of members of the Bank. Derivative transactions may be either over-the-counter with a counterparty (uncleared derivatives) or cleared through a futures commission merchant (clearing member) with a DCO as the counterparty (cleared derivatives). Once a derivative transaction has been accepted for clearing by a DCO, the executing counterparty is replaced with the DCO. We are not a derivatives dealer and do not trade derivatives for short-term profit. Types of Derivatives We primarily use the following derivatives instruments to reduce funding costs and/or to manage our interest-rate risks. • Interest-Rate Swaps. An interest-rate swap is an agreement between two entities to exchange cash flows in the future. The agreement sets the dates on which the cash flows will be exchanged and the manner in which the cash flows will be calculated. One of the simplest forms of an interest-rate swap involves the promise by one party to pay cash flows equivalent to the interest on a notional amount at a predetermined fixed rate for a given period of time to the counterparty. In return for this promise, this party receives cash flows equivalent to the interest on the same notional amount at a variable-rate index for the same period of time from the counterparty. The variable-rate indices we utilize in our derivative transactions are LIBOR and the overnight-index swap (OIS) rate based on the federal funds effective rate. • Optional Termination Interest-Rate Swaps. In an optional termination interest-rate swap, one counterparty has the right, but not the obligation, to terminate the interest-rate swap prior to its stated maturity date. We use optional termination interest-rate swaps to hedge callable CO bonds and putable advances. In most cases, we own an option to terminate the hedged item, that is, redeem a callable bond or demand repayment of a putable advance on specified dates, and the counterparty to the optional termination interest-rate swap owns the option to terminate the interest-rate swap on those same dates. • Forward-Start Interest-Rate Swaps. A forward-start interest-rate swap is an interest-rate swap (as described above) with a deferred effective date. We designate forward-start interest-rate swaps as cash-flow hedges of expected debt issuances. • Interest-Rate Cap and Floor Agreements. In an interest-rate cap agreement, a cash flow is generated if the price or rate of an underlying variable rises above a certain threshold or cap price. In an interest-rate floor agreement, a cash flow is generated if the price or rate of an underlying variable falls below a certain threshold or floor price. These agreements are intended to serve as protection against the interest rate on a variable-rate asset or liability falling below or rising above a certain level. Types of Assets and Liabilities Hedged Investments. We use derivatives to manage the interest-rate and prepayment risk associated with certain investment securities that are classified either as available-for-sale or as trading securities. We may also manage the risk arising from changing market prices or cash flows of certain investment securities classified as trading by entering into economic hedges that offset the changes in fair value or cash flows of the securities. These economic hedges are not specifically designated as hedges of individual assets, but rather are collectively managed to provide an offset to the changes in the fair values of the assets. The market-value changes of trading securities are included in net unrealized gains (losses) on trading securities in the statement of operations, while the changes in fair value of the associated derivatives are included in other income as net gains on derivatives and hedging activities. Advances. We offer a wide range of fixed- and variable-rate advance products with different maturities, interest rates, payment characteristics and optionality. We may use interest-rate swaps to manage the repricing and/or options characteristics of advances to more closely match the characteristics of our funding liabilities. Typically, we hedge the fair value of fixed-rate advances with interest-rate swaps where we pay a fixed-rate coupon and receive a variable-rate coupon, effectively converting the advance to a floating-rate advance. We also hedge the fair value of certain floating-rate advances that contain either an interest-rate cap or floor, or both a cap and a floor with a derivative containing an offsetting cap and/or floor. With each issuance of a putable advance, we effectively purchase from the borrower an embedded put option that enables us to terminate a fixed-rate advance on predetermined put dates, and offer, subject to certain conditions, replacement funding at then-current advances rates. We may hedge a putable advance by entering into a derivative that is cancelable by the derivative counterparty, where we pay a fixed-rate coupon and receive a variable-rate coupon. This type of hedge is treated as a fair-value hedge. The swap counterparty would normally exercise its option to cancel the derivative at par on any defined exercise date if interest rates had risen, and at that time, we could, at our option, require immediate repayment of the advance. Additionally, the borrower's ability to prepay an advance can create interest-rate risk. When a borrower prepays an advance, we could suffer lower future income if the principal portion of the prepaid advance were invested in lower-yielding assets that continue to be funded by higher-cost debt. To protect against this risk, we generally charge a prepayment fee that makes us financially indifferent to a borrower's decision to prepay an advance. If the advance is hedged with a derivative instrument, the prepayment fee will generally offset the cost of terminating the designated hedge. When we offer advances (other than short-term advances) that a borrower may prepay without a prepayment fee, we usually finance such advances with callable debt with an interest-rate swap cancellable by us. COs. We may enter into derivatives to hedge (or partially hedge, depending on the risk strategy) the interest-rate risk associated with our specific debt issuances, including using derivatives to change the effective interest-rate sensitivity of debt to better match the characteristics of funded assets. We endeavor to manage the risk arising from changing market prices and volatility of a CO by matching the cash inflow on the derivative with the cash outflow on the CO. As an example of such a hedging strategy, when fixed-rate COs are issued, we may simultaneously enter into a matching derivative in which we receive a fixed-interest cash flows designed to mirror in timing and amount the interest cash outflows we pay on the CO. At the same time, we may pay variable cash flows that closely match the interest payments we receive on short-term or variable-rate assets. In some cases, the hedged CO may have a nonstatic coupon that is subject to fair-value risk and that is matched by the receivable coupon on the hedging interest-rate swap. These transactions are treated as fair-value hedges. In a typical cash-flow hedge of anticipated CO issuance, we may enter into interest-rate swaps for the anticipated issuance of fixed-rate CO bonds to lock in a spread between an earning asset and the cost of funding. The interest-rate swap is terminated upon issuance of the fixed-rate CO bond. Changes in fair value of the hedging derivative, to the extent that the hedge is effective, will be recorded in accumulated other comprehensive loss and reclassified into earnings in the period or periods during which the cash flows of the fixed-rate CO bond affects earnings (beginning upon issuance and continuing over the life of the CO bond). Firm Commitments. Mortgage loan purchase commitments are considered derivatives. When the mortgage loan purchase commitment derivative settles, the current market value of the commitment is included with the basis of the mortgage loan. The basis adjustments on the resulting performing loans are then amortized into net interest income over the life of the loans. We may also hedge a firm commitment for a forward-starting advance through the use of an interest-rate swap. In this case, the interest-rate swap functions as the hedging instrument for both the firm commitment and the subsequent advance and is treated as a fair value hedge. The fair-value change associated with the firm commitment is recorded as a basis adjustment of the advance at the time the commitment is terminated and the advance is issued. The basis adjustment is then amortized into interest income over the life of the advance. Financial Statement Impact and Additional Financial Information. The notional amount of derivatives is a factor in determining periodic interest payments or cash flows received and paid. However, the notional amount of derivatives reflects our involvement in the various classes of financial instruments and represents neither the actual amounts exchanged nor our overall exposure to credit and market risk; the overall risk is much smaller. The risks of derivatives can be measured meaningfully on a portfolio basis that takes into account the counterparties, the types of derivatives, the tenor of the derivatives, the items being hedged, and any offsets between the derivatives and the items being hedged. Table 12.1 - Fair Value of Derivative Instruments (dollars in thousands) December 31, 2019 December 31, 2018 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 12,128,105 $ 14,734 $ (12,805 ) $ 11,980,699 $ 12,811 $ (296,324 ) Forward-start interest-rate swaps 17,000 19 — 282,000 — (753 ) Total derivatives designated as hedging instruments 12,145,105 14,753 (12,805 ) 12,262,699 12,811 (297,077 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 2,902,300 349 (31,000 ) 927,800 682 (12,475 ) Mortgage-delivery commitments (1) 49,911 227 — 50,773 339 — Total derivatives not designated as hedging instruments 2,952,211 576 (31,000 ) 978,573 1,021 (12,475 ) Total notional amount of derivatives $ 15,097,316 $ 13,241,272 Total derivatives before netting and collateral adjustments 15,329 (43,805 ) 13,832 (309,552 ) Netting adjustments and cash collateral, including related accrued interest (2) 144,402 33,534 8,571 53,752 Derivative assets and derivative liabilities $ 159,731 $ (10,271 ) $ 22,403 $ (255,800 ) _______________________ (1) Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income. (2) Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $178.5 million and $62.8 million at December 31, 2019 , and 2018 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $561 thousand and $471 thousand at December 31, 2019 and 2018 . Beginning on January 1, 2019, changes in fair value of the derivative hedging instrument and the hedged item attributable to the hedged risk for designated fair-value hedges are recorded in net interest income in the same line as the earnings effect of the hedged item. For designated cash-flow hedges, the entire change in the fair value of the hedging instrument (assuming it is included in the assessment of hedge effectiveness) is reported in other comprehensive income until the hedged transaction affects earnings. At that time, this amount is reclassified from other comprehensive income and recorded in net interest income in the same line as the earnings effect of the hedged item. Prior to January 1, 2019, for both fair value and cash-flow hedges, any hedge ineffectiveness (which represented the amount by which the change in the fair value of the derivative differed from the change in the fair value of the hedged item or the variability in the cash flows of the forecasted transaction attributable to the hedged risk) was recorded in noninterest income as net gains on derivatives and hedging activities. Tables 12.2 and 12.3 presents the net gains (losses) on qualifying fair-value and cash flow hedging relationships. Beginning on January 1, 2019, gains (losses) on derivatives include unrealized changes in fair value as well as net interest settlements. Table 12.2 - Net Gains (Losses) on Fair Value Hedging Relationships (dollars in thousands) For the Year Ended December 31, 2019 Advances Available-for-sale Securities CO Bonds Total interest income (expense) in the statements of operations $ 854,599 $ 115,942 $ (598,585 ) Gains (losses) on fair value hedging relationships Changes in fair value: Derivatives $ (72,488 ) $ (24,274 ) $ 55,777 Hedged items 73,530 21,329 (56,091 ) Net changes in fair value before price alignment interest 1,042 (2,945 ) (314 ) Price alignment interest (1) 1,316 3,769 (786 ) Net interest settlements on derivatives (2)(3) 39,085 (22,249 ) (17,482 ) Net gains (losses) on qualifying fair-value hedging relationships 41,443 (21,425 ) (18,582 ) Amortization/accretion of discontinued fair-value hedging relationships (1,934 ) — (2,567 ) Net gains (losses) on derivatives and hedging activities recorded in net interest income $ 39,509 $ (21,425 ) $ (21,149 ) For the Year Ended December 31, 2018 Advances Available-for-sale Securities CO Bonds Total income (expense) in the statements of operations $ 867,215 $ 143,952 $ (545,228 ) Gains (losses) on fair value hedging relationships Changes in fair value: Derivatives $ 447 $ 43,771 $ (5,680 ) Hedged items 257 (42,022 ) 5,254 Net changes in fair value 704 1,749 (426 ) Net interest settlements on derivatives (2)(3) 51,522 (26,040 ) (27,895 ) Net gains (losses) on qualifying fair-value hedging relationships 52,226 (24,291 ) (28,321 ) Amortization/accretion of discontinued fair-value hedging relationships (1,475 ) — 945 Less: net changes in fair value (4) (704 ) (1,749 ) 426 Net gains (losses) on derivatives and hedging activities recorded in net interest income $ 50,047 $ (26,040 ) $ (26,950 ) For the Year Ended December 31, 2017 Advances Available-for-sale Securities CO Bonds Total income (expense) in the statements of operations $ 514,176 $ 118,270 $ (421,622 ) Gains (losses) on fair value hedging relationships Changes in fair value: Derivatives $ 52,055 $ 20,747 $ 4,611 Hedged items (52,633 ) (19,011 ) (8,077 ) Net changes in fair value (578 ) 1,736 (3,466 ) Net interest settlements on derivatives (2)(3) (24,663 ) (32,053 ) 6,694 Net (losses) gains on qualifying fair-value hedging relationships (25,241 ) (30,317 ) 3,228 Amortization/accretion of discontinued fair-value hedging relationships (2,176 ) — 1,903 Less: net changes in fair value (4) 578 (1,736 ) 3,466 Net (losses) gains on derivatives and hedging activities recorded in net interest income $ (26,839 ) $ (32,053 ) $ 8,597 _______________________ (1) Relates to derivatives for which variation margin payments are characterized as daily settled contracts. (2) Represents interest income/expense on derivatives in qualifying fair-value hedging relationships. Net interest settlements on derivatives that are not in qualifying fair-value hedging relationships are reported in other income. (3) Excludes the interest income/expense of the respective hedged items recorded in net interest income. (4) In 2018 and 2017, net changes in fair value were recorded in net gains on derivatives and hedging activities in other income. Table 12.3 - Net Gains (Losses) on Cash Flow Hedging Relationships (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Forward-start interest rate swaps - CO Bonds Losses reclassified from accumulated other comprehensive loss into interest expense $ (5,218 ) $ (3,171 ) $ (10,575 ) (Losses) gains recognized in other comprehensive income (6,131 ) 7,907 (2,838 ) Gains recognized in net gains on derivatives and hedging activities 227 280 For the years ended December 31, 2019 , 2018 , and 2017 , there were no reclassifications from accumulated other comprehensive loss into earnings as a result of the discontinuance of cash-flow hedges because the original forecasted transactions were not expected to occur by the end of the originally specified time period or within a two-month period thereafter. As of December 31, 2019 , the maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions is two years . As of December 31, 2019 , the amount of deferred net losses on derivatives accumulated in other comprehensive loss related to cash flow hedges expected to be reclassified to earnings during the next 12 months is $7.0 million . Table 12.4 - Cumulative Basis Adjustments for Fair-Value Hedges (dollars in thousands) December 31, 2019 Line Item in Statement of Condition of Hedged Item Amortized Cost of Hedged Asset/ Liability (1) Basis Adjustments for Active Hedging Relationships Included in Amortized Cost Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost Cumulative Amount of Fair Value Hedging Basis Adjustments Advances $ 5,115,016 $ 38,988 $ 10,835 $ 49,823 Available-for-sale securities 4,053,138 226,346 — 226,346 Consolidated bonds 3,359,616 (4,840 ) 36,906 32,066 _______________________ (1) Includes only the portion of amortized cost representing the hedged items in fair-value hedging relationships. Table 12.5 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Derivatives designated as hedging instruments: Total net gains (losses) related to fair-value hedges (1) $ 2,027 $ (2,308 ) Total net gains related to cash-flow hedges (2) 227 280 Total net gains (losses) related to derivatives designated as hedging instruments 2,254 (2,028 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps $ (614 ) 682 434 Mortgage-delivery commitments 1,945 421 1,768 Total net gains related to derivatives not designated as hedging instruments 1,331 1,103 2,202 Other (3) 88 (1,021 ) 377 Net gains on derivatives and hedging activities $ 1,419 $ 2,336 $ 551 ______________________ (1) Consists of interest-rate swaps. (2) Consists of forward-start interest-rate swaps. (3) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount. Termination of Derivatives and Impact on Statement of Cash Flows . During the year ended December 31, 2019 , we terminated certain uncleared interest-rate exchange agreements with a total notional amount of $611.9 million which were indexed to three-month LIBOR on the floating leg of the swaps. The net fair value of these derivative transactions, from our perspective, was $(251.5) million , which was transferred to the bilateral counterparty upon termination, and securities collateral that we had pledged against this obligation was returned to us. This cash payment is included in net change in derivatives and hedging activities, within the operating activities section of the statement of cash flows for the year ended December 31, 2019 . Simultaneously with the termination of these derivatives, we entered into replacement interest-rate exchange agreements (the replacement derivatives) having the same notional amount of $611.9 million and which are indexed to the OIS rate based on the federal funds effective rate on the floating leg of the swaps. Upon settlement of the replacement derivatives, the Bank received an initial upfront payment of $251.5 million . The replacement derivatives are cleared through a derivatives clearing organization (DCO), which called for variation margin to be delivered. Because the replacement derivatives include off-market terms and this large initial upfront payment, all payments for the replacement derivatives are classified as net payments on derivative contracts with a financing element, within the financing activities section of the statement of cash flows. Managing Credit Risk on Derivatives. We are subject to credit risk on our hedging activities due to the risk of nonperformance by nonmember counterparties (including DCOs and their clearing members acting as agent to the DCOs as well as uncleared counterparties) to the derivative agreements. We manage credit risk through credit analysis, collateral requirements and adherence to the requirements set forth in our policies, U.S. Commodity Futures Trading Commission (the CFTC) regulations, and FHFA regulations. Uncleared Derivatives. All counterparties must execute master-netting agreements prior to entering into any uncleared derivative with us. Our master-netting agreements for uncleared derivatives contain bilateral-collateral exchange agreements that require that credit exposure beyond a defined threshold amount (which may be zero) be secured by readily marketable, U.S. Treasury, U.S. Government-guaranteed, or GSE securities, or cash. The level of these collateral threshold amounts (when applicable) varies according to the counterparty's Standard & Poor's Rating Service (S&P) or Moody's Investors Services (Moody's) long-term credit ratings. Credit exposures are then measured daily and adjustments to collateral positions are made in accordance with the terms of the master-netting agreements. These master-netting agreements also contain bilateral ratings-tied termination events permitting us to terminate all outstanding derivatives transactions with a counterparty in the event of a specified rating downgrade by Moody's or S&P. Based on credit analyses and collateral requirements, we do not anticipate any credit losses on our derivative agreements. We execute uncleared derivatives with nonmember counterparties with long-term ratings of single-A (or equivalent) or better by the major NRSROs at the time of the transaction, although risk-reducing trades may be permitted for counterparties whose ratings have fallen below these ratings. Some of these counterparties or their affiliates buy, sell, and distribute COs. See Note 14 — Consolidated Obligations for additional information. Certain of our uncleared derivatives master-netting agreements contain provisions that require us to post additional collateral with our uncleared derivatives counterparties if our credit ratings are lowered. Under the terms that govern such agreements, if our credit rating is lowered by Moody's or S&P to a certain level, we are required to deliver additional collateral on uncleared derivatives in a net liability position, unless the collateral delivery threshold is set to zero. In the event of a split between such credit ratings, the lower rating governs. The aggregate fair value of all uncleared derivatives with these provisions that were in a net-liability position (before cash collateral and related accrued interest) at December 31, 2019 , was $38.7 million for which we had delivered collateral with a post-haircut value of $38.6 million in accordance with the terms of the master-netting agreements. Securities collateral is subject to valuation haircuts in accordance with the terms of the master-netting arrangements. Table 12.6 sets forth the post-haircut value of incremental collateral that certain uncleared derivatives counterparties could have required us to deliver based on incremental credit rating downgrades at December 31, 2019 . Table 12.6 - Post Haircut Value of Incremental Collateral to be Delivered as of December 31, 2019 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 302 AA- A+, A or A- — A- below A- 5,801 _______________________ (1) Ratings are expressed in this table according to S&P's conventions but include the equivalent of such rating by Moody's. If there is a split rating, the lower rating is used. Cleared Derivatives. For cleared derivatives, the DCO is our counterparty. The DCO notifies the clearing member of the required initial and variation margin and our agent (clearing member) in turn notifies us. We utilize two DCOs, for all cleared derivative transactions, CME Inc. and LCH Ltd. Based upon their rulebooks, we characterize variation margin payments as daily settlement payments, rather than as collateral. At both DCOs, posted initial margin is considered collateral. We post initial margin and exchange variation margin through a clearing member which acts as our agent to the DCO and which guarantees our performance to the DCO, subject to the terms of relevant agreements. These arrangements expose us to credit risk in the event that one of our clearing members or one of the DCOs fails to meet its obligations. The use of cleared derivatives is intended to mitigate credit risk exposure because the DCO, which is fully secured at all times through margin received from its clearing members, is substituted for the credit risk exposure of individual counterparties in uncleared derivatives, and collateral is posted at least once daily for changes in the fair value of cleared derivatives through a clearing member. For cleared derivatives, the DCO determines initial margin requirements. We clear our trades via clearing members of the DCOs. These clearing members who act as our agent to the DCOs are CFTC-registered futures commission merchants. Our clearing members may require us to post margin in excess of DCO requirements based on our credit or other considerations, including but not limited to, credit rating downgrades. We were not required to post any such excess margin by our clearing members based on credit considerations at December 31, 2019 . Offsetting of Certain Derivatives. We present derivatives, any related cash collateral received or pledged, and associated accrued interest, on a net basis by counterparty. We have analyzed the rights, rules, and regulations governing our cleared and non-cleared derivatives and determined that those rights, rules, and regulations should result in a net claim with each of our counterparties (which, in the context of cleared derivatives is through each of our clearing members with the related DCO) upon an event of default (solely in the case of non- cleared derivatives) or the bankruptcy, insolvency or a similar proceeding involving our counterparty (and/or one of our clearing members, in the case of cleared derivatives). For this purpose, "net claim" generally means a single net amount reflecting the aggregation of all amounts indirectly owed by us to the relevant counterparty and indirectly payable to us from the relevant counterparty. Table 12.7 presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of December 31, 2019 and 2018 , and the fair value of derivatives that are not subject to such netting. Derivatives subject to netting include any related cash collateral received from or pledged to counterparties. Table 12.7 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) December 31, 2019 Derivative Instruments Meeting Netting Requirements Non-cash Collateral (Received) or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 4,950 $ (3,519 ) $ 227 $ 1,658 $ (995 ) $ — $ 663 Cleared 10,152 147,921 158,073 — — 158,073 Total $ 159,731 $ 158,736 Derivative Liabilities Uncleared $ (42,199 ) $ 31,928 $ — $ (10,271 ) $ 82 $ 9,333 $ (856 ) Cleared (1,606 ) 1,606 — — — — Total $ (10,271 ) $ (856 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2019 , we had additional net credit exposure of $300 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2018 Derivative Instruments Meeting Netting Requirements Non-cash Collateral (Received) or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 12,862 $ (11,886 ) $ 339 $ 1,315 $ (396 ) $ — $ 919 Cleared 631 20,457 21,088 — — 21,088 Total $ 22,403 $ 22,007 Derivative Liabilities Uncleared $ (306,848 ) $ 51,048 $ — $ (255,800 ) $ 6,104 $ 237,054 $ (12,642 ) Cleared (2,704 ) 2,704 — — — — Total $ (255,800 ) $ (12,642 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2018 , we had additional net credit exposure of $639 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2019
Deposits [Abstract]
Deposits [Text Block]	Deposits We offer demand, overnight and term deposits for members and qualifying nonmembers. Members that service mortgage loans may deposit funds collected in connection with mortgage loans pending disbursement of such funds to the owners of the mortgage loans, which we classify as "other" in the following table. Deposits classified as demand, overnight, and other pay interest based on a daily interest rate. Term deposits pay interest based on a fixed rate determined at the issuance of the deposit. The average interest rate paid on average deposits during 2019 and 2018 was 1.16 percent and 1.07 percent , respectively. Table 13.1 - Deposits (dollars in thousands) December 31, 2019 December 31, 2018 Interest-bearing Demand and overnight $ 613,143 $ 444,486 Term 800 800 Other 2,589 2,961 Noninterest-bearing Other 57,777 26,631 Total deposits $ 674,309 $ 474,878

Consolidated Obligations

Consolidated Obligations	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Consolidated Obligations [Text Block]	Consolidated Obligations COs consist of CO bonds and CO discount notes. CO bonds may be issued to raise short-, intermediate-, and long-term funds and are not subject to any statutory or regulatory limits on maturity. CO discount notes are issued to raise short-term funds and have original maturities of up to one year. These notes sell at less than their face amount and are redeemed at par value when they mature. Although we are primarily liable for the portion of COs issued for which we received issuance proceeds, we are also jointly and severally liable with the other FHLBanks for the payment of principal and interest on all COs. The FHFA, at its discretion, may require any FHLBank to make principal or interest payments due on any CO whether or not the CO represents a primary liability of such FHLBank. Although an FHLBank has never paid the principal or interest payments due on a CO on behalf of another FHLBank, if that event should occur, FHFA regulations provide that the paying FHLBank is entitled to reimbursement from the noncomplying FHLBank for any payments made on its behalf and other associated costs, including interest to be determined by the FHFA. If, however, the FHFA determines that the noncomplying FHLBank is unable to satisfy its repayment obligations, the FHFA may allocate the outstanding liabilities of the noncomplying FHLBank among the remaining FHLBanks on a pro rata basis in proportion to each FHLBank's participation in all COs outstanding or in any other manner it may determine to ensure that the FHLBanks operate in a safe and sound manner. See Note 20 – Commitments and Contingencies for additional information regarding the FHLBanks' joint and several liability. The par values of the FHLBanks' outstanding COs, including COs on which other FHLBanks are primarily liable, were approximately $1.0 trillion at both December 31, 2019 and 2018 . Regulations require each FHLBank to maintain unpledged qualifying assets equal to outstanding COs for which it is primarily liable. Such qualifying assets include cash; secured advances; obligations of or fully guaranteed by the U.S.; obligations, participations, or other instruments of or issued by Fannie Mae or Ginnie Mae; mortgages, obligations, or other securities which are or ever have been sold by Freddie Mac under the FHLBank Act; and such securities as fiduciary and trust funds may invest in under the laws of the state in which the FHLBank is located. Any assets subject to a lien or pledge for the benefit of holders of any issues of COs are treated as if they were free from lien or pledge for purposes of compliance with these regulations. CO Bonds. Table 14.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 9,455,725 2.03 % $ 9,638,270 2.01 % Due after one year through two years 6,442,960 2.02 5,375,845 2.24 Due after two years through three years 2,154,920 2.18 3,864,560 2.17 Due after three years through four years 1,319,915 2.45 1,891,975 2.20 Due after four years through five years 1,211,080 2.48 1,338,515 2.39 Thereafter 3,220,205 3.33 3,792,150 3.25 Total par value 23,804,805 2.26 % 25,901,315 2.30 % Premiums 63,056 49,118 Discounts (11,434 ) (15,222 ) Hedging adjustments 32,066 (22,527 ) Total $ 23,888,493 $ 25,912,684 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. CO bonds outstanding were issued with either fixed-rate coupon-payment terms or variable-rate coupon-payment terms that may use a variety of indices for interest-rate resets, such as LIBOR and the Secured Overnight Financing Rate (SOFR). To meet the expected specific needs of certain investors in CO bonds, both fixed-rate CO bonds and variable-rate CO bonds may contain features which may result in complex coupon-payment terms and call options. When these CO bonds are issued, we may enter into derivatives containing features that offset the terms and embedded options, if any, of the CO bonds. Table 14.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds December 31, 2019 December 31, 2018 Noncallable and nonputable $ 20,954,805 $ 20,419,315 Callable 2,850,000 5,482,000 Total par value $ 23,804,805 $ 25,901,315 Table 14.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date December 31, 2019 December 31, 2018 Due in one year or less $ 11,297,725 $ 13,435,270 Due after one year through two years 6,432,960 5,602,845 Due after two years through three years 2,019,920 2,802,560 Due after three years through four years 1,332,915 1,366,975 Due after four years through five years 926,080 1,156,515 Thereafter 1,795,205 1,537,150 Total par value $ 23,804,805 $ 25,901,315 Table 14.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds December 31, 2019 December 31, 2018 Fixed-rate $ 17,681,805 $ 21,216,315 Simple variable-rate 5,568,000 2,853,000 Step-up (1) 555,000 1,832,000 Total par value $ 23,804,805 $ 25,901,315 _______________________ (1) Step-up bonds pay interest at increasing fixed rates for specified intervals over the life of the CO bond and can be called at our option on the step-up dates. CO Discount Notes. Outstanding CO discount notes for which we were primarily liable, all of which are due within one year, were as follows: Table 14.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) December 31, 2019 $ 27,681,169 $ 27,733,146 1.59 % December 31, 2018 $ 33,065,822 $ 33,147,065 2.37 % _______________________ (1) The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program

Affordable Housing Program	12 Months Ended
	Dec. 31, 2019
Affordable Housing Program [Abstract]
Affordable Housing Program [Text Block]	Affordable Housing Program The FHLBank Act requires each FHLBank to establish and maintain an AHP to provide subsidies in the form of direct grants and below-market interest-rate advances (AHP advances). These funds are intended to assist in the purchase, construction, or rehabilitation of housing for very low-, low-, and moderate-income households. Each FHLBank is required to contribute to its AHP the greater of 10 percent of its previous year's net income before interest expense associated with mandatorily redeemable capital stock and the assessment for AHP (AHP earnings), or the prorated sum required to ensure the aggregate contribution by the FHLBanks is no less than $100 million for each year. We accrue this expense monthly based on our AHP earnings, and the accruals are accumulated into our AHP payable account. We reduce our AHP payable account as we disburse the funds either in the form of direct grants to member institutions or as a discount on below-market-rate AHP advances. If we experience a net loss during a quarter, but still have AHP earnings for the year, our obligation to the AHP would be calculated based on our AHP earnings for that calendar year. In annual periods where our AHP earnings are zero or less, our AHP assessment is zero since our required annual contribution is limited to our annual AHP earnings. If the result of the aggregate 10 percent calculation described above is less than $100 million for all the FHLBanks, then each FHLBank would be required to contribute such prorated sums as may be required to ensure that the aggregate contributions by the FHLBanks equals $100 million . The proration would be made on the basis of the income of the FHLBanks for the year, except that the required annual AHP contribution for an FHLBank cannot exceed its AHP earnings for the year pursuant to an FHFA regulation. Each FHLBank's required annual AHP contribution is limited to its annual net earnings. Our AHP expense for 2019 , 2018 , and 2017 was $21.3 million , $24.3 million , and $21.3 million , respectively. There was no shortfall, as described above, in 2019 , 2018 , or 2017 . If an FHLBank is experiencing financial instability and finds that its required AHP contributions are contributing to the financial instability, the FHLBank may apply to the FHFA for a temporary suspension of its contributions. We did not make such an application in 2019 , 2018 , or 2017 . Table 15.1 - AHP Liability (dollars in thousands) 2019 2018 Balance at beginning of year $ 83,965 $ 81,600 AHP expense for the period 21,302 24,299 AHP direct grant disbursements (15,723 ) (17,729 ) AHP subsidy for AHP advance disbursements (3,450 ) (4,360 ) Return of previously disbursed grants and subsidies 37 155 Balance at end of year $ 86,131 $ 83,965

Capital

Capital	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Capital [Text Block]	Capital We are subject to capital requirements under our capital plan, the FHLBank Act, and FHFA regulations and guidance: 1. Risk-based capital. We are required to maintain at all times permanent capital, defined as Class B stock, including Class B stock classified as mandatorily redeemable capital stock, and retained earnings, in an amount at least equal to the sum of our credit-risk capital requirement, market-risk capital requirement, and operations-risk capital requirement, calculated in accordance with FHFA rules and regulations, referred to herein as the risk-based capital requirement. Only permanent capital satisfies the risk-based capital requirement. 2. Total regulatory capital. We are required to maintain at all times a total capital-to-assets ratio of at least four percent . Total regulatory capital is the sum of permanent capital, the amount paid-in for Class A stock, the amount of any general loss allowance if consistent with GAAP and not established for specific assets, and other amounts from sources determined by the FHFA as available to absorb losses. We have never issued Class A stock. 3. Leverage capital. We are required to maintain at all times a leverage capital-to-assets ratio of at least five percent . Leverage capital is defined as the sum of permanent capital weighted 1.5 times and all other capital without a weighting factor. The FHFA has authority to require us to maintain a greater amount of permanent capital than is required as defined by the risk-based capital requirements. Table 16.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements December 31, December 31, Permanent capital Class B capital stock $ 1,869,130 $ 2,528,854 Mandatorily redeemable capital stock 5,806 31,868 Retained earnings 1,463,154 1,395,012 Total permanent capital $ 3,338,090 $ 3,955,734 Risk-based capital requirement Credit-risk capital $ 235,213 $ 289,080 Market-risk capital 207,426 187,183 Operations-risk capital 132,792 142,879 Total risk-based capital requirement $ 575,431 $ 619,142 Permanent capital in excess of risk-based capital requirement $ 2,762,659 $ 3,336,592 December 31, 2019 December 31, 2018 Required Actual Required Actual Capital Ratio Risk-based capital $ 575,431 $ 3,338,090 $ 619,142 $ 3,955,734 Total regulatory capital $ 2,226,512 $ 3,338,090 $ 2,543,733 $ 3,955,734 Total capital-to-asset ratio 4.0 % 6.0 % 4.0 % 6.2 % Leverage Ratio Leverage capital $ 2,783,141 $ 5,007,135 $ 3,179,666 $ 5,933,601 Leverage capital-to-assets ratio 5.0 % 9.0 % 5.0 % 9.3 % We are a cooperative whose members own most of our capital stock. Former members (including certain nonmembers that own our capital stock as a result of merger or acquisition, relocation, or involuntary termination of membership) own the remaining capital stock to support business transactions still carried on our statement of condition. Shares of capital stock cannot be purchased or sold except between us and our members at $100 per share par value. We have only issued Class B stock and each member is required to purchase Class B stock equal to the sum of 0.20 percent of certain member assets eligible to secure advances under the FHLBank Act (the membership stock investment requirement), and 3.00 percent for overnight advances, 4.00 percent for all other advances, and 0.25 percent for outstanding letters of credit (collectively, the activity-based stock-investment requirement). Prior to January 16, 2019, the membership stock investment requirement was equal to 0.35 percent of certain member assets eligible to secure advances under the FHLBank Act. Members may redeem Class B stock after no sooner than five years' notice provided in accordance with our capital plan (the redemption-notice period). The effective date of termination of membership for any member that voluntarily withdraws from membership is the end of the redemption-notice period, at which time any stock that is held as a condition of membership shall be divested, subject to any other applicable restrictions. At that time, any stock held pursuant to activity-based stock investment requirements shall remain outstanding until such requirements are eliminated by disposition of the related business activity. Any member that withdraws from membership may not be readmitted to membership in any FHLBank until five years from the divestiture date for all capital stock that is held as a condition of membership. This restriction does not apply if the member is transferring its membership from one FHLBank to another on an uninterrupted basis. The redemption-notice period can also be triggered by the involuntary termination of membership of a member by our board of directors or by the FHFA, the merger or acquisition of a member into a nonmember institution, or the relocation of a member to a principal location outside our district. At the end of the redemption-notice period, if the former member's activity-based stock investment requirement is greater than zero, we may require the associated remaining obligations to us to be satisfied in full prior to allowing the member to redeem the remaining shares. Because our Class B stock is subject to redemption in certain instances, we can experience a reduction in our capital, particularly due to membership terminations due to merger and acquisition activity. However, there are several mitigants to this risk, including, but not limited to, the following: • the activity-based stock-investment requirement allows us to retain stock beyond the redemption-notice period if the associated member-related activity is still outstanding, until the obligations are paid in full; • the redemption notice period allows for a significant period in which we can restructure our balance sheet to accommodate a reduction in capital; • our board of directors may modify the membership stock-investment requirement (MSIR) or the activity-based stock-investment requirement (ABSIR), or both, to address expected shortfalls in capitalization due to membership termination; • our board of directors or the FHFA may suspend redemptions in the event that such redemptions would cause us not to meet our minimum regulatory capital requirements; and • the growth in our retained earnings, which are included in our equity capital, helps offset the risk that our capital could be reduced by redemptions. Our board of directors may declare and pay dividends in either cash or capital stock, subject to limitations in applicable law and our capital plan. Restricted Retained Earnings. At December 31, 2019 , our contribution requirement totaled $502.4 million . As of December 31, 2019 and 2018 , restricted retained earnings totaled $348.8 million and $310.7 million , respectively. These restricted retained earnings are not available to pay dividends. Mandatorily Redeemable Capital Stock. We will reclassify capital stock subject to redemption from equity to liability once a member exercises a written notice of redemption, gives notice of intent to withdraw from membership, or attains nonmember status by merger or acquisition, charter termination, or involuntary termination from membership. Dividends related to capital stock classified as a liability are accrued at the expected dividend rate and reported as interest expense in the statement of operations. If a member cancels its written notice of redemption or notice of withdrawal, we will reclassify mandatorily redeemable capital stock from a liability to equity. After the reclassification, dividends on the capital stock would no longer be classified as interest expense. Redemption of capital stock is subject to the redemption-notice period and our satisfaction of applicable minimum capital requirements. For the years ended December 31, 2019 , 2018 , and 2017 , dividends on mandatorily redeemable capital stock of $974 thousand , $1.9 million , and $1.6 million , respectively, were recorded as interest expense. Table 16.2 - Mandatorily Redeemable Capital Stock (dollars in thousands) 2019 2018 2017 Balance at beginning of year $ 31,868 $ 35,923 $ 32,687 Capital stock subject to mandatory redemption reclassified from capital — 309 8,670 Redemption/repurchase of mandatorily redeemable capital stock (26,062 ) (4,364 ) (5,434 ) Balance at end of year $ 5,806 $ 31,868 $ 35,923 The number of stockholders holding mandatorily redeemable capital stock was nine , ten , and nine at December 31, 2019 , 2018 , and 2017 , respectively. Consistent with our capital plan, we are not required to redeem membership stock until the expiration of the redemption-notice period. Furthermore, we are not required to redeem activity-based stock until the later of the expiration of the redemption-notice period or the activity to which the capital stock relates no longer remains outstanding. If activity-based stock becomes excess stock as a result of an activity-based asset no longer outstanding, we may repurchase such shares, in our sole discretion, subject to the statutory and regulatory restrictions on excess capital-stock redemption. The year of redemption in the following table represents the end of the redemption-notice period. However, as discussed above, if activity to which the capital stock relates remains outstanding beyond the redemption-notice period, the activity-based stock associated with this activity will remain outstanding until the activity no longer remains outstanding. Table 16.3 - Mandatorily Redeemable Capital Stock by Expiry of Redemption Notice Period (dollars in thousands) December 31, 2019 December 31, 2018 Past redemption date (1) $ 5,663 $ 4,076 Due in one year or less — 27,379 Due after one year through two years — — Due after two years through three years 93 — Due after three years through four years 40 363 Due after four years through five years — 40 Thereafter (2) 10 10 Total $ 5,806 $ 31,868 _______________________ (1) Amount represents mandatorily redeemable capital stock that has reached the end of the five-year redemption-notice period but the member-related activity (for example, advances) remains outstanding. Accordingly, these shares of stock will not be redeemed until the activity is no longer outstanding. (2) Amount represents reclassifications to mandatorily redeemable capital stock resulting from an FHFA rule effective February 19, 2016, that makes captive insurance companies ineligible for membership. Captive insurance company members that were admitted as members prior to September 12, 2014, will have their memberships terminated no later than February 19, 2021. A member may cancel or revoke its written notice of redemption or its notice of withdrawal from membership prior to the end of the redemption-notice period. Our capital plan provides that we will charge the member a cancellation fee in the amount of 2.0 percent of the par amount of the shares of Class B stock that is the subject of the redemption notice. We will assess a redemption-cancellation fee unless the board of directors decides that it has a bona fide business purpose for waiving the imposition of the fee, and such a waiver is consistent with the FHLBank Act. Excess Capital Stock. Our capital plan provides us with the discretion to repurchase capital stock from a member at par value if that stock is not required by the member to meet its total stock investment requirement (excess capital stock) subject to all applicable limitations. In conducting any repurchases, we repurchase any shares that are the subject of an outstanding redemption notice from the member from whom we are repurchasing prior to repurchasing any other shares that are in excess of the member's total stock-investment requirement (TSIR). On June 1, 2017, we began daily repurchases of excess stock held by any shareholder whose excess stock exceeds the lesser of $10.0 million or 25 percent of the shareholder's total stock investment requirement, subject to a minimum repurchase of $100,000 . On August 11, 2017, we began repurchasing excess stock held by any shareholder whose excess stock exceeds the lesser of $10.0 million or 10 percent of the shareholder’s total stock investment requirement, subject to a minimum repurchase of $100,000 . In addition to these daily repurchases, shareholders may request that we voluntarily repurchase excess stock shares at any time. We may also allow the member to sell the excess capital stock at par value to another one of our members. At December 31, 2019 and 2018 , members and nonmembers with capital stock outstanding held excess capital stock totaling $79.7 million and $88.7 million , respectively, representing approximately 4.3 percent and 3.5 percent , respectively, of total capital stock outstanding. FHFA rules limit our ability to create member excess capital stock under certain circumstances. We may not pay dividends in the form of capital stock or issue new excess capital stock to members if our excess capital stock exceeds one percent of our total assets or if the issuance of excess capital stock would cause our excess capital stock to exceed one percent of our total assets. At December 31, 2019 , we had excess capital stock outstanding totaling 0.1 percent of our total assets. For the year ended December 31, 2019 , we complied with the FHFA's excess capital stock rule. Capital Classification Determination. We are subject to the FHFA's regulation on FHLBank capital classification and critical capital levels (the Capital Rule). The Capital Rule, among other things, defines criteria for four capital classifications and corrective action requirements for FHLBanks that are classified in any classification other than adequately capitalized. An adequately capitalized FHLBank is one that has sufficient permanent and total capital to satisfy its risk-based and minimum capital requirements. We satisfied these requirements at December 31, 2019 . However, pursuant to the Capital Rule, the FHFA has discretion to reclassify an FHLBank and modify or add to corrective action requirements for a particular capital classification. If we become classified into a capital classification other than adequately capitalized, we will be subject to the corrective action requirements for that capital classification in addition to being subject to prohibitions on declaring dividends and redeeming or repurchasing capital stock. By letter dated March 19, 2020 , the Director of the FHFA notified us that, based on December 31, 2019 financial information, we met the definition of adequately capitalized under the Capital Rule.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Loss [Text Block]	Accumulated Other Comprehensive Loss Table 17.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 14,478 — (2,838 ) — 11,640 Accretion of noncredit loss — 32,815 — — 32,815 Net actuarial loss — — — (586 ) (586 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 1,346 — — 1,346 Amortization - hedging activities (2) — — 10,589 — 10,589 Amortization - pension and postretirement benefits (3) — — — 770 770 Other comprehensive income 14,478 34,161 7,751 184 56,574 Balance, December 31, 2017 (122,331 ) (158,218 ) (40,436 ) (5,955 ) (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (30,627 ) — 7,907 — (22,720 ) Accretion of noncredit loss — 28,834 — — 28,834 Net actuarial loss — — — (670 ) (670 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 230 — — 230 Amortization - hedging activities (4) — — 3,410 — 3,410 Amortization - pension and postretirement benefits (3) — — — 1,349 1,349 Other comprehensive (loss) income (30,627 ) 29,064 11,317 679 10,433 Balance, December 31, 2018 (152,958 ) (129,154 ) (29,119 ) (5,276 ) (316,507 ) Cumulative effect of change in accounting principle — — (175 ) — (175 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 79,036 — (6,131 ) — 72,905 Noncredit other-than-temporary impairment losses — (181 ) — — (181 ) Noncredit losses included in basis of securities sold — 29,517 — — 29,517 Accretion of noncredit loss — 22,806 — — 22,806 Net actuarial loss — — — (2,195 ) (2,195 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 976 — — 976 Amortization - hedging activities (5) — — 5,218 — 5,218 Amortization - pension and postretirement benefits (3) — — — 664 664 Table 17.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Other comprehensive income (loss) 79,036 53,118 (913 ) (1,531 ) 129,710 Balance, December 31, 2019 $ (73,922 ) $ (76,036 ) $ (30,207 ) $ (6,807 ) $ (186,972 ) _______________________ (1) Recorded in net other-than-temporary impairment losses on investment securities, credit portion in the statement of operations. (2) Amortization of hedging activities includes $10.6 million recorded in CO bond interest expense and $14 thousand recorded in net gains on derivatives and hedging activities in the statement of operations. (3) Recorded in other expenses in the statement of operations. (4) Amortization of hedging activities includes $3.2 million recorded in CO bond interest expense and $239 thousand recorded in net gains on derivatives and hedging activities in the statement of operations. (5) Recorded in CO bond interest expense.

Employee Retirement Plans

Employee Retirement Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Retirement Plans [Text Block]	Employee Retirement Plans Qualified Defined Benefit Multiemployer Plan. We participate in the Pentegra Defined Benefit Plan for Financial Institutions (the Pentegra Defined Benefit Plan), a funded, tax-qualified, noncontributory defined-benefit pension plan. The Pentegra Defined Benefit Plan is treated as a multiemployer plan for accounting purposes, but operates as a multiple-employer plan under the Employee Retirement Income Security Act of 1974, as amended (ERISA), and the Internal Revenue Code. Accordingly, certain multiemployer plan disclosures are not applicable to the Pentegra Defined Benefit Plan. Under the Pentegra Defined Benefit Plan, contributions made by a participating employer may be used to provide benefits to employees of other participating employers since assets contributed by an employer are not segregated in a separate account or restricted to provide benefits only to employees of that employer. Also, in the event a participating employer is unable to meet its contribution requirements, the required contributions for the other participating employers could increase proportionately. The plan covers substantially all of our employees. For the years ended December 31, 2019 , 2018 and 2017 , in addition to our required contribution, we made voluntary contributions of $6.0 million , $6.0 million and $6.2 million , respectively, to the Pentegra Defined Benefit Plan. We were not required to nor did we pay a funding improvement surcharge to the plan for the years ended December 31, 2019 , 2018 , and 2017 . The Pentegra Defined Benefit Plan operates on a fiscal year from July 1 through June 30. The Pentegra Defined Benefit Plan files one Form 5500 on behalf of all employers who participate in the plan. The Employer Identification Number is 13-5645888 and the three-digit plan number is 333 . We do not have any collective bargaining agreements in place. The Pentegra Defined Benefit Plan's annual valuation process includes calculating the plan's funded status and separately calculating the funded status of each participating employer. The funded status is defined as the market value of assets divided by the funding target ( 100 percent of the present value of all benefit liabilities accrued at that date). As permitted by ERISA, the Pentegra Defined Benefit Plan accepts contributions for the prior plan year up to eight and a half months after the asset valuation date. Accordingly, the market value of assets at the valuation date (July 1) will increase by any subsequent contributions designated for the immediately preceding plan year ended June 30. The most recent Form 5500 available for the Pentegra Defined Benefit Plan is for the plan year ended June 30, 2018. For the Pentegra Defined Benefit Plan plan years ended June 30, 2017 and 2016, our contributions did not represent more than five percent of the total contributions to the Pentegra Defined Benefit Plan. Table 18.1 - Pentegra Defined Benefit Plan Net Pension Cost and Funded Status (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Net pension cost $ 6,559 $ 6,472 $ 6,727 Pentegra Defined Benefit Plan funded status as of July 1 (1) 108.6 % (2) 111.0 % (3) 111.8 % Our funded status as of July 1 (1) 113.9 % 123.1 % 122.9 % ______________________ (1) The funded status is calculated in accordance with a provision contained in the Highway and Transportation Funding Act of 2014 (HATFA), which was signed into law on August 8, 2014, and which modifies the interest rates that had been set by the Moving Ahead for Progress in the 21st Century Act (MAP-21). MAP-21, signed into law in 2012, changed the calculation of the discount rate used in measuring the pension plan liability. MAP-21 allows plan sponsors to measure the pension plan liability using a 25-year average of interest rates plus or minus a corridor. Prior to MAP-21, the discount rate used in measuring the pension plan liability was based on the 24-month average of interest rates. HATFA amended MAP-21 by extending the time period and reducing the rate at which the 25-year corridors widen. Over time, the pension funding stabilization effect of MAP-21 will decline because the 24-month smoothed segment rates and the amended 25-year corridors are likely to converge. (2) The funded status as of July 1, 2019, is preliminary and may increase because the plan's participants were permitted to make contributions for the plan year ended June 30, 2019, through March 15, 2020. Contributions made on or before March 15, 2020, and designated for the plan year ended June 30, 2019, will be included in the final valuation as of July 1, 2019. The final funded status as of July 1, 2019, will not be available until the Form 5500 for the plan year July 1, 2019, through June 30, 2020 is filed. This Form 5500 is due to be filed no later than April 2021. (3) The funded status as of July 1, 2018, is preliminary and may increase because the plan's participants were permitted to make contributions for the plan year ended June 30, 2018, through March 15, 2019. Contributions made on or before March 15, 2019, and designated for the plan year ended June 30, 2018, will be included in the final valuation as of July 1, 2018. The final funded status as of July 1, 2018, will not be available until the Form 5500 for the plan year July 1, 2018, through June 30, 2019 is filed. This Form 5500 is due to be filed no later than April 2020. Qualified Defined Contribution Plan. We also participate in the Pentegra Defined Contribution Plan for Financial Institutions, a tax-qualified defined contribution plan. The plan covers substantially all of our employees. We contribute a percentage of the participants' compensation by making a matching contribution equal to a percentage of voluntary employee contributions, subject to certain limitations. Our matching contributions are charged to compensation and benefits expense and are not considered to be material. Nonqualified Defined Contribution Plan. We also maintain the Thrift Benefit Equalization Plan, a nonqualified, unfunded deferred compensation plan covering certain of our senior officers and directors. The plan's liability consists of the accumulated compensation deferrals and the accumulated earnings on these deferrals. Our obligation from this plan was $ 12.6 million and $9.7 million at December 31, 2019 and 2018 , respectively, which is recorded in other liabilities on the statement of condition. We maintain a rabbi trust, which is recorded in other assets on the statement of condition, intended to satisfy future benefit obligations. Our matching contributions are charged to compensation and benefits expense and are not considered to be material. Nonqualified Supplemental Defined Benefit Retirement Plan. We also maintain a nonqualified, single-employer unfunded defined-benefit plan covering certain senior officers, for which our obligation is detailed below. We maintain a rabbi trust which is recorded in other assets on the statement of condition, intended to satisfy future benefit obligations. Postretirement Benefits. We sponsor a fully insured postretirement benefit program that includes life insurance benefits for eligible retirees. We provide life insurance to all employees who retire on or after age 55 after completing six years of service. No contributions are required from the retirees. There are no funded plan assets that have been designated to provide postretirement benefits. Table 18.2 - Pension and Postretirement Benefit Obligation, Fair Value of Plan Assets, and Funded Status (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits December 31, 2019 December 31, 2018 December 31, 2019 December 31, 2018 Change in benefit obligation (1) Benefit obligation at beginning of year $ 22,321 $ 19,366 $ 955 $ 1,056 Service cost 1,235 1,490 38 45 Interest cost 699 654 42 37 Actuarial loss 1,874 831 321 (161 ) Benefits paid (6 ) (5 ) (17 ) (22 ) Settlements — (15 ) — — Benefit obligation at end of year 26,123 22,321 1,339 955 Change in plan assets Fair value of plan assets at beginning of year — — — — Employer contribution 6 20 17 22 Benefits paid (6 ) (5 ) (17 ) (22 ) Settlements — (15 ) — — Fair value of plan assets at end of year — — — — Funded status at end of year $ (26,123 ) $ (22,321 ) $ (1,339 ) $ (955 ) ______________________ (1) Represents the projected benefit obligation for the nonqualified supplemental defined benefit retirement plan and the accumulated postretirement benefit obligation for postretirement benefits. Table 18.3 - Pension and Postretirement Benefits Recognized in Accumulated Other Comprehensive Loss (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits December 31, 2019 December 31, 2018 December 31, 2019 December 31, 2018 Net actuarial loss $ 6,223 $ 4,920 $ 437 $ 123 Prior service cost 148 234 — — Total $ 6,371 $ 5,154 $ 437 $ 123 The accumulated benefit obligation for the nonqualified supplemental defined benefit retirement plan was $22.7 million and $18.3 million at December 31, 2019 and 2018 , respectively. Table 18.4 - Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2019 2018 2017 2019 2018 2017 Net Periodic Benefit Cost Service cost $ 1,235 $ 1,490 $ 1,179 $ 38 $ 45 $ 38 Interest cost 699 654 600 42 37 36 Amortization of prior service cost 86 86 86 — — — Amortization of net actuarial loss 571 1,248 676 7 15 8 Net periodic benefit cost 2,591 3,478 2,541 87 97 82 Other Changes in Benefit Obligations Recognized in Accumulated Other Comprehensive Loss Amortization of prior service cost (86 ) (86 ) (86 ) — — — Amortization of net actuarial loss (571 ) (1,248 ) (676 ) (7 ) (15 ) (8 ) Net actuarial loss (gain) 1,874 831 459 321 (161 ) 127 Total amount recognized in other comprehensive income 1,217 (503 ) (303 ) 314 (176 ) 119 Total amount recognized in net periodic benefit cost and other comprehensive income $ 3,808 $ 2,975 $ 2,238 $ 401 $ (79 ) $ 201 The estimated net actuarial loss and prior service cost that will be amortized from accumulated other comprehensive loss into net periodic benefit cost during 2020 is $811 thousand for our nonqualified supplemental defined benefit retirement plan and $27 thousand for our postretirement benefits. Table 18.5 - Pension and Postretirement Benefit Plan Key Assumptions Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2019 2018 2019 2018 Benefit obligation Discount rate 2.68 % 3.81 % 3.25 % 4.25 % Salary increases 5.50 % 5.50 % — — Net periodic benefit cost Discount rate 3.81 % 3.09 % 4.25 % 3.64 % Salary increases 5.50 % 5.50 % — — The discount rate for the nonqualified supplemental defined benefit retirement plan was determined by using a discounted cash-flow analysis using the FTSE Pension Discount Curve as of December 31, 2019 . Our nonqualified supplemental defined benefit retirement plan and postretirement benefits are not funded; therefore, no contributions will be made in 2020 other than the payment of benefits. Table 18.6 - Estimated Future Benefit Payments (dollars in thousands) Estimated Future Payments Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2020 $ 6,066 $ 18 2021 2,459 19 2022 1,900 21 2023 2,464 23 2024 4,083 26 2025-2029 9,268 168

Fair Values

Fair Values	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value [Text Block]	Fair Values Fair-Value Methodologies and Techniques We have determined the fair-value amounts below using available market and other pertinent information and our best judgment of appropriate valuation methods. Fair value is the price in an orderly transaction between market participants to sell an asset or transfer a liability in the principal (or advantageous) market for the asset or liability at the measurement date (an exit price). Although we use our best judgment in estimating the fair value of these financial instruments, there are inherent limitations in any estimation technique or valuation methodology. For example, because an active secondary market does not exist for a portion of our financial instruments, in certain cases, fair values are not subject to precise quantification or verification and may change as economic and market factors and evaluation of those factors change. Therefore, these fair values are not necessarily indicative of the amounts that would be realized in current market transactions, although they do reflect our judgment of how a market participant would estimate the fair values. Additionally, these values do not represent an estimate of the overall market value of the Bank as a going concern, which would take into account, among other things, future business opportunities and the net profitability of assets and liabilities. Fair-Value Hierarchy. GAAP establishes a fair-value hierarchy and 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. An entity must disclose the level within the fair value hierarchy in which the measurements are classified. The fair-value hierarchy prioritizes the inputs used to measure fair value into three broad levels: Level 1 Quoted prices (unadjusted) for identical assets or liabilities in an active market that the reporting entity can access on the measurement date. An active market for the asset or liability is a market in which the transaction for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. If the asset or liability has a specified or 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: (1) quoted prices for similar assets or liabilities in active markets; (2) quoted prices for identical or similar assets or liabilities in markets that are not active; (3) 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, volatilities, and prepayment speeds); and (4) inputs that are derived principally from or corroborated by observable market data (e.g., implied spreads). Level 3 Unobservable inputs for the asset or liability. We review the 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 would be reported as transfers in/out as of the beginning of the quarter in which the changes occur. There were no such transfers during the years ended December 31, 2019 and 2018 . Table 19.1 presents the carrying value, fair value, and fair value hierarchy of our financial assets and liabilities at December 31, 2019 and 2018 . We record trading securities, available-for-sale securities, derivative assets, derivative liabilities, and certain other assets at fair value on a recurring basis, and on occasion certain private-label MBS, certain mortgage loans, and certain other assets on a non-recurring basis. We record all other financial assets and liabilities at amortized cost. Refer to Table 19.2 for further details about the financial assets and liabilities held at fair value on either a recurring or non-recurring basis. Table 19.1 - Fair Value Summary (dollars in thousands) December 31, 2019 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 69,416 $ 69,416 $ 69,416 $ — $ — $ — Interest-bearing deposits 1,253,873 1,253,873 1,253,873 — — — Securities purchased under agreements to resell 3,500,000 3,500,003 — 3,500,003 — — Federal funds sold 860,000 859,999 — 859,999 — — Trading securities (1) 2,250,264 2,250,264 — 2,250,264 — — Available-for-sale securities (1) 7,409,000 7,409,000 — 7,344,348 64,652 — Held-to-maturity securities 871,107 1,035,410 — 456,942 578,468 — Advances 34,595,363 34,735,775 — 34,735,775 — — Mortgage loans, net 4,501,251 4,634,141 — 4,615,737 18,404 — Accrued interest receivable 112,163 112,163 — 112,163 — — Derivative assets (1) 159,731 159,731 — 15,329 — 144,402 Other assets (1) 31,939 31,939 13,894 18,045 — — Liabilities: Deposits (674,309 ) (674,269 ) — (674,269 ) — — COs: Bonds (23,888,493 ) (24,226,123 ) — (24,226,123 ) — — Discount notes (27,681,169 ) (27,681,470 ) — (27,681,470 ) — — Mandatorily redeemable capital stock (5,806 ) (5,806 ) (5,806 ) — — — Accrued interest payable (104,477 ) (104,477 ) — (104,477 ) — — Derivative liabilities (1) (10,271 ) (10,271 ) — (43,805 ) — 33,534 Other: Commitments to extend credit for advances — (3,884 ) — (3,884 ) — — Standby letters of credit (1,723 ) (1,723 ) — (1,723 ) — — December 31, 2018 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 10,431 $ 10,431 $ 10,431 $ — $ — $ — Interest-bearing deposits 593,199 593,199 593,199 — — — Securities purchased under agreements to resell 6,499,000 6,499,078 — 6,499,078 — — Federal funds sold 1,500,000 1,500,002 — 1,500,002 — — Trading securities (1) 163,038 163,038 — 163,038 — — Available-for-sale securities (1) 5,849,944 5,849,944 — 5,800,343 49,601 — Held-to-maturity securities 1,295,023 1,528,929 — 638,164 890,765 — Advances 43,192,222 43,167,700 — 43,167,700 — — Mortgage loans, net 4,299,402 4,238,087 — 4,217,487 20,600 — Accrued interest receivable 112,751 112,751 — 112,751 — — Derivative assets (1) 22,403 22,403 — 13,832 — 8,571 Other assets (1) 25,059 25,059 9,988 15,071 — — Liabilities: Deposits (474,878 ) (474,848 ) — (474,848 ) — — COs: Bonds (25,912,684 ) (25,843,163 ) — (25,843,163 ) — — Discount notes (33,065,822 ) (33,062,585 ) — (33,062,585 ) — — Mandatorily redeemable capital stock (31,868 ) (31,868 ) (31,868 ) — — — Accrued interest payable (112,043 ) (112,043 ) — (112,043 ) — — Derivative liabilities (1) (255,800 ) (255,800 ) — (309,552 ) — 53,752 Other: Commitments to extend credit for advances — (4,164 ) — (4,164 ) — — Standby letters of credit (1,257 ) (1,257 ) — (1,257 ) — — _______________________ (1) Carried at fair value and measured on a recurring basis. (2) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. Summary of Valuation Methodologies and Primary Inputs The valuation methodologies 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 nonrecurring basis in the Statement of Condition are listed below. The fair values and level within the fair value hierarchy of these assets and liabilities are reported in Table 19.2. Investment Securities. We determine the fair values of our investment securities, other than HFA floating-rate securities, based on prices obtained for each of these securities that we request from multiple designated third-party pricing vendors. The fair value of each such security is the average of such vendor prices that are within a cluster pricing tolerance range. A cluster is defined as a group of available vendor prices for a given security that is within a defined price tolerance range of the median vendor price depending on the security type. An outlier is any vendor price that is outside of the defined cluster and is evaluated for reasonableness. 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. Vendor prices that are outside of a defined cluster are identified as outliers and are subject to additional review including, but not limited to, comparison to prices provided by an additional third-party valuation vendor, prices for similar securities, and/or nonbinding dealer estimates, or the use of internal model prices, which we believe reflect the facts and circumstances that a market participant would consider. We also perform this analysis in those limited instances where no third-party vendor price or only one third-party vendor price is available to determine fair value. If the analysis indicates that an outlier is not representative of fair value and that the average of the vendor prices within the tolerance threshold of the median price is the best estimate, then we use the average of the vendor prices within the tolerance threshold of the median price as the final price. If, on the other hand, we determine that an outlier (or some other price identified in the analysis) is a better estimate of fair value, then the outlier (or the other price as appropriate) is used as the final price. In all cases, the final price is used to determine the fair value of the security. As of December 31, 2019 , multiple vendor prices were received for substantially all of our investment securities and the final prices for substantially all of those securities were computed by averaging the prices received. The relative proximity of the prices received supports our conclusion that the final computed prices are reasonable estimates of fair value. Based on the current low level of market activity for private-label residential MBS, the nonrecurring fair-value measurements for such securities as of December 31, 2019 and 2018 , fell within Level 3 of the fair-value hierarchy. Our fixed-rate HFA securities fall within Level 3 of the fair-value hierarchy due to the current lack of market activities for these bonds. Investment Securities – HFA Floating Rate Securities. The fair value is determined by calculating the present value of the expected future cash flows. The discount rates used in these calculations are the rates for securities with similar terms. Our floating rate HFA securities fall within Level 3 of the fair-value hierarchy due to the current lack of market activity for these bonds. Mortgage Loans. The fair value of impaired conventional mortgage loans is based on the lower of the carrying value of the loans or fair value of the collateral less estimated costs to sell. The fair value of impaired government mortgage loans is equal to the unpaid principal balance. REO. Fair value is derived from third-party valuations of the property, which fall within Level 3 of the fair-value hierarchy. Derivative Assets/Liabilities - Interest-Rate-Exchange Agreements . We base the fair values of interest-rate-exchange agreements on available market prices of derivatives having similar terms, including accrued interest receivable and payable. The fair-value methodology uses standard valuation techniques for derivatives such as discounted cash-flow analysis and comparisons with similar instruments. The fair values of all interest-rate-exchange agreements are netted by clearing member and/or by counterparty, including cash collateral received from or delivered to the counterparty. If these netted amounts are positive, they are classified as an asset, and if negative, they are classified as a liability. We generally use a midmarket pricing convention based on the bid-ask spread as a practical expedient for fair-value measurements. Because these estimates are made at a specific point in time, they are susceptible to material near-term changes. We have evaluated the potential for the fair value of the instruments to be affected by counterparty risk and our own credit risk and have determined that no adjustments were significant to the overall fair-value measurements. The discounted cash-flow model uses market-observable inputs (inputs that are actively quoted and can be validated to external sources), including the following: • Discount rate assumption . At December 31, 2019 and 2018 , we used either the OIS rate based on the federal funds effective rate curve or the LIBOR swap curve depending on the terms of the International Swaps and Derivatives Association (ISDA) agreement we have with each derivative counterparty. • Forward interest-rate assumption . LIBOR swap curve or OIS based on the federal funds effective rate. • Volatility assumption . Market-based expectations of future interest-rate volatility implied from current market prices for similar options. Derivative Assets/Liabilities – Commitments to Invest in Mortgage Loans . Commitments to invest in mortgage loans are recorded as derivatives in the statement of condition. The fair values of such commitments are based on the end-of-day delivery commitment prices provided by the FHLBank of Chicago and a spread, derived from MBS TBA delivery commitment prices with adjustment for the contractual features of the MPF program, such as servicing and credit-enhancement features. Subjectivity of Estimates. Estimates of the fair value of financial assets and liabilities using the methodologies described above 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. Since these estimates are made as of a specific point in time, they are susceptible to material near-term changes. Fair Value Measured on a Recurring and Nonrecurring Basis. Table 19.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (dollars in thousands) December 31, 2019 Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (1) Total Assets: Carried at fair value on a recurring basis Trading securities: Corporate bonds $ — $ 5,896 $ — $ — $ 5,896 U.S. Treasury obligations 2,240,236 2,240,236 U.S. government-guaranteed – single-family MBS — 4,047 — — 4,047 GSE – single-family MBS — 85 — — 85 Total trading securities — 2,250,264 — — 2,250,264 Available-for-sale securities: HFA securities — — 64,652 — 64,652 Supranational institutions — 416,429 — — 416,429 U.S. government-owned corporations — 296,761 — — 296,761 GSE — 123,786 — — 123,786 U.S. government guaranteed – single-family MBS — 57,714 — — 57,714 U.S. government guaranteed – multifamily MBS — 282,617 — — 282,617 GSE – single-family MBS — 2,590,271 — — 2,590,271 GSE – multifamily MBS — 3,576,770 — — 3,576,770 Total available-for-sale securities — 7,344,348 64,652 — 7,409,000 Derivative assets: Interest-rate-exchange agreements — 15,102 — 144,402 159,504 Mortgage delivery commitments — 227 — — 227 Total derivative assets — 15,329 — 144,402 159,731 Other assets 13,894 18,045 — — 31,939 Total assets carried at fair value on a recurring basis $ 13,894 $ 9,627,986 $ 64,652 $ 144,402 $ 9,850,934 Carried at fair value on a nonrecurring basis (2) Held-to-maturity securities: Private-label MBS $ — $ — $ 6,856 $ — $ 6,856 Mortgage loans held for portfolio — — 1,198 — 1,198 REO — — 78 — 78 Total assets carried at fair value on a nonrecurring basis $ — $ — $ 8,132 $ — $ 8,132 Liabilities: Carried at fair value on a recurring basis Derivative liabilities Interest-rate-exchange agreements $ — $ (43,805 ) $ — $ 33,534 $ (10,271 ) Total liabilities carried at fair value on a recurring basis $ — $ (43,805 ) $ — $ 33,534 $ (10,271 ) December 31, 2018 Level 1 Level 2 Level 3 Netting (1) Total Assets: Carried at fair value on a recurring basis Trading securities: Corporate bonds $ — $ 6,102 $ — $ — $ 6,102 U.S. government-guaranteed – single-family MBS — 5,344 — — 5,344 GSE – single-family MBS — 148 — — 148 GSE – multifamily MBS — 151,444 — — 151,444 Total trading securities — 163,038 — — 163,038 Available-for-sale securities: HFA securities — — 49,601 — 49,601 Supranational institutions — 405,155 — — 405,155 U.S. government-owned corporations — 273,169 — — 273,169 GSE — 115,627 — — 115,627 U.S. government guaranteed – single-family MBS — 75,658 — — 75,658 U.S. government guaranteed – multifamily MBS — 361,134 — — 361,134 GSE – single-family MBS — 3,562,159 — — 3,562,159 GSE – multifamily MBS — 1,007,441 — — 1,007,441 Total available-for-sale securities — 5,800,343 49,601 — 5,849,944 Derivative assets: Interest-rate-exchange agreements — 13,493 — 8,571 22,064 Mortgage delivery commitments — 339 — — 339 Total derivative assets — 13,832 — 8,571 22,403 Other assets 9,988 15,071 — — 25,059 Total assets carried at fair value on a recurring basis $ 9,988 $ 5,992,284 $ 49,601 $ 8,571 $ 6,060,444 Carried at fair value on a nonrecurring basis (2) Held-to-maturity securities: Private-label MBS $ — $ — $ 1,668 $ — $ 1,668 Mortgage loans held for portfolio — — 1,144 — 1,144 REO — — 361 — 361 Total assets carried at fair value on a nonrecurring basis $ — $ — $ 3,173 $ — $ 3,173 Liabilities: Carried at fair value on a recurring basis Derivative liabilities Interest-rate-exchange agreements $ — $ (309,552 ) $ — $ 53,752 $ (255,800 ) Total liabilities carried at fair value on a recurring basis $ — $ (309,552 ) $ — $ 53,752 $ (255,800 ) _______________________ (1) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. (2) We measure certain held-to-maturity investment securities, mortgage loans held for portfolio, and REO at fair value on a nonrecurring basis, that is, they are not measured at fair value on an ongoing basis but are subject to fair-value adjustments only in certain circumstances (for example, upon recognizing an other-than-temporary impairment on a held-to-maturity security). The fair values presented are as of the date the fair value adjustment was recorded. Table 19.3 presents a reconciliation of available-for-sale securities that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended December 31, 2019 , 2018 , and 2017 . Table 19.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Balance at beginning of year $ 49,601 $ 37,683 $ 8,146 Purchases 13,820 12,800 33,350 Unrealized gains (losses) included in other comprehensive income 1,231 (882 ) (3,813 ) Balance at end of year $ 64,652 $ 49,601 $ 37,683

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies Joint and Several Liability. COs are backed by the financial resources of the FHLBanks. The FHFA has authority to require any FHLBank to repay all or a portion of the principal and interest on COs for which another FHLBank is the primary obligor. No FHLBank has ever been asked or required to repay the principal or interest on any CO on behalf of another FHLBank. We evaluate the financial condition of the other FHLBanks primarily based on known regulatory actions, publicly available financial information, and individual long-term credit-rating action as of each period-end presented. Based on this evaluation, as of December 31, 2019 , and through the filing of this report, we do not believe it is likely that we will be required to repay the principal or interest on any CO on behalf of another FHLBank. We have considered applicable FASB guidance and determined it is not necessary to recognize a liability for the fair value of our joint and several liability for all of the COs. The joint and several obligation is mandated by the FHLBank Act, as implemented by FHFA regulations, and is not the result of an arms-length transaction among the FHLBanks. The FHLBanks have no control over the amount of the guaranty or the determination of how each FHLBank would perform under the joint and several obligation. Because the FHLBanks are subject to the authority of the FHFA as it relates to decisions involving the allocation of the joint and several liability for the FHLBanks' COs, the FHLBanks' joint and several obligation is excluded from the initial recognition and measurement provisions. Accordingly, we have not recognized a liability for our joint and several obligation related to other FHLBanks' COs at December 31, 2019 and 2018 . The par amounts of other FHLBanks' outstanding COs for which we are jointly and severally liable totaled $ 974.4 billion and $972.6 billion at December 31, 2019 and 2018 , respectively. See Note 14 — Consolidated Obligations for additional information. Off-Balance-Sheet Commitments Table 20.1 - Off-Balance Sheet Commitments (dollars in thousands) December 31, 2019 December 31, 2018 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 7,484,754 $ 215,014 $ 7,699,768 $ 6,028,851 $ 226,438 $ 6,255,289 Commitments for unused lines of credit - advances (2) 1,143,828 — 1,143,828 1,177,377 — 1,177,377 Commitments to make additional advances 434,253 88,167 522,420 159,401 59,894 219,295 Commitments to invest in mortgage loans 49,911 — 49,911 50,773 — 50,773 Unsettled CO bonds, at par — — — 105,400 — 105,400 Unsettled CO discount notes, at par 500,000 — 500,000 600,000 — 600,000 __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At December 31, 2019 and 2018 , these amounts totaled $ 27.2 million and $32.6 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $1.8 million and $675 thousand at December 31, 2019 and 2018 , respectively. (2) Commitments for unused line-of-credit advances are generally for periods of up to 12 months . Since many of these commitments are not expected to be drawn upon, the total commitment amount does not necessarily indicate future liquidity requirements. Standby Letters of Credit. We issue standby letters of credit on behalf of our 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 state and local government agencies. Standby letters of credit are executed for members for a fee. If we are required to make payment for a beneficiary's draw, our strategy is to take prompt action to recover the funds paid to the third-party beneficiary, including converting the payment amount into a collateralized advance to the primary obligor, withdrawing the payment amount from the primary obligor's demand deposit account with us, or selling collateral pledged by the primary obligor in a commercially reasonable manner to offset the payment amount. Historically, standby letters of credit usually expire without being drawn upon. At December 31, 2019 , the terms of these standby letters of credit have original expiration periods of up to 20 years , expiring no later than 2027 . Currently, we offer new standby letters of credit with expiration periods of up to 10 years . Unearned fees for the value of the guarantees related to standby letters of credit are recorded in other liabilities and totaled $1.7 million and $1.3 million at December 31, 2019 and 2018 , respectively. We monitor the creditworthiness of our members and housing associates that have standby letter of credit agreements outstanding based on our evaluations of the financial condition of the member or housing associate. We review available financial data, which can include regulatory call reports filed by depository institution members, regulatory financial statements filed with the appropriate state insurance department by insurance company members, audited financial statements of housing associates, SEC filings, and rating-agency reports to ensure that potentially troubled members are identified as soon as possible. In addition, we have access to most members' regulatory examination reports. We analyze this information on a regular basis. Standby letters of credit are fully collateralized at the time of issuance. Based on our credit analyses and collateral requirements, we have not deemed it necessary to record any additional liability on these commitments. Commitments to Invest in Mortgage Loans. Commitments to invest in mortgage loans are generally for periods not to exceed 45 business days. Such commitments are recorded as derivatives at their fair values on the statement of condition. Pledged Collateral. We have pledged securities as collateral related to derivatives. See Note 12 — Derivatives and Hedging Activities for additional information about our pledged collateral and other credit-risk-related contingent features. Legal Proceedings . We are subject to various legal proceedings arising in the normal course of business from time to time. We would record an accrual for a loss contingency when it is probable that a loss has been incurred and the amount can be reasonably estimated. Management does not anticipate that the ultimate liability, if any, arising out of these matters will have a material effect on our financial condition, results of operations, or cash flows. Other commitments and contingencies are discussed in Note 9 — Advances , Note 12 — Derivatives and Hedging Activities , Note 14 — Consolidated Obligations , Note 15 — Affordable Housing Program , Note 16 — Capital , and Note 18 — Employee Retirement Plans .

Transactions with Shareholders

Transactions with Shareholders	12 Months Ended
	Dec. 31, 2019
Transactions with Shareholders [Abstract]
Transactions with Shareholders [Text Block]	Transactions with Shareholders We are a cooperative whose members own our capital stock and may receive dividends on their investment in our capital stock. In addition, certain former members and nonmembers that still have outstanding transactions with us are also required to maintain their investment in our capital stock until the transactions mature or are paid off. All advances are issued to members or housing associates, and mortgage loans held for portfolio are generally acquired from our members or housing associates. We also maintain demand-deposit accounts for members and housing associates primarily to facilitate settlement activities that are directly related to advances, mortgage-loan purchases, and other transactions between us and the member or housing associate. In instances where the member has an officer or director who serves as a director of the Bank, those transactions are subject to the same eligibility and credit criteria, as well as the same terms and conditions, as transactions with all other members. Related Parties. We define related parties as members who owned 10 percent or more of the voting interests of our capital stock outstanding at year end. Each member eligible to vote is entitled to cast by ballot one vote for each share of stock that it was required to hold as of the record date, which is December 31, of the year prior to each election, subject to the limitation that no member may cast more votes than the average number of shares of our stock that is required to be held by all members located in such member's state. Under the FHLBank Act and FHFA regulations, each member directorship is designated to one of the six states in our district. Eligible members are permitted to vote all their eligible shares for one candidate for each open member directorship in the state in which the member is located and for each open independent directorship. A nonmember stockholder is not entitled to cast votes for the election of directors unless it was a member as of the record date. At December 31, 2019 and 2018 , no shareholder owned more than 10 percent of the total voting interests due to statutory limits on members' voting rights, therefore, we did not have any related parties. Shareholder Concentrations. We consider shareholder concentrations as members or nonmembers whose capital stock holdings (including mandatorily redeemable capital stock) are in excess of 10 percent of total capital stock outstanding at December 31, 2019 . Table 21.1 - Shareholder Concentrations, Balance Sheet (dollars in thousands) Capital Stock Outstanding Percent of Total Capital Stock Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of December 31, 2019 Citizens Bank, N.A. $ 222,684 11.9 % $ 5,005,773 14.5 % $ 1,678 3.5 % As of December 31, 2018 Citizens Bank, N.A. $ 339,003 13.2 % $ 7,656,146 17.7 % $ 5,005 8.3 % We held sufficient collateral to support the advances to the above institution such that we do not expect to incur any credit losses on these advances. Table 21.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Citizens Bank, N.A. Interest income on advances $ 95,692 $ 134,753 $ 63,568 Fees on letters of credit 6,489 4,415 3,368 During 2019 and 2017 , we did not receive any prepayment fees from Citizens Bank, N.A. We received prepayment fees of $298,000 from Citizens Bank, N.A. and the corresponding principal amount prepaid to us was $3.2 million during 2018. Transactions with Directors' Institutions. We provide, in the ordinary course of business, products and services to members whose officers or directors serve on our board of directors. In accordance with FHFA regulations, transactions with directors' institutions are conducted on the same terms as those with any other member. Table 21.3 - Transactions with Directors' Institutions (dollars in thousands) Capital Stock Outstanding Percent of Total Capital Stock Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of December 31, 2019 $ 112,811 6.0 % $ 2,224,141 6.4 % $ 3,581 7.4 % As of December 31, 2018 113,337 4.4 2,147,602 5.0 3,576 6.0

Transactions with Other FHLBank

Transactions with Other FHLBanks	12 Months Ended
	Dec. 31, 2019
Transactions with Other FHLBanks [Abstract]
Transactions with Other FHLBanks [Text Block]	Transactions with Other FHLBanks We may occasionally enter into transactions with other FHLBanks. These transactions are summarized below. Overnight Funds . We may borrow or lend unsecured overnight funds from or to other FHLBanks. All such transactions are at current market rates. Interest income and interest expense related to these transactions with other FHLBanks are included within other interest income and interest expense from other borrowings in the statement of operations. Interest income on loans to other FHLBanks was $25 thousand , $21 thousand and $43 thousand for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Interest expense for loans from other FHLBanks was $20 thousand , $36 thousand , and $6 thousand for the years ended December 31, 2019 , 2018 , and 2017 , respectively. MPF Mortgage Loans. We pay a transaction-services fee and a membership fee to the FHLBank of Chicago for our participation in the MPF program. For the years ended December 31, 2019 , 2018 , and 2017 , we recorded $2.8 million , $2.5 million , and $2.2 million , respectively in MPF transaction-services fee expense to the FHLBank of Chicago which has been recorded in the statement of operations as other expense. The membership fee has been recorded in the statement of operations as an operating expense, and totaled $600 thousand for each of the years ended December 31, 2019 , 2018 and 2017 . COs. From time to time, one FHLBank may transfer to another FHLBank the COs for which the transferring FHLBank was originally the primary obligor but upon transfer the assuming FHLBank becomes the primary obligor. During the year ended December 31, 2019 , we transferred debt obligations with a par amount of $10.0 million and a fair value of approximately $12.7 million on the day they were transferred. During the years ended December 31, 2018 and 2017 , there were no transfers of COs between us and other FHLBanks.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On February 13, 2020 , the board of directors declared a cash dividend at an annualized rate of 5.46 percent based on capital stock balances outstanding during the fourth quarter of 2019 . The dividend, including dividends classified as interest on mandatorily redeemable capital stock, amounted to $24.3 million and was paid on March 3, 2020 . During the first quarter of 2020 , a gain of $40.7 million was realized on the sale of held-to-maturity securities, which had an amortized cost of $121.0 million , and of which at least 85 percent of the principal outstanding at acquisition had been collected.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Use of Estimates, Policy	These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). The preparation of financial statements in accordance with GAAP requires management to make subjective assumptions and estimates that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported amounts of income and expenses. The most significant of these estimates include but are not limited to, accounting for derivatives and hedging activities, estimation of fair values, and amortization of premiums and discounts associated with prepayable mortgage-backed securities. Actual results could differ from these estimates.
Fair Value Measurement, Policy	We determine the fair-value amounts recorded on the statement of condition and in the note disclosures for the periods presented by using available market and other pertinent information, and reflect our best judgment of appropriate valuation methods. Although we use our best judgment in estimating the fair value of these financial instruments, there are inherent
Derivatives, Offsetting Fair Value Amounts, Policy	We present certain financial instruments on a net basis when they are subject to a legal right of offset and all other requirements for netting are met (collectively referred to as the netting requirements). For these financial instruments, we have elected to offset our asset and liability positions, as well as cash collateral received or pledged, when we have met the netting requirements. The net exposure for these financial instruments can change on a daily basis; therefore, there may be a delay between the time this exposure change is identified and additional collateral is requested, and the time when this collateral is received or pledged. Likewise, there may be a delay for excess collateral to be returned. For derivative instruments that meet the requirements for netting, any excess cash collateral received or pledged is recognized as a derivative liability or derivative asset. See Note 12 — Derivatives and Hedging Activities for additional information regarding these agreements.
Investment, Policy	Securities classified as trading are held for liquidity purposes and carried at fair value. We record changes in the fair value of these investments through other income as net unrealized gains (losses) on trading securities. FHFA regulations prohibit trading in or the speculative use of these instruments and limit the credit risks we have from these instruments.We amortize premiums and accrete discounts on mortgage-backed securities (MBS) using the level-yield method over the estimated lives of the securities. This method requires a retrospective adjustment of the effective yield each time we change the estimated life, based on actual prepayments received and changes in expected prepayments, as if the new estimate had been known since the original acquisition date of the securities. We estimate prepayment speeds on each individual security using the most recent three months of historical constant prepayment rates, as available, or may subscribe to third-party data services that provide estimates of future cash flows, from which we determine expected asset lives. We amortize premiums and accrete discounts on other investments using the level-yield method to the contractual maturity of the securities. We classify investments as trading, available-for-sale, or held-to-maturity at the date of acquisition. Purchases and sales of securities are recorded on a trade date basis. We evaluate our individual available-for-sale and held-to-maturity securities in an unrealized loss position for other-than-temporary impairment each quarter. An investment is considered impaired when its fair value is less than its amortized cost. We consider other-than-temporary impairment to have occurred if we: • have an intent to sell the investment; • believe it is more likely than not that we will be required to sell the investment before the recovery of its amortized cost based on available evidence; or • do not expect to recover the entire amortized cost of the debt security. Recognition of Other-than-Temporary Impairment. If either of the first two conditions above is met, we recognize an other-than-temporary impairment charge in earnings equal to the entire difference between the security's amortized cost and its fair value as of the statement of condition date. For securities in an unrealized loss position that meet neither of the first two conditions (excluding agency MBS) and for each of our private-label MBS, we perform an analysis to determine if we will recover the entire amortized cost of each of these securities. The present value of the cash flows expected to be collected is compared with the amortized cost of the debt security to determine whether a credit loss exists. If the present value of the cash flows expected to be collected is less than the amortized cost of the debt security, the security is deemed to be other-than-temporarily impaired and the carrying value of the debt security is adjusted to its fair value. However, rather than recognizing the entire difference between the amortized cost and fair value in earnings, only the amount of the impairment representing the credit loss (that is, the credit component) is recognized in earnings, while the amount related to all other factors (that is, the noncredit component) is recognized in other comprehensive income (loss). For a security that is determined to be other-than-temporarily impaired, in the event that the present value of the cash flows expected to be collected is less than the fair value of the security, the credit loss on the security is limited to the amount of that security's unrealized losses. In performing a detailed cash-flow analysis, we estimate the cash flows expected to be collected. If this estimate results in a present value of expected cash flows (discounted at the security's effective yield) that is less than the amortized cost basis of a security (that is, a credit loss exists), other-than-temporary impairment is considered to have occurred. For determining the present value of variable-rate and hybrid private-label residential MBS, we use the effective interest rate derived from a variable-rate index, such as one-month London Interbank Offered Rate (LIBOR), plus the contractual spread, plus or minus a fixed-spread adjustment when there is an existing discount or premium on the security. Because the implied forward yield curve of a selected variable-rate index changes over time, the effective interest rates derived from that index will also change over time and would therefore impact the present value of the subject security. Interest Income Recognition. Upon subsequent evaluation of a debt security when there is no additional other-than-temporary impairment, we adjust the accretable yield on a prospective basis if there is a significant increase in the security's expected future cash flows. This adjusted yield is used to calculate the amount to be recognized into income over the remaining life of the security so as to match the amount and timing of future cash flows expected to be collected. Subsequent changes in estimated cash flows that are deemed significant will change the accretable yield on a prospective basis. For debt securities classified as held-to-maturity, the other-than-temporary impairment recognized in other comprehensive income (loss) is accreted to the carrying value of each security on a prospective basis, based on the amount and timing of future estimated cash flows. The estimated cash flows and accretable yield are re-evaluated each quarter. We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter.
Federal Home Loan Bank Advances , Policy	We report advances at amortized cost. Advances carried at amortized cost are reported net of premiums/discounts and any hedging adjustments, as discussed in Note 9 — Advances . We generally record our advances at par. However, we may record premiums or discounts on advances in the following cases: • Advances may be acquired from another FHLBank when one of our members acquires a member of another FHLBank. In these cases, we may purchase the advances from the other FHLBank at a price that results in a fair market yield for the acquired advance. • When the prepayment of an advance is followed by disbursement of a new advance and the transactions effectively represent a modification of the previous advance, the prepayment fee received is deferred, recorded as a discount to the modified advance, and accreted over the life of the new advance. • When an advance is modified under our advance restructuring program and our analysis of the restructuring concludes that the transaction is an extinguishment of the prior advance rather than a modification, the deferred prepayment fee is recognized into income immediately, recorded as premium on the new advance, and amortized over the life of the new advance. • When we make an AHP advance, the present value of the variation in the cash flow caused by the difference in the interest rate between the AHP advance rate and our related cost of funds for comparable maturity funding is charged against the AHP liability and recorded as a discount on the AHP advance. • Advances issued under our Jobs for New England (JNE) and Helping to House New England (HHNE) programs have an interest rate at a significant discount to market rates. Due to the below market interest rate, we record a discount on the advance and an interest rate subsidy expense at the time that we transact the advance. The subsidy expense is recorded in other expense in the statement of operations. We amortize the premiums and accrete the discounts on advances to interest income using the level-yield method. We record interest on advances to interest income as earned. Prepayment Fees. We charge borrowers a prepayment fee when they prepay certain advances before the original maturity. We record prepayment fees net of hedging fair-value adjustments included in the carrying value of the advance as advances interest income on the statement of operations. Advance Modifications. In cases in which we fund a new advance concurrently with or within a short period of time of the prepayment of an existing advance by the same member, we evaluate whether the new advance meets the accounting criteria to qualify as a modification of the existing advance or whether it constitutes a new advance. We compare the present value of cash flows on the new advance with the present value of cash flows remaining on the existing advance. If there is at least a 10 percent difference in the present value of cash flows or if we conclude the difference between the advances is more than minor based on a qualitative assessment of the modifications made to the advance's original contractual terms, the advance is accounted for as a new advance. In all other instances, the new advance is accounted for as a modification. If a new advance qualifies as a modification of the existing advance, the net prepayment fee on the prepaid advance is deferred, recorded in the basis of the modified advance, and amortized to interest income over the life of the modified advance using the level-yield method. This amortization is recorded in advance-interest income. If the modified advance is hedged, changes in fair value are recorded after the amortization of the basis adjustment in advance interest income. Prior to January 1, 2019, this amortization resulted in offsetting amounts being recorded in net interest income and net gains (losses) on derivatives and hedging activities in other income. For prepaid advances that were hedged and meet the hedge-accounting requirements, we terminate the hedging relationship upon prepayment and record the prepayment fee net of the hedging fair-value adjustment in the basis of the advance as advance-interest income. If we fund a new advance to a member concurrent with or within a short period of time after the prepayment of a previous advance to that member, we evaluate whether the new advance qualifies as a modification of the original hedged advance. If the new advance qualifies as a modification of the original hedged advance, the hedging fair-value adjustment and the prepayment fee are included in the carrying amount of the modified advance and are amortized in interest income over the life of the modified advance using the level-yield method. If the modified advance is also hedged and the hedge meets the hedging criteria, the modified advance is marked to fair value after the modification, and subsequent fair-value changes are recorded in advance interest income. Prior to January 1, 2019, subsequent fair value changes were recorded in other income as net gains (losses) on derivatives and hedging activities. If a new advance does not qualify as a modification of an existing advance, prepayment of the existing advance is treated as an advance termination and any prepayment fee, net of hedging adjustments, is recorded to advance-interest income in the statement of operations.
Commitment Fees, Policy	We record commitment fees for standby letters of credit to members as deferred fee income when received, and amortize these fees on a straight-line basis to service-fees income in other income over the term of the standby letter of credit. Based upon past experience, we believe the likelihood of standby letters of credit being drawn upon is remote.
Loans and Leases Receivable, Held-for-investment, Policy	Accordingly, these investments are reported at their principal amount outstanding net of unamortized premiums, discounts, unrealized gains and losses from investments initially classified as mortgage loan commitments, direct write-downs, and the allowance for credit losses on mortgage loans.
Loans and Leases Receivable, Origination Fees, Discounts or Premiums, and Direct Costs to Acquire Loans, Policy	We record other nonorigination fees in connection with our MPF program activities in other income. Such fees include delivery-commitment-extension fees, pair-off fees, price-adjustment fees, and counterparty fees in connection with MPF products under which we facilitate third party investment in loans (non-investment MPF products) such as with the MPF Xtra ® We compute the amortization of mortgage-loan-origination fees (premiums and discounts) as interest income using the level-yield method over the contractual term to maturity of each individual loan, which results in income recognition in a manner that is effectively proportionate to the actual repayment behavior of the underlying assets and reflects the contractual terms of the assets without regard to changes in estimated prepayments based on assumptions about future borrower behavior.
Loans and Leases Receivable, Nonaccrual Loan and Lease Status, Policy	We place conventional mortgage loans on nonaccrual status when the collection of the contractual principal or interest is 90 days or more past due. When a conventional mortgage loan is placed on nonaccrual status, accrued but uncollected interest is reversed against interest income in the current period. We generally record cash payments received on nonaccrual loans first as interest income and then as a reduction of principal as specified in the contractual agreement, unless we consider the collection of the remaining principal amount due to be doubtful. If we consider the collection of the remaining principal amount to be doubtful, cash payments received are applied first solely to principal until the remaining principal amount due is expected to be collected and then as a recovery of any charge-off, if applicable, followed by recording interest income. A loan on nonaccrual status may be restored to accrual status when the collection of the contractual principal and interest is less than 90 days past due. We do not place government mortgage loans on nonaccrual status when the collection of the contractual principal or interest is 90 days or more past due because of the U.S. government guarantee of the loan and the contractual obligations of each related servicer,
Impaired Financing Receivable, Policy	A charge-off is recorded if it is estimated that the recorded investment in a loan will not be recovered. We evaluate whether to record a charge-off on a conventional mortgage loan upon the occurrence of a confirming event. Confirming events include, but are not limited to, the occurrence of foreclosure or notification of a claim against any of the credit-enhancements. We charge off the portion of outstanding conventional mortgage loan balances in excess of fair value of the underlying property, less cost to sell and adjusted for any available credit-enhancements for loans that are 180 or more days past due, when the borrower has filed for bankruptcy protection and the loan is at least 30 days past due, or when there is evidence of fraud.An impaired loan is considered collateral-dependent if repayment is expected to be provided solely by the sale of the underlying property; that is, there is no other available and reliable source of repayment. A loan that is considered collateral-dependent is measured for impairment based on the fair value of the underlying property less estimated selling costs, with any shortfall recognized as an allowance for loan loss or charged-off. Interest income on impaired loans is recognized in the same manner as non-accrual loans.
Loans and Leases Receivable, Troubled Debt Restructuring, Policy	We consider a troubled debt restructuring of a financing receivable to have occurred when we grant a concession to a borrower that we would not otherwise consider for economic or legal reasons related to the borrower's financial difficulties. We place conventional mortgage loans that are deemed to be troubled debt restructurings as a result of our modification program on nonaccrual when payments are 60 days or more past due. We consider a troubled debt restructuring of a financing receivable to have occurred when we grant a concession to a borrower that we would not otherwise consider for economic or legal reasons related to the borrower's financial difficulties. We have granted a concession when we do not expect to collect all amounts due to us under the original contract as a result of the restructuring.
Loans and Leases Receivable, Real Estate Acquired Through Foreclosure, Policy	REO is recorded as other assets in the statement of condition and is carried at the lower of cost or fair value less estimated selling costs. At December 31, 2019 and 2018 , we had $1.3 million and $818 thousand , respectively, in assets classified as REO. Fair value is derived from third-party valuations of the property. If the fair value of the REO less estimated selling costs is less than the recorded investment in the MPF loan at the date of transfer, we recognize a charge-off to the allowance for credit losses. Subsequent realized gains and realized or unrealized losses are included in other income (loss) in the statement of operations.
Derivatives, Policy	All derivatives are recognized on the statement of condition at fair value and are reported as either derivative assets or derivative liabilities, net of cash collateral and accrued interest received from or pledged to clearing members and/or counterparties. We offset fair-value amounts recognized for derivatives and fair-value amounts recognized for the right to reclaim cash collateral (a receivable) or the obligation to return cash collateral (a payable) arising from derivatives recognized at fair value executed with the same clearing member and/or counterparty when the netting requirements have been met. If these netted amounts are positive, they are classified as an asset and, if negative, they are classified as a liability. Derivative assets and derivative liabilities reported on the statement of condition also include net accrued interest. Cash flows associated with derivatives are reflected as cash flows from operating activities in the statement of cash flows unless the derivative meets the criteria to be a financing derivative. Each derivative is designated as one of the following: • a qualifying hedge of the change in fair value of a recognized asset or liability or an unrecognized firm commitment (a fair value hedge); • a qualifying hedge of a forecasted transaction (a cash-flow hedge); or • a nonqualifying hedge of an asset or liability (an economic hedge) for asset-liability-management purposes. We utilize two derivatives clearing organizations (DCOs), for all cleared derivative transactions, Chicago Mercantile Exchange, Inc. (CME Inc.) and LCH Limited (LCH Ltd.). At both DCOs, variation margin is characterized as daily settlement payments and initial margin is considered collateral. Accounting for Fair-Value and Cash-Flow Hedges. If hedging relationships meet certain criteria, including, but not limited to, formal documentation of the hedging relationship and an expectation to be highly effective, they qualify for fair-value or cash-flow hedge accounting. For cash-flow hedges, we measure effectiveness using the hypothetical derivative method, which compares the cumulative change in fair value of the actual derivative designated as the hedging instrument to the cumulative change in fair value of a hypothetical derivative having terms that identically match the critical terms of the hedged forecasted transaction. Derivatives that are used in fair-value hedges are typically executed at the same time as the hedged items, and we designate the hedged item in a qualifying hedge relationship as of the trade date. We then record the changes in fair value of the derivative and the hedged item beginning on the trade date. Beginning January 1, 2019, we adopted new hedge accounting guidance which, among other things, impacts the presentation of gains (losses) on derivatives and hedging activities for qualifying hedges as follows: • Changes in the fair value of a derivative that is designated and qualifies as a fair-value hedge, along with changes in the fair value of the hedged asset or liability that are attributable to the hedged risk, are recorded in net interest income in the same line as the earnings effect of the hedged item. • Changes in the fair value of a derivative that is designated and qualifies as a cash-flow hedge are recorded in other comprehensive income (loss), a component of capital, until the hedged transaction affects earnings. Prior to January 1, 2019, for both fair-value and cash-flow hedges, any hedge ineffectiveness (which represented the amount by which the change in the fair value of the derivative differed from the change in the fair value of the hedged item or the variability in the cash flows of the forecasted transaction attributable to the hedged risk) was recorded in non-interest income as net gains (losses) on derivatives and hedging activities. Accounting for Economic Hedges. An economic hedge is defined as a derivative hedging specific or nonspecific assets, liabilities, or firm commitments that does not qualify or was not designated for fair-value or cash-flow hedge accounting, but is an acceptable hedging strategy under our risk-management policy. These economic hedging strategies also comply with FHFA regulatory requirements prohibiting speculative derivative transactions. An economic hedge introduces the potential for earnings variability caused by the changes in fair value of the derivatives that are recorded in income but not offset by corresponding changes in the fair value of the economically hedged assets, liabilities, or firm commitments. As a result, we recognize only the net interest and the change in fair value of these derivatives in other income (loss) as net gains (losses) on derivatives and hedging activities with no offsetting fair-value adjustments for the economically hedged assets, liabilities, or firm commitments. Accrued Interest Receivable and Payable. The differential between accrual of interest receivable and payable on derivatives designated as a fair-value hedge or as a cash-flow hedge is recognized through adjustments to the interest income or interest expense of the designated hedged investment securities, advances, COs, or other financial instruments. The differential between accrual of interest receivable and payable on economic hedges is recognized in other income (loss), along with changes in fair value of these derivatives, as net gains (losses) on derivatives and hedging activities. Managing Credit Risk on Derivatives. We are subject to credit risk on our hedging activities due to the risk of nonperformance by nonmember counterparties (including DCOs and their clearing members acting as agent to the DCOs as well as uncleared counterparties) to the derivative agreements. We manage credit risk through credit analysis, collateral requirements and adherence to the requirements set forth in our policies, U.S. Commodity Futures Trading Commission (the CFTC) regulations, and FHFA regulations. Uncleared Derivatives. All counterparties must execute master-netting agreements prior to entering into any uncleared derivative with us. Our master-netting agreements for uncleared derivatives contain bilateral-collateral exchange agreements that require that credit exposure beyond a defined threshold amount (which may be zero) be secured by readily marketable, U.S. Treasury, U.S. Government-guaranteed, or GSE securities, or cash. The level of these collateral threshold amounts (when applicable) varies according to the counterparty's Standard & Poor's Rating Service (S&P) or Moody's Investors Services (Moody's) long-term credit ratings. Credit exposures are then measured daily and adjustments to collateral positions are made in accordance with the terms of the master-netting agreements. These master-netting agreements also contain bilateral ratings-tied termination events permitting us to terminate all outstanding derivatives transactions with a counterparty in the event of a specified rating downgrade by Moody's or S&P. Based on credit analyses and collateral requirements, we do not anticipate any credit losses on our derivative agreements.
Derivatives, Hedge Discontinuances, Policy	We may discontinue hedge accounting prospectively when: • we determine that the derivative is no longer effective in offsetting changes in the fair value or cash flows of a hedged item attributable to the hedged risk (including hedged items such as firm commitments or forecasted transactions); • the derivative and/or the hedged item expires or is sold, terminated, or exercised; • it is no longer probable that the forecasted transaction in a cash-flow hedge will occur in the originally expected period or within the following two months; • a hedged firm commitment in a fair-value hedge no longer meets the definition of a firm commitment; or • we determine that designating the derivative as a hedging instrument is no longer appropriate. If hedge accounting is discontinued because we determine that the derivative no longer qualifies as an effective fair-value hedge of an existing hedged item, we either terminate the derivative or continue to carry the derivative on the statement of condition at its fair value and cease to adjust the hedged asset or liability for changes in fair value. We will then begin to amortize the cumulative basis adjustment on the hedged item into earnings over the remaining life of the hedged item using the level-yield method. If hedge accounting is discontinued because we determine that the derivative no longer qualifies as an effective cash-flow hedge of an existing hedged item, we will continue to carry the derivative on the statement of condition at its fair value and amortize the cumulative other comprehensive loss adjustment to earnings when earnings are affected by the existing hedged item. If it is no longer probable that a forecasted transaction will occur by the end of the originally expected period or within two months thereafter, we immediately recognize in earnings the gain or loss that was in accumulated other comprehensive loss. If hedge accounting is discontinued because the hedged item no longer meets the definition of a firm commitment, we will continue to carry the derivative on the statement of condition at its fair value, removing from the statement of condition any asset or liability that was recorded to recognize the firm commitment and recording it as a gain or loss in current period earnings.
Derivatives, Embedded Derivatives, Policy	We may issue debt, make advances, or purchase financial instruments in which a derivative is embedded. Upon execution of these transactions, we assess whether the economic characteristics of the embedded derivative are clearly and closely related to the economic characteristics of the remaining component of the advance, debt, or other financial instrument (the host contract) and whether a separate, nonembedded instrument with the same terms as the embedded instrument would meet the definition of a derivative. When we determine that (1) the embedded derivative has economic characteristics that are not clearly and closely related to the economic characteristics of the host contract and (2) a separate, stand-alone instrument with the same terms would qualify as a derivative instrument, the embedded derivative is separated from the host contract, carried at fair value, and designated as a stand-alone derivative instrument. If the entire contract (the host contract and the embedded derivative) is to be measured at fair value, with changes in fair value reported in current earnings (for example, an investment security classified as trading, as well as hybrid financial instruments) or if we cannot reliably identify and measure the embedded derivative for purposes of separating that derivative from its host contract, the entire contract is carried on the statement of condition at fair value and no portion of the contract is designated as a hedging instrument.
Property, Plant and Equipment, Policy [Policy Text Block]	We record premises, software, and equipment at cost less accumulated depreciation and amortization and compute depreciation on a straight-line basis over estimated useful lives ranging from three years to 10 years
Internal Use Software, Policy [Policy Text Block]	The cost of purchased software and certain costs incurred in developing computer software for internal use are capitalized and amortized over future periods.
Lessee, Leases [Policy Text Block]	We lease office space and office equipment to run our business operations. For leases with a term of 12 months or less, we have made an accounting policy election to not recognize lease right-of-use assets and lease liabilities.
Debt, Policy	We record COs at amortized cost. Discounts and Premiums. We accrete discounts and amortize premiums on COs to interest expense using the level-yield method over the contractual term to maturity of the CO. Concessions on COs. We pay concessions to dealers in connection with the issuance of certain COs. The Office of Finance prorates the amounts paid to dealers based upon the percentage of debt issued that we assumed. We record concessions paid on COs as a direct reduction from their carrying amounts, consistent with the presentation of discounts on COs. These dealer concessions are amortized using the level-yield method over the contractual term to maturity of the COs. The amortization of those concessions is included in CO interest expense on the statement of operations.
Shares Subject to Mandatory Redemption, Changes in Redemption Value, Policy	We reclassify stock subject to redemption from equity to a liability after a member exercises a written redemption request, gives notice of intent to withdraw from membership, or attains nonmember status by merger or acquisition, charter termination, or other involuntary termination from membership, since the shares meet the definition of a mandatorily redeemable financial instrument upon such instances. Member shares meeting this definition are reclassified to a liability at fair value. Dividends declared on mandatorily redeemable capital stock are accrued at the expected dividend rate for Class B stock and reflected as interest expense on the statement of operations. The repayment of these mandatorily redeemable financial instruments is reflected as cash outflows in the financing activities section of the statement of cash flows once settled. We do not take into consideration our members' right to cancel a redemption request in determining when shares of capital stock should be classified as a liability because such cancellation would be subject to a cancellation fee equal to two percent of the par amount of the shares of Class B stock that is the subject of the redemption notice. If a member cancels its written notice of redemption or notice of withdrawal, we will reclassify mandatorily redeemable capital stock from a liability to equity. After the reclassification, dividends on the capital stock will no longer be classified as interest expense.
Restricted Retained Earnings [Policy Text Block]	The joint capital enhancement agreement, as amended (the Joint Capital Agreement) requires each FHLBank to contribute 20 percent of its quarterly net income to a separate restricted retained earnings account at that FHLBank until that account balance equals at least 1 percent of that FHLBank's average balance of outstanding COs (excluding fair-value adjustments) for the previous quarter. Restricted retained earnings are not available to pay dividends, and we present them separate from other retained earnings on the statement of condition.
Gains On Litigation Settlements, Policy	Litigation settlement gains, net of related legal expenses, are recorded in other income (loss). A litigation settlement gain is considered realized and recorded when we receive cash or assets that are readily convertible to known amounts of cash or claims to cash. In addition, a litigation settlement gain is considered realizable and recorded when we enter 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, we consider potential litigation settlement gains to be gain contingencies, and therefore they are not recorded in the statement of operations. The related legal expenses are contingent-based fees and are only incurred and recorded upon a litigation settlement gain.
Regulator Expenses Cost Assessed On Federal Home Loan Bank [Policy Text Block]	We fund a portion of the costs of operating the FHFA. The portion of the FHFA's expenses and working capital fund paid by the FHLBanks is allocated among the FHLBanks based on the ratio of each FHLBank's minimum required regulatory capital to the aggregate minimum required regulatory capital of every FHLBank. We must pay an amount equal to one-half of our annual assessment twice each year .
Office Of Finance Cost Assessed on Federal Home Loan Bank [Policy Text Block]	Each FHLBank's proportionate share of Office of Finance operating and capital expenditures has been calculated using a formula based upon the following components: (1) two-thirds based upon each FHLBank's share of total COs outstanding and (2) one-third
Federal Home Loan Bank Assessments, Policy	The FHLBank Act requires us to establish and fund an AHP based on positive annual net earnings, providing grants to members to assist in the purchase, construction, or rehabilitation of housing for very low- to moderate-income households. We charge the required funding for the AHP to earnings and establish a liability, except when annual net earnings are zero or negative, in which case there is no requirement to fund an AHP. We also issue AHP advances at interest rates below the customary interest rate for nonsubsidized advances. A discount on the AHP advance and charge against the AHP liability is recorded for the present value of the variation in the cash flow caused by the difference in the interest rate between the AHP advance rate and our related cost of funds for comparable maturity funding. The discount on AHP advances is accreted to interest income on advances using the level-yield method over the life of the advance.
Cash and Cash Equivalents, Policy	In the statement of cash flows, we consider noninterest bearing cash and due from banks as cash and cash equivalents. Federal funds sold and interest-bearing deposits are not treated as cash equivalents for purposes of the statement of cash flows, but are instead treated as short-term investments and are reflected in the investing activities section of the statement of cash flows.
Segment Reporting, Policy [Policy Text Block]	We report on an enterprise-wide basis. The enterprise-wide method of evaluating our financial information reflects the manner in which the chief operating decision-maker manages the business.
Reclassification, Policy	Certain amounts in the 2018 and 2017 financial statements have been reclassified to conform to the financial statement presentation for the year ended December 31, 2019 .
Federal Home Loan Bank Advances, Prepayment Fees, Policy [Policy Text Block]	We record prepayment fees received from borrowers on certain prepaid advances net of any associated basis adjustments related to hedging activities on those advances and net of deferred prepayment fees on advance prepayments considered to be loan modifications. Additionally, for certain advances products, the prepayment-fee provisions of the advance agreement could result in either a payment from the borrower or to the borrower when such an advance is prepaid, based upon market conditions at the time of prepayment (referred to as a symmetrical prepayment fee). Advances with a symmetrical prepayment fee provision are hedged with derivatives containing offsetting terms, so that we are financially indifferent to the borrower's decision to prepay such advances. The net amount of prepayment fees is reflected as interest income in the statement of operations.
Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]	Conventional Mortgage Loans Held for Portfolio Our methodology for determining our loan loss reserve consists of estimating loan loss severity using a third-party model incorporating delinquency to default transition performance of the loans, relevant market conditions affecting the performance of the loans, and portfolio level credit protection, particularly credit-enhancements, as discussed below under — Credit-Enhancements. Our inputs to the third-party model consist of loan-related characteristics, such as credit scores, occupancy statuses, loan-to-value ratios, property types, and locations. We update our view of the loan transition performance and market conditions quarterly and periodically adjust our methodology to reflect the changes in the loans’ performances and the market. • secured member credit products, such as our advances and letters of credit; • investments in government mortgage loans held for portfolio; • investments in conventional mortgage loans held for portfolio; • investments via term securities purchased under agreements to resell; and • investments via term federal funds sold.
Finance, Loan and Lease Receivables, Held-for-investment, Allowance and Nonperforming Loans, Nonperforming Loans Policy [Policy Text Block]	Individually Evaluated Mortgage Loans. Certain conventional mortgage loans, primarily impaired mortgage loans that are considered collateral-dependent, may be specifically identified for purposes of calculating the allowance for credit losses. A mortgage loan is considered collateral-dependent if repayment is expected to be provided by the sale of the underlying property, that is, if it is considered likely that the borrower will default. The estimated credit losses on impaired collateral-dependent loans may be separately determined because sufficient information exists to make a reasonable estimate of the inherent loss on these loans on an individual loan basis. Loans that are considered collateral-dependent are measured for impairment based on the fair value of the underlying property less estimated selling costs. The incurred loss of an individually evaluated mortgage loan is equal to the difference between the carrying value of the loan and the estimated fair value of the collateral, less estimated selling costs, and may include expected proceeds from primary mortgage insurance and other applicable credit-enhancements. Additionally, for our investments in loans modified under our temporary loan modification plan, on the effective date of a loan modification we measure the present value of expected future cash flows discounted at the loan's effective interest rate and reduce the carrying value of the loan accordingly. Collectively Evaluated Mortgage Loans. We evaluate the credit risk of our investments in conventional mortgage loans for impairment on a collective basis that considers loan-pool-specific attribute data at the master commitment pool level (including historical delinquency migration), applies estimated loss severities, and incorporates available credit-enhancements to establish our best estimate of probable incurred losses at the reporting date. Migration analysis is a methodology for estimating the rate of default experienced on pools of similar loans based on our historical experience. We apply migration analysis to conventional loans that are currently not past due, loans that are 30 to 59 days past due, 60 to 89 days past due, and 90 to 179 days past due. We then estimate the dollar amount of loans in these categories that we believe are likely to migrate to a realized loss position and apply a loss severity factor to estimate losses that would be incurred at the statement of condition date. The losses are then reduced by the probable cash flows resulting from available credit-enhancement. Credit-enhancement cash flows that are projected and assessed as not probable of receipt are not considered in reducing estimated losses.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Summary of Valuation Methodologies and Primary Inputs The valuation methodologies 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 nonrecurring basis in the Statement of Condition are listed below. The fair values and level within the fair value hierarchy of these assets and liabilities are reported in Table 19.2. Investment Securities. We determine the fair values of our investment securities, other than HFA floating-rate securities, based on prices obtained for each of these securities that we request from multiple designated third-party pricing vendors. The fair value of each such security is the average of such vendor prices that are within a cluster pricing tolerance range. A cluster is defined as a group of available vendor prices for a given security that is within a defined price tolerance range of the median vendor price depending on the security type. An outlier is any vendor price that is outside of the defined cluster and is evaluated for reasonableness. 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. Vendor prices that are outside of a defined cluster are identified as outliers and are subject to additional review including, but not limited to, comparison to prices provided by an additional third-party valuation vendor, prices for similar securities, and/or nonbinding dealer estimates, or the use of internal model prices, which we believe reflect the facts and circumstances that a market participant would consider. We also perform this analysis in those limited instances where no third-party vendor price or only one third-party vendor price is available to determine fair value. If the analysis indicates that an outlier is not representative of fair value and that the average of the vendor prices within the tolerance threshold of the median price is the best estimate, then we use the average of the vendor prices within the tolerance threshold of the median price as the final price. If, on the other hand, we determine that an outlier (or some other price identified in the analysis) is a better estimate of fair value, then the outlier (or the other price as appropriate) is used as the final price. In all cases, the final price is used to determine the fair value of the security. As of December 31, 2019 , multiple vendor prices were received for substantially all of our investment securities and the final prices for substantially all of those securities were computed by averaging the prices received. The relative proximity of the prices received supports our conclusion that the final computed prices are reasonable estimates of fair value. Based on the current low level of market activity for private-label residential MBS, the nonrecurring fair-value measurements for such securities as of December 31, 2019 and 2018 , fell within Level 3 of the fair-value hierarchy. Our fixed-rate HFA securities fall within Level 3 of the fair-value hierarchy due to the current lack of market activities for these bonds. Investment Securities – HFA Floating Rate Securities. The fair value is determined by calculating the present value of the expected future cash flows. The discount rates used in these calculations are the rates for securities with similar terms. Our floating rate HFA securities fall within Level 3 of the fair-value hierarchy due to the current lack of market activity for these bonds. Mortgage Loans. The fair value of impaired conventional mortgage loans is based on the lower of the carrying value of the loans or fair value of the collateral less estimated costs to sell. The fair value of impaired government mortgage loans is equal to the unpaid principal balance. REO. Fair value is derived from third-party valuations of the property, which fall within Level 3 of the fair-value hierarchy. Derivative Assets/Liabilities - Interest-Rate-Exchange Agreements . We base the fair values of interest-rate-exchange agreements on available market prices of derivatives having similar terms, including accrued interest receivable and payable. The fair-value methodology uses standard valuation techniques for derivatives such as discounted cash-flow analysis and comparisons with similar instruments. The fair values of all interest-rate-exchange agreements are netted by clearing member and/or by counterparty, including cash collateral received from or delivered to the counterparty. If these netted amounts are positive, they are classified as an asset, and if negative, they are classified as a liability. We generally use a midmarket pricing convention based on the bid-ask spread as a practical expedient for fair-value measurements. Because these estimates are made at a specific point in time, they are susceptible to material near-term changes. We have evaluated the potential for the fair value of the instruments to be affected by counterparty risk and our own credit risk and have determined that no adjustments were significant to the overall fair-value measurements. The discounted cash-flow model uses market-observable inputs (inputs that are actively quoted and can be validated to external sources), including the following: • Discount rate assumption . At December 31, 2019 and 2018 , we used either the OIS rate based on the federal funds effective rate curve or the LIBOR swap curve depending on the terms of the International Swaps and Derivatives Association (ISDA) agreement we have with each derivative counterparty. • Forward interest-rate assumption . LIBOR swap curve or OIS based on the federal funds effective rate. • Volatility assumption . Market-based expectations of future interest-rate volatility implied from current market prices for similar options. Derivative Assets/Liabilities – Commitments to Invest in Mortgage Loans . Commitments to invest in mortgage loans are recorded as derivatives in the statement of condition. The fair values of such commitments are based on the end-of-day delivery commitment prices provided by the FHLBank of Chicago and a spread, derived from MBS TBA delivery commitment prices with adjustment for the contractual features of the MPF program, such as servicing and credit-enhancement features.
Joint and Several Liability Policy [Policy Text Block]	We evaluate the financial condition of the other FHLBanks primarily based on known regulatory actions, publicly available financial information, and individual long-term credit-rating action as of each period-end presented.

Trading Securities (Tables)

Trading Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Trading Securities by Major Security Type [Table Text Block]	Table 5.1 - Trading Securities by Major Security Type (dollars in thousands) December 31, 2019 December 31, 2018 Corporate bonds $ 5,896 $ 6,102 U.S. Treasury obligations 2,240,236 — 2,246,132 6,102 MBS U.S. government-guaranteed – single-family 4,047 5,344 GSE – single-family 85 148 GSE – multifamily — 151,444 4,132 156,936 Total $ 2,250,264 $ 163,038
Gain (Loss) on Securities [Table Text Block]	Table 5.2 - Unrealized and Realized Gains (Losses) on Trading Securities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Net unrealized gains (losses) on trading securities held at year end $ 1,379 $ (4,515 ) $ (6,145 ) Net unrealized and realized gains on trading securities sold or matured during the year (92 ) — 67 Net unrealized gains (losses) on trading securities $ 1,287 $ (4,515 ) $ (6,078 )

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Available-for-Sale (AFS) Securities by Major Security Type [Table Text Block]	Table 6.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) December 31, 2019 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value State housing-finance-agency obligations (HFA securities) $ 69,320 $ — $ (4,668 ) $ 64,652 Supranational institutions 429,354 — (12,925 ) 416,429 U.S. government-owned corporations 323,192 — (26,431 ) 296,761 GSE 130,935 — (7,149 ) 123,786 952,801 — (51,173 ) 901,628 MBS U.S. government guaranteed – single-family 60,003 — (2,289 ) 57,714 U.S. government guaranteed – multifamily 283,674 — (1,057 ) 282,617 GSE – single-family 2,598,325 5,323 (13,377 ) 2,590,271 GSE – multifamily 3,588,119 3,109 (14,458 ) 3,576,770 6,530,121 8,432 (31,181 ) 6,507,372 Total $ 7,482,922 $ 8,432 $ (82,354 ) $ 7,409,000 December 31, 2018 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 55,500 $ — $ (5,899 ) $ 49,601 Supranational institutions 419,222 — (14,067 ) 405,155 U.S. government-owned corporations 297,729 — (24,560 ) 273,169 GSE 122,423 — (6,796 ) 115,627 894,874 — (51,322 ) 843,552 MBS U.S. government guaranteed – single-family 79,075 20 (3,437 ) 75,658 U.S. government guaranteed – multifamily 368,103 — (6,969 ) 361,134 GSE – single-family 3,649,964 681 (88,486 ) 3,562,159 GSE – multifamily 1,010,886 168 (3,613 ) 1,007,441 5,108,028 869 (102,505 ) 5,006,392 Total $ 6,002,902 $ 869 $ (153,827 ) $ 5,849,944 _______________________ (1) Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
AFS Securities in a Continuous Unrealized Loss Position [Table Text Block]	Table 6.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position (dollars in thousands) December 31, 2019 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 12,229 $ (1,591 ) $ 52,423 $ (3,077 ) $ 64,652 $ (4,668 ) Supranational institutions — — 416,429 (12,925 ) 416,429 (12,925 ) U.S. government-owned corporations — — 296,761 (26,431 ) 296,761 (26,431 ) GSE — — 123,786 (7,149 ) 123,786 (7,149 ) 12,229 (1,591 ) 889,399 (49,582 ) 901,628 (51,173 ) MBS U.S. government guaranteed – single-family 10,885 (1 ) 45,490 (2,288 ) 56,375 (2,289 ) U.S. government guaranteed – multifamily — — 282,617 (1,057 ) 282,617 (1,057 ) GSE – single-family 189,402 (968 ) 1,423,927 (12,409 ) 1,613,329 (13,377 ) GSE – multifamily 1,800,586 (13,242 ) 405,778 (1,216 ) 2,206,364 (14,458 ) 2,000,873 (14,211 ) 2,157,812 (16,970 ) 4,158,685 (31,181 ) Total temporarily impaired $ 2,013,102 $ (15,802 ) $ 3,047,211 $ (66,552 ) $ 5,060,313 $ (82,354 ) December 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 11,118 $ (1,682 ) $ 38,483 $ (4,217 ) $ 49,601 $ (5,899 ) Supranational institutions — — 405,155 (14,067 ) 405,155 (14,067 ) U.S. government-owned corporations — — 273,169 (24,560 ) 273,169 (24,560 ) GSE — — 115,627 (6,796 ) 115,627 (6,796 ) 11,118 (1,682 ) 832,434 (49,640 ) 843,552 (51,322 ) MBS U.S. government guaranteed – single-family — — 57,679 (3,437 ) 57,679 (3,437 ) U.S. government guaranteed – multifamily — — 361,134 (6,969 ) 361,134 (6,969 ) GSE – single-family 53,122 (388 ) 3,417,076 (88,098 ) 3,470,198 (88,486 ) GSE – multifamily 902,850 (3,613 ) — — 902,850 (3,613 ) 955,972 (4,001 ) 3,835,889 (98,504 ) 4,791,861 (102,505 ) Total temporarily impaired $ 967,090 $ (5,683 ) $ 4,668,323 $ (148,144 ) $ 5,635,413 $ (153,827 )
Investments Classified by Contractual Maturity Date [Table Text Block]	Table 6.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 7,600 $ 7,563 $ — $ — Due after one year through five years 61,720 57,089 55,500 49,601 Due after five years through 10 years 477,232 463,465 465,248 450,102 Due after 10 years 406,249 373,511 374,126 343,849 952,801 901,628 894,874 843,552 MBS (1) 6,530,121 6,507,372 5,108,028 5,006,392 Total $ 7,482,922 $ 7,409,000 $ 6,002,902 $ 5,849,944 _______________________ (1) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities by Major Security Type [Table Text Block]	Table 7.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) December 31, 2019 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value HFA securities $ 87,250 $ — $ 87,250 $ — $ (3,845 ) $ 83,405 MBS U.S. government guaranteed – single-family 6,987 — 6,987 129 — 7,116 GSE – single-family 303,604 — 303,604 5,197 (246 ) 308,555 GSE – multifamily 140,661 — 140,661 612 (2 ) 141,271 Private-label 408,640 (76,035 ) 332,605 162,904 (446 ) 495,063 859,892 (76,035 ) 783,857 168,842 (694 ) 952,005 Total $ 947,142 $ (76,035 ) $ 871,107 $ 168,842 $ (4,539 ) $ 1,035,410 December 31, 2018 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value U.S. agency obligations $ 208 $ — $ 208 $ — $ — $ 208 HFA securities 104,465 — 104,465 4 (4,612 ) 99,857 104,673 — 104,673 4 (4,612 ) 100,065 MBS U.S. government guaranteed – single-family 8,173 — 8,173 158 — 8,331 GSE – single-family 412,639 — 412,639 6,861 (1,389 ) 418,111 GSE – multifamily 209,786 — 209,786 1,728 — 211,514 Private-label 688,905 (129,153 ) 559,752 234,083 (2,927 ) 790,908 1,319,503 (129,153 ) 1,190,350 242,830 (4,316 ) 1,428,864 Total $ 1,424,176 $ (129,153 ) $ 1,295,023 $ 242,834 $ (8,928 ) $ 1,528,929
Held-to-maturity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities in a Continuous Unrealized Loss Position [Table Text Block]	Table 7.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position (dollars in thousands) December 31, 2019 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 3,089 $ (1 ) $ 80,316 $ (3,844 ) $ 83,405 $ (3,845 ) MBS GSE – single-family 32,335 (101 ) 16,465 (145 ) 48,800 (246 ) GSEs – multifamily 949 (2 ) — — 949 (2 ) Private-label 913 (9 ) 23,999 (574 ) 24,912 (583 ) 34,197 (112 ) 40,464 (719 ) 74,661 (831 ) Total $ 37,286 $ (113 ) $ 120,780 $ (4,563 ) $ 158,066 $ (4,676 ) December 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 6,196 $ (9 ) $ 92,822 $ (4,603 ) $ 99,018 $ (4,612 ) MBS GSE – single-family 69,377 (580 ) 52,237 (809 ) 121,614 (1,389 ) Private-label 25,680 (331 ) 114,937 (4,587 ) 140,617 (4,918 ) 95,057 (911 ) 167,174 (5,396 ) 262,231 (6,307 ) Total $ 101,253 $ (920 ) $ 259,996 $ (9,999 ) $ 361,249 $ (10,919 )
HTM Securities by Contractual Maturity [Table Text Block]	Table 7.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 3,090 $ 3,090 $ 3,089 $ 1,043 $ 1,043 $ 1,047 Due after one year through five years — — — 6,205 6,205 6,196 Due after five years through 10 years 15,405 15,405 15,270 16,865 16,865 16,639 Due after 10 years 68,755 68,755 65,046 80,560 80,560 76,183 87,250 87,250 83,405 104,673 104,673 100,065 MBS (2) 859,892 783,857 952,005 1,319,503 1,190,350 1,428,864 Total $ 947,142 $ 871,107 $ 1,035,410 $ 1,424,176 $ 1,295,023 $ 1,528,929 _______________________ (1) Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss. (2) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.
HTM Securities proceeds from sale and gains and losses [Table Text Block]	Table 7.4 - Proceeds from Sale and Gains and Losses on Held-to-Maturity Securities (1) (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Proceeds from sale of held-to-maturity securities $ 185,177 $ — $ — Amortized cost of held-to-maturity securities 173,146 — — Realized net gain from sale of held-to-maturity securities $ 12,031 $ — $ — _______________________ (1) The securities sold had less than 15 percent of the acquired principal outstanding at the time of the sale. Such sales are treated as maturities for the purposes of security classification. The sale does not impact our ability and intent to hold the remaining investments classified as held-to-maturity through their stated maturity dates.

Other-Than-Temporary Impairme_2

Other-Than-Temporary Impairment (Tables)	12 Months Ended
	Dec. 31, 2019
Other than Temporary Impairment Losses, Investments [Abstract]
Significant Inputs for OTTI [Table Text Block]	For those securities for which a credit loss was recognized during the year ended December 31, 2019 , Table 8.1 presents a summary of the average projected values over the remaining lives of the securities for the significant inputs used to measure the amount of the credit loss recognized in earnings, as well as related current credit-enhancement. Credit-enhancement is defined as the percentage of subordinated tranches, over-collateralization, and other credit-enhancement, if any, in a security structure that will generally absorb losses before we will experience a credit loss on the security. The calculated averages represent the dollar-weighted average of Alt-A other-than-temporarily impaired private-label residential MBS. Table 8.1 - Significant Inputs and Current Credit Enhancement for Securities with a Credit Loss in 2019 (dollars in thousands) Weighted Average of Significant Inputs Weighted Average Current Credit Enhancement Private-label MBS by Classification Par Value Projected Prepayment Rates Projected Default Rates Projected Loss Severities Private-label residential MBS - Alt-A (1) $ 39,989 12.3 % 22.9 % 55.1 % 5.7 % _______________________ (1) Securities are classified based upon the current performance characteristics of the underlying loan pool and therefore the manner in which the loan pool backing the security has been modeled (as prime, Alt-A, or subprime), rather than their classification of the security at the time of issuance.
Total Securities Other-than-Temporarily Impaired during the Life of the Security [Table Text Block]	Table 8.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) December 31, 2019 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 3,796 $ 3,474 $ 2,510 $ 3,590 Private-label residential MBS – Alt-A 561,825 383,439 308,368 470,192 Total other-than-temporarily impaired securities $ 565,621 $ 386,913 $ 310,878 $ 473,782 _______________________ (1) Securities are classified based on the classifications of their underlying loan composition at the time of issuance. We instituted and are continuing litigation related to certain of the private-label MBS in which we invested. Our complaint asserts, among others, claims for untrue or misleading statements in the sale of securities. It is possible that classifications of private-label MBS as provided herein when based on classification at the time of issuance as disclosed by those securities' issuance documents, as well as other statements about the securities, are inaccurate.
Rollforward of the Amounts Related to Credit Losses Recognized into Earnings [Table Text Block]	Table 8.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Balance at beginning of year $ 422,035 $ 452,523 $ 490,404 Additions: Credit losses for which other-than-temporary impairment was not previously recognized 128 — — Additional credit losses for which an other-than-temporary impairment charge was previously recognized 1,084 532 1,454 Reductions: Securities sold or matured during the year (56,710 ) — (5,600 ) Portion of increase in cash flows expected to be collected over the remaining life of the security that are recognized in the current period as interest income (26,907 ) (31,020 ) (33,735 ) Balance at end of year $ 339,630 $ 422,035 $ 452,523

Advances (Tables)

Advances (Tables)	12 Months Ended
	Dec. 31, 2019
Advances [Abstract]
Advances [Table Text Block]	Table 9.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 5,101 2.05 % $ 12,332 2.88 % Due in one year or less 18,972,466 1.96 24,029,592 2.48 Due after one year through two years 8,600,922 2.16 11,413,640 2.55 Due after two years through three years 2,200,019 2.16 2,832,290 2.47 Due after three years through four years 1,766,314 2.71 1,648,076 2.37 Due after four years through five years 1,726,754 2.15 1,980,468 2.24 Thereafter 1,312,311 2.68 1,351,987 2.99 Total par value 34,583,887 2.10 % 43,268,385 2.50 % Premiums 3,397 3,935 Discounts (41,744 ) (36,528 ) Fair value of bifurcated derivatives (1) 29,983 13,051 Hedging adjustments 19,840 (56,621 ) Total $ 34,595,363 $ 43,192,222 _________________________ (1) At December 31, 2019 and 2018 , we had certain advances with embedded features that met the requirements to be separated from the host contract and designated as stand-alone derivatives. Table 9.5 - Advances Prepayment Fees (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Prepayment fees received from borrowers $ 33,809 $ 409 $ 1,568 Hedging fair-value adjustments on prepaid advances 1,923 264 (218 ) Net discounts (premiums) associated with prepaid advances 157 (159 ) (137 ) Deferred recognition of prepayment fees received from borrowers on advance prepayments deemed to be loan modifications (1,793 ) (298 ) (315 ) Prepayment fees recognized in income on advance restructurings deemed to be extinguishments 915 — — Advance prepayment fees recognized in income, net $ 35,011 $ 216 $ 898 Table 9.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (dollars in thousands) December 31, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 5,101 $ 12,332 Due in one year or less 25,116,961 32,748,467 Due after one year through two years 3,450,922 3,913,640 Due after two years through three years 1,949,499 2,672,290 Due after three years through four years 1,461,314 1,261,176 Due after four years through five years 1,309,679 1,362,468 Thereafter 1,290,411 1,298,012 Total par value $ 34,583,887 $ 43,268,385 Table 9.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances December 31, 2019 December 31, 2018 Fixed-rate Due in one year or less $ 18,733,966 $ 23,822,091 Due after one year 9,372,625 9,748,187 Total fixed-rate 28,106,591 33,570,278 Variable-rate Due in one year or less 243,601 219,832 Due after one year 6,233,695 9,478,275 Total variable-rate 6,477,296 9,698,107 Total par value $ 34,583,887 $ 43,268,385 Table 9.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value December 31, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 5,101 $ 12,332 Due in one year or less 20,240,466 25,199,892 Due after one year through two years 8,603,422 11,652,840 Due after two years through three years 2,001,019 2,834,790 Due after three years through four years 965,814 1,367,576 Due after four years through five years 1,598,254 1,152,468 Thereafter 1,169,811 1,048,487 Total par value $ 34,583,887 $ 43,268,385

Mortgage Loans Held for Portf_2

Mortgage Loans Held for Portfolio (Tables)	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	Table 10.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) December 31, 2019 December 31, 2018 Conventional mortgage loans $ 4,140,255 $ 3,902,555 Government mortgage loans 292,203 328,651 Total par value $ 4,432,458 $ 4,231,206 Table 10.1 - Mortgage Loans Held for Portfolio (dollars in thousands) December 31, 2019 December 31, 2018 Real estate Fixed-rate 15-year single-family mortgages $ 339,042 $ 392,128 Fixed-rate 20- and 30-year single-family mortgages 4,093,416 3,839,078 Premiums 66,776 67,671 Discounts (1,607 ) (1,800 ) Deferred derivative gains, net 4,124 2,825 Total mortgage loans held for portfolio 4,501,751 4,299,902 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,501,251 $ 4,299,402

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Recorded Investment in Delinquent Mortgage Loans [Table Text Block]	Table 11.1 sets forth the payment status for our investments in mortgage loans based on recorded investment as well as other delinquency statistics at December 31, 2019 and 2018 : Table 11.1 - Credit Quality Indicator and Other Delinquency Statistics (dollars in thousands) December 31, 2019 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 36,336 $ 11,630 $ 47,966 Past due 60-89 days delinquent 6,911 3,471 10,382 Past due 90 days or more delinquent 10,696 5,570 16,266 Total past due 53,943 20,671 74,614 Total current loans 4,171,676 278,924 4,450,600 Total mortgage loans $ 4,225,619 $ 299,595 $ 4,525,214 Other delinquency statistics In process of foreclosure, included above (1) $ 2,813 $ 2,222 $ 5,035 Serious delinquency rate (2) 0.26 % 1.86 % 0.36 % Past due 90 days or more still accruing interest $ — $ 5,570 $ 5,570 Loans on nonaccrual status (3) $ 11,510 $ — $ 11,510 December 31, 2018 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 23,045 $ 10,884 $ 33,929 Past due 60-89 days delinquent 7,019 3,344 10,363 Past due 90 days or more delinquent 7,384 6,670 14,054 Total past due 37,448 20,898 58,346 Total current loans 3,947,096 316,285 4,263,381 Total mortgage loans $ 3,984,544 $ 337,183 $ 4,321,727 Other delinquency statistics In process of foreclosure, included above (1) $ 3,467 $ 2,086 $ 5,553 Serious delinquency rate (2) 0.20 % 1.98 % 0.34 % Past due 90 days or more still accruing interest $ — $ 6,670 $ 6,670 Loans on nonaccrual status (3) $ 7,975 $ — $ 7,975 _______________________ (1) Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported. (2) Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class. (3) Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan.
Rollforward of Allowance for Credit Losses on Mortgage Loans [Table Text Block]	Table 11.2 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the years ended December 31, 2019 , 2018 , and 2017 , as well as the recorded investment in mortgage loans by impairment methodology at December 31, 2019 , 2018 , and 2017 . The recorded investment in a loan is the par amount of the loan, adjusted for accrued interest, unamortized premiums or discounts, deferred derivative gains and losses, and direct write-downs. The recorded investment is net of any valuation allowance. Table 11.2 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) 2019 2018 2017 Allowance for credit losses Balance, beginning of year $ 500 $ 500 $ 650 (Charge-offs) recoveries (85 ) 34 (54 ) Provision for (reduction of) credit losses 85 (34 ) (96 ) Balance, end of year $ 500 $ 500 $ 500 Ending balance, individually evaluated for impairment $ — $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 500 $ 500 Recorded investment, end of year (1) Individually evaluated for impairment $ 13,395 $ 15,402 $ 17,668 Collectively evaluated for impairment $ 4,212,224 $ 3,969,142 $ 3,632,833 _________________________ (1) These amounts exclude government mortgage loans because we make no allowance for credit losses based on our investments in government mortgage loans, as discussed above under — Government Mortgage Loans Held for Portfolio.

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments [Table Text Block]	Table 12.1 - Fair Value of Derivative Instruments (dollars in thousands) December 31, 2019 December 31, 2018 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 12,128,105 $ 14,734 $ (12,805 ) $ 11,980,699 $ 12,811 $ (296,324 ) Forward-start interest-rate swaps 17,000 19 — 282,000 — (753 ) Total derivatives designated as hedging instruments 12,145,105 14,753 (12,805 ) 12,262,699 12,811 (297,077 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 2,902,300 349 (31,000 ) 927,800 682 (12,475 ) Mortgage-delivery commitments (1) 49,911 227 — 50,773 339 — Total derivatives not designated as hedging instruments 2,952,211 576 (31,000 ) 978,573 1,021 (12,475 ) Total notional amount of derivatives $ 15,097,316 $ 13,241,272 Total derivatives before netting and collateral adjustments 15,329 (43,805 ) 13,832 (309,552 ) Netting adjustments and cash collateral, including related accrued interest (2) 144,402 33,534 8,571 53,752 Derivative assets and derivative liabilities $ 159,731 $ (10,271 ) $ 22,403 $ (255,800 ) _______________________ (1) Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income. (2) Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $178.5 million and $62.8 million at December 31, 2019 , and 2018 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $561 thousand and $471 thousand at December 31, 2019 and 2018 .
Net Gains (Losses) on Derivatives and Hedging Activities [Table Text Block]	Table 12.5 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Derivatives designated as hedging instruments: Total net gains (losses) related to fair-value hedges (1) $ 2,027 $ (2,308 ) Total net gains related to cash-flow hedges (2) 227 280 Total net gains (losses) related to derivatives designated as hedging instruments 2,254 (2,028 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps $ (614 ) 682 434 Mortgage-delivery commitments 1,945 421 1,768 Total net gains related to derivatives not designated as hedging instruments 1,331 1,103 2,202 Other (3) 88 (1,021 ) 377 Net gains on derivatives and hedging activities $ 1,419 $ 2,336 $ 551 ______________________ (1) Consists of interest-rate swaps. (2) Consists of forward-start interest-rate swaps. (3) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount. Tables 12.2 and 12.3 presents the net gains (losses) on qualifying fair-value and cash flow hedging relationships. Beginning on January 1, 2019, gains (losses) on derivatives include unrealized changes in fair value as well as net interest settlements. Table 12.2 - Net Gains (Losses) on Fair Value Hedging Relationships (dollars in thousands) For the Year Ended December 31, 2019 Advances Available-for-sale Securities CO Bonds Total interest income (expense) in the statements of operations $ 854,599 $ 115,942 $ (598,585 ) Gains (losses) on fair value hedging relationships Changes in fair value: Derivatives $ (72,488 ) $ (24,274 ) $ 55,777 Hedged items 73,530 21,329 (56,091 ) Net changes in fair value before price alignment interest 1,042 (2,945 ) (314 ) Price alignment interest (1) 1,316 3,769 (786 ) Net interest settlements on derivatives (2)(3) 39,085 (22,249 ) (17,482 ) Net gains (losses) on qualifying fair-value hedging relationships 41,443 (21,425 ) (18,582 ) Amortization/accretion of discontinued fair-value hedging relationships (1,934 ) — (2,567 ) Net gains (losses) on derivatives and hedging activities recorded in net interest income $ 39,509 $ (21,425 ) $ (21,149 ) For the Year Ended December 31, 2018 Advances Available-for-sale Securities CO Bonds Total income (expense) in the statements of operations $ 867,215 $ 143,952 $ (545,228 ) Gains (losses) on fair value hedging relationships Changes in fair value: Derivatives $ 447 $ 43,771 $ (5,680 ) Hedged items 257 (42,022 ) 5,254 Net changes in fair value 704 1,749 (426 ) Net interest settlements on derivatives (2)(3) 51,522 (26,040 ) (27,895 ) Net gains (losses) on qualifying fair-value hedging relationships 52,226 (24,291 ) (28,321 ) Amortization/accretion of discontinued fair-value hedging relationships (1,475 ) — 945 Less: net changes in fair value (4) (704 ) (1,749 ) 426 Net gains (losses) on derivatives and hedging activities recorded in net interest income $ 50,047 $ (26,040 ) $ (26,950 ) For the Year Ended December 31, 2017 Advances Available-for-sale Securities CO Bonds Total income (expense) in the statements of operations $ 514,176 $ 118,270 $ (421,622 ) Gains (losses) on fair value hedging relationships Changes in fair value: Derivatives $ 52,055 $ 20,747 $ 4,611 Hedged items (52,633 ) (19,011 ) (8,077 ) Net changes in fair value (578 ) 1,736 (3,466 ) Net interest settlements on derivatives (2)(3) (24,663 ) (32,053 ) 6,694 Net (losses) gains on qualifying fair-value hedging relationships (25,241 ) (30,317 ) 3,228 Amortization/accretion of discontinued fair-value hedging relationships (2,176 ) — 1,903 Less: net changes in fair value (4) 578 (1,736 ) 3,466 Net (losses) gains on derivatives and hedging activities recorded in net interest income $ (26,839 ) $ (32,053 ) $ 8,597 _______________________ (1) Relates to derivatives for which variation margin payments are characterized as daily settled contracts. (2) Represents interest income/expense on derivatives in qualifying fair-value hedging relationships. Net interest settlements on derivatives that are not in qualifying fair-value hedging relationships are reported in other income. (3) Excludes the interest income/expense of the respective hedged items recorded in net interest income. (4) In 2018 and 2017, net changes in fair value were recorded in net gains on derivatives and hedging activities in other income. Table 12.3 - Net Gains (Losses) on Cash Flow Hedging Relationships (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Forward-start interest rate swaps - CO Bonds Losses reclassified from accumulated other comprehensive loss into interest expense $ (5,218 ) $ (3,171 ) $ (10,575 ) (Losses) gains recognized in other comprehensive income (6,131 ) 7,907 (2,838 ) Gains recognized in net gains on derivatives and hedging activities 227 280
Gains (Losses) By Type of Hedged Item [Table Text Block]	Table 12.4 - Cumulative Basis Adjustments for Fair-Value Hedges (dollars in thousands) December 31, 2019 Line Item in Statement of Condition of Hedged Item Amortized Cost of Hedged Asset/ Liability (1) Basis Adjustments for Active Hedging Relationships Included in Amortized Cost Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost Cumulative Amount of Fair Value Hedging Basis Adjustments Advances $ 5,115,016 $ 38,988 $ 10,835 $ 49,823 Available-for-sale securities 4,053,138 226,346 — 226,346 Consolidated bonds 3,359,616 (4,840 ) 36,906 32,066 _______________________ (1) Includes only the portion of amortized cost representing the hedged items in fair-value hedging relationships.
Derivatives Not Designated as Hedging Instruments [Table Text Block]	Table 12.5 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Derivatives designated as hedging instruments: Total net gains (losses) related to fair-value hedges (1) $ 2,027 $ (2,308 ) Total net gains related to cash-flow hedges (2) 227 280 Total net gains (losses) related to derivatives designated as hedging instruments 2,254 (2,028 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps $ (614 ) 682 434 Mortgage-delivery commitments 1,945 421 1,768 Total net gains related to derivatives not designated as hedging instruments 1,331 1,103 2,202 Other (3) 88 (1,021 ) 377 Net gains on derivatives and hedging activities $ 1,419 $ 2,336 $ 551 ______________________ (1) Consists of interest-rate swaps. (2) Consists of forward-start interest-rate swaps. (3) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount.
Post-haircut Value of Incremental Collateral Based on Incremental Credit Rating Downgrades [Table Text Block]	Table 12.6 sets forth the post-haircut value of incremental collateral that certain uncleared derivatives counterparties could have required us to deliver based on incremental credit rating downgrades at December 31, 2019 . Table 12.6 - Post Haircut Value of Incremental Collateral to be Delivered as of December 31, 2019 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 302 AA- A+, A or A- — A- below A- 5,801 _______________________ (1) Ratings are expressed in this table according to S&P's conventions but include the equivalent of such rating by Moody's. If there is a split rating, the lower rating is used.
Offsetting Assets [Table Text Block]	Table 12.7 presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of December 31, 2019 and 2018 , and the fair value of derivatives that are not subject to such netting. Derivatives subject to netting include any related cash collateral received from or pledged to counterparties. Table 12.7 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) December 31, 2019 Derivative Instruments Meeting Netting Requirements Non-cash Collateral (Received) or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 4,950 $ (3,519 ) $ 227 $ 1,658 $ (995 ) $ — $ 663 Cleared 10,152 147,921 158,073 — — 158,073 Total $ 159,731 $ 158,736 Derivative Liabilities Uncleared $ (42,199 ) $ 31,928 $ — $ (10,271 ) $ 82 $ 9,333 $ (856 ) Cleared (1,606 ) 1,606 — — — — Total $ (10,271 ) $ (856 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2019 , we had additional net credit exposure of $300 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2018 Derivative Instruments Meeting Netting Requirements Non-cash Collateral (Received) or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 12,862 $ (11,886 ) $ 339 $ 1,315 $ (396 ) $ — $ 919 Cleared 631 20,457 21,088 — — 21,088 Total $ 22,403 $ 22,007 Derivative Liabilities Uncleared $ (306,848 ) $ 51,048 $ — $ (255,800 ) $ 6,104 $ 237,054 $ (12,642 ) Cleared (2,704 ) 2,704 — — — — Total $ (255,800 ) $ (12,642 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2018 , we had additional net credit exposure of $639 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.
Offsetting Liabilities [Table Text Block]	Table 12.7 presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of December 31, 2019 and 2018 , and the fair value of derivatives that are not subject to such netting. Derivatives subject to netting include any related cash collateral received from or pledged to counterparties. Table 12.7 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) December 31, 2019 Derivative Instruments Meeting Netting Requirements Non-cash Collateral (Received) or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 4,950 $ (3,519 ) $ 227 $ 1,658 $ (995 ) $ — $ 663 Cleared 10,152 147,921 158,073 — — 158,073 Total $ 159,731 $ 158,736 Derivative Liabilities Uncleared $ (42,199 ) $ 31,928 $ — $ (10,271 ) $ 82 $ 9,333 $ (856 ) Cleared (1,606 ) 1,606 — — — — Total $ (10,271 ) $ (856 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2019 , we had additional net credit exposure of $300 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2018 Derivative Instruments Meeting Netting Requirements Non-cash Collateral (Received) or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 12,862 $ (11,886 ) $ 339 $ 1,315 $ (396 ) $ — $ 919 Cleared 631 20,457 21,088 — — 21,088 Total $ 22,403 $ 22,007 Derivative Liabilities Uncleared $ (306,848 ) $ 51,048 $ — $ (255,800 ) $ 6,104 $ 237,054 $ (12,642 ) Cleared (2,704 ) 2,704 — — — — Total $ (255,800 ) $ (12,642 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2018 , we had additional net credit exposure of $639 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2019
Deposits [Abstract]
Interest-bearing and Non-interest-bearing Deposits [Table Text Block]	Table 13.1 - Deposits (dollars in thousands) December 31, 2019 December 31, 2018 Interest-bearing Demand and overnight $ 613,143 $ 444,486 Term 800 800 Other 2,589 2,961 Noninterest-bearing Other 57,777 26,631 Total deposits $ 674,309 $ 474,878

Consolidated Obligations (Table

Consolidated Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
CO Bonds by Year of Contractual Maturity [Table Text Block]	Table 14.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) December 31, 2019 December 31, 2018 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 9,455,725 2.03 % $ 9,638,270 2.01 % Due after one year through two years 6,442,960 2.02 5,375,845 2.24 Due after two years through three years 2,154,920 2.18 3,864,560 2.17 Due after three years through four years 1,319,915 2.45 1,891,975 2.20 Due after four years through five years 1,211,080 2.48 1,338,515 2.39 Thereafter 3,220,205 3.33 3,792,150 3.25 Total par value 23,804,805 2.26 % 25,901,315 2.30 % Premiums 63,056 49,118 Discounts (11,434 ) (15,222 ) Hedging adjustments 32,066 (22,527 ) Total $ 23,888,493 $ 25,912,684 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Table 14.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date December 31, 2019 December 31, 2018 Due in one year or less $ 11,297,725 $ 13,435,270 Due after one year through two years 6,432,960 5,602,845 Due after two years through three years 2,019,920 2,802,560 Due after three years through four years 1,332,915 1,366,975 Due after four years through five years 926,080 1,156,515 Thereafter 1,795,205 1,537,150 Total par value $ 23,804,805 $ 25,901,315
CO Bonds Long-term Debt Instruments [Table Text Block]	Table 14.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds December 31, 2019 December 31, 2018 Fixed-rate $ 17,681,805 $ 21,216,315 Simple variable-rate 5,568,000 2,853,000 Step-up (1) 555,000 1,832,000 Total par value $ 23,804,805 $ 25,901,315 _______________________ (1) Step-up bonds pay interest at increasing fixed rates for specified intervals over the life of the CO bond and can be called at our option on the step-up dates. Table 14.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds December 31, 2019 December 31, 2018 Noncallable and nonputable $ 20,954,805 $ 20,419,315 Callable 2,850,000 5,482,000 Total par value $ 23,804,805 $ 25,901,315
CO Discount Notes [Table Text Block]	Outstanding CO discount notes for which we were primarily liable, all of which are due within one year, were as follows: Table 14.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) December 31, 2019 $ 27,681,169 $ 27,733,146 1.59 % December 31, 2018 $ 33,065,822 $ 33,147,065 2.37 % _______________________ (1) The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program (Tab

Affordable Housing Program (Tables)	12 Months Ended
	Dec. 31, 2019
Affordable Housing Program [Abstract]
Roll-forward of the AHP Liability[Table Text Block]	Table 15.1 - AHP Liability (dollars in thousands) 2019 2018 Balance at beginning of year $ 83,965 $ 81,600 AHP expense for the period 21,302 24,299 AHP direct grant disbursements (15,723 ) (17,729 ) AHP subsidy for AHP advance disbursements (3,450 ) (4,360 ) Return of previously disbursed grants and subsidies 37 155 Balance at end of year $ 86,131 $ 83,965

Capital (Tables)

Capital (Tables)	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Compliance with Regulatory Capital Requirements [Table Text Block]	Table 16.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements December 31, December 31, Permanent capital Class B capital stock $ 1,869,130 $ 2,528,854 Mandatorily redeemable capital stock 5,806 31,868 Retained earnings 1,463,154 1,395,012 Total permanent capital $ 3,338,090 $ 3,955,734 Risk-based capital requirement Credit-risk capital $ 235,213 $ 289,080 Market-risk capital 207,426 187,183 Operations-risk capital 132,792 142,879 Total risk-based capital requirement $ 575,431 $ 619,142 Permanent capital in excess of risk-based capital requirement $ 2,762,659 $ 3,336,592 December 31, 2019 December 31, 2018 Required Actual Required Actual Capital Ratio Risk-based capital $ 575,431 $ 3,338,090 $ 619,142 $ 3,955,734 Total regulatory capital $ 2,226,512 $ 3,338,090 $ 2,543,733 $ 3,955,734 Total capital-to-asset ratio 4.0 % 6.0 % 4.0 % 6.2 % Leverage Ratio Leverage capital $ 2,783,141 $ 5,007,135 $ 3,179,666 $ 5,933,601 Leverage capital-to-assets ratio 5.0 % 9.0 % 5.0 % 9.3 %
Mandatorily redeemable capital stock [Table Text Block]	Table 16.3 - Mandatorily Redeemable Capital Stock by Expiry of Redemption Notice Period (dollars in thousands) December 31, 2019 December 31, 2018 Past redemption date (1) $ 5,663 $ 4,076 Due in one year or less — 27,379 Due after one year through two years — — Due after two years through three years 93 — Due after three years through four years 40 363 Due after four years through five years — 40 Thereafter (2) 10 10 Total $ 5,806 $ 31,868 _______________________ (1) Amount represents mandatorily redeemable capital stock that has reached the end of the five-year redemption-notice period but the member-related activity (for example, advances) remains outstanding. Accordingly, these shares of stock will not be redeemed until the activity is no longer outstanding. (2) Amount represents reclassifications to mandatorily redeemable capital stock resulting from an FHFA rule effective February 19, 2016, that makes captive insurance companies ineligible for membership. Captive insurance company members that were admitted as members prior to September 12, 2014, will have their memberships terminated no later than February 19, 2021. Table 16.2 - Mandatorily Redeemable Capital Stock (dollars in thousands) 2019 2018 2017 Balance at beginning of year $ 31,868 $ 35,923 $ 32,687 Capital stock subject to mandatory redemption reclassified from capital — 309 8,670 Redemption/repurchase of mandatorily redeemable capital stock (26,062 ) (4,364 ) (5,434 ) Balance at end of year $ 5,806 $ 31,868 $ 35,923

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Loss [Table Text Block]	Accumulated Other Comprehensive Loss Table 17.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 14,478 — (2,838 ) — 11,640 Accretion of noncredit loss — 32,815 — — 32,815 Net actuarial loss — — — (586 ) (586 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 1,346 — — 1,346 Amortization - hedging activities (2) — — 10,589 — 10,589 Amortization - pension and postretirement benefits (3) — — — 770 770 Other comprehensive income 14,478 34,161 7,751 184 56,574 Balance, December 31, 2017 (122,331 ) (158,218 ) (40,436 ) (5,955 ) (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (30,627 ) — 7,907 — (22,720 ) Accretion of noncredit loss — 28,834 — — 28,834 Net actuarial loss — — — (670 ) (670 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 230 — — 230 Amortization - hedging activities (4) — — 3,410 — 3,410 Amortization - pension and postretirement benefits (3) — — — 1,349 1,349 Other comprehensive (loss) income (30,627 ) 29,064 11,317 679 10,433 Balance, December 31, 2018 (152,958 ) (129,154 ) (29,119 ) (5,276 ) (316,507 ) Cumulative effect of change in accounting principle — — (175 ) — (175 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 79,036 — (6,131 ) — 72,905 Noncredit other-than-temporary impairment losses — (181 ) — — (181 ) Noncredit losses included in basis of securities sold — 29,517 — — 29,517 Accretion of noncredit loss — 22,806 — — 22,806 Net actuarial loss — — — (2,195 ) (2,195 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 976 — — 976 Amortization - hedging activities (5) — — 5,218 — 5,218 Amortization - pension and postretirement benefits (3) — — — 664 664 Table 17.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Other comprehensive income (loss) 79,036 53,118 (913 ) (1,531 ) 129,710 Balance, December 31, 2019 $ (73,922 ) $ (76,036 ) $ (30,207 ) $ (6,807 ) $ (186,972 ) _______________________ (1) Recorded in net other-than-temporary impairment losses on investment securities, credit portion in the statement of operations. (2) Amortization of hedging activities includes $10.6 million recorded in CO bond interest expense and $14 thousand recorded in net gains on derivatives and hedging activities in the statement of operations. (3) Recorded in other expenses in the statement of operations. (4) Amortization of hedging activities includes $3.2 million recorded in CO bond interest expense and $239 thousand recorded in net gains on derivatives and hedging activities in the statement of operations. (5) Recorded in CO bond interest expense.

Employee Retirement Plans (Tabl

Employee Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Schedule of Net Funded Status [Table Text Block]	Table 18.1 - Pentegra Defined Benefit Plan Net Pension Cost and Funded Status (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Net pension cost $ 6,559 $ 6,472 $ 6,727 Pentegra Defined Benefit Plan funded status as of July 1 (1) 108.6 % (2) 111.0 % (3) 111.8 % Our funded status as of July 1 (1) 113.9 % 123.1 % 122.9 % ______________________ (1) The funded status is calculated in accordance with a provision contained in the Highway and Transportation Funding Act of 2014 (HATFA), which was signed into law on August 8, 2014, and which modifies the interest rates that had been set by the Moving Ahead for Progress in the 21st Century Act (MAP-21). MAP-21, signed into law in 2012, changed the calculation of the discount rate used in measuring the pension plan liability. MAP-21 allows plan sponsors to measure the pension plan liability using a 25-year average of interest rates plus or minus a corridor. Prior to MAP-21, the discount rate used in measuring the pension plan liability was based on the 24-month average of interest rates. HATFA amended MAP-21 by extending the time period and reducing the rate at which the 25-year corridors widen. Over time, the pension funding stabilization effect of MAP-21 will decline because the 24-month smoothed segment rates and the amended 25-year corridors are likely to converge. (2) The funded status as of July 1, 2019, is preliminary and may increase because the plan's participants were permitted to make contributions for the plan year ended June 30, 2019, through March 15, 2020. Contributions made on or before March 15, 2020, and designated for the plan year ended June 30, 2019, will be included in the final valuation as of July 1, 2019. The final funded status as of July 1, 2019, will not be available until the Form 5500 for the plan year July 1, 2019, through June 30, 2020 is filed. This Form 5500 is due to be filed no later than April 2021. (3) The funded status as of July 1, 2018, is preliminary and may increase because the plan's participants were permitted to make contributions for the plan year ended June 30, 2018, through March 15, 2019. Contributions made on or before March 15, 2019, and designated for the plan year ended June 30, 2018, will be included in the final valuation as of July 1, 2018. The final funded status as of July 1, 2018, will not be available until the Form 5500 for the plan year July 1, 2018, through June 30, 2019 is filed. This Form 5500 is due to be filed no later than April 2020.
Change in Benefit Obligation [Table Text Block]	Table 18.2 - Pension and Postretirement Benefit Obligation, Fair Value of Plan Assets, and Funded Status (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits December 31, 2019 December 31, 2018 December 31, 2019 December 31, 2018 Change in benefit obligation (1) Benefit obligation at beginning of year $ 22,321 $ 19,366 $ 955 $ 1,056 Service cost 1,235 1,490 38 45 Interest cost 699 654 42 37 Actuarial loss 1,874 831 321 (161 ) Benefits paid (6 ) (5 ) (17 ) (22 ) Settlements — (15 ) — — Benefit obligation at end of year 26,123 22,321 1,339 955 Change in plan assets Fair value of plan assets at beginning of year — — — — Employer contribution 6 20 17 22 Benefits paid (6 ) (5 ) (17 ) (22 ) Settlements — (15 ) — — Fair value of plan assets at end of year — — — — Funded status at end of year $ (26,123 ) $ (22,321 ) $ (1,339 ) $ (955 ) ______________________ (1) Represents the projected benefit obligation for the nonqualified supplemental defined benefit retirement plan and the accumulated postretirement benefit obligation for postretirement benefits.
Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block]	Table 18.3 - Pension and Postretirement Benefits Recognized in Accumulated Other Comprehensive Loss (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits December 31, 2019 December 31, 2018 December 31, 2019 December 31, 2018 Net actuarial loss $ 6,223 $ 4,920 $ 437 $ 123 Prior service cost 148 234 — — Total $ 6,371 $ 5,154 $ 437 $ 123
Net Periodic Benefit Cost [Table Text Block]	Table 18.4 - Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2019 2018 2017 2019 2018 2017 Net Periodic Benefit Cost Service cost $ 1,235 $ 1,490 $ 1,179 $ 38 $ 45 $ 38 Interest cost 699 654 600 42 37 36 Amortization of prior service cost 86 86 86 — — — Amortization of net actuarial loss 571 1,248 676 7 15 8 Net periodic benefit cost 2,591 3,478 2,541 87 97 82 Other Changes in Benefit Obligations Recognized in Accumulated Other Comprehensive Loss Amortization of prior service cost (86 ) (86 ) (86 ) — — — Amortization of net actuarial loss (571 ) (1,248 ) (676 ) (7 ) (15 ) (8 ) Net actuarial loss (gain) 1,874 831 459 321 (161 ) 127 Total amount recognized in other comprehensive income 1,217 (503 ) (303 ) 314 (176 ) 119 Total amount recognized in net periodic benefit cost and other comprehensive income $ 3,808 $ 2,975 $ 2,238 $ 401 $ (79 ) $ 201
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	Table 18.4 - Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income (dollars in thousands) Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2019 2018 2017 2019 2018 2017 Net Periodic Benefit Cost Service cost $ 1,235 $ 1,490 $ 1,179 $ 38 $ 45 $ 38 Interest cost 699 654 600 42 37 36 Amortization of prior service cost 86 86 86 — — — Amortization of net actuarial loss 571 1,248 676 7 15 8 Net periodic benefit cost 2,591 3,478 2,541 87 97 82 Other Changes in Benefit Obligations Recognized in Accumulated Other Comprehensive Loss Amortization of prior service cost (86 ) (86 ) (86 ) — — — Amortization of net actuarial loss (571 ) (1,248 ) (676 ) (7 ) (15 ) (8 ) Net actuarial loss (gain) 1,874 831 459 321 (161 ) 127 Total amount recognized in other comprehensive income 1,217 (503 ) (303 ) 314 (176 ) 119 Total amount recognized in net periodic benefit cost and other comprehensive income $ 3,808 $ 2,975 $ 2,238 $ 401 $ (79 ) $ 201
Defined Benefit Plan, Assumptions [Table Text Block]	Table 18.5 - Pension and Postretirement Benefit Plan Key Assumptions Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2019 2018 2019 2018 Benefit obligation Discount rate 2.68 % 3.81 % 3.25 % 4.25 % Salary increases 5.50 % 5.50 % — — Net periodic benefit cost Discount rate 3.81 % 3.09 % 4.25 % 3.64 % Salary increases 5.50 % 5.50 % — —
Schedule of Expected Benefit Payments [Table Text Block]	Table 18.6 - Estimated Future Benefit Payments (dollars in thousands) Estimated Future Payments Nonqualified Supplemental Defined Benefit Retirement Plan Postretirement Benefits 2020 $ 6,066 $ 18 2021 2,459 19 2022 1,900 21 2023 2,464 23 2024 4,083 26 2025-2029 9,268 168

Fair Values (Tables)

Fair Values (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments [Table Text Block]	Table 19.1 presents the carrying value, fair value, and fair value hierarchy of our financial assets and liabilities at December 31, 2019 and 2018 . We record trading securities, available-for-sale securities, derivative assets, derivative liabilities, and certain other assets at fair value on a recurring basis, and on occasion certain private-label MBS, certain mortgage loans, and certain other assets on a non-recurring basis. We record all other financial assets and liabilities at amortized cost. Refer to Table 19.2 for further details about the financial assets and liabilities held at fair value on either a recurring or non-recurring basis. Table 19.1 - Fair Value Summary (dollars in thousands) December 31, 2019 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 69,416 $ 69,416 $ 69,416 $ — $ — $ — Interest-bearing deposits 1,253,873 1,253,873 1,253,873 — — — Securities purchased under agreements to resell 3,500,000 3,500,003 — 3,500,003 — — Federal funds sold 860,000 859,999 — 859,999 — — Trading securities (1) 2,250,264 2,250,264 — 2,250,264 — — Available-for-sale securities (1) 7,409,000 7,409,000 — 7,344,348 64,652 — Held-to-maturity securities 871,107 1,035,410 — 456,942 578,468 — Advances 34,595,363 34,735,775 — 34,735,775 — — Mortgage loans, net 4,501,251 4,634,141 — 4,615,737 18,404 — Accrued interest receivable 112,163 112,163 — 112,163 — — Derivative assets (1) 159,731 159,731 — 15,329 — 144,402 Other assets (1) 31,939 31,939 13,894 18,045 — — Liabilities: Deposits (674,309 ) (674,269 ) — (674,269 ) — — COs: Bonds (23,888,493 ) (24,226,123 ) — (24,226,123 ) — — Discount notes (27,681,169 ) (27,681,470 ) — (27,681,470 ) — — Mandatorily redeemable capital stock (5,806 ) (5,806 ) (5,806 ) — — — Accrued interest payable (104,477 ) (104,477 ) — (104,477 ) — — Derivative liabilities (1) (10,271 ) (10,271 ) — (43,805 ) — 33,534 Other: Commitments to extend credit for advances — (3,884 ) — (3,884 ) — — Standby letters of credit (1,723 ) (1,723 ) — (1,723 ) — — December 31, 2018 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 10,431 $ 10,431 $ 10,431 $ — $ — $ — Interest-bearing deposits 593,199 593,199 593,199 — — — Securities purchased under agreements to resell 6,499,000 6,499,078 — 6,499,078 — — Federal funds sold 1,500,000 1,500,002 — 1,500,002 — — Trading securities (1) 163,038 163,038 — 163,038 — — Available-for-sale securities (1) 5,849,944 5,849,944 — 5,800,343 49,601 — Held-to-maturity securities 1,295,023 1,528,929 — 638,164 890,765 — Advances 43,192,222 43,167,700 — 43,167,700 — — Mortgage loans, net 4,299,402 4,238,087 — 4,217,487 20,600 — Accrued interest receivable 112,751 112,751 — 112,751 — — Derivative assets (1) 22,403 22,403 — 13,832 — 8,571 Other assets (1) 25,059 25,059 9,988 15,071 — — Liabilities: Deposits (474,878 ) (474,848 ) — (474,848 ) — — COs: Bonds (25,912,684 ) (25,843,163 ) — (25,843,163 ) — — Discount notes (33,065,822 ) (33,062,585 ) — (33,062,585 ) — — Mandatorily redeemable capital stock (31,868 ) (31,868 ) (31,868 ) — — — Accrued interest payable (112,043 ) (112,043 ) — (112,043 ) — — Derivative liabilities (1) (255,800 ) (255,800 ) — (309,552 ) — 53,752 Other: Commitments to extend credit for advances — (4,164 ) — (4,164 ) — — Standby letters of credit (1,257 ) (1,257 ) — (1,257 ) — — _______________________ (1) Carried at fair value and measured on a recurring basis. (2) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
Fair Value Measured on Recurring and Nonrecurring Basis [Table Text Block]	Table 19.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (dollars in thousands) December 31, 2019 Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (1) Total Assets: Carried at fair value on a recurring basis Trading securities: Corporate bonds $ — $ 5,896 $ — $ — $ 5,896 U.S. Treasury obligations 2,240,236 2,240,236 U.S. government-guaranteed – single-family MBS — 4,047 — — 4,047 GSE – single-family MBS — 85 — — 85 Total trading securities — 2,250,264 — — 2,250,264 Available-for-sale securities: HFA securities — — 64,652 — 64,652 Supranational institutions — 416,429 — — 416,429 U.S. government-owned corporations — 296,761 — — 296,761 GSE — 123,786 — — 123,786 U.S. government guaranteed – single-family MBS — 57,714 — — 57,714 U.S. government guaranteed – multifamily MBS — 282,617 — — 282,617 GSE – single-family MBS — 2,590,271 — — 2,590,271 GSE – multifamily MBS — 3,576,770 — — 3,576,770 Total available-for-sale securities — 7,344,348 64,652 — 7,409,000 Derivative assets: Interest-rate-exchange agreements — 15,102 — 144,402 159,504 Mortgage delivery commitments — 227 — — 227 Total derivative assets — 15,329 — 144,402 159,731 Other assets 13,894 18,045 — — 31,939 Total assets carried at fair value on a recurring basis $ 13,894 $ 9,627,986 $ 64,652 $ 144,402 $ 9,850,934 Carried at fair value on a nonrecurring basis (2) Held-to-maturity securities: Private-label MBS $ — $ — $ 6,856 $ — $ 6,856 Mortgage loans held for portfolio — — 1,198 — 1,198 REO — — 78 — 78 Total assets carried at fair value on a nonrecurring basis $ — $ — $ 8,132 $ — $ 8,132 Liabilities: Carried at fair value on a recurring basis Derivative liabilities Interest-rate-exchange agreements $ — $ (43,805 ) $ — $ 33,534 $ (10,271 ) Total liabilities carried at fair value on a recurring basis $ — $ (43,805 ) $ — $ 33,534 $ (10,271 ) December 31, 2018 Level 1 Level 2 Level 3 Netting (1) Total Assets: Carried at fair value on a recurring basis Trading securities: Corporate bonds $ — $ 6,102 $ — $ — $ 6,102 U.S. government-guaranteed – single-family MBS — 5,344 — — 5,344 GSE – single-family MBS — 148 — — 148 GSE – multifamily MBS — 151,444 — — 151,444 Total trading securities — 163,038 — — 163,038 Available-for-sale securities: HFA securities — — 49,601 — 49,601 Supranational institutions — 405,155 — — 405,155 U.S. government-owned corporations — 273,169 — — 273,169 GSE — 115,627 — — 115,627 U.S. government guaranteed – single-family MBS — 75,658 — — 75,658 U.S. government guaranteed – multifamily MBS — 361,134 — — 361,134 GSE – single-family MBS — 3,562,159 — — 3,562,159 GSE – multifamily MBS — 1,007,441 — — 1,007,441 Total available-for-sale securities — 5,800,343 49,601 — 5,849,944 Derivative assets: Interest-rate-exchange agreements — 13,493 — 8,571 22,064 Mortgage delivery commitments — 339 — — 339 Total derivative assets — 13,832 — 8,571 22,403 Other assets 9,988 15,071 — — 25,059 Total assets carried at fair value on a recurring basis $ 9,988 $ 5,992,284 $ 49,601 $ 8,571 $ 6,060,444 Carried at fair value on a nonrecurring basis (2) Held-to-maturity securities: Private-label MBS $ — $ — $ 1,668 $ — $ 1,668 Mortgage loans held for portfolio — — 1,144 — 1,144 REO — — 361 — 361 Total assets carried at fair value on a nonrecurring basis $ — $ — $ 3,173 $ — $ 3,173 Liabilities: Carried at fair value on a recurring basis Derivative liabilities Interest-rate-exchange agreements $ — $ (309,552 ) $ — $ 53,752 $ (255,800 ) Total liabilities carried at fair value on a recurring basis $ — $ (309,552 ) $ — $ 53,752 $ (255,800 ) _______________________ (1) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. (2) We measure certain held-to-maturity investment securities, mortgage loans held for portfolio, and REO at fair value on a nonrecurring basis, that is, they are not measured at fair value on an ongoing basis but are subject to fair-value adjustments only in certain circumstances (for example, upon recognizing an other-than-temporary impairment on a held-to-maturity security). The fair values presented are as of the date the fair value adjustment was recorded.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Table 19.3 presents a reconciliation of available-for-sale securities that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended December 31, 2019 , 2018 , and 2017 . Table 19.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Balance at beginning of year $ 49,601 $ 37,683 $ 8,146 Purchases 13,820 12,800 33,350 Unrealized gains (losses) included in other comprehensive income 1,231 (882 ) (3,813 ) Balance at end of year $ 64,652 $ 49,601 $ 37,683

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	Table 20.1 - Off-Balance Sheet Commitments (dollars in thousands) December 31, 2019 December 31, 2018 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 7,484,754 $ 215,014 $ 7,699,768 $ 6,028,851 $ 226,438 $ 6,255,289 Commitments for unused lines of credit - advances (2) 1,143,828 — 1,143,828 1,177,377 — 1,177,377 Commitments to make additional advances 434,253 88,167 522,420 159,401 59,894 219,295 Commitments to invest in mortgage loans 49,911 — 49,911 50,773 — 50,773 Unsettled CO bonds, at par — — — 105,400 — 105,400 Unsettled CO discount notes, at par 500,000 — 500,000 600,000 — 600,000 __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At December 31, 2019 and 2018 , these amounts totaled $ 27.2 million and $32.6 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $1.8 million and $675 thousand at December 31, 2019 and 2018 , respectively. (2) Commitments for unused line-of-credit advances are generally for periods of up to 12 months . Since many of these commitments are not expected to be drawn upon, the total commitment amount does not necessarily indicate future liquidity requirements.

Transactions with Shareholders

Transactions with Shareholders (Tables)	12 Months Ended
	Dec. 31, 2019
Transactions with Shareholders [Abstract]
Schedule of Transactions with Shareholders [Table Text Block]	Shareholder Concentrations. We consider shareholder concentrations as members or nonmembers whose capital stock holdings (including mandatorily redeemable capital stock) are in excess of 10 percent of total capital stock outstanding at December 31, 2019 . Table 21.1 - Shareholder Concentrations, Balance Sheet (dollars in thousands) Capital Stock Outstanding Percent of Total Capital Stock Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of December 31, 2019 Citizens Bank, N.A. $ 222,684 11.9 % $ 5,005,773 14.5 % $ 1,678 3.5 % As of December 31, 2018 Citizens Bank, N.A. $ 339,003 13.2 % $ 7,656,146 17.7 % $ 5,005 8.3 %
Schedule of Transactions with Shareholders, Interest Income [Table Text Block]	Table 21.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Year Ended December 31, 2019 2018 2017 Citizens Bank, N.A. Interest income on advances $ 95,692 $ 134,753 $ 63,568 Fees on letters of credit 6,489 4,415 3,368
Schedule of Transactions with Shareholders, Transactions with Directors' Financial Institutions [Table Text Block]	Transactions with Directors' Institutions. We provide, in the ordinary course of business, products and services to members whose officers or directors serve on our board of directors. In accordance with FHFA regulations, transactions with directors' institutions are conducted on the same terms as those with any other member. Table 21.3 - Transactions with Directors' Institutions (dollars in thousands) Capital Stock Outstanding Percent of Total Capital Stock Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of December 31, 2019 $ 112,811 6.0 % $ 2,224,141 6.4 % $ 3,581 7.4 % As of December 31, 2018 113,337 4.4 2,147,602 5.0 3,576 6.0

Background Information Narrativ

Background Information Narratives (Details)	Dec. 31, 2019
Background Information [Abstract]
Number of Federal Home Loan Banks	11
Number of states we conduct business	6

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Line Items]
Securities purchased under agreements to resell	$ 3,500,000	$ 6,499,000
Securities purchased under agreements to resell, average balance	5,500,000	4,000,000
Securties purchased under agreements to resell, maximum amount outstanding at any month-end	7,000,000	6,500,000
Real Estate Acquired Through Foreclosure	$ 1,300	$ 818
Quarterly percentage of net income contributed to restricted retained earnings per the Joint Capital Enhancement Agreement	20.00%
Percent of average balance of outstanding consolidated obligations prescribed per the Joint Capital Enhancement Agreement for each previous quarter	1.00%
Minimum [Member]
Accounting Policies [Line Items]
Premises, software, and equipment, useful life	3 years
Definition of related party, minimum percent	10.00%
Maximum [Member]
Accounting Policies [Line Items]
Premises, software, and equipment, useful life	10 years
Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
Lease Right Of Use Asset	$ 10,300
Lease Liability	10,400
Other Expense [Member]
Accounting Policies [Line Items]
Operating Lease, Cost	$ 2,600

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Guidance Leases (Details) - Accounting Standards Update 2016-02 [Member] $ in Millions	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right-of-use asset	$ 11.9
Operating lease, liability	$ 12.5

Cash and Due From Bank - Narrat

Cash and Due From Bank - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash and Due from Banks [Abstract]
Average collected cash balances with commercial banks	$ 19.3	$ 16.3

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 2,250,264	$ 163,038
Corporate bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	5,896	6,102
US Treasury Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	2,240,236	0
Other Than Mortgage-backed Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	2,246,132	6,102
U.S. government-guaranteed - single-family MBS [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	4,047	5,344
MBS [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	4,132	156,936
GSEs - single-family [Member] | Government Sponsored Enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	85	148
GSEs - multifamily [Member] | Government Sponsored Enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 0	$ 151,444

Trading Securities - Net Unreal

Trading Securities - Net Unrealized (Losses) Gains (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Trading, Gain (Loss) [Abstract]
Net unrealized gains (losses) on trading securities held at year end	$ 1,379	$ (4,515)	$ (6,145)
Net unrealized and realized gains on trading securities sold or matured during the year	(92)	0	67
Net unrealized gains (losses) on trading securities	$ 1,287	$ (4,515)	$ (6,078)

Available-for-Sale Securities M

Available-for-Sale Securities Major Security Types (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	$ 7,482,922	$ 6,002,902
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		8,432	869
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(82,354)	(153,827)
Available-for-sale securities Fair Value		7,409,000	5,849,944
States or local housing-finance-agency obligations (HFA securities) [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	69,320	55,500
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(4,668)	(5,899)
Available-for-sale securities Fair Value		64,652	49,601
Supranational institutions [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	429,354	419,222
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(12,925)	(14,067)
Available-for-sale securities Fair Value		416,429	405,155
U.S. government-owned corporations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	323,192	297,729
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(26,431)	(24,560)
Available-for-sale securities Fair Value		296,761	273,169
GSEs [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	130,935	122,423
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(7,149)	(6,796)
Available-for-sale securities Fair Value		123,786	115,627
Other Than Mortgage-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	952,801	894,874
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(51,173)	(51,322)
Available-for-sale securities Fair Value		901,628	843,552
U.S. government-guaranteed - single-family MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	60,003	79,075
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	20
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(2,289)	(3,437)
Available-for-sale securities Fair Value		57,714	75,658
U.S. government guaranteed - multifamily MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	283,674	368,103
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(1,057)	(6,969)
Available-for-sale securities Fair Value		282,617	361,134
MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	6,530,121	5,108,028
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		8,432	869
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(31,181)	(102,505)
Available-for-sale securities Fair Value		6,507,372	5,006,392
Single Family [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	2,598,325	3,649,964
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		5,323	681
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(13,377)	(88,486)
Available-for-sale securities Fair Value		2,590,271	3,562,159
Multifamily [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	3,588,119	1,010,886
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		3,109	168
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(14,458)	(3,613)
Available-for-sale securities Fair Value		$ 3,576,770	$ 1,007,441
[1]	Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.

Available-for-Sale Securities S

Available-for-Sale Securities Securities with Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	$ 2,013,102	$ 967,090
Less than 12 Months, Unrealized Losses	(15,802)	(5,683)
12 Months or More, Fair Value	3,047,211	4,668,323
12 Months or More, Unrealized Losses	(66,552)	(148,144)
Total Fair Value	5,060,313	5,635,413
Total Unrealized Losses	(82,354)	(153,827)
HFA securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	12,229	11,118
Less than 12 Months, Unrealized Losses	(1,591)	(1,682)
12 Months or More, Fair Value	52,423	38,483
12 Months or More, Unrealized Losses	(3,077)	(4,217)
Total Fair Value	64,652	49,601
Total Unrealized Losses	(4,668)	(5,899)
Supranational institutions [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	416,429	405,155
12 Months or More, Unrealized Losses	(12,925)	(14,067)
Total Fair Value	416,429	405,155
Total Unrealized Losses	(12,925)	(14,067)
U.S. government-owned corporations [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	296,761	273,169
12 Months or More, Unrealized Losses	(26,431)	(24,560)
Total Fair Value	296,761	273,169
Total Unrealized Losses	(26,431)	(24,560)
GSEs [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	123,786	115,627
12 Months or More, Unrealized Losses	(7,149)	(6,796)
Total Fair Value	123,786	115,627
Total Unrealized Losses	(7,149)	(6,796)
Other Than Mortgage-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	12,229	11,118
Less than 12 Months, Unrealized Losses	(1,591)	(1,682)
12 Months or More, Fair Value	889,399	832,434
12 Months or More, Unrealized Losses	(49,582)	(49,640)
Total Fair Value	901,628	843,552
Total Unrealized Losses	(51,173)	(51,322)
U.S. government-guaranteed - single-family MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	10,885	0
Less than 12 Months, Unrealized Losses	(1)	0
12 Months or More, Fair Value	45,490	57,679
12 Months or More, Unrealized Losses	(2,288)	(3,437)
Total Fair Value	56,375	57,679
Total Unrealized Losses	(2,289)	(3,437)
U.S. government guaranteed - multifamily MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	282,617	361,134
12 Months or More, Unrealized Losses	(1,057)	(6,969)
Total Fair Value	282,617	361,134
Total Unrealized Losses	(1,057)	(6,969)
MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	2,000,873	955,972
Less than 12 Months, Unrealized Losses	(14,211)	(4,001)
12 Months or More, Fair Value	2,157,812	3,835,889
12 Months or More, Unrealized Losses	(16,970)	(98,504)
Total Fair Value	4,158,685	4,791,861
Total Unrealized Losses	(31,181)	(102,505)
GSEs - single-family [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	189,402	53,122
Less than 12 Months, Unrealized Losses	(968)	(388)
12 Months or More, Fair Value	1,423,927	3,417,076
12 Months or More, Unrealized Losses	(12,409)	(88,098)
Total Fair Value	1,613,329	3,470,198
Total Unrealized Losses	(13,377)	(88,486)
GSEs - multifamily [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	1,800,586	902,850
Less than 12 Months, Unrealized Losses	(13,242)	(3,613)
12 Months or More, Fair Value	405,778	0
12 Months or More, Unrealized Losses	(1,216)	0
Total Fair Value	2,206,364	902,850
Total Unrealized Losses	$ (14,458)	$ (3,613)

Available-for-Sale Securities R

Available-for-Sale Securities Redemption Terms (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	$ 7,482,922	$ 6,002,902
Available-for-sale securities Fair Value		7,409,000	5,849,944
Other Than Mortgage-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, amortized cost		7,600	0
Due in one year or less, fair value		7,563	0
Due after one year through five years, amortized cost		61,720	55,500
Due after one year through five years, fair value		57,089	49,601
Due after five years through 10 years, amortized cost		477,232	465,248
Due after five years through 10 years, fair value		463,465	450,102
Due after 10 years, amortized cost		406,249	374,126
Due after 10 years, fair value		373,511	343,849
Amortized Cost	[1]	952,801	894,874
Available-for-sale securities Fair Value		901,628	843,552
MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	6,530,121	5,108,028
Available-for-sale securities Fair Value		6,507,372	5,006,392
Amortized Cost MBS	[2]	6,530,121	5,108,028
Fair Value MBS	[2]	$ 6,507,372	$ 5,006,392
[1]	Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.
[2]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities Maj

Held-to-Maturity Securities Major Security Types (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 947,142	$ 1,424,176
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(76,035)	(129,153)
Carrying Value	[1],[2]	871,107	1,295,023
Gross Unrecognized Holding Gains		168,842	242,834
Gross Unrecognized Holding Losses		(4,539)	(8,928)
Held-to-maturity securities Fair Value		1,035,410	1,528,929
U.S. agency obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost			208
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss			0
Carrying Value			208
Gross Unrecognized Holding Gains			0
Gross Unrecognized Holding Losses			0
Held-to-maturity securities Fair Value			208
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		87,250	104,465
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		87,250	104,465
Gross Unrecognized Holding Gains		0	4
Gross Unrecognized Holding Losses		(3,845)	(4,612)
Held-to-maturity securities Fair Value		83,405	99,857
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		87,250	104,673
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss			0
Carrying Value	[1]	87,250	104,673
Gross Unrecognized Holding Gains			4
Gross Unrecognized Holding Losses			(4,612)
Held-to-maturity securities Fair Value		83,405	100,065
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		6,987	8,173
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		6,987	8,173
Gross Unrecognized Holding Gains		129	158
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		7,116	8,331
GSEs – MBS [Member] | GSEs - single-family [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		303,604	412,639
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		303,604	412,639
Gross Unrecognized Holding Gains		5,197	6,861
Gross Unrecognized Holding Losses		(246)	(1,389)
Held-to-maturity securities Fair Value		308,555	418,111
GSEs – MBS [Member] | GSEs - multifamily [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		140,661	209,786
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		140,661	209,786
Gross Unrecognized Holding Gains		612	1,728
Gross Unrecognized Holding Losses		(2)	0
Held-to-maturity securities Fair Value		141,271	211,514
Private-label residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		408,640	688,905
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(76,035)	(129,153)
Carrying Value		332,605	559,752
Gross Unrecognized Holding Gains		162,904	234,083
Gross Unrecognized Holding Losses		(446)	(2,927)
Held-to-maturity securities Fair Value		495,063	790,908
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	859,892	1,319,503
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(76,035)	(129,153)
Carrying Value	[1],[3]	783,857	1,190,350
Gross Unrecognized Holding Gains		168,842	242,830
Gross Unrecognized Holding Losses		(694)	(4,316)
Held-to-maturity securities Fair Value	[3]	$ 952,005	$ 1,428,864
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,035,410 and $1,528,929 at December 31, 2019 and 2018 , respectively.
[3]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Held-to-Maturity Securities Fai

Held-to-Maturity Securities Fair Value and Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	$ 37,286	$ 101,253
Less than 12 Months, Unrealized Losses	(113)	(920)
12 Months or More, Fair Value	120,780	259,996
12 Months or More, Unrealized Losses	(4,563)	(9,999)
Total Fair Value	158,066	361,249
Total Unrealized Losses	(4,676)	(10,919)
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	3,089	6,196
Less than 12 Months, Unrealized Losses	(1)	(9)
12 Months or More, Fair Value	80,316	92,822
12 Months or More, Unrealized Losses	(3,844)	(4,603)
Total Fair Value	83,405	99,018
Total Unrealized Losses	(3,845)	(4,612)
GSEs – MBS [Member] | Single Family [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	32,335	69,377
Less than 12 Months, Unrealized Losses	(101)	(580)
12 Months or More, Fair Value	16,465	52,237
12 Months or More, Unrealized Losses	(145)	(809)
Total Fair Value	48,800	121,614
Total Unrealized Losses	(246)	(1,389)
GSEs – MBS [Member] | Multifamily [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	949
Less than 12 Months, Unrealized Losses	(2)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	949
Total Unrealized Losses	(2)
Private-label residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	913	25,680
Less than 12 Months, Unrealized Losses	(9)	(331)
12 Months or More, Fair Value	23,999	114,937
12 Months or More, Unrealized Losses	(574)	(4,587)
Total Fair Value	24,912	140,617
Total Unrealized Losses	(583)	(4,918)
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	34,197	95,057
Less than 12 Months, Unrealized Losses	(112)	(911)
12 Months or More, Fair Value	40,464	167,174
12 Months or More, Unrealized Losses	(719)	(5,396)
Total Fair Value	74,661	262,231
Total Unrealized Losses	$ (831)	$ (6,307)

Held-to-Maturity Securities Red

Held-to-Maturity Securities Redemption Terms (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 947,142	$ 1,424,176
Carrying Value	[1],[2]	871,107	1,295,023
Fair Value		1,035,410	1,528,929
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Due in one year or less, Amortized Cost		3,090	1,043
Due in one year or less, Carrying Value	[1]	3,090	1,043
Due in one year or less, Fair Value		3,089	1,047
Due after one year through five years, Amortized Cost		0	6,205
Due after one year through five years, Carrying Value	[1]	0	6,205
Due after one year through five years, Fair Value		0	6,196
Due after five years through 10 years, Amortized Cost		15,405	16,865
Due after five years through 10 years, Carrying Value	[1]	15,405	16,865
Due after five years through 10 years, Fair Value		15,270	16,639
Due after 10 years, Amortized Cost		68,755	80,560
Due after 10 years, Carrying Value	[1]	68,755	80,560
Due after 10 years, Fair Value		65,046	76,183
Amortized Cost		87,250	104,673
Carrying Value	[1]	87,250	104,673
Fair Value		83,405	100,065
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	859,892	1,319,503
Carrying Value	[1],[3]	783,857	1,190,350
Fair Value	[3]	$ 952,005	$ 1,428,864
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,035,410 and $1,528,929 at December 31, 2019 and 2018 , respectively.
[3]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Held-to-Maturity Securities Pro

Held-to-Maturity Securities Proceeds from Sale and Gross Gains and Losses on HTM Securities (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Held-to-maturity, Sale, Excluding Other-than-temporary Impairment [Abstract]
Proceeds from sale of held-to-maturity securities	[1]	$ 185,177	$ 0	$ 0
Amortized cost of held-to-maturity securities	[1]	173,146	0	0
Realized net gain from sale of held-to-maturity securities	[1]	$ 12,031	$ 0	$ 0
[1]	The securities sold had less than 15 percent of the acquired principal outstanding at the time of the sale. Such sales are treated as maturities for the purposes of security classification. The sale does not impact our ability and intent to hold the remaining investments classified as held-to-maturity through their stated maturity dates.

Other-Than-Temporary Impairme_3

Other-Than-Temporary Impairment Projected Home Prices Recoveries (Details)	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
OTTI Governance Committee projected housing price decline rate over 12-month period	4.00%
OTTI Governance Committee projected housing price increase rate over 12-month period	8.00%
Minimum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Projected short-term house price change - increase rate for majority of markets	2.00%
Maximum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Projected short-term house price change - increase rate for majority of markets	6.00%

Other-Than-Temporary Impairme_4

Other-Than-Temporary Impairment Significant Inputs (Details) - Residential Mortgage Backed Securities [Member] - Alt-A [Member] - Mortgage-backed Securities, Issued by Private Enterprises [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 39,989
Project Prepayment Rates - Weighted Average Percent	12.30%
Projected Default Rates, Weighted Average Percent	22.90%
Projected Loss Severities, Weighted Average Percent	55.10%
Current Credit Enhancement, Weighted Average Percent	5.70%
[1]	Securities are classified based upon the current performance characteristics of the underlying loan pool and therefore the manner in which the loan pool backing the security has been modeled (as prime, Alt-A, or subprime), rather than their classification of the security at the time of issuance.

Other-Than-Temporary Impairme_5

Other-Than-Temporary Impairment OTTI Credit Losses Recognized During Life of Security (Details) - Residential Mortgage Backed Securities [Member] - Mortgage-backed Securities, Issued by Private Enterprises [Member] - Held-to-maturity Securities [Member] $ in Thousands	Dec. 31, 2019USD ($)	[1]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	$ 565,621
Amortized Cost	386,913
Carrying Value	310,878
Fair Value	473,782
Prime [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	3,796
Amortized Cost	3,474
Carrying Value	2,510
Fair Value	3,590
Alt-A [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	561,825
Amortized Cost	383,439
Carrying Value	308,368
Fair Value	$ 470,192
[1]	Securities are classified based on the classifications of their underlying loan composition at the time of issuance. We instituted and are continuing litigation related to certain of the private-label MBS in which we invested. Our complaint asserts, among others, claims for untrue or misleading statements in the sale of securities. It is possible that classifications of private-label MBS as provided herein when based on classification at the time of issuance as disclosed by those securities' issuance documents, as well as other statements about the securities, are inaccurate.

Other-Than-Temporary Impairme_6

Other-Than-Temporary Impairment Roll-forward of Amounts Related to Credit Losses Recognized in Earnings (Details) - Held-to-maturity Securities [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at beginning of year	$ 422,035	$ 452,523	$ 490,404
Credit losses for which other-than-temporary impairment was not previously recognized	128	0	0
Additional credit losses for which an other-than-temporary impairment charge was previously recognized	1,084	532	1,454
Securities sold or matured during the year	(56,710)	0	(5,600)
Portion of increase in cash flows expected to be collected over the remaining life of the security that are recognized in the current period as interest income	(26,907)	(31,020)	(33,735)
Balance at end of year	$ 339,630	$ 422,035	$ 452,523

Advances - Outstanding by Year

Advances - Outstanding by Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Maturity, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts		$ 5,101	$ 12,332
Due in one year or less		18,972,466	24,029,592
Due after one year through two years		8,600,922	11,413,640
Due after two years through three years		2,200,019	2,832,290
Due after three years through four years		1,766,314	1,648,076
Due after four years through five years		1,726,754	1,980,468
Thereafter		1,312,311	1,351,987
Total par value		$ 34,583,887	$ 43,268,385
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Rolling Year [Abstract]
Overdrawn demand-deposit accounts, Weighted average rate		2.05%	2.88%
Due in one year or less, Weighted average rate		1.96%	2.48%
Due after one year through two years, Weighted average rate		2.16%	2.55%
Due after two years through three years, Weighted average rate		2.16%	2.47%
Due after three years through four years, Weighted average rate		2.71%	2.37%
Due after four years through five years, Weighted average rate		2.15%	2.24%
Thereafter, Weighted average rate		2.68%	2.99%
Total Weighted average rate		2.10%	2.50%
Premiums		$ 3,397	$ 3,935
Discounts		(41,744)	(36,528)
Fair value of bifurcated derivatives	[1]	29,983	13,051
Hedging adjustments		19,840	(56,621)
Total Advances		$ 34,595,363	$ 43,192,222
[1]	At December 31, 2019 and 2018 , we had certain advances with embedded features that met the requirements to be separated from the host contract and designated as stand-alone derivatives.

Advances - Outstanding by Yea_2

Advances - Outstanding by Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	$ 5,101	$ 12,332
Due in one year or less	25,116,961	32,748,467
Due after one year through two years	3,450,922	3,913,640
Due after two years through three years	1,949,499	2,672,290
Due after three years through four years	1,461,314	1,261,176
Due after four years through five years	1,309,679	1,362,468
Thereafter	1,290,411	1,298,012
Total par value	$ 34,583,887	$ 43,268,385

Advances - Outstanding by the E

Advances - Outstanding by the Earlier of Contractual Maturity or Next Put Date (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	$ 5,101	$ 12,332
Due in one year or less	20,240,466	25,199,892
Due after one year through two years	8,603,422	11,652,840
Due after two years through three years	2,001,019	2,834,790
Due after three years through four years	965,814	1,367,576
Due after four years through five years	1,598,254	1,152,468
Thereafter	1,169,811	1,048,487
Total par value	$ 34,583,887	$ 43,268,385

Advances - Interest-Rate-Paymen

Advances - Interest-Rate-Payment Terms (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Fixed Rate [Abstract]
Due in one year or less - fixed rate	$ 18,733,966	$ 23,822,091
Due after one year - fixed rate	9,372,625	9,748,187
Total fixed-rate	28,106,591	33,570,278
Federal Home Loan Bank, Advances, Floating Rate [Abstract]
Due in one year or less - variable rate	243,601	219,832
Due after one year - variable rate	6,233,695	9,478,275
Total variable-rate	6,477,296	9,698,107
Total par value	$ 34,583,887	$ 43,268,385

Advances - Narratives (Details)

Advances - Narratives (Details) $ in Billions	12 Months Ended
	Dec. 31, 2019Borrowers	Dec. 31, 2018USD ($)Borrowers	Dec. 31, 2017USD ($)
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount		$ 12.3	$ 16.4
Minimum amount of advances outstanding per borrower		$ 1
Federal Home Loan Bank Advances [Member]
Credit Risk Exposure and Security Terms [Abstract]
Number of financial institutions with more than $1.0 billion advances borrowing | Borrowers	5	6
Total outstanding advances greater than $1.0 billion per borrower as a percentage of advances outstanding	35.60%	37.90%
Minimum [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank Advances Maturities	1 day
Interest rates of advances outstanding	(0.35%)	0.00%
Maximum [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank Advances Maturities	30 years
Interest rates of advances outstanding	7.72%	7.72%

Advances Advances - Prepayment

Advances Advances - Prepayment Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances Prepayment Fees [Abstract]
Prepayment fees received from borrowers	$ 33,809	$ 409	$ 1,568
Hedging fair-value adjustments on prepaid advances	1,923	264	(218)
Net discounts (premiums) associated with prepaid advances	157	(159)	(137)
Deferred recognition of prepayment fees received from borrowers on advance prepayments deemed to be loan modifications	(1,793)	(298)	(315)
Prepayment fees recognized in income on advance restructurings deemed to be extinguishments	915	0	0
Advance prepayment fees recognized in income, net	$ 35,011	$ 216	$ 898

Mortgage Loans Held for Portf_3

Mortgage Loans Held for Portfolio (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Par Value	$ 4,432,458	$ 4,231,206
Premiums	66,776	67,671
Discounts	(1,607)	(1,800)
Deferred derivative gains, net	4,124	2,825
Total mortgage loans held for portfolio	4,501,751	4,299,902
Allowance for credit losses	(500)	(500)
Total mortgage loans, net of allowance for credit losses	$ 4,501,251	4,299,402
Fixed-rate 15-year single-family mortgages
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Original contractual terms	15 years
Minimum [Member] | Fixed-rate 20- and 30-year single-family mortgages
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Original contractual terms	20 years
Maximum [Member] | Fixed-rate 20- and 30-year single-family mortgages
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Original contractual terms	30 years
Government Mortgage Loans [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Par Value	$ 292,203	328,651
Single Family [Member] | Fixed-rate 15-year single-family mortgages
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Par Value	339,042	392,128
Single Family [Member] | Fixed-rate 20- and 30-year single-family mortgages
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Par Value	4,093,416	3,839,078
Conventional Mortgage Loans [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Par Value	4,140,255	3,902,555
Allowance for credit losses	$ (500)	$ (500)	$ (500)	$ (650)

Allowance for credit losses - C

Allowance for credit losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Mortgage Loans Past Due [Line Items]
Total past due		$ 74,614	$ 58,346
Total current loans		4,450,600	4,263,381
Total mortgage loans		4,525,214	4,321,727
In process of foreclosure, included above	[1]	$ 5,035	$ 5,553
Serious delinquency rate	[2]	0.36%	0.34%
Past due 90 days or more still accruing interest		$ 5,570	$ 6,670
Loans on nonaccrual status	[3]	$ 11,510	7,975
Number of days past due, loans at serious delinquent status		90 days
Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		$ 20,671	20,898
Total current loans		278,924	316,285
Total mortgage loans		299,595	337,183
In process of foreclosure, included above	[1]	$ 2,222	$ 2,086
Serious delinquency rate	[2]	1.86%	1.98%
Past due 90 days or more still accruing interest		$ 5,570	$ 6,670
Loans on nonaccrual status	[3]	0	0
Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		53,943	37,448
Total current loans		4,171,676	3,947,096
Total mortgage loans		4,225,619	3,984,544
In process of foreclosure, included above	[1]	$ 2,813	$ 3,467
Serious delinquency rate	[2]	0.26%	0.20%
Past due 90 days or more still accruing interest		$ 0	$ 0
Loans on nonaccrual status	[3]	11,510	7,975
Past due 30-59 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		47,966	33,929
Past due 30-59 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		11,630	10,884
Past due 30-59 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		36,336	23,045
Past due 60-89 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		10,382	10,363
Past due 60-89 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		3,471	3,344
Past due 60-89 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		6,911	7,019
Past due 90 days or more delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		16,266	14,054
Past due 90 days or more delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		5,570	6,670
Past due 90 days or more delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		$ 10,696	$ 7,384
[1]	Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported.
[2]	Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class.
[3]	Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan.

Allowance for credit losses - N

Allowance for credit losses - Narratives (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Maximum Exposure Under First Loss Account	$ 28.5	$ 25.3
Recorded investment of trouble debt restructuring	$ 7.2	$ 8.5

Allowance for credit losses - A

Allowance for credit losses - Allowance Rollforward (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year		$ 500
Provision for (reduction of ) credit losses		85	$ (34)	$ (96)
Balance, end of year		500	500
Conventional Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year		500	500	650
(Charge-offs) recoveries		(85)	34	(54)
Provision for (reduction of ) credit losses		85	(34)	(96)
Balance, end of year		500	500	500
Ending balance, individually evaluated for impairment		0	0	0
Ending balance, collectively evaluated for impairment		500	500	500
Recorded Investment Individually evaluated for impairment	[1]	13,395	15,402	17,668
Recorded Investment Collectively evaluated for impairment	[1]	$ 4,212,224	$ 3,969,142	$ 3,632,833
[1]	These amounts exclude government mortgage loans because we make no allowance for credit losses based on our investments in government mortgage loans, as discussed above under — Government Mortgage Loans Held for Portfolio.

Derivatives and Hedging Activ_3

Derivatives and Hedging Activities Derivatives in Statement of Condition (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		$ 15,097,316	$ 13,241,272
Derivative Assets, before netting and collateral adjustments		15,329	13,832
Derivative Liabilities, before netting and collateral adjustments		(43,805)	(309,552)
Derivative Asset, netting adjustments and cash collateral including related accrued interest	[1],[2]	144,402	8,571
Derivative Liability, netting adjustments and cash collateral including related accrued interest	[1],[2]	33,534	53,752
Derivative assets		159,731	22,403
Derivative liabilities		(10,271)	(255,800)
Cash collateral and related accrued interest posted		178,500	62,800
Cash collateral and related accrued interest received		561	471
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		12,145,105	12,262,699
Derivative Assets, before netting and collateral adjustments		14,753	12,811
Derivative Liabilities, before netting and collateral adjustments		(12,805)	(297,077)
Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		12,128,105	11,980,699
Derivative Assets, before netting and collateral adjustments		14,734	12,811
Derivative Liabilities, before netting and collateral adjustments		(12,805)	(296,324)
Designated as Hedging Instrument [Member] | Forward-start interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		17,000	282,000
Derivative Assets, before netting and collateral adjustments		19	0
Derivative Liabilities, before netting and collateral adjustments		0	(753)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		2,952,211	978,573
Derivative Assets, before netting and collateral adjustments		576	1,021
Derivative Liabilities, before netting and collateral adjustments		(31,000)	(12,475)
Not Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		2,902,300	927,800
Derivative Assets, before netting and collateral adjustments		349	682
Derivative Liabilities, before netting and collateral adjustments		(31,000)	(12,475)
Mortgage Receivable [Member] | Not Designated as Hedging Instrument [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[3]	49,911	50,773
Derivative Assets, before netting and collateral adjustments	[3]	227	339
Derivative Liabilities, before netting and collateral adjustments	[3]	$ 0	$ 0
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $178.5 million and $62.8 million at December 31, 2019 , and 2018 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $561 thousand and $471 thousand at December 31, 2019 and 2018 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income.

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Interest Income/Expense (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Interest income on advances		$ 854,599	$ 867,215	$ 514,176
Interest income on available-for-sale securities		115,942	143,952	118,270
Interest expense on consolidated obligations bonds		(598,585)	(545,228)	(421,622)
Advances [Member] | Interest Rate Contract [Member] | Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives		(72,488)
Hedge items		73,530
Net changes in fair value before price alignment interest		1,042
Price alignment interest	[1]	1,316
Net interest settlements on derivatives	[2],[3]	39,085
Net gains (losses) on qualifying fair-value hedging relationships		41,443
Amortization/accretion of discontinued fair-value hedging relationships		(1,934)
Net gain (losses) on derivatives and hedging activities recorded in net interest income		39,509
Advances [Member] | Interest Rate Contract [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives			447	52,055
Hedge items			257	(52,633)
Net changes in fair value			704	(578)
Net interest settlements on derivatives	[2],[3]		51,522	(24,663)
Net gains (losses) on qualifying fair-value hedging relationships			52,226	(25,241)
Amortization/accretion of discontinued fair-value hedging relationships			(1,475)	(2,176)
Less: net changes In fair value	[4]		(704)	578
Net gain (losses) on derivatives and hedging activities recorded in net interest income			50,047	(26,839)
Available-for-sale Securities [Member] | Interest Rate Contract [Member] | Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives		(24,274)
Hedge items		21,329
Net changes in fair value before price alignment interest		(2,945)
Price alignment interest	[1]	3,769
Net interest settlements on derivatives	[2],[3]	(22,249)
Net gains (losses) on qualifying fair-value hedging relationships		(21,425)
Amortization/accretion of discontinued fair-value hedging relationships		0
Net gain (losses) on derivatives and hedging activities recorded in net interest income		(21,425)
Available-for-sale Securities [Member] | Interest Rate Contract [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives			43,771	20,747
Hedge items			(42,022)	(19,011)
Net changes in fair value			1,749	1,736
Net interest settlements on derivatives	[2],[3]		(26,040)	(32,053)
Net gains (losses) on qualifying fair-value hedging relationships			(24,291)	(30,317)
Amortization/accretion of discontinued fair-value hedging relationships			0	0
Less: net changes In fair value	[4]		(1,749)	(1,736)
Net gain (losses) on derivatives and hedging activities recorded in net interest income			(26,040)	(32,053)
COs - bonds [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives		55,777
Hedge items		(56,091)
Net changes in fair value before price alignment interest		(314)
Price alignment interest	[1]	(786)
Net interest settlements on derivatives	[2],[3]	(17,482)
Net gains (losses) on qualifying fair-value hedging relationships		(18,582)
Amortization/accretion of discontinued fair-value hedging relationships		(2,567)
Net gain (losses) on derivatives and hedging activities recorded in net interest income		$ (21,149)
COs - bonds [Member] | Interest Rate Contract [Member] | Interest Expense [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives			(5,680)	4,611
Hedge items			5,254	(8,077)
Net changes in fair value			(426)	(3,466)
Net interest settlements on derivatives	[2],[3]		(27,895)	6,694
Net gains (losses) on qualifying fair-value hedging relationships			(28,321)	3,228
Amortization/accretion of discontinued fair-value hedging relationships			945	1,903
Less: net changes In fair value	[4]		426	3,466
Net gain (losses) on derivatives and hedging activities recorded in net interest income			$ (26,950)	$ 8,597
[1]	Relates to derivatives for which variation margin payments are characterized as daily settled contracts.
[2]	Excludes the interest income/expense of the respective hedged items recorded in net interest income.
[3]	Represents interest income/expense on derivatives in qualifying fair-value hedging relationships. Net interest settlements on derivatives that are not in qualifying fair-value hedging relationships are reported in other income.
[4]	In 2018 and 2017, net changes in fair value were recorded in net gains on derivatives and hedging activities in other income.

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities Net Gains (Losses) on Cash Flow Hedging Relationships (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Expense [Member] | Forward-start interest rate swaps [Member] | COs - bonds [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Losses reclassified from accumulated other comprehensive loss into interest expense		$ (5,218)
Losses reclassified from accumulated other comprehensive loss into interest expense			$ (3,171)	$ (10,575)
Gain (Loss) on Derivative Instruments [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain recognized in net gains on derivatives and hedging activities	[1]		227	280
Gain (Loss) on Derivative Instruments [Member] | Forward-start interest rate swaps [Member] | COs - bonds [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain recognized in net gains on derivatives and hedging activities			227	280
Other Comprehensive Income (Loss) [Member] | Forward-start interest rate swaps [Member] | COs - bonds [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
(Losses) gains recognized in other comprehensive income		$ (6,131)	$ 7,907	$ (2,838)
[1]	Consists of forward-start interest-rate swaps.

Derivatives and Hedging Activ_6

Derivatives and Hedging Activities Basis Adjustments for Fair Value Hedges (Details) $ in Thousands	Dec. 31, 2019USD ($)
Advances [Member]
Derivatives, Fair Value [Line Items]
Amortized Cost of Hedged Asset/(Liability)	$ 5,115,016	[1]
Basis Adjustments for Active Hedging Relationships Included in Amortized Cost	38,988
Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost	10,835
Cumulative Amount of Fair Value Hedging Basis Adjustments	49,823
Available-for-sale Securities [Member]
Derivatives, Fair Value [Line Items]
Amortized Cost of Hedged Asset/(Liability)	4,053,138	[1]
Basis Adjustments for Active Hedging Relationships Included in Amortized Cost	226,346
Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost	0
Cumulative Amount of Fair Value Hedging Basis Adjustments	226,346
COs - bonds [Member]
Derivatives, Fair Value [Line Items]
Amortized Cost of Hedged Asset/(Liability)	3,359,616	[1]
Basis Adjustments for Active Hedging Relationships Included in Amortized Cost	(4,840)
Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost	36,906
Cumulative Amount of Fair Value Hedging Basis Adjustments	$ 32,066
[1]	Includes only the portion of amortized cost representing the hedged items in fair-value hedging relationships.

Derivatives and Hedging Activ_7

Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Other Income/Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		$ 1,419
Net gains on derivatives and hedging activities			$ 2,336	$ 551
Gain (Loss) on Derivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses) related to fair-value hedges	[1]		2,027	(2,308)
Total net gains related to cash-flow hedges	[2]		227	280
Total net gains (losses) related to derivatives designated as hedging instruments			2,254	(2,028)
Total net gains related to derivatives not designated as hedging instruments		1,331	1,103	2,202
Other	[3]		(1,021)	377
Net gains on derivatives and hedging activities			2,336	551
Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other	[3]	88
Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains on derivatives and hedging activities		1,419
Interest-rate swaps [Member] | Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		(614)	682	434
Mortgage Receivable [Member] | Mortgage-delivery commitments [Member] | Gain (Loss) on Derivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		$ 1,945	$ 421	$ 1,768
[1]	Consists of interest-rate swaps.
[2]	Consists of forward-start interest-rate swaps.
[3]	Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount.

Derivatives and Hedging Activ_8

Derivatives and Hedging Activities Narratives (Details) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 28, 2019
Derivative [Line Items]
Reclassifications from accumulated other comprehensive loss into earnings as a result of the discontinuance of cash-flow hedges		$ 0	$ 0	$ 0
Maximum length of time which we are hedging our exposure to the variability in future cash flows for forecasted transactions		2 years
Deferred net losses on derivatives accumulated in other comprehensive loss related to cash flow hedges expected to be reclassified to earnings during the next 12 months		$ 7,000,000
Aggregate fair value of all uncleared derivatives in a net-liability position (before cash collateral and related accrued interest)		38,700,000
Post-haircut value of collateral already posted		38,600,000
Rating Downgrade from AAPlus to AA or AAMinus [Member]
Derivative [Line Items]
Incremental collateral	[1]	302,000
Rating Downgrade From AMinus to below AMinus [Member]
Derivative [Line Items]
Incremental collateral	[1]	5,801,000
Rating Downgrade From AAMinus to APlus, A or AMinus [Member]
Derivative [Line Items]
Incremental collateral	[1]	$ 0
Terminated Derivative [Member]
Derivative [Line Items]
Terminated derivatives notional amount					$ 611,900,000
Terminated derivatives settlement amount					(251,500,000)
Replacement Derivatives [Member]
Derivative [Line Items]
Replacement derivatives notional amount					611,900,000
Replacement derivatives settlement amount					$ 251,500,000
[1]	Ratings are expressed in this table according to S&P's conventions but include the equivalent of such rating by Moody's. If there is a split rating, the lower rating is used.

Derivatives and Hedging Activ_9

Derivatives and Hedging Activities Fair Value of Derivative Instruments With or Without Legal Rights of Offset (Details) - USD ($) $ in Thousands		Dec. 31, 2019		Dec. 31, 2018
Derivative [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	$ 144,402		$ 8,571
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2]	33,534		53,752
Derivative assets		159,731		22,403
Derivative liabilities		(10,271)		(255,800)
Derivative Asset, Fair value, amount offset against collateral		158,736		22,007
Derivative Liability, Fair value, amount offset against collateral		(856)		(12,642)
Derivative Liabilities, additional net exposure, collateral pledged to counterparties in excess of net liabilities		300		639
Uncleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		4,950		12,862
Derivative Liability, total gross recognized amount		(42,199)		(306,848)
Derivative Assets, Netting Adjustments and Cash Collateral		(3,519)	[3]	(11,886)	[4]
Derivative liability, Netting Adjustments and Cash Collateral		31,928	[3]	51,048	[4]
Derivative assets		1,658		1,315
Derivative liabilities		(10,271)		(255,800)
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		(995)	[5]	(396)	[6]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		82	[5]	6,104	[6]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		9,333	[5]	237,054	[6]
Derivative Asset, Fair value, amount offset against collateral		663		919
Derivative Liability, Fair value, amount offset against collateral		(856)		(12,642)
Cleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		10,152		631
Derivative Liability, total gross recognized amount		(1,606)		(2,704)
Derivative Assets, Netting Adjustments and Cash Collateral		147,921	[3]	20,457	[4]
Derivative liability, Netting Adjustments and Cash Collateral		1,606	[3]	2,704	[4]
Derivative assets		158,073		21,088
Derivative liabilities		0		0
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		0	[5]	0	[6]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Asset, Fair value, amount offset against collateral		158,073		21,088
Derivative Liability, Fair value, amount offset against collateral		0		0
Mortgage Receivable [Member] | Uncleared derivatives [Member] | Mortgage-delivery commitments [Member]
Derivative [Line Items]
Derivative Asset, Mortgage delivery commitments		227		339
Derivative Liabilities, Mortgage delivery commitments		$ 0		$ 0
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $178.5 million and $62.8 million at December 31, 2019 , and 2018 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $561 thousand and $471 thousand at December 31, 2019 and 2018 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Includes gross amounts of netting adjustments and cash collateral.
[4]	Includes gross amounts of netting adjustments and cash collateral.
[5]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2019 , we had additional net credit exposure of $300 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.
[6]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2018 , we had additional net credit exposure of $639 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.

Deposits Narratives (Details)

Deposits Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Average interest rates paid on average deposits	1.16%	1.07%
Interest-bearing deposits demand and overnight	$ 613,143	$ 444,486
Interest-bearing deposits Term	800	800
Interest-bearing deposits other	2,589	2,961
Non-interest bearing deposits other	57,777	26,631
Total deposits	$ 674,309	$ 474,878

Consolidated Obligations CO Bon

Consolidated Obligations CO Bonds - Narratives (Details) - USD ($) $ in Trillions	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Obligation with Joint and Several Liability Arrangement, Amount Outstanding	$ 1	$ 1

Consolidated Obligations CO B_2

Consolidated Obligations CO Bonds - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Schedule of Short-term and Long-term Debt [Line Items]
Due in one year or less		$ 9,455,725	$ 9,638,270
Due in one year or less, weighted average rate	[1]	2.03%	2.01%
Due after one year through two years		$ 6,442,960	$ 5,375,845
Due after one year through two years, weighted average rate	[1]	2.02%	2.24%
Due after two years through three years		$ 2,154,920	$ 3,864,560
Due after two years through three years, weighted average rate	[1]	2.18%	2.17%
Due after three years through four years		$ 1,319,915	$ 1,891,975
Due after three years through four years, weighted average rate	[1]	2.45%	2.20%
Due after four years through five years		$ 1,211,080	$ 1,338,515
Due after four years through five years, weighted average rate	[1]	2.48%	2.39%
Thereafter		$ 3,220,205	$ 3,792,150
Thereafter, weighted average rate	[1]	3.33%	3.25%
Total par value		$ 23,804,805	$ 25,901,315
Hedging adjustments		32,066	(22,527)
Total		$ 23,888,493	$ 25,912,684
COs - bonds [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value, weighted average rate	[1]	2.26%	2.30%
Premiums		$ 63,056	$ 49,118
Discounts		$ (11,434)	$ (15,222)
[1]	The CO bonds' weighted-average rate excludes concession fees.

Consolidated Obligations CO B_3

Consolidated Obligations CO Bonds - Outstanding By Call Features (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 23,804,805	$ 25,901,315
Noncallable and nonputable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	20,954,805	20,419,315
Callable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 2,850,000	$ 5,482,000

Consolidated Obligations CO B_4

Consolidated Obligations CO Bonds - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Due in one year or less	$ 9,455,725	$ 9,638,270
Due after one year through two years	6,442,960	5,375,845
Due after two years through three years	2,154,920	3,864,560
Due after three years through four years	1,319,915	1,891,975
Due after four years through five years	1,211,080	1,338,515
Thereafter	3,220,205	3,792,150
Total par value	23,804,805	25,901,315
Earlier Of Contractual Maturity Or Next Call Date [Member]
Debt Instrument [Line Items]
Due in one year or less	11,297,725	13,435,270
Due after one year through two years	6,432,960	5,602,845
Due after two years through three years	2,019,920	2,802,560
Due after three years through four years	1,332,915	1,366,975
Due after four years through five years	926,080	1,156,515
Thereafter	1,795,205	1,537,150
Total par value	$ 23,804,805	$ 25,901,315

Consolidated Obligations CO B_5

Consolidated Obligations CO Bonds - Interest-Rate-Payment Type (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total par value		$ 23,804,805	$ 25,901,315
Fixed-rate [Member]
Debt Instrument [Line Items]
Total par value		17,681,805	21,216,315
Simple variable-rate [Member]
Debt Instrument [Line Items]
Total par value		5,568,000	2,853,000
Step-up [Member]
Debt Instrument [Line Items]
Total par value	[1]	$ 555,000	$ 1,832,000
[1]	Step-up bonds pay interest at increasing fixed rates for specified intervals over the life of the CO bond and can be called at our option on the step-up dates.

Consolidated Obligations CO - D

Consolidated Obligations CO - Discount Notes (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Federal Home Loan Bank, Consolidated Obligations, Discount Notes		$ 27,681,169	$ 33,065,822
Par value		$ 27,733,146	$ 33,147,065
Weighted Average Rate	[1]	1.59%	2.37%
[1]	The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program Narr

Affordable Housing Program Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Affordable Housing Program [Roll Forward]
Balance at beginning of year	$ 83,965	$ 81,600
AHP expense for the period	21,302	24,299	$ 21,307
AHP direct grant disbursements	(15,723)	(17,729)	(18,628)
AHP subsidy for AHP advance disbursements	(3,450)	(4,360)
Return of previously disbursed grants and subsidies	37	155
Balance at end of year	$ 86,131	$ 83,965	$ 81,600
FHLBanks [Member]
Affordable Housing Program [Line Items]
Affordable Housing Program Contribution Requirement, Percent	10.00%
Affordable Housing Program Contribution Requirement, Amount	$ 100,000

Capital Requirements (Details)

Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Capital-to-asset ratio, Required	4.00%	4.00%
Leverage capital-to-assets ratio, Required	5.00%	5.00%
Multiplier for Determining Permanent Capital in Leverage Capital Calculation	1.5
Class B capital stock	$ 1,869,130	$ 2,528,854
Mandatorily redeemable capital stock	5,806	31,868	$ 35,923	$ 32,687
Retained earnings	1,463,154	1,395,012
Total permanent capital	3,338,090	3,955,734
Credit-risk capital	235,213	289,080
Market-risk capital	207,426	187,183
Operations-risk capital	132,792	142,879
Total risk-based capital requirement	575,431	619,142
Permanent capital in excess of risk-based capital requirement	2,762,659	3,336,592
Regulatory capital, Required	2,226,512	2,543,733
Leverage capital, Required	2,783,141	3,179,666
Risk-based capital, Actual	3,338,090	3,955,734
Regulatory capital, Actual	$ 3,338,090	$ 3,955,734
Capital-to-asset ratio, Actual	6.00%	6.20%
Leverage capital, Actual	$ 5,007,135	$ 5,933,601
Leverage capital-to-assets ratio, Actual	9.00%	9.30%
Contribution requirement - Restricted Retained Earnings	$ 502,400
Restricted retained earnings	$ 348,817	$ 310,670

Capital Narratives (Details)

Capital Narratives (Details) - USD ($)	2 Months Ended	12 Months Ended			17 Months Ended
	Aug. 10, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Jan. 16, 2019
Dividends on mandatorily redeemable capital stock		$ 974,000	$ 1,923,000	$ 1,558,000
Minimum repurchase of excess capital stock	$ 100,000				$ 100,000
Excess capital stock		$ 79,700,000	$ 88,700,000		$ 88,700,000
Excess capital stock to total capital stock outstanding, percent		4.30%	3.50%		3.50%
Excess capital stock to total assets, percent		0.10%
Certain member assets eligible to secure advances [Member]
Class B stock purchase requirement		0.20%
Overnight advances [Member]
Class B stock purchase requirement		3.00%
All other advances greater than overnight [Member]
Class B stock purchase requirement		4.00%
Outstanding letters of credit [Member]
Class B stock purchase requirement		0.25%
Certain member assets rligible to secure advances prior to January 16, 2019 [Member]
Class B stock purchase requirement						0.35%
Common Class B [Member]
Common Stock, Class B, putable par value per share		$ 100	$ 100		$ 100
Minimum [Member]
Repurchase of excess capital stock held by shareholders, excess stock exceeds, amount	$ 10,000,000				$ 10,000,000
Repurchase of excess capital stock held by shareholders, excess stock exceeds, percentage	25.00%		10.00%		10.00%

Capital Mandatorily Redeemable

Capital Mandatorily Redeemable Capital Stock (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Mandatorily Redeemable Capital Stock [Roll Forward]
Balance at beginning of year	$ 31,868	$ 35,923	$ 32,687
Capital stock subject to mandatory redemption reclassified from capital	0	309	8,670
Redemption/repurchase of mandatorily redeemable capital stock	(26,062)	(4,364)	(5,434)
Balance at end of year	$ 5,806	$ 31,868	$ 35,923
Number of stockholders holding mandatorily redeemable capital stock	9	10	9

Capital Mandatorily Redeemabl_2

Capital Mandatorily Redeemable Capital Stock by Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Past redemption date	[1]	$ 5,663	$ 4,076
Due in one year or less		0	27,379
Due after one year through two years		0	0
Due after two years through three years		93	0
Due after three years through four years		40	363
Due after four years through five years		0	40
Thereafter	[2]	10	10
Total		$ 5,806	$ 31,868	$ 35,923	$ 32,687
Member withdrawal cancellation fee		2.00%
[1]	Amount represents mandatorily redeemable capital stock that has reached the end of the five-year redemption-notice period but the member-related activity (for example, advances) remains outstanding. Accordingly, these shares of stock will not be redeemed until the activity is no longer outstanding.
[2]	Amount represents reclassifications to mandatorily redeemable capital stock resulting from an FHFA rule effective February 19, 2016, that makes captive insurance companies ineligible for membership. Captive insurance company members that were admitted as members prior to September 12, 2014, will have their memberships terminated no later than February 19, 2021.

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		$ 598,585	$ 545,228		$ 421,622
Amortization of hedging activities recorded in net gains (losses) on derivatives and hedging activities			2,336		551
Accumulated Other Comprehensive Income (Loss) Before Tax1 [Roll Forward]
Beginning of period		3,607,359	3,265,130		3,244,778
Other comprehensive income (loss)		129,710	10,433		56,574
Period end		3,145,312	3,607,359		3,265,130
Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) Before Tax1 [Roll Forward]
Beginning of period		(29,119)	(40,436)		(48,187)
Cumulative effect of change in accounting principle		(175)
Net Unrealized Gains (Losses)		(6,131)	7,907		(2,838)
Amortization - hedging activities			3,410	[1]	10,589	[2]
Amortization - hedging activities	[3]	5,218
Other comprehensive income (loss)		(913)	11,317		7,751
Period end		(30,207)	(29,119)		(40,436)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) Before Tax1 [Roll Forward]
Beginning of period		(5,276)	(5,955)		(6,139)
Net actuarial (loss) gain		(2,195)	(670)		(586)
Amortization - pension and postretirement benefits	[4]	664	1,349		770
Other comprehensive income (loss)		(1,531)	679		184
Period end		(6,807)	(5,276)		(5,955)
Total [Member]
Accumulated Other Comprehensive Income (Loss) Before Tax1 [Roll Forward]
Beginning of period		(316,507)	(326,940)		(383,514)
Cumulative effect of change in accounting principle		(175)
Net Unrealized Gains (Losses)		72,905	(22,720)		11,640
Noncredit other-than-temporary impairment losses		(181)
Noncredit losses included in basis of securities sold		29,517
Accretion of noncredit loss		22,806	28,834		32,815
Net actuarial (loss) gain		(2,195)	(670)		(586)
Noncredit other-than-temporary impairment losses reclassified to credit loss	[5]	976	230		1,346
Amortization - hedging activities			3,410	[1]	10,589	[2]
Amortization - hedging activities	[3]	5,218
Amortization - pension and postretirement benefits	[4]	664	1,349		770
Other comprehensive income (loss)		129,710	10,433		56,574
Period end		(186,972)	(316,507)		(326,940)
Available-for-sale Securities [Member] | Net Unrealized Loss on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) Before Tax1 [Roll Forward]
Beginning of period		(152,958)	(122,331)		(136,809)
Net Unrealized Gains (Losses)		79,036	(30,627)		14,478
Other comprehensive income (loss)		79,036	(30,627)		14,478
Period end		(73,922)	(152,958)		(122,331)
Held-to-maturity Securities [Member] | Noncredit Portion of Other-Than-Temporary Impairment Losses on Held-to-Maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) Before Tax1 [Roll Forward]
Beginning of period		(129,154)	(158,218)		(192,379)
Noncredit other-than-temporary impairment losses		(181)
Noncredit losses included in basis of securities sold		29,517
Accretion of noncredit loss		22,806	28,834		32,815
Noncredit other-than-temporary impairment losses reclassified to credit loss	[5]	976	230		1,346
Other comprehensive income (loss)		53,118	29,064		34,161
Period end		$ (76,036)	(129,154)		(158,218)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds			3,200		10,600
Amortization of hedging activities recorded in net gains (losses) on derivatives and hedging activities			$ 239		$ 14
[1]	Amortization of hedging activities includes $3.2 million recorded in CO bond interest expense and $239 thousand recorded in net gains on derivatives and hedging activities in the statement of operations.
[2]	Amortization of hedging activities includes $10.6 million recorded in CO bond interest expense and $14 thousand recorded in net gains on derivatives and hedging activities in the statement of operations.
[3]	Recorded in CO bond interest expense.
[4]	Recorded in other expenses in the statement of operations.
[5]	Recorded in net other-than-temporary impairment losses on investment securities, credit portion in the statement of operations.

Employee Retirement Plans - Net

Employee Retirement Plans - Net Pension Cost and Funded Status (Details) - Pentegra Defined Benefit Plan [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Net pension cost		$ 6,559		$ 6,472		$ 6,727
Pentegra Defined Benefit Plan funded status as of July 1	[2]	108.60%	[1]	111.00%	[3]	111.80%
Our funded status as of July 1	[2]	113.90%		123.10%		122.90%
[1]	The funded status as of July 1, 2019, is preliminary and may increase because the plan's participants were permitted to make contributions for the plan year ended June 30, 2019, through March 15, 2020. Contributions made on or before March 15, 2020, and designated for the plan year ended June 30, 2019, will be included in the final valuation as of July 1, 2019. The final funded status as of July 1, 2019, will not be available until the Form 5500 for the plan year July 1, 2019, through June 30, 2020 is filed. This Form 5500 is due to be filed no later than April 2021.
[2]	The funded status is calculated in accordance with a provision contained in the Highway and Transportation Funding Act of 2014 (HATFA), which was signed into law on August 8, 2014, and which modifies the interest rates that had been set by the Moving Ahead for Progress in the 21st Century Act (MAP-21). MAP-21, signed into law in 2012, changed the calculation of the discount rate used in measuring the pension plan liability. MAP-21 allows plan sponsors to measure the pension plan liability using a 25-year average of interest rates plus or minus a corridor. Prior to MAP-21, the discount rate used in measuring the pension plan liability was based on the 24-month average of interest rates. HATFA amended MAP-21 by extending the time period and reducing the rate at which the 25-year corridors widen. Over time, the pension funding stabilization effect of MAP-21 will decline because the 24-month smoothed segment rates and the amended 25-year corridors are likely to converge.
[3]	The funded status as of July 1, 2018, is preliminary and may increase because the plan's participants were permitted to make contributions for the plan year ended June 30, 2018, through March 15, 2019. Contributions made on or before March 15, 2019, and designated for the plan year ended June 30, 2018, will be included in the final valuation as of July 1, 2018. The final funded status as of July 1, 2018, will not be available until the Form 5500 for the plan year July 1, 2018, through June 30, 2019 is filed. This Form 5500 is due to be filed no later than April 2020.

Employee Retirement Plans - Non

Employee Retirement Plans - Nonqualified Supplemental Defined Benefit and Postretirement Benefits (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	[1]	$ 22,321		$ 19,366
Service Cost		1,235	[1]	1,490	[1]	$ 1,179
Interest Cost		699	[1]	654	[1]	600
Actuarial loss	[1]	1,874		831
Benefits paid	[1]	(6)		(5)
Settlements	[1]	0		(15)
Benefit obligation at end of year	[1]	26,123		22,321		19,366
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		0		0
Employer contribution		6		20
Benefits paid		(6)		(5)
Settlements		0		(15)
Fair value of plan assets at end of year		0		0		0
Funded status at end of year		(26,123)		(22,321)
Other Postretirement Benefit Plan, Defined Benefit [Member]
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	[1]	955		1,056
Service Cost		38	[1]	45	[1]	38
Interest Cost		42	[1]	37	[1]	36
Actuarial loss	[1]	321		(161)
Benefits paid	[1]	(17)		(22)
Settlements	[1]	0		0
Benefit obligation at end of year	[1]	1,339		955		1,056
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		0		0
Employer contribution		17		22
Benefits paid		(17)		(22)
Settlements		0		0
Fair value of plan assets at end of year		0		0		$ 0
Funded status at end of year		$ (1,339)		$ (955)
[1]	Represents the projected benefit obligation for the nonqualified supplemental defined benefit retirement plan and the accumulated postretirement benefit obligation for postretirement benefits.

Employee Retirement Plans - Amo

Employee Retirement Plans - Amounts Recognized in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 6,223	$ 4,920
Prior service cost	148	234
Total	6,371	5,154
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	437	123
Prior service cost	0	0
Total	$ 437	$ 123

Employees Retirement Plans - Co

Employees Retirement Plans - Components of net periodic benefit cost and other amounts recognized in AOCL (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Total amount recognized in other comprehensive income	$ 1,531		$ (679)		$ (184)
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	1,235	[1]	1,490	[1]	1,179
Interest Cost	699	[1]	654	[1]	600
Amortization of prior service cost	86		86		86
Amortization of net actuarial loss	571		1,248		676
Net periodic benefit cost	2,591		3,478		2,541
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Amortization of prior service cost	(86)		(86)		(86)
Amortization of net actuarial loss	(571)		(1,248)		(676)
Net actuarial loss (gain)	1,874		831		459
Total amount recognized in other comprehensive income	1,217		(503)		(303)
Total amount recognized in net periodic benefit cost and other comprehensive income	3,808		2,975		2,238
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	38	[1]	45	[1]	38
Interest Cost	42	[1]	37	[1]	36
Amortization of prior service cost	0		0		0
Amortization of net actuarial loss	7		15		8
Net periodic benefit cost	87		97		82
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Amortization of prior service cost	0		0		0
Amortization of net actuarial loss	(7)		(15)		(8)
Net actuarial loss (gain)	321		(161)		127
Total amount recognized in other comprehensive income	314		(176)		119
Total amount recognized in net periodic benefit cost and other comprehensive income	$ 401		$ (79)		$ 201
[1]	Represents the projected benefit obligation for the nonqualified supplemental defined benefit retirement plan and the accumulated postretirement benefit obligation for postretirement benefits.

Employee Retirement Plans - Nar

Employee Retirement Plans - Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Employer Identification Number	04-6002575
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation	$ 22,700	$ 18,300
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	811
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	$ 27
Multiemployer Plans, Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Multiemployer Plan Number	333
Pentegra Defined Benefit Plan, Voluntary Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Multiemployer Plan, Voluntary Contributions	$ 6,000	6,000	$ 6,200
Thrift Benefit Equalization Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Deferred Compensation Arrangement with Individual, Recorded Liability	$ 12,600	$ 9,700

Employee Retirement Plans - Key

Employee Retirement Plans - Key Assumptions used for actuarial calculations (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Salary increases	5.50%	5.50%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Salary increases	5.50%	5.50%
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.68%	3.81%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.81%	3.09%
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	3.25%	4.25%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.25%	3.64%

Employee Retirement Plans - Exp

Employee Retirement Plans - Expected future benefit payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	$ 6,066
2021	2,459
2022	1,900
2023	2,464
2024	4,083
2025-2029	9,268
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	18
2021	19
2022	21
2023	23
2024	26
2025-2029	$ 168

Fair Values Carrying Value and

Fair Values Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 69,416		$ 10,431
Trading securities		2,250,264		163,038
Available-for-sale securities Fair Value		7,409,000		5,849,944
Held-to-maturity securities	[1],[2]	871,107		1,295,023
Held-to-maturity securities Fair Value		1,035,410		1,528,929
Accrued interest receivable		112,163		112,751
Derivative assets		159,731		22,403
Derivative Assets, Netting Adjustments and Cash Collateral	[3],[4]	144,402		8,571
Mandatorily redeemable capital stock		(5,806)		(31,868)	$ (35,923)	$ (32,687)
Accrued interest payable		(104,477)		(112,043)
Derivative liabilities		(10,271)		(255,800)
Derivative liability, Netting Adjustments and Cash Collateral	[3],[4]	33,534		53,752
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		69,416		10,431
Interest-bearing deposits		1,253,873		593,199
Securities purchased under agreements to resell		0		0
Federal funds sold		0		0
Trading securities	[5]	0		0
Available-for-sale securities Fair Value	[5]	0		0
Held-to-maturity securities Fair Value		0		0
Advances		0		0
Mortgage loans, net		0		0
Accrued interest receivable		0		0
Derivative assets		0	[5]	0
Other assets	[5]	13,894		9,988
Deposits		0		0
Mandatorily redeemable capital stock		(5,806)		(31,868)
Accrued interest payable		0		0
Derivative liabilities	[5]	0		0
Level 1 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 1 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 1 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0		0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		0		0
Interest-bearing deposits		0		0
Securities purchased under agreements to resell		3,500,003		6,499,078
Federal funds sold		859,999		1,500,002
Trading securities	[5]	2,250,264		163,038
Available-for-sale securities Fair Value	[5]	7,344,348		5,800,343
Held-to-maturity securities Fair Value		456,942		638,164
Advances		34,735,775		43,167,700
Mortgage loans, net		4,615,737		4,217,487
Accrued interest receivable		112,163		112,751
Derivative assets		15,329	[5]	13,832
Other assets	[5]	18,045		15,071
Deposits		(674,269)		(474,848)
Mandatorily redeemable capital stock		0		0
Accrued interest payable		(104,477)		(112,043)
Derivative liabilities	[5]	(43,805)		(309,552)
Level 2 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(3,884)		(4,164)
Level 2 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,723)		(1,257)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(27,681,470)		(33,062,585)
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
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	[5]	0		0
Available-for-sale securities Fair Value	[5]	64,652		49,601
Held-to-maturity securities Fair Value		578,468		890,765
Advances		0		0
Mortgage loans, net		18,404		20,600
Accrued interest receivable		0		0
Derivative assets		0	[5]	0
Other assets	[5]	0		0
Deposits		0		0
Mandatorily redeemable capital stock		0		0
Accrued interest payable		0		0
Derivative liabilities	[5]	0		0
Level 3 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 3 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 3 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0		0
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		69,416		10,431
Interest-bearing deposits		1,253,873		593,199
Securities purchased under agreements to resell		3,500,000		6,499,000
Federal funds sold		860,000		1,500,000
Trading securities	[5]	2,250,264		163,038
Available-for-sale securities Fair Value	[5]	7,409,000		5,849,944
Held-to-maturity securities		871,107		1,295,023
Advances		34,595,363		43,192,222
Mortgage loans, net		4,501,251		4,299,402
Accrued interest receivable		112,163		112,751
Derivative assets		159,731	[5]	22,403
Other assets	[5]	31,939		25,059
Deposits		(674,309)		(474,878)
Mandatorily redeemable capital stock		(5,806)		(31,868)
Accrued interest payable		(104,477)		(112,043)
Derivative liabilities	[5]	(10,271)		(255,800)
Carrying Value [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Carrying Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,723)		(1,257)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(27,681,169)		(33,065,822)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		69,416		10,431
Interest-bearing deposits		1,253,873		593,199
Securities purchased under agreements to resell		3,500,003		6,499,078
Federal funds sold		859,999		1,500,002
Trading securities	[5]	2,250,264		163,038
Available-for-sale securities Fair Value	[5]	7,409,000		5,849,944
Held-to-maturity securities Fair Value		1,035,410		1,528,929
Advances		34,735,775		43,167,700
Mortgage loans, net		4,634,141		4,238,087
Accrued interest receivable		112,163		112,751
Derivative assets		159,731	[5]	22,403
Other assets	[5]	31,939		25,059
Deposits		(674,269)		(474,848)
Mandatorily redeemable capital stock		(5,806)		(31,868)
Accrued interest payable		(104,477)		(112,043)
Derivative liabilities	[5]	(10,271)		(255,800)
Total Fair Value [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(3,884)		(4,164)
Total Fair Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,723)		(1,257)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(27,681,470)		(33,062,585)
COs - bonds [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		0		0
COs - bonds [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		(24,226,123)		(25,843,163)
COs - bonds [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		0		0
COs - bonds [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		(23,888,493)		(25,912,684)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (24,226,123)		$ (25,843,163)
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,035,410 and $1,528,929 at December 31, 2019 and 2018 , respectively.
[3]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $178.5 million and $62.8 million at December 31, 2019 , and 2018 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $561 thousand and $471 thousand at December 31, 2019 and 2018 .
[4]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[5]	Carried at fair value and measured on a recurring basis.

Fair Values Fair Value of Asset

Fair Values Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands		Dec. 31, 2019		Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		$ 2,250,264		$ 163,038
Available-for-sale securities Fair Value		7,409,000		5,849,944
Derivative assets		159,731		22,403
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	144,402		8,571
Fair value of held-to-maturity securities		1,035,410		1,528,929
Derivative liabilities		(10,271)		(255,800)
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2]	33,534		53,752
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	0		0
Available-for-sale securities Fair Value	[3]	0		0
Derivative assets		0	[3]	0
Other assets	[3]	13,894		9,988
Fair value of held-to-maturity securities		0		0
Mortgage loans held for portfolio		0		0
Derivative liabilities	[3]	0		0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	2,250,264		163,038
Available-for-sale securities Fair Value	[3]	7,344,348		5,800,343
Derivative assets		15,329	[3]	13,832
Other assets	[3]	18,045		15,071
Fair value of held-to-maturity securities		456,942		638,164
Mortgage loans held for portfolio		4,615,737		4,217,487
Derivative liabilities	[3]	(43,805)		(309,552)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	0		0
Available-for-sale securities Fair Value	[3]	64,652		49,601
Derivative assets		0	[3]	0
Other assets	[3]	0		0
Fair value of held-to-maturity securities		578,468		890,765
Mortgage loans held for portfolio		18,404		20,600
Derivative liabilities	[3]	0		0
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[4]	144,402		8,571
Derivative liability, Netting Adjustments and Cash Collateral	[4]	33,534		53,752
Recurring [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[4]	144,402		8,571
Derivative liability, Netting Adjustments and Cash Collateral	[4]	33,534		53,752
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Derivative assets		0		0
Other assets		13,894		9,988
Total assets carried at fair value		13,894		9,988
Total liabilities carried at fair value		0		0
Recurring [Member] | Level 1 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		2,250,264		163,038
Available-for-sale securities Fair Value		7,344,348		5,800,343
Derivative assets		15,329		13,832
Other assets		18,045		15,071
Total assets carried at fair value		9,627,986		5,992,284
Total liabilities carried at fair value		(43,805)		(309,552)
Recurring [Member] | Level 2 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		15,102		13,493
Derivative liabilities		(43,805)		(309,552)
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		64,652		49,601
Derivative assets		0		0
Other assets		0		0
Total assets carried at fair value		64,652		49,601
Total liabilities carried at fair value		0		0
Recurring [Member] | Level 3 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets carried at fair value	[5]	0		0
Mortgage loans held for portfolio	[5]	0		0
REO	[5]	0		0
Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets carried at fair value	[5]	0		0
Mortgage loans held for portfolio	[5]	0		0
REO	[5]	0		0
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets carried at fair value	[5]	8,132		3,173
Mortgage loans held for portfolio	[5]	1,198		1,144
REO	[5]	78		361
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	2,250,264		163,038
Available-for-sale securities Fair Value	[3]	7,409,000		5,849,944
Derivative assets		159,731	[3]	22,403
Other assets	[3]	31,939		25,059
Fair value of held-to-maturity securities		1,035,410		1,528,929
Mortgage loans held for portfolio		4,634,141		4,238,087
Derivative liabilities	[3]	(10,271)		(255,800)
Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		2,250,264		163,038
Available-for-sale securities Fair Value		7,409,000		5,849,944
Derivative assets		159,731		22,403
Other assets		31,939		25,059
Total assets carried at fair value		9,850,934		6,060,444
Total liabilities carried at fair value		(10,271)		(255,800)
Estimate of Fair Value Measurement [Member] | Recurring [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		159,504		22,064
Derivative liabilities		(10,271)		(255,800)
Estimate of Fair Value Measurement [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets carried at fair value	[5]	8,132		3,173
Mortgage loans held for portfolio	[5]	1,198		1,144
REO	[5]	78		361
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		5,896		6,102
Corporate bonds [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Corporate bonds [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		5,896		6,102
Corporate bonds [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Corporate bonds [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		5,896		6,102
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		2,240,236		0
US Treasury Securities [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		2,240,236
US Treasury Securities [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		2,240,236
U.S. government-guaranteed - single-family MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		4,047		5,344
Available-for-sale securities Fair Value		57,714		75,658
Fair value of held-to-maturity securities		7,116		8,331
U.S. government-guaranteed - single-family MBS [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
U.S. government-guaranteed - single-family MBS [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		4,047		5,344
Available-for-sale securities Fair Value		57,714		75,658
U.S. government-guaranteed - single-family MBS [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
U.S. government-guaranteed - single-family MBS [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		4,047		5,344
Available-for-sale securities Fair Value		57,714		75,658
U.S. government guaranteed - multifamily MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		282,617		361,134
U.S. government guaranteed - multifamily MBS [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government guaranteed - multifamily MBS [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		282,617		361,134
U.S. government guaranteed - multifamily MBS [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government guaranteed - multifamily MBS [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		282,617		361,134
Mortgage Receivable [Member] | Recurring [Member] | Level 1 [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Mortgage Receivable [Member] | Recurring [Member] | Level 2 [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		227		339
Mortgage Receivable [Member] | Recurring [Member] | Level 3 [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Mortgage Receivable [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		227		339
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		495,063		790,908
HFA securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		64,652		49,601
Fair value of held-to-maturity securities		83,405		99,857
HFA securities [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
HFA securities [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
HFA securities [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		64,652		49,601
HFA securities [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		64,652		49,601
Supranational institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		416,429		405,155
Supranational institutions [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
Supranational institutions [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		416,429		405,155
Supranational institutions [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
Supranational institutions [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		416,429		405,155
U.S. government-owned corporations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		296,761		273,169
U.S. government-owned corporations [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government-owned corporations [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		296,761		273,169
U.S. government-owned corporations [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government-owned corporations [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		296,761		273,169
GSEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		123,786		115,627
GSEs [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
GSEs [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		123,786		115,627
GSEs [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
GSEs [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		123,786		115,627
Single Family [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		85		148
Available-for-sale securities Fair Value		2,590,271		3,562,159
Fair value of held-to-maturity securities		308,555		418,111
Single Family [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Single Family [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		85		148
Available-for-sale securities Fair Value		2,590,271		3,562,159
Single Family [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Single Family [Member] | Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		85		148
Available-for-sale securities Fair Value		2,590,271		3,562,159
Multifamily [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		151,444
Available-for-sale securities Fair Value		3,576,770		1,007,441
Fair value of held-to-maturity securities		141,271		211,514
Multifamily [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				0
Available-for-sale securities Fair Value		0		0
Multifamily [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				151,444
Available-for-sale securities Fair Value		3,576,770		1,007,441
Multifamily [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				0
Available-for-sale securities Fair Value		0		0
Multifamily [Member] | Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				151,444
Available-for-sale securities Fair Value		3,576,770		1,007,441
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[5]	0		0
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[5]	0		0
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[5]	6,856		1,668
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[5]	$ 6,856		$ 1,668
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $178.5 million and $62.8 million at December 31, 2019 , and 2018 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $561 thousand and $471 thousand at December 31, 2019 and 2018 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Carried at fair value and measured on a recurring basis.
[4]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[5]	We measure certain held-to-maturity investment securities, mortgage loans held for portfolio, and REO at fair value on a nonrecurring basis, that is, they are not measured at fair value on an ongoing basis but are subject to fair-value adjustments only in certain circumstances (for example, upon recognizing an other-than-temporary impairment on a held-to-maturity security). The fair values presented are as of the date the fair value adjustment was recorded.

Estimated Fair Value Level 3 Re

Estimated Fair Value Level 3 Reconciliation - Roll Forward (Details) - HFA securities [Member] - Level 3 [Member] - Recurring [Member] - Available-for-sale Securities [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of year	$ 49,601	$ 37,683	$ 8,146
Purchases	13,820	12,800	33,350
Unrealized gains (losses) included in other comprehensive income	1,231	(882)	(3,813)
Balance at end of year	$ 64,652	$ 49,601	$ 37,683

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Value of the guarantees related to standby letters of credit		$ 66,843	$ 48,898
Maximum term of commitments to invest in mortgage loans		45 days
Other FHLBanks [Member]
Loss Contingencies [Line Items]
Par value of other FHLBanks' outstanding COs for which we are jointly and severally liable		$ 974,400,000	972,600,000
Maximum [Member]
Loss Contingencies [Line Items]
Standby letters of credit, original terms		20 years
Standby letters of credit, current terms		10 years
Standby letters of credit [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[1]	$ 7,484,754	6,028,851
Off-balance-sheet Commitments Expiring After One Year	[1]	215,014	226,438
Total Off-balance Sheet Commitments	[1]	7,699,768	6,255,289
Value of the guarantees related to standby letters of credit		1,700	1,300
Commitments of unused lines of credit - advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[2]	1,143,828	1,177,377
Off-balance-sheet Commitments Expiring After One Year	[2]	0	0
Total Off-balance Sheet Commitments	[2]	$ 1,143,828	1,177,377
Commitments of unused lines of credit - advances [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Period for commitments for unused line-of-credit advances		12 months
Commitments to make additional advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 434,253	159,401
Off-balance-sheet Commitments Expiring After One Year		88,167	59,894
Total Off-balance Sheet Commitments		522,420	219,295
Unsettled CO bonds, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		0	105,400
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		0	105,400
Unsettled CO discount notes, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		500,000	600,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		500,000	600,000
Standby Letters of Credit Issuance Commitments [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		27,200	32,600
Off-balance-sheet Commitments Expiring After One Year		1,800	675
Mortgage Receivable [Member] | Commitments to invest in mortgage loans [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		49,911	50,773
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		$ 49,911	$ 50,773
[1]	The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At December 31, 2019 and 2018 , these amounts totaled $ 27.2 million and $32.6 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $1.8 million and $675 thousand at December 31, 2019 and 2018 , respectively.
[2]	Commitments for unused line-of-credit advances are generally for periods of up to 12 months . Since many of these commitments are not expected to be drawn upon, the total commitment amount does not necessarily indicate future liquidity requirements.

Transactions with Shareholder_2

Transactions with Shareholders (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 1,869,130,000	$ 2,528,854,000
Par Value of Advances	34,583,887,000	43,268,385,000
Total Accrued Interest Receivable	112,163,000	112,751,000
Interest income on advances	854,599,000	867,215,000	$ 514,176,000
Fees on letters of credit	12,987,000	10,268,000	8,697,000
Prepayment fees received on advances	35,011,000	216,000	898,000
Citizens Bank, N.A. [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 222,684,000	$ 339,003,000
Percent of Total Capital Stock Outstanding	11.90%	13.20%
Par Value of Advances	$ 5,005,773,000	$ 7,656,146,000
Percentage of Total Par Value of Advances	14.50%	17.70%
Total Accrued Interest Receivable	$ 1,678,000	$ 5,005,000
Percent of Total Accrued Interest Receivable on Advances	3.50%	8.30%
Interest income on advances	$ 95,692,000	$ 134,753,000	63,568,000
Fees on letters of credit	6,489,000	4,415,000	$ 3,368,000
Prepayment fees received on advances		298,000
Federal Home Loan Bank, advances, prepaid		3,200,000
Directors' Financial Institutions [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 112,811,000	$ 113,337,000
Percent of Total Capital Stock Outstanding	6.00%	4.40%
Par Value of Advances	$ 2,224,141,000	$ 2,147,602,000
Percentage of Total Par Value of Advances	6.40%	5.00%
Total Accrued Interest Receivable	$ 3,581,000	$ 3,576,000
Percent of Total Accrued Interest Receivable on Advances	7.40%	6.00%
Minimum [Member]
Transactions with Shareholders [Line Items]
Definition of related party, minimum percent	10.00%
Definition of shareholder concentration, minimum percent	10.00%

Transactions with Other FHLBa_2

Transactions with Other FHLBanks (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Transactions with Other FHLBanks [Line Items]
Bonds transferred to other FHLBanks - par amount	$ 10,000,000
Bonds transferred to other FHLBanks at fair value	12,697,000	$ 0	$ 0
FHLBanks [Member]
Transactions with Other FHLBanks [Line Items]
Interest Income on loans to other FHLBanks	25,000	21,000	43,000
Interest expense for loans from other FHLBanks	20,000	36,000	6,000
Federal Home Loan Bank of Chicago [Member]
Transactions with Other FHLBanks [Line Items]
MPF transaction-services fee expense	2,800,000	2,500,000	2,200,000
MPF membership fee expense	$ 600,000	$ 600,000	$ 600,000

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands		Mar. 03, 2020	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 13, 2020
Subsequent Event [Line Items]
Realized net gain from sale of held-to-maturity securities	[1]			$ 12,031	$ 0	$ 0
Amortized cost of realized gain from sale of held-to-maturity securities	[1]			$ 173,146	$ 0	$ 0
Subsequent Event [Member]
Subsequent Event [Line Items]
Realized net gain from sale of held-to-maturity securities			$ 40,700
Amortized cost of realized gain from sale of held-to-maturity securities			$ 121,000
Common Class B [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Annualized rate of cash dividend							5.46%
Dividend, including dividends on mandatorily redeemable capital stock		$ 24,300
[1]	The securities sold had less than 15 percent of the acquired principal outstanding at the time of the sale. Such sales are treated as maturities for the purposes of security classification. The sale does not impact our ability and intent to hold the remaining investments classified as held-to-maturity through their stated maturity dates.