Federal Home Loan Bank of Boston 10-Q 8 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	000-51402
Entity Registrant Name	FEDERAL HOME LOAN BANK OF BOSTON
Entity Incorporation, State or Country Code	X1
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
Entity Address, Postal Zip Code	02199
City Area Code	(617)
Local Phone Number	292-9600
Amendment Flag	false
Entity Central Index Key	0001331463
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
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		17,988,176

Statements of Condition (unaudi

Statements of Condition (unaudited) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks		$ 28,739	$ 10,431
Interest-bearing deposits		1,146,961	593,199
Securities purchased under agreements to resell		5,000,000	6,499,000
Federal funds sold		250,000	1,500,000
Investment securities:
Trading securities		1,097,963	163,038
Available-for-sale securities - includes $3,025 pledged as collateral at December 31, 2018, that may be repledged		5,281,570	5,849,944
Held-to-maturity securities - includes $695 and $3,456 pledged as collateral at June 30, 2019, and December 31, 2018, respectively that may be repledged	[1],[2]	1,186,937	1,295,023
Total investment securities		7,566,470	7,308,005
Advances		37,096,797	43,192,222
Mortgage loans held for portfolio, net of allowance for credit losses of $500 at June 30, 2019, and December 31, 2018		4,421,028	4,299,402
Accrued interest receivable		117,793	112,751
Derivative assets, net		67,761	22,403
Other assets		83,983	55,904
Total Assets		55,779,532	63,593,317
Deposits
Interest-bearing		561,887	448,247
Non-interest-bearing		32,961	26,631
Total deposits		594,848	474,878
Consolidated obligations (COs):
Bonds		25,292,490	25,912,684
Discount notes		26,424,978	33,065,822
Total consolidated obligations		51,717,468	58,978,506
Mandatorily redeemable capital stock		17,107	31,868
Accrued interest payable		119,293	112,043
Affordable Housing Program (AHP) payable		85,991	83,965
Derivative liabilities, net		11,714	255,800
Other liabilities		58,895	48,898
Total liabilities		52,605,316	59,985,958
Commitments and contingencies (Note 18)
Capital
Capital stock – Class B – putable ($100 par value), 19,953 shares and 25,289 shares issued and outstanding at June 30, 2019, and December 31, 2018, respectively		1,995,252	2,528,854
Retained earnings:
Unrestricted		1,087,641	1,084,342
Restricted		328,685	310,670
Total retained earnings		1,416,326	1,395,012
Accumulated other comprehensive loss		(237,362)	(316,507)
Total capital		3,174,216	3,607,359
Total Liabilities and Capital		$ 55,779,532	$ 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 $ 1,409,594 and $1,528,929 at June 30, 2019 , and December 31, 2018 , respectively.

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 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)	695	3,456
Allowance for credit losses	500	500
Fair value of held-to-maturity securities	$ 1,409,594	$ 1,528,929
Common Class B [Member]
Common Stock, Class B, putable shares issued	19,953	25,289
Common Stock, Class B, putable par value per share	$ 100	$ 100
Common Stock, Class B, putable shares outstanding	19,953	25,289

Statements of Operations (unaud

Statements of Operations (unaudited) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018
INTEREST INCOME
Advances		$ 223,869	$ 213,920	[1]	$ 471,746	$ 391,370	[1]
Prepayment fees on advances, net		3,806	7		30,737	163
Securities purchased under agreements to resell		36,210	13,266		76,071	23,629
Federal funds sold		13,261	29,036		37,555	51,797
Investment securities:
Trading securities		2,502	2,508		4,247	5,013
Available-for-sale securities		21,655	37,221	[1]	42,946	77,999	[1]
Held-to-maturity securities		17,494	19,536		35,891	38,097
Total investment securities		41,651	59,265		83,084	121,109
Mortgage loans held for portfolio		37,587	33,782		74,956	66,807
Other		5,408	814		9,083	1,148
Total interest income		361,792	350,090		783,232	656,023
Consolidated obligations:
Bonds		150,715	136,556	[1]	305,532	255,757	[1]
Discount notes		151,253	133,361		329,192	238,341
Total consolidated obligations		301,968	269,917		634,724	494,098
Deposits		1,809	916		3,614	2,263
Mandatorily redeemable capital stock		259	469		566	955
Other borrowings		23	30		27	38
Total interest expense		304,059	271,332		638,931	497,354
NET INTEREST INCOME		57,733	78,758		144,301	158,669
Provision for (reduction of) credit losses		12	(3)		15	6
NET INTEREST INCOME AFTER PROVISION FOR (REDUCTION OF) CREDIT LOSSES		57,721	78,761		144,286	158,663
OTHER INCOME (LOSS)
Net other-than-temporary impairment losses on investment securities, credit portion		(314)	(257)		(417)	(336)
Loss on early extinguishment of debt		0	0		(9,865)	0
Service fees		3,329	2,463		6,293	4,819
Net unrealized gains (losses) on trading securities		1,328	(1,024)		1,054	(2,988)
Net losses on derivatives and hedging activities		(962)			(414)
Net gains on derivatives and hedging activities	[1]		458			1,598
Other		294	81		288	422
Total other income (loss)		3,675	1,721		(3,061)	3,515
OTHER EXPENSE
Compensation and benefits		9,568	10,033		20,187	20,776
Other operating expenses		6,745	6,292		12,536	12,174
Federal Housing Finance Agency (the FHFA)		989	831		1,978	1,761
Office of Finance		800	797		1,617	1,627
Other		3,687	3,219		4,758	5,302
Total other expense		21,789	21,172		41,076	41,640
INCOME BEFORE ASSESSMENTS		39,607	59,310		100,149	120,538
AHP assessments		3,987	5,978		10,072	12,149
NET INCOME		$ 35,620	$ 53,332		$ 90,077	$ 108,389
[1]	Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019.

Statements of Comprehensive Inc

Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 35,620	$ 53,332	$ 90,077	$ 108,389
Other comprehensive income:
Net unrealized gains (losses) on available-for-sale securities	36,293	(13,968)	70,358	(45,590)
Net noncredit portion of other-than-temporary impairment recoveries on held-to-maturity securities	6,275	7,594	12,516	15,022
Net unrealized (losses) gains relating to hedging activities	(1,312)	3,599	(3,905)	13,703
Pension and postretirement benefits	190	(970)	351	(785)
Total other comprehensive income (loss)	41,446	(3,745)	79,320	(17,650)
Comprehensive income	$ 77,066	$ 49,587	$ 169,397	$ 90,739

Statements of Capital (unaudite

Statements of Capital (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	$ 2,963,804	$ 3,318,568	$ 3,607,359	$ 3,265,130
Comprehensive income	77,066	49,587	169,397	90,739
Proceeds from sale of capital stock	555,112	467,579	836,504	875,911
Repurchase of capital stock	(390,100)	(311,360)	(1,370,106)	(679,231)
Shares reclassified to mandatorily redeemable capital stock				(291)
Cash dividends on capital stock	(31,666)	(31,917)	(68,938)	(59,801)
Period end	3,174,216	3,492,457	3,174,216	3,492,457
Retained Earnings, Unrestricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,090,811	1,057,195	1,084,342	1,041,033
Cumulative effect of change in accounting principle	175		175
Comprehensive income	28,496	42,665	72,062	86,711
Cash dividends on capital stock	(31,666)	(31,917)	(68,938)	(59,801)
Period end	1,087,641	1,067,943	1,087,641	1,067,943
Retained Earnings, Restricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	321,561	278,327	310,670	267,316
Comprehensive income	7,124	10,667	18,015	21,678
Period end	328,685	288,994	328,685	288,994
Retained Earnings, Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,412,372	1,335,522	1,395,012	1,308,349
Cumulative effect of change in accounting principle	175		175
Comprehensive income	35,620	53,332	90,077	108,389
Cash dividends on capital stock	(31,666)	(31,917)	(68,938)	(59,801)
Period end	1,416,326	1,356,937	1,416,326	1,356,937
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	(278,808)	(340,845)	(316,507)	(326,940)
Cumulative effect of change in accounting principle	(175)		(175)
Comprehensive income	41,446	(3,745)	79,320	(17,650)
Period end	$ (237,362)	$ (344,590)	$ (237,362)	$ (344,590)
Common Class B [Member] | Capital Stock Class B - Putable
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period, shares	18,302	23,239	25,289	22,837
Beginning of period	$ 1,830,240	$ 2,323,891	$ 2,528,854	$ 2,283,721
Proceeds from sale of capital stock, shares	5,552	4,676	8,365	8,759
Proceeds from sale of capital stock	$ 555,112	$ 467,579	$ 836,504	$ 875,911
Repurchase of capital stock, shares	(3,901)	(3,114)	(13,701)	(6,792)
Repurchase of capital stock	$ (390,100)	$ (311,360)	$ (1,370,106)	$ (679,231)
Shares reclassified to mandatorily redeemable capital stock, shares				(3)
Shares reclassified to mandatorily redeemable capital stock				$ (291)
Period end, shares	19,953	24,801	19,953	24,801
Period end	$ 1,995,252	$ 2,480,110	$ 1,995,252	$ 2,480,110

Statements of Cash Flows (unaud

Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
OPERATING ACTIVITIES
Net Income			$ 90,077	$ 108,389
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			7,892	(1,632)
Provision for credit losses	$ 12	$ (3)	15	6
Net change in derivatives and hedging activities			(298,252)	68,059
Net other-than-temporary impairment losses on investment securities, credit portion	314	257	417	336
Loss on early extinguishment of debt	0	0	9,865	0
Other adjustments			2,288	2,395
Net change in:
Market value of trading securities			(1,054)	2,988
Accrued interest receivable			(5,042)	(10,123)
Other assets			(4,406)	(2,550)
Accrued interest payable			7,250	16,831
Other liabilities			676	(1,509)
Total adjustments			(280,351)	74,801
Net cash (used in) provided by operating activities			(190,274)	183,190
INVESTING ACTIVITIES
Interest-bearing deposits			(590,233)	(220,623)
Securities purchased under agreements to resell			1,499,000	2,350,000
Federal funds sold			1,250,000	(3,160,000)
Loans to other FHLBanks			0	400,000
Trading securities:
Proceeds			67,576	762,424
Purchases			(1,001,467)	(749,072)
Available-for-sale securities:
Proceeds			924,182	616,956
Purchases			(267,797)	0
Held-to-maturity securities:
Proceeds			132,174	180,692
Advances to members:
Repaid			268,055,560	342,766,341
Originated			(261,863,678)	(346,562,802)
Mortgage loans held for portfolio:
Proceeds			200,205	200,748
Purchases			(325,607)	(279,350)
Other investing activities			(25)	1,638
Net cash provided by (used in) investing activities			8,079,890	(3,693,048)
FINANCING ACTIVITIES
Net change in deposits			119,900	75,961
Net payments on derivatives with a financing element			(38,540)	0
Net proceeds from issuance of consolidated obligations:
Discount notes			74,857,450	98,706,575
Bonds			5,182,056	6,537,266
Payments for maturing and retiring consolidated obligations:
Discount notes			(81,505,625)	(95,189,122)
Bonds			(5,869,248)	(6,967,720)
Proceeds from issuance of capital stock			836,504	875,911
Payments for repurchase of capital stock			(1,370,106)	(679,231)
Payments for redemption of mandatorily redeemable capital stock			(14,761)	(4,346)
Cash dividends paid			(68,938)	(59,804)
Net cash (used in) provided by financing activities			(7,871,308)	3,295,490
Net increase (decrease) in cash and due from banks			18,308	(214,368)
Cash and due from banks at beginning of the period			10,431	261,673	$ 261,673
Cash and due from banks at end of the period	$ 28,739	$ 47,305	28,739	47,305	10,431
Supplemental disclosures:
Interest paid			637,183	471,049
AHP payments			6,454	10,308	$ 17,729
Noncash receipt of trading securities			0	7,130
Noncash transfers of mortgage loans held for portfolio to other assets			606	1,046
Lease liabilities arising from obtaining right-of-use assets			$ 11,946	$ 0

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2019
Disclosure Text Block [Abstract]
Nature of Operations [Text Block]	The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information. In the opinion of management, all adjustments considered necessary have been included. All such adjustments consist of normal recurring accruals. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. The results of operations for interim periods are not necessarily indicative of the results to be expected for the year ending December 31, 2019. These interim financial statements do not include all the information and footnotes required by GAAP for complete annual financial statements and accordingly should be read in conjunction with the Federal Home Loan Bank of Boston's audited financial statements and related notes in our Annual Report on Form 10-K for the year ended December 31, 2018, filed with the Securities and Exchange Commission (the SEC) on March 22, 2019 (the 2018 Annual Report). Unless otherwise indicated or the context requires otherwise, all references in this discussion to “the Bank,” "we," "us," "our," or similar references mean the Federal Home Loan Bank of Boston.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies As of June 30, 2019 , we have not made any significant changes to the significant accounting policies described in Item 8 — Financial Statements and Supplementary Data — Note 2 — Summary of Significant Accounting Policies in the 2018 Annual Report other than described below. These changes relate to the Financial Accounting Standards Board (FASB) guidance that became effective January 1, 2019 for Targeted Improvements to Accounting for Hedging Activitie s as well as for Leases . See Note 3 — Recently Issued and Adopted Accounting Guidance for additional information. Investment Securities 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. Advances 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. Derivatives 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. Premises, Software, Equipment and Leases 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 . We amortize leasehold improvements on a straight-line basis over the shorter of the estimated useful life of the improvement or the remaining term of the lease. We capitalize improvements and major renewals but expense ordinary maintenance and repairs when incurred. We include gains and losses on disposal of premises, software, and equipment in other income (loss) on the statement of operations. The cost of purchased software and certain costs incurred in developing computer software for internal use are capitalized and amortized over future periods. 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. At June 30, 2019 , we included in the statement of condition $10.8 million of operating lease right-of-use assets in other assets as well as $11.3 million of operating lease liabilities in other liabilities. We have recognized operating lease costs in the other operating expense line of the statement of operations of $646,000 and $1.3 million for the three and six months ended June 30, 2019 .

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	6 Months Ended
	Jun. 30, 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 11 — 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. Becoming effective January 1, 2020 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. Early application is permitted as of the interim and annual reporting periods beginning after December 15, 2018; however, we do not intend to adopt the new guidance early. 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. We are currently evaluating the effect this guidance may have on our financial condition, results of operations and cash flows. A preliminary assessment of the anticipated impacts on our financial condition for certain asset classes is the following: • No allowance for credit losses will be required for advances, U.S. government or agency securities, U.S. government-owned corporations, U.S. government-guaranteed securities and securities issued by government sponsored enterprises on the basis of the zero-loss expectations; • We do not expect to recognize an allowance for credit losses for short-term investments (including federal funds sold and interest-bearing deposits), securities purchased under agreements to resell, securities issued by supranational institutions, or state or local housing-finance-agency obligations; and • We do not expect a significant change in methodology for modeling credit losses for private-label MBS. Although we are still evaluating the expected impact on our financial condition for mortgage loans held for portfolio, we expect the adoption of the guidance will result in an increase in the allowance for credit losses given the requirement to assess losses for the entire estimated life of the financial asset. The overall effect on our financial condition, results of operations, and cash flows will depend upon the composition of our financial assets held at the date of adoption as well as the economic conditions and forecasts at that time.

Trading Securities

Trading Securities	6 Months Ended
	Jun. 30, 2019
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Trading Securities (and Certain Trading Assets) Disclosure [Text Block]	Trading Securities Table 4.1 - Trading Securities by Major Security Type (dollars in thousands) June 30, 2019 December 31, 2018 Corporate bonds $ 6,208 $ 6,102 U.S. Treasury obligations 1,003,118 — 1,009,326 6,102 Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 4,701 5,344 Government sponsored enterprise (GSEs) – single-family 107 148 GSEs – multifamily 83,829 151,444 88,637 156,936 Total $ 1,097,963 $ 163,038 Net unrealized gains or losses on trading securities for the six months ended June 30, 2019 and 2018 , amounted to net gains of $1.1 million and net losses of $3.0 million , respectively. 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	6 Months Ended
	Jun. 30, 2019
Debt Securities, Available-for-sale [Abstract]
Available-for-Sale Securities Disclosure [Text Block]	Available-for-Sale Securities Table 5.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) June 30, 2019 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value State or local housing-finance-agency obligations (HFA securities) $ 55,500 $ — $ (3,940 ) $ 51,560 Supranational institutions 434,918 — (15,733 ) 419,185 U.S. government-owned corporations 322,295 — (32,237 ) 290,058 GSEs 131,096 — (9,199 ) 121,897 943,809 — (61,109 ) 882,700 MBS U.S. government guaranteed – single-family 68,392 7 (1,841 ) 66,558 U.S. government guaranteed – multifamily 339,951 — (2,501 ) 337,450 GSEs – single-family 3,181,514 4,011 (20,522 ) 3,165,003 GSEs – multifamily 830,504 545 (1,190 ) 829,859 4,420,361 4,563 (26,054 ) 4,398,870 Total $ 5,364,170 $ 4,563 $ (87,163 ) $ 5,281,570 _______________________ (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. 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 GSEs 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 GSEs – single-family 3,649,964 681 (88,486 ) 3,562,159 GSEs – 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 5.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position (dollars in thousands) June 30, 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 $ 11,552 $ (1,248 ) $ 40,008 $ (2,692 ) $ 51,560 $ (3,940 ) Supranational institutions — — 419,185 (15,733 ) 419,185 (15,733 ) U.S. government-owned corporations — — 290,058 (32,237 ) 290,058 (32,237 ) GSEs — — 121,897 (9,199 ) 121,897 (9,199 ) 11,552 (1,248 ) 871,148 (59,861 ) 882,700 (61,109 ) MBS U.S. government guaranteed – single-family 13,578 (1 ) 51,504 (1,840 ) 65,082 (1,841 ) U.S. government guaranteed – multifamily — — 337,450 (2,501 ) 337,450 (2,501 ) GSEs – single-family 22,012 (44 ) 2,287,693 (20,478 ) 2,309,705 (20,522 ) GSEs – multifamily 661,092 (1,190 ) — — 661,092 (1,190 ) 696,682 (1,235 ) 2,676,647 (24,819 ) 3,373,329 (26,054 ) Total temporarily impaired $ 708,234 $ (2,483 ) $ 3,547,795 $ (84,680 ) $ 4,256,029 $ (87,163 ) 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 ) GSEs — — 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 ) GSEs – single-family 53,122 (388 ) 3,417,076 (88,098 ) 3,470,198 (88,486 ) GSEs – 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 5.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) June 30, 2019 December 31, 2018 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 7,600 $ 7,457 $ — $ — Due after one year through five years 47,900 44,104 55,500 49,601 Due after five years through 10 years 483,205 466,369 465,248 450,102 Due after 10 years 405,104 364,770 374,126 343,849 943,809 882,700 894,874 843,552 MBS (1) 4,420,361 4,398,870 5,108,028 5,006,392 Total $ 5,364,170 $ 5,281,570 $ 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	6 Months Ended
	Jun. 30, 2019
Debt Securities, Held-to-maturity [Abstract]
Held-to-maturity Securities Disclosure [Text Block]	Held-to-Maturity Securities Table 6.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) June 30, 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 $ 101,005 $ — $ 101,005 $ 4 $ (4,608 ) $ 96,401 MBS U.S. government guaranteed – single-family 7,609 — 7,609 148 — 7,757 GSEs – single-family 358,498 — 358,498 6,406 (313 ) 364,591 GSEs – multifamily 207,120 — 207,120 2,123 — 209,243 Private-label – residential 622,943 (116,622 ) 506,321 220,673 (1,559 ) 725,435 Asset-backed securities (ABS) backed by home equity loans 6,399 (15 ) 6,384 16 (233 ) 6,167 1,202,569 (116,637 ) 1,085,932 229,366 (2,105 ) 1,313,193 Total $ 1,303,574 $ (116,637 ) $ 1,186,937 $ 229,370 $ (6,713 ) $ 1,409,594 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 GSEs – single-family 412,639 — 412,639 6,861 (1,389 ) 418,111 GSEs – multifamily 209,786 — 209,786 1,728 — 211,514 Private-label – residential 682,124 (129,135 ) 552,989 234,063 (2,671 ) 784,381 ABS backed by home equity loans 6,781 (18 ) 6,763 20 (256 ) 6,527 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 6.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position (dollars in thousands) June 30, 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 $ 6,197 $ (7 ) $ 89,364 $ (4,601 ) $ 95,561 $ (4,608 ) MBS GSEs – single-family 892 (8 ) 46,957 (305 ) 47,849 (313 ) Private-label – residential 23,828 (341 ) 89,794 (2,785 ) 113,622 (3,126 ) ABS backed by home equity loans 670 (5 ) 5,375 (228 ) 6,045 (233 ) 25,390 (354 ) 142,126 (3,318 ) 167,516 (3,672 ) Total $ 31,587 $ (361 ) $ 231,490 $ (7,919 ) $ 263,077 $ (8,280 ) 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 GSEs – single-family 69,377 (580 ) 52,237 (809 ) 121,614 (1,389 ) Private-label – residential 24,921 (326 ) 109,296 (4,336 ) 134,217 (4,662 ) ABS backed by home equity loans 759 (5 ) 5,641 (251 ) 6,400 (256 ) 95,057 (911 ) 167,174 (5,396 ) 262,231 (6,307 ) Total $ 101,253 $ (920 ) $ 259,996 $ (9,999 ) $ 361,249 $ (10,919 ) Table 6.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) June 30, 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 $ 835 $ 835 $ 839 $ 1,043 $ 1,043 $ 1,047 Due after one year through five years 6,205 6,205 6,197 6,205 6,205 6,196 Due after five years through 10 years 16,145 16,145 15,982 16,865 16,865 16,639 Due after 10 years 77,820 77,820 73,383 80,560 80,560 76,183 101,005 101,005 96,401 104,673 104,673 100,065 MBS (2) 1,202,569 1,085,932 1,313,193 1,319,503 1,190,350 1,428,864 Total $ 1,303,574 $ 1,186,937 $ 1,409,594 $ 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.

Other-Than-Temporary Impairment

Other-Than-Temporary Impairment	6 Months Ended
	Jun. 30, 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 June 30, 2019 . At June 30, 2019 , we held certain available-for-sale securities in an unrealized loss position. These unrealized losses reflect the impact of normal yield and spread fluctuations attendant with security markets. 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 June 30, 2019 . Private-Label Residential MBS and ABS Backed by Home Equity Loans. For those securities for which a credit loss was recognized during the three months ended June 30, 2019 , Table 7.1 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 7.1 - Significant Inputs and Current Credit Enhancement for Securities with a Current Period Credit Loss (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) $ 42,077 11.6 % 22.7 % 52.5 % 8.2 % _______________________ (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 7.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) June 30, 2019 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 22,079 $ 18,795 $ 14,894 $ 20,597 Private-label residential MBS – Alt-A 744,851 533,651 420,930 635,846 ABS backed by home equity loans – Subprime 146 138 123 139 Total other-than-temporarily impaired securities $ 767,076 $ 552,584 $ 435,947 $ 656,582 _______________________ (1) Securities are classified based on the classifications of their underlying loan composition at the time of issuance. We have instituted 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 7.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Balance at beginning of period $ 414,595 $ 445,286 $ 422,035 $ 452,523 Additions: Credit losses for which other-than-temporary impairment was not previously recognized 93 — 102 — Additional credit losses for which an other-than-temporary impairment charge was previously recognized 221 257 315 336 Reductions: Securities matured during the period — — (485 ) — 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 (1) (6,962 ) (8,228 ) (14,020 ) (15,544 ) Balance at end of period $ 407,947 $ 437,315 $ 407,947 $ 437,315 _______________________ (1) For the three and six months ended June 30, 2019 , the amount excludes an additional $15 thousand and $263 thousand , respectively, for bonds previously paid off.

Advances

Advances	6 Months Ended
	Jun. 30, 2019
Advances [Abstract]
Federal Home Loan Bank, Advances [Text Block]	Advances General Terms. At both June 30, 2019 , and December 31, 2018 , we had advances outstanding with interest rates ranging from zero percent to 7.72 percent . Table 8.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) June 30, 2019 December 31, 2018 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 446 2.67 % $ 12,332 2.88 % Due in one year or less 24,192,583 2.44 24,029,592 2.48 Due after one year through two years 5,600,803 2.42 11,413,640 2.55 Due after two years through three years 2,782,869 2.54 2,832,290 2.47 Due after three years through four years 2,073,720 2.65 1,648,076 2.37 Due after four years through five years 1,363,453 2.40 1,980,468 2.24 Thereafter 1,062,673 2.88 1,351,987 2.99 Total par value 37,076,547 2.47 % 43,268,385 2.50 % Premiums 14,661 13,347 Discounts (38,045 ) (38,036 ) Fair value of bifurcated derivatives (1) 33,837 13,051 Hedging adjustments 9,797 (64,525 ) Total $ 37,096,797 $ 43,192,222 _________________________ (1) At June 30, 2019 , and December 31, 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 8.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (dollars in thousands) June 30, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 446 $ 12,332 Due in one year or less 27,543,358 32,748,467 Due after one year through two years 3,350,803 3,913,640 Due after two years through three years 2,571,269 2,672,290 Due after three years through four years 1,538,520 1,261,176 Due after four years through five years 1,063,453 1,362,468 Thereafter 1,008,698 1,298,012 Total par value $ 37,076,547 $ 43,268,385 Table 8.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value June 30, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 446 $ 12,332 Due in one year or less 25,312,183 25,199,892 Due after one year through two years 5,776,703 11,652,840 Due after two years through three years 2,762,369 2,834,790 Due after three years through four years 1,261,620 1,367,576 Due after four years through five years 1,060,053 1,152,468 Thereafter 903,173 1,048,487 Total par value $ 37,076,547 $ 43,268,385 Table 8.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances June 30, 2019 December 31, 2018 Fixed-rate $ 33,080,226 $ 33,570,278 Variable-rate 3,996,321 9,698,107 Total par value $ 37,076,547 $ 43,268,385 Credit-Risk Exposure and Security Terms . Our potential credit risk from advances is principally concentrated in commercial banks, insurance companies, savings institutions, and credit unions. At June 30, 2019 , and December 31, 2018 , we had $12.2 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 six borrowers at both June 30, 2019 , and December 31, 2018 , representing 32.9 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 10 — Allowance for Credit Losses . Prepayment Fees. Table 8.5 - Advances Prepayment Fees (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Prepayment fees received from borrowers $ 2,669 $ 5 $ 28,855 $ 65 Hedging fair-value adjustments on prepaid advances 1,399 2 1,926 98 Net (premiums) discounts associated with prepaid advances (61 ) — 157 — Deferred recognition of prepayment fees received from borrowers on advance prepayments deemed to be loan modifications (201 ) — (201 ) — Advance prepayment fees recognized in income, net $ 3,806 $ 7 $ 30,737 $ 163

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	6 Months Ended
	Jun. 30, 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. Table 9.1 - Mortgage Loans Held for Portfolio (dollars in thousands) June 30, 2019 December 31, 2018 Real estate Fixed-rate 15-year single-family mortgages $ 362,600 $ 392,128 Fixed-rate 20- and 30-year single-family mortgages 3,989,123 3,839,078 Premiums 67,790 67,671 Discounts (1,762 ) (1,800 ) Deferred derivative gains, net 3,777 2,825 Total mortgage loans held for portfolio 4,421,528 4,299,902 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,421,028 $ 4,299,402 Table 9.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) June 30, 2019 December 31, 2018 Conventional mortgage loans $ 4,036,974 $ 3,902,555 Government mortgage loans 314,749 328,651 Total par value $ 4,351,723 $ 4,231,206 See Note 10 — 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. "Mortgage Partnership Finance," and "MPF" are registered trademarks of the Federal Home Loan Bank of Chicago.

Allowance for Credit Losses

Allowance for Credit Losses	6 Months Ended
	Jun. 30, 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. For additional information see Item 8 — Financial Statements and Supplementary Data — Note 11 — Allowance for Credit Losses in the 2018 Annual Report. 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. At June 30, 2019 , and December 31, 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 secured member credit products during the six months ended June 30, 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 June 30, 2019 , and December 31, 2018 . At June 30, 2019 , and December 31, 2018 , no liability to reflect an allowance for credit losses for off-balance-sheet credit exposures was recorded. See Note 18 — Commitments and Contingencies for additional information on our off-balance-sheet credit exposure. Government Mortgage Loans Held for Portfolio 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 June 30, 2019 , and December 31, 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. For additional information see Item 8 — Financial Statements and Supplementary Data — Note 11 — Allowance for Credit Losses in the 2018 Annual Report. Conventional Mortgage Loans Held for Portfolio For information on conventional mortgage loans held for portfolio see Item 8 — Financial Statements and Supplementary Data — Note 11 — Allowance for Credit Losses in the 2018 Annual Report. Credit Quality Indicators. Key credit quality indicators for mortgage loans include past due loans, nonaccrual loans, loans in process of foreclosure, and impaired loans. Table 10.1 sets forth certain key credit quality indicators for our investments in mortgage loans at June 30, 2019 , and December 31, 2018 (dollars in thousands): Table 10.1 - Recorded Investment in Delinquent Mortgage Loans (dollars in thousands) June 30, 2019 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 26,089 $ 11,736 $ 37,825 Past due 60-89 days delinquent 4,522 3,422 7,944 Past due 90 days or more delinquent 10,216 5,664 15,880 Total past due 40,827 20,822 61,649 Total current loans 4,080,680 301,961 4,382,641 Total mortgage loans $ 4,121,507 $ 322,783 $ 4,444,290 Other delinquency statistics In process of foreclosure, included above (1) $ 4,159 $ 2,721 $ 6,880 Serious delinquency rate (2) 0.26 % 1.75 % 0.37 % Past due 90 days or more still accruing interest $ — $ 5,664 $ 5,664 Loans on nonaccrual status (3) $ 10,951 $ — $ 10,951 _______________________ (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. 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. For additional information see Item 8 — Financial Statements and Supplementary Data — Note 11 — Allowance for Credit Losses in the 2018 Annual Report. Allowance for Credit Losses on Mortgage Loans. Table 10.2 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the three and six months ended June 30, 2019 and 2018 , as well as the recorded investment in mortgage loans by impairment methodology at June 30, 2019 and 2018 . 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 10.2 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Allowance for credit losses Balance, beginning of period $ 500 $ 500 $ 500 $ 500 (Charge-offs) recoveries (12 ) 3 (15 ) (6 ) Provision for (reduction of) credit losses 12 (3 ) 15 6 Balance, end of period $ 500 $ 500 $ 500 $ 500 Ending balance, individually evaluated for impairment $ — $ — $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 500 $ 500 $ 500 Recorded investment, end of period (1) Individually evaluated for impairment $ 14,447 $ 15,653 $ 14,447 $ 15,653 Collectively evaluated for impairment $ 4,107,060 $ 3,725,529 $ 4,107,060 $ 3,725,529 _________________________ (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 Activit

Derivatives and Hedging Activities	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities Table 11.1 - Fair Value of Derivative Instruments (dollars in thousands) June 30, 2019 December 31, 2018 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 10,858,944 $ 9,625 $ (19,724 ) $ 11,980,699 $ 12,811 $ (296,324 ) Forward-start interest-rate swaps 93,000 14 (7 ) 282,000 — (753 ) Total derivatives designated as hedging instruments 10,951,944 9,639 (19,731 ) 12,262,699 12,811 (297,077 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,806,800 569 (33,472 ) 927,800 682 (12,475 ) Mortgage-delivery commitments (1) 53,555 200 (8 ) 50,773 339 — Total derivatives not designated as hedging instruments 1,860,355 769 (33,480 ) 978,573 1,021 (12,475 ) Total notional amount of derivatives $ 12,812,299 $ 13,241,272 Total derivatives before netting and collateral adjustments 10,408 (53,211 ) 13,832 (309,552 ) Netting adjustments and cash collateral, including related accrued interest (2) 57,353 41,497 8,571 53,752 Derivative assets and derivative liabilities $ 67,761 $ (11,714 ) $ 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 $99.3 million and $62.8 million at June 30, 2019 , and December 31, 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 $401 thousand and $471 thousand at June 30, 2019 , and December 31, 2018 , respectively. 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 (losses) on derivatives and hedging activities. Table 11.2 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 11.2 - Net Gains (Losses) on Fair Value and Cash Flow Hedging Relationships (dollars in thousands) For the Three Months Ended June 30, 2019 Interest Income/Expense Advances Available-for-sale Securities Consolidated Obligation Bonds Other Comprehensive Income (Loss) Total interest income (expense) in the statements of operations $ 223,869 $ 21,655 $ (150,715 ) Gains (losses) on fair-value hedging relationships Interest rate contracts Derivatives (1) $ (36,409 ) $ (35,719 ) $ 29,302 $ — Hedged items 48,044 31,270 (34,568 ) — Net gains (losses) on fair value hedging relationships $ 11,635 $ (4,449 ) $ (5,266 ) $ — Gains (losses) on cash-flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,131 ) $ — Recognized in other comprehensive loss — — — (2,443 ) For the Three Months Ended June 30, 2018 (2) Interest Income/Expense Net Gains (Losses) on Derivatives and Hedging Activities Other Comprehensive Income (Loss) Advances Available-for-sale Securities Consolidated Obligation Bonds Total income (expense) in the statements of operations $ 213,920 $ 37,221 $ (136,556 ) $ 458 Gains (losses) on fair value hedging relationships Interest rate contracts Derivatives (1) $ 14,537 $ (6,464 ) $ (8,513 ) $ 13,385 $ — Hedged items — — — (12,910 ) — Net gains (losses) on fair value hedging relationships $ 14,537 $ (6,464 ) $ (8,513 ) $ 475 $ — Gains (losses) on cash flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,014 ) $ — $ — Recognized in income for hedge ineffectiveness — — — 85 — Recognized in other comprehensive loss for hedge effectiveness — — — — 2,582 _______________________ (1) Includes net interest settlements. (2) Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019. Table 11.2 - Net Gains (Losses) on Fair Value and Cash Flow Hedging Relationships (dollars in thousands) For the Six Months Ended June 30, 2019 Interest Income/Expense Advances Available-for-sale Securities Consolidated Obligation Bonds Other Comprehensive Income (Loss) Total interest income (expense) in the statements of operations $ 471,746 $ 42,946 $ (305,532 ) Gains (losses) on fair-value hedging relationships Interest rate contracts Derivatives (1) $ (44,769 ) $ (64,699 ) $ 53,863 $ — Hedged items 73,272 50,385 (69,276 ) — Net gains (losses) on fair value hedging relationships $ 28,503 $ (14,314 ) $ (15,413 ) $ — Gains (losses) on cash-flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,917 ) $ — Recognized in other comprehensive loss — — — (5,822 ) For the Six Months Ended June 30, 2018 (2) Interest Income/Expense Net Gains (Losses) on Derivatives and Hedging Activities Other Comprehensive Income (Loss) Advances Available-for-sale Securities Consolidated Obligation Bonds Total income (expense) in the statements of operations $ 391,370 $ 77,999 $ (255,757 ) $ 1,598 Gains (losses) on fair value hedging relationships Interest rate contracts Derivatives (1) $ 20,232 $ (13,775 ) $ (11,530 ) $ 50,257 $ — Hedged items — — — (48,674 ) — Net gains (losses) on fair value hedging relationships $ 20,232 $ (13,775 ) $ (11,530 ) $ 1,583 $ — Gains (losses) on cash flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,948 ) $ — $ — Recognized in income for hedge ineffectiveness — — — 161 — Recognized in other comprehensive loss for hedge effectiveness — — — — 11,748 _______________________ (1) Includes net interest settlements. (2) Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019. For the six months ended June 30, 2019 and 2018 , 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 June 30, 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 June 30, 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 $6.8 million . Table 11.3 - Cumulative Basis Adjustments for Fair-Value Hedges (dollars in thousands) June 30, 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 $ 5,312,448 $ 43,634 $ 10,335 $ 53,969 Available-for-sale securities 1,157,556 252,353 — 252,353 Consolidated bonds (4,775,299 ) (9,638 ) (37,111 ) (46,749 ) _______________________ (1) Includes only the portion of amortized cost representing the hedged items in fair-value hedging relationships. Table 11.4 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Derivatives designated as hedging instruments: Total net gains related to fair-value hedges (1) $ 475 $ 1,583 Total net gains related to cash-flow hedges (2) 85 161 Total net gains related to derivatives designated as hedging instruments 560 1,744 Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps $ (1,427 ) 98 $ (1,487 ) 722 Mortgage-delivery commitments 462 51 1,070 (467 ) Total net (losses) gains related to derivatives not designated as hedging instruments (965 ) 149 (417 ) 255 Other (3) 3 (251 ) 3 (401 ) Net (losses) gains on derivatives and hedging activities $ (962 ) $ 458 $ (414 ) $ 1,598 ______________________ (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 six months ended June 30, 2019 , we terminated certain uncleared interest-rate exchange agreements with a total notional amount of $611.9 million and were indexed to three-month London Interbank Offered Rate (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 six months ended June 30, 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 enter into derivatives that we clear (cleared derivatives) with a DCO, our counterparty for such derivatives. We also enter into derivatives that are not cleared (uncleared derivatives) under master-netting agreements. 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 Investors Services (Moody's) or Standard & Poor's Rating Service (S&P) to a certain level, we are required to deliver additional collateral on uncleared derivatives in a net liability position. 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 June 30, 2019 , was $46.7 million for which we had delivered collateral with a post-haircut value of $46.2 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 11.5 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 June 30, 2019 . Table 11.5 - Post Haircut Value of Incremental Collateral to be Delivered as of June 30, 2019 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 370 AA- A+, A or A- — A- below A- 7,372 _______________________ (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 U.S. Commodity Futures Trading Commission (the 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 June 30, 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 derivatives and determined that those rights, rules, and regulations should result in a net claim through each of our clearing members with the related DCO upon an event of default including a bankruptcy, insolvency or similar proceeding involving the DCO or one of our clearing members, or both. For this purpose, "net claim" generally means a single net amount reflecting the aggregation of all amounts indirectly owed by us to the relevant DCO and indirectly payable to us from the relevant DCO. Table 11.6 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 June 30, 2019 , and December 31, 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 11.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) June 30, 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 $ 7,875 $ (5,897 ) $ 200 $ 2,178 $ (1,171 ) $ — $ 1,007 Cleared 2,332 63,251 65,583 — — 65,583 Total $ 67,761 $ 66,590 Derivative Liabilities Uncleared $ (52,883 ) $ 41,177 $ (8 ) $ (11,714 ) $ 700 $ 9,762 $ (1,252 ) Cleared (320 ) 320 — — — — Total $ (11,714 ) $ (1,252 ) _______________________ (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 June 30, 2019 , we had additional net credit exposure of $371 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 $ 12,861 $ (11,885 ) $ 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	6 Months Ended
	Jun. 30, 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. Table 12.1 - Deposits (dollars in thousands) June 30, 2019 December 31, 2018 Interest-bearing Demand and overnight $ 558,060 $ 444,486 Term 1,303 800 Other 2,524 2,961 Noninterest-bearing Other 32,961 26,631 Total deposits $ 594,848 $ 474,878

Consolidated Obligations

Consolidated Obligations	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Consolidated Obligations [Text Block]	Consolidated Obligations CO Bonds. CO bonds for which we have received issuance proceeds and are primarily liable were as follows: Table 13.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) June 30, 2019 December 31, 2018 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 9,921,050 2.27 % $ 9,638,270 2.01 % Due after one year through two years 5,117,975 2.16 5,375,845 2.24 Due after two years through three years 3,190,500 2.21 3,864,560 2.17 Due after three years through four years 1,903,105 2.28 1,891,975 2.20 Due after four years through five years 1,061,715 2.50 1,338,515 2.39 Thereafter 4,021,335 3.21 3,792,150 3.25 Total par value 25,215,680 2.40 % 25,901,315 2.30 % Premiums 82,048 88,434 Discounts (14,876 ) (16,133 ) Hedging adjustments 9,638 (60,932 ) $ 25,292,490 $ 25,912,684 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Table 13.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds June 30, 2019 December 31, 2018 Noncallable and nonputable $ 20,558,680 $ 20,419,315 Callable 4,657,000 5,482,000 Total par value $ 25,215,680 $ 25,901,315 Table 13.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date June 30, 2019 December 31, 2018 Due in one year or less $ 13,328,050 $ 13,435,270 Due after one year through two years 5,004,975 5,602,845 Due after two years through three years 2,583,500 2,802,560 Due after three years through four years 1,648,105 1,366,975 Due after four years through five years 804,715 1,156,515 Thereafter 1,846,335 1,537,150 Total par value $ 25,215,680 $ 25,901,315 Table 13.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds June 30, 2019 December 31, 2018 Fixed-rate $ 20,017,680 $ 21,216,315 Simple variable-rate 3,741,000 2,853,000 Step-up 1,457,000 1,832,000 Total par value $ 25,215,680 $ 25,901,315 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 13.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) June 30, 2019 $ 26,424,978 $ 26,499,124 2.31 % 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	6 Months Ended
	Jun. 30, 2019
Affordable Housing Program [Abstract]
Affordable Housing Program [Text Block]	Affordable Housing Program Table 14.1 - AHP Liability (dollars in thousands) June 30, 2019 December 31, 2018 Balance at beginning of period $ 83,965 $ 81,600 AHP expense for the period 10,072 24,299 AHP direct grant disbursements (6,454 ) (17,729 ) AHP subsidy for AHP advance disbursements (1,598 ) (4,360 ) Return of previously disbursed grants and subsidies 6 155 Balance at end of period $ 85,991 $ 83,965

Capital

Capital	6 Months Ended
	Jun. 30, 2019
Stockholders' Equity Note [Abstract]
Capital [Text Block]	Capital We are subject to capital requirements under our capital plan, the FHLBank Act, 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 15.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements June 30, December 31, Permanent capital Class B capital stock $ 1,995,252 $ 2,528,854 Mandatorily redeemable capital stock 17,107 31,868 Retained earnings 1,416,326 1,395,012 Total permanent capital $ 3,428,685 $ 3,955,734 Risk-based capital requirement Credit-risk capital $ 265,041 $ 289,080 Market-risk capital 162,581 187,183 Operations-risk capital 128,287 142,879 Total risk-based capital requirement $ 555,909 $ 619,142 Permanent capital in excess of risk-based capital requirement $ 2,872,776 $ 3,336,592 June 30, 2019 December 31, 2018 Required Actual Required Actual Capital Ratio Risk-based capital $ 555,909 $ 3,428,685 $ 619,142 $ 3,955,734 Total regulatory capital $ 2,231,181 $ 3,428,685 $ 2,543,733 $ 3,955,734 Total capital-to-asset ratio 4.0 % 6.1 % 4.0 % 6.2 % Leverage Ratio Leverage capital $ 2,788,977 $ 5,143,028 $ 3,179,666 $ 5,933,601 Leverage capital-to-assets ratio 5.0 % 9.2 % 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.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2019
AOCI Attributable to Parent [Abstract]
Accumulated Other Comprehensive Loss [Text Block]	Accumulated Other Comprehensive Loss Table 16.1 - 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 Gain (Loss) Relating to Hedging Activities Pension and Postretirement Benefits Total Balance, March 31, 2018 $ (153,953 ) $ (150,790 ) $ (30,332 ) $ (5,770 ) $ (340,845 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (13,968 ) — 2,582 — (11,386 ) Accretion of noncredit loss — 7,462 — — 7,462 Net actuarial loss — — — (1,460 ) (1,460 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 132 — — 132 Amortization - hedging activities (2) — — 1,017 — 1,017 Amortization - pension and postretirement benefits (3) — — — 490 490 Other comprehensive (loss) income (13,968 ) 7,594 3,599 (970 ) (3,745 ) Balance, June 30, 2018 $ (167,921 ) $ (143,196 ) $ (26,733 ) $ (6,740 ) $ (344,590 ) Balance, March 31, 2019 $ (118,893 ) $ (122,913 ) $ (31,887 ) $ (5,115 ) $ (278,808 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 36,293 — (2,443 ) — 33,850 Noncredit other-than-temporary impairment losses — (101 ) — — (101 ) Accretion of noncredit loss — 6,188 — — 6,188 Net actuarial gain — — — 19 19 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 188 — — 188 Amortization - hedging activities (4) — — 1,131 — 1,131 Amortization - pension and postretirement benefits (3) — — — 171 171 Other comprehensive income (loss) 36,293 6,275 (1,312 ) 190 41,446 Balance, June 30, 2019 $ (82,600 ) $ (116,638 ) $ (33,199 ) $ (4,925 ) $ (237,362 ) _______________________ (1) Recorded in net other-than-temporary impairment losses in investment securities, credit portion in the statement of operations. (2) Amortization of hedging activities includes $1.0 million recorded in CO bond interest expense and $3 thousand recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Recorded in CO bond interest expense. Table 16.1 - 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 Gain (Loss) Relating to Hedging Activities Pension and Postretirement Benefits Total Balance, December 31, 2017 $ (122,331 ) $ (158,218 ) $ (40,436 ) $ (5,955 ) $ (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (45,590 ) — 11,748 — (33,842 ) Accretion of noncredit loss — 14,818 — — 14,818 Net actuarial loss — — — (1,460 ) (1,460 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 204 — — 204 Amortization - hedging activities (2) — — 1,955 — 1,955 Amortization - pension and postretirement benefits (3) — — — 675 675 Other comprehensive (loss) income (45,590 ) 15,022 13,703 (785 ) (17,650 ) Balance, June 30, 2018 $ (167,921 ) $ (143,196 ) $ (26,733 ) $ (6,740 ) $ (344,590 ) 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) 70,358 — (5,822 ) — 64,536 Noncredit other-than-temporary impairment losses — (181 ) — — (181 ) Accretion of noncredit loss — 12,479 — — 12,479 Net actuarial gain — — — 19 19 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 218 — — 218 Amortization - hedging activities (4) — — 1,917 — 1,917 Amortization - pension and postretirement benefits (3) — — — 332 332 Other comprehensive income (loss) 70,358 12,516 (3,905 ) 351 79,320 Balance, June 30, 2019 $ (82,600 ) $ (116,638 ) $ (33,199 ) $ (4,925 ) $ (237,362 ) _______________________ (1) Recorded in net other-than-temporary impairment losses in investment securities, credit portion in the statement of operations. (2) Amortization of hedging activities includes $1.9 million recorded in CO bond interest expense and $7 thousand recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Recorded in CO bond interest expense.

Fair Values

Fair Values	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value [Text Block]	Fair Values A fair-value hierarchy is used to prioritize the inputs of valuation techniques used to measure fair value. A description of the application of the fair-value hierarchy, valuation techniques, and significant inputs is disclosed in Item 8 — Financial Statements and Supplementary Data — Note 19 — Fair Values in the 2018 Annual Report. There have been no material changes in the fair-value hierarchy classification of financial assets and liabilities, valuation techniques, or significant inputs during the three months ended June 30, 2019 . Table 17.1 presents the carrying value, fair value, and fair value hierarchy of our financial assets and liabilities at June 30, 2019 , and December 31, 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 17.2 for further details about the financial assets and liabilities held at fair value on either a recurring or nonrecurring basis. Table 17.1 - Fair Value Summary (dollars in thousands) June 30, 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 $ 28,739 $ 28,739 $ 28,739 $ — $ — $ — Interest-bearing deposits 1,146,961 1,146,961 1,146,961 — — — Securities purchased under agreements to resell 5,000,000 5,000,054 — 5,000,054 — — Federal funds sold 250,000 250,000 — 250,000 — — Trading securities (1) 1,097,963 1,097,963 — 1,097,963 — — Available-for-sale securities (1) 5,281,570 5,281,570 — 5,230,010 51,560 — Held-to-maturity securities 1,186,937 1,409,594 — 581,591 828,003 — Advances 37,096,797 37,208,993 — 37,208,993 — — Mortgage loans, net 4,421,028 4,508,857 — 4,488,116 20,741 — Accrued interest receivable 117,793 117,793 — 117,793 — — Derivative assets (1) 67,761 67,761 — 10,408 — 57,353 Other assets (1) 30,746 30,746 12,200 18,546 — — Liabilities: Deposits (594,848 ) (594,831 ) — (594,831 ) — — COs: Bonds (25,292,490 ) (25,565,210 ) — (25,565,210 ) — — Discount notes (26,424,978 ) (26,426,741 ) — (26,426,741 ) — — Mandatorily redeemable capital stock (17,107 ) (17,107 ) (17,107 ) — — — Accrued interest payable (119,293 ) (119,293 ) — (119,293 ) — — Derivative liabilities (1) (11,714 ) (11,714 ) — (53,211 ) — 41,497 Other: Commitments to extend credit for advances — (2,946 ) — (2,946 ) — — Standby letters of credit (1,746 ) (1,746 ) — (1,746 ) — — _______________________ (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. 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 a Recurring and Nonrecurring Basis. Table 17.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (dollars in thousands) June 30, 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 $ — $ 6,208 $ — $ — $ 6,208 U.S. Treasury obligations — 1,003,118 — — 1,003,118 U.S. government-guaranteed – single-family MBS — 4,701 — — 4,701 GSEs – single-family MBS — 107 — — 107 GSEs – multifamily MBS — 83,829 — — 83,829 Total trading securities — 1,097,963 — — 1,097,963 Available-for-sale securities: State or local HFA securities — — 51,560 — 51,560 Supranational institutions — 419,185 — — 419,185 U.S. government-owned corporations — 290,058 — — 290,058 GSEs — 121,897 — — 121,897 U.S. government guaranteed – single-family MBS — 66,558 — — 66,558 U.S. government guaranteed – multifamily MBS — 337,450 — — 337,450 GSEs – single-family MBS — 3,165,003 — — 3,165,003 GSEs – multifamily MBS — 829,859 — — 829,859 Total available-for-sale securities — 5,230,010 51,560 — 5,281,570 Derivative assets: Interest-rate-exchange agreements — 10,208 — 57,353 67,561 Mortgage delivery commitments — 200 — — 200 Total derivative assets — 10,408 — 57,353 67,761 Other assets 12,200 18,546 — — 30,746 Total assets carried at fair value on a recurring basis $ 12,200 $ 6,356,927 $ 51,560 $ 57,353 $ 6,478,040 Carried at fair value on a nonrecurring basis (2) Held-to-maturity securities: Private-label residential MBS $ — $ — $ 7,048 $ — $ 7,048 Mortgage loans held for portfolio — — 472 — 472 REO — — 5 — 5 Total assets carried at fair value on a nonrecurring basis $ — $ — $ 7,525 $ — $ 7,525 Liabilities: Carried at fair value on a recurring basis Derivative liabilities Interest-rate-exchange agreements $ — $ (53,203 ) $ — $ 41,497 $ (11,706 ) Mortgage delivery commitments — (8 ) — — (8 ) Total liabilities carried at fair value on a recurring basis $ — $ (53,211 ) $ — $ 41,497 $ (11,714 ) _______________________ (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 real estate owned property (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. 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 GSEs – single-family MBS — 148 — — 148 GSEs – multifamily MBS — 151,444 — — 151,444 Total trading securities — 163,038 — — 163,038 Available-for-sale securities: State or local HFA securities — — 49,601 — 49,601 Supranational institutions — 405,155 — — 405,155 U.S. government-owned corporations — 273,169 — — 273,169 GSEs — 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 GSEs – single-family MBS — 3,562,159 — — 3,562,159 GSEs – 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 residential 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 17.3 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 three and six months ended June 30, 2019 and 2018 . Table 17.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Balance at beginning of period $ 50,348 $ 37,495 $ 49,601 $ 37,683 Unrealized gains (losses) included in other comprehensive income 1,212 105 1,959 (83 ) Balance at end of period $ 51,560 $ 37,600 $ 51,560 $ 37,600

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 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 June 30, 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 June 30, 2019 , and December 31, 2018 . The par amounts of other FHLBanks' outstanding COs for which we are jointly and severally liable totaled $ 996.7 billion and $972.6 billion at June 30, 2019 , and December 31, 2018 , respectively. See Note 13 — Consolidated Obligations for additional information. Off-Balance-Sheet Commitments Table 18.1 - Off-Balance Sheet Commitments (dollars in thousands) June 30, 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) $ 7,850,041 $ 282,032 $ 8,132,073 $ 6,028,851 $ 226,438 $ 6,255,289 Commitments for unused lines of credit - advances (2) 1,162,632 — 1,162,632 1,177,377 — 1,177,377 Commitments to make additional advances 122,330 60,310 182,640 159,401 59,894 219,295 Commitments to invest in mortgage loans 53,555 — 53,555 50,773 — 50,773 Unsettled CO bonds, at par 23,000 — 23,000 105,400 — 105,400 Unsettled CO discount notes, at par — — — 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 June 30, 2019 , and December 31, 2018 , these amounts totaled $ 27.0 million and $32.6 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $675 thousand at December 31, 2018 . (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 federal and state 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. The terms of these standby letters of credit have original expiration periods of up to 20 years , currently 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 June 30, 2019 , and December 31, 2018 , respectively. 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 11 — 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.

Transactions with Shareholders

Transactions with Shareholders	6 Months Ended
	Jun. 30, 2019
Transactions with Shareholders [Abstract]
Transactions with Shareholders [Text Block]	Transactions with Shareholders 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 any time during the period. Table 19.1 - 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 June 30, 2019 Citizens Bank, N.A. $ 121,572 6.0 % $ 2,555,961 6.9 % $ 1,855 3.2 % 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 19.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, Citizens Bank, N.A. 2019 2018 2019 2018 Interest income on advances $ 21,958 $ 29,192 $ 61,071 $ 56,084 Fees on letters of credit 1,641 984 3,519 2,081 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 19.3 - 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 June 30, 2019 $ 86,052 4.3 % $ 1,728,192 4.7 % $ 3,234 5.5 % As of December 31, 2018 113,337 4.4 2,147,602 5.0 3,576 6.0

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On July 26, 2019 , the board of directors declared a cash dividend at an annualized rate of 6.04 percent based on capital stock balances outstanding during the second quarter of 2019. The dividend, including dividends classified as interest on mandatorily redeemable capital stock, amounted to $28.1 million and was paid on August 2, 2019 .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Investment, Policy	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. We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter.
Property, Plant and Equipment, Policy	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	The cost of purchased software and certain costs incurred in developing computer software for internal use are capitalized and amortized over future periods.
Federal Home Loan Bank Advances , Policy	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.
Derivatives, Policy	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.
Fair Value of Financial Instruments, Policy [Policy Text Block]	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). We measure certain held-to-maturity investment securities, mortgage loans held for portfolio, and real estate owned property (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
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)	6 Months Ended
	Jun. 30, 2019
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Trading Securities by Major Security Type [Table Text Block]	Table 4.1 - Trading Securities by Major Security Type (dollars in thousands) June 30, 2019 December 31, 2018 Corporate bonds $ 6,208 $ 6,102 U.S. Treasury obligations 1,003,118 — 1,009,326 6,102 Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 4,701 5,344 Government sponsored enterprise (GSEs) – single-family 107 148 GSEs – multifamily 83,829 151,444 88,637 156,936 Total $ 1,097,963 $ 163,038

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Securities, Available-for-sale [Line Items]
Available-for-Sale (AFS) Securities by Major Security Type [Table Text Block]	Table 5.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) June 30, 2019 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value State or local housing-finance-agency obligations (HFA securities) $ 55,500 $ — $ (3,940 ) $ 51,560 Supranational institutions 434,918 — (15,733 ) 419,185 U.S. government-owned corporations 322,295 — (32,237 ) 290,058 GSEs 131,096 — (9,199 ) 121,897 943,809 — (61,109 ) 882,700 MBS U.S. government guaranteed – single-family 68,392 7 (1,841 ) 66,558 U.S. government guaranteed – multifamily 339,951 — (2,501 ) 337,450 GSEs – single-family 3,181,514 4,011 (20,522 ) 3,165,003 GSEs – multifamily 830,504 545 (1,190 ) 829,859 4,420,361 4,563 (26,054 ) 4,398,870 Total $ 5,364,170 $ 4,563 $ (87,163 ) $ 5,281,570 _______________________ (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. 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 GSEs 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 GSEs – single-family 3,649,964 681 (88,486 ) 3,562,159 GSEs – 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 5.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position (dollars in thousands) June 30, 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 $ 11,552 $ (1,248 ) $ 40,008 $ (2,692 ) $ 51,560 $ (3,940 ) Supranational institutions — — 419,185 (15,733 ) 419,185 (15,733 ) U.S. government-owned corporations — — 290,058 (32,237 ) 290,058 (32,237 ) GSEs — — 121,897 (9,199 ) 121,897 (9,199 ) 11,552 (1,248 ) 871,148 (59,861 ) 882,700 (61,109 ) MBS U.S. government guaranteed – single-family 13,578 (1 ) 51,504 (1,840 ) 65,082 (1,841 ) U.S. government guaranteed – multifamily — — 337,450 (2,501 ) 337,450 (2,501 ) GSEs – single-family 22,012 (44 ) 2,287,693 (20,478 ) 2,309,705 (20,522 ) GSEs – multifamily 661,092 (1,190 ) — — 661,092 (1,190 ) 696,682 (1,235 ) 2,676,647 (24,819 ) 3,373,329 (26,054 ) Total temporarily impaired $ 708,234 $ (2,483 ) $ 3,547,795 $ (84,680 ) $ 4,256,029 $ (87,163 ) 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 ) GSEs — — 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 ) GSEs – single-family 53,122 (388 ) 3,417,076 (88,098 ) 3,470,198 (88,486 ) GSEs – 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 5.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) June 30, 2019 December 31, 2018 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 7,600 $ 7,457 $ — $ — Due after one year through five years 47,900 44,104 55,500 49,601 Due after five years through 10 years 483,205 466,369 465,248 450,102 Due after 10 years 405,104 364,770 374,126 343,849 943,809 882,700 894,874 843,552 MBS (1) 4,420,361 4,398,870 5,108,028 5,006,392 Total $ 5,364,170 $ 5,281,570 $ 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)	6 Months Ended
	Jun. 30, 2019
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities by Major Security Type [Table Text Block]	Table 6.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) June 30, 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 $ 101,005 $ — $ 101,005 $ 4 $ (4,608 ) $ 96,401 MBS U.S. government guaranteed – single-family 7,609 — 7,609 148 — 7,757 GSEs – single-family 358,498 — 358,498 6,406 (313 ) 364,591 GSEs – multifamily 207,120 — 207,120 2,123 — 209,243 Private-label – residential 622,943 (116,622 ) 506,321 220,673 (1,559 ) 725,435 Asset-backed securities (ABS) backed by home equity loans 6,399 (15 ) 6,384 16 (233 ) 6,167 1,202,569 (116,637 ) 1,085,932 229,366 (2,105 ) 1,313,193 Total $ 1,303,574 $ (116,637 ) $ 1,186,937 $ 229,370 $ (6,713 ) $ 1,409,594 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 GSEs – single-family 412,639 — 412,639 6,861 (1,389 ) 418,111 GSEs – multifamily 209,786 — 209,786 1,728 — 211,514 Private-label – residential 682,124 (129,135 ) 552,989 234,063 (2,671 ) 784,381 ABS backed by home equity loans 6,781 (18 ) 6,763 20 (256 ) 6,527 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 6.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position (dollars in thousands) June 30, 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 $ 6,197 $ (7 ) $ 89,364 $ (4,601 ) $ 95,561 $ (4,608 ) MBS GSEs – single-family 892 (8 ) 46,957 (305 ) 47,849 (313 ) Private-label – residential 23,828 (341 ) 89,794 (2,785 ) 113,622 (3,126 ) ABS backed by home equity loans 670 (5 ) 5,375 (228 ) 6,045 (233 ) 25,390 (354 ) 142,126 (3,318 ) 167,516 (3,672 ) Total $ 31,587 $ (361 ) $ 231,490 $ (7,919 ) $ 263,077 $ (8,280 ) 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 GSEs – single-family 69,377 (580 ) 52,237 (809 ) 121,614 (1,389 ) Private-label – residential 24,921 (326 ) 109,296 (4,336 ) 134,217 (4,662 ) ABS backed by home equity loans 759 (5 ) 5,641 (251 ) 6,400 (256 ) 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 6.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) June 30, 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 $ 835 $ 835 $ 839 $ 1,043 $ 1,043 $ 1,047 Due after one year through five years 6,205 6,205 6,197 6,205 6,205 6,196 Due after five years through 10 years 16,145 16,145 15,982 16,865 16,865 16,639 Due after 10 years 77,820 77,820 73,383 80,560 80,560 76,183 101,005 101,005 96,401 104,673 104,673 100,065 MBS (2) 1,202,569 1,085,932 1,313,193 1,319,503 1,190,350 1,428,864 Total $ 1,303,574 $ 1,186,937 $ 1,409,594 $ 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.

Other-Than-Temporary Impairme_2

Other-Than-Temporary Impairment (Tables)	6 Months Ended
	Jun. 30, 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 three months ended June 30, 2019 , Table 7.1 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 7.1 - Significant Inputs and Current Credit Enhancement for Securities with a Current Period Credit Loss (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) $ 42,077 11.6 % 22.7 % 52.5 % 8.2 % _______________________ (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 7.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) June 30, 2019 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 22,079 $ 18,795 $ 14,894 $ 20,597 Private-label residential MBS – Alt-A 744,851 533,651 420,930 635,846 ABS backed by home equity loans – Subprime 146 138 123 139 Total other-than-temporarily impaired securities $ 767,076 $ 552,584 $ 435,947 $ 656,582 _______________________ (1) Securities are classified based on the classifications of their underlying loan composition at the time of issuance. We have instituted 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 7.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Balance at beginning of period $ 414,595 $ 445,286 $ 422,035 $ 452,523 Additions: Credit losses for which other-than-temporary impairment was not previously recognized 93 — 102 — Additional credit losses for which an other-than-temporary impairment charge was previously recognized 221 257 315 336 Reductions: Securities matured during the period — — (485 ) — 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 (1) (6,962 ) (8,228 ) (14,020 ) (15,544 ) Balance at end of period $ 407,947 $ 437,315 $ 407,947 $ 437,315 _______________________ (1) For the three and six months ended June 30, 2019 , the amount excludes an additional $15 thousand and $263 thousand , respectively, for bonds previously paid off.

Advances (Tables)

Advances (Tables)	6 Months Ended
	Jun. 30, 2019
Advances [Abstract]
Advances [Table Text Block]	Table 8.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances June 30, 2019 December 31, 2018 Fixed-rate $ 33,080,226 $ 33,570,278 Variable-rate 3,996,321 9,698,107 Total par value $ 37,076,547 $ 43,268,385 Table 8.5 - Advances Prepayment Fees (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Prepayment fees received from borrowers $ 2,669 $ 5 $ 28,855 $ 65 Hedging fair-value adjustments on prepaid advances 1,399 2 1,926 98 Net (premiums) discounts associated with prepaid advances (61 ) — 157 — Deferred recognition of prepayment fees received from borrowers on advance prepayments deemed to be loan modifications (201 ) — (201 ) — Advance prepayment fees recognized in income, net $ 3,806 $ 7 $ 30,737 $ 163 Table 8.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (dollars in thousands) June 30, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 446 $ 12,332 Due in one year or less 27,543,358 32,748,467 Due after one year through two years 3,350,803 3,913,640 Due after two years through three years 2,571,269 2,672,290 Due after three years through four years 1,538,520 1,261,176 Due after four years through five years 1,063,453 1,362,468 Thereafter 1,008,698 1,298,012 Total par value $ 37,076,547 $ 43,268,385 Table 8.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value June 30, 2019 December 31, 2018 Overdrawn demand-deposit accounts $ 446 $ 12,332 Due in one year or less 25,312,183 25,199,892 Due after one year through two years 5,776,703 11,652,840 Due after two years through three years 2,762,369 2,834,790 Due after three years through four years 1,261,620 1,367,576 Due after four years through five years 1,060,053 1,152,468 Thereafter 903,173 1,048,487 Total par value $ 37,076,547 $ 43,268,385 Table 8.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) June 30, 2019 December 31, 2018 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 446 2.67 % $ 12,332 2.88 % Due in one year or less 24,192,583 2.44 24,029,592 2.48 Due after one year through two years 5,600,803 2.42 11,413,640 2.55 Due after two years through three years 2,782,869 2.54 2,832,290 2.47 Due after three years through four years 2,073,720 2.65 1,648,076 2.37 Due after four years through five years 1,363,453 2.40 1,980,468 2.24 Thereafter 1,062,673 2.88 1,351,987 2.99 Total par value 37,076,547 2.47 % 43,268,385 2.50 % Premiums 14,661 13,347 Discounts (38,045 ) (38,036 ) Fair value of bifurcated derivatives (1) 33,837 13,051 Hedging adjustments 9,797 (64,525 ) Total $ 37,096,797 $ 43,192,222 _________________________ (1) At June 30, 2019 , and December 31, 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.

Mortgage Loans Held for Portf_2

Mortgage Loans Held for Portfolio (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	Table 9.1 - Mortgage Loans Held for Portfolio (dollars in thousands) June 30, 2019 December 31, 2018 Real estate Fixed-rate 15-year single-family mortgages $ 362,600 $ 392,128 Fixed-rate 20- and 30-year single-family mortgages 3,989,123 3,839,078 Premiums 67,790 67,671 Discounts (1,762 ) (1,800 ) Deferred derivative gains, net 3,777 2,825 Total mortgage loans held for portfolio 4,421,528 4,299,902 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,421,028 $ 4,299,402 Table 9.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) June 30, 2019 December 31, 2018 Conventional mortgage loans $ 4,036,974 $ 3,902,555 Government mortgage loans 314,749 328,651 Total par value $ 4,351,723 $ 4,231,206

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Recorded Investment in Delinquent Mortgage Loans [Table Text Block]	Table 10.1 sets forth certain key credit quality indicators for our investments in mortgage loans at June 30, 2019 , and December 31, 2018 (dollars in thousands): Table 10.1 - Recorded Investment in Delinquent Mortgage Loans (dollars in thousands) June 30, 2019 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 26,089 $ 11,736 $ 37,825 Past due 60-89 days delinquent 4,522 3,422 7,944 Past due 90 days or more delinquent 10,216 5,664 15,880 Total past due 40,827 20,822 61,649 Total current loans 4,080,680 301,961 4,382,641 Total mortgage loans $ 4,121,507 $ 322,783 $ 4,444,290 Other delinquency statistics In process of foreclosure, included above (1) $ 4,159 $ 2,721 $ 6,880 Serious delinquency rate (2) 0.26 % 1.75 % 0.37 % Past due 90 days or more still accruing interest $ — $ 5,664 $ 5,664 Loans on nonaccrual status (3) $ 10,951 $ — $ 10,951 _______________________ (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. 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 10.2 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the three and six months ended June 30, 2019 and 2018 , as well as the recorded investment in mortgage loans by impairment methodology at June 30, 2019 and 2018 . 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 10.2 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Allowance for credit losses Balance, beginning of period $ 500 $ 500 $ 500 $ 500 (Charge-offs) recoveries (12 ) 3 (15 ) (6 ) Provision for (reduction of) credit losses 12 (3 ) 15 6 Balance, end of period $ 500 $ 500 $ 500 $ 500 Ending balance, individually evaluated for impairment $ — $ — $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 500 $ 500 $ 500 Recorded investment, end of period (1) Individually evaluated for impairment $ 14,447 $ 15,653 $ 14,447 $ 15,653 Collectively evaluated for impairment $ 4,107,060 $ 3,725,529 $ 4,107,060 $ 3,725,529 _________________________ (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)	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments [Table Text Block]	Table 11.1 - Fair Value of Derivative Instruments (dollars in thousands) June 30, 2019 December 31, 2018 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 10,858,944 $ 9,625 $ (19,724 ) $ 11,980,699 $ 12,811 $ (296,324 ) Forward-start interest-rate swaps 93,000 14 (7 ) 282,000 — (753 ) Total derivatives designated as hedging instruments 10,951,944 9,639 (19,731 ) 12,262,699 12,811 (297,077 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,806,800 569 (33,472 ) 927,800 682 (12,475 ) Mortgage-delivery commitments (1) 53,555 200 (8 ) 50,773 339 — Total derivatives not designated as hedging instruments 1,860,355 769 (33,480 ) 978,573 1,021 (12,475 ) Total notional amount of derivatives $ 12,812,299 $ 13,241,272 Total derivatives before netting and collateral adjustments 10,408 (53,211 ) 13,832 (309,552 ) Netting adjustments and cash collateral, including related accrued interest (2) 57,353 41,497 8,571 53,752 Derivative assets and derivative liabilities $ 67,761 $ (11,714 ) $ 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 $99.3 million and $62.8 million at June 30, 2019 , and December 31, 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 $401 thousand and $471 thousand at June 30, 2019 , and December 31, 2018 , respectively.
Net Gains (Losses) on Derivatives and Hedging Activities [Table Text Block]	Table 11.2 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 11.2 - Net Gains (Losses) on Fair Value and Cash Flow Hedging Relationships (dollars in thousands) For the Three Months Ended June 30, 2019 Interest Income/Expense Advances Available-for-sale Securities Consolidated Obligation Bonds Other Comprehensive Income (Loss) Total interest income (expense) in the statements of operations $ 223,869 $ 21,655 $ (150,715 ) Gains (losses) on fair-value hedging relationships Interest rate contracts Derivatives (1) $ (36,409 ) $ (35,719 ) $ 29,302 $ — Hedged items 48,044 31,270 (34,568 ) — Net gains (losses) on fair value hedging relationships $ 11,635 $ (4,449 ) $ (5,266 ) $ — Gains (losses) on cash-flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,131 ) $ — Recognized in other comprehensive loss — — — (2,443 ) For the Three Months Ended June 30, 2018 (2) Interest Income/Expense Net Gains (Losses) on Derivatives and Hedging Activities Other Comprehensive Income (Loss) Advances Available-for-sale Securities Consolidated Obligation Bonds Total income (expense) in the statements of operations $ 213,920 $ 37,221 $ (136,556 ) $ 458 Gains (losses) on fair value hedging relationships Interest rate contracts Derivatives (1) $ 14,537 $ (6,464 ) $ (8,513 ) $ 13,385 $ — Hedged items — — — (12,910 ) — Net gains (losses) on fair value hedging relationships $ 14,537 $ (6,464 ) $ (8,513 ) $ 475 $ — Gains (losses) on cash flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,014 ) $ — $ — Recognized in income for hedge ineffectiveness — — — 85 — Recognized in other comprehensive loss for hedge effectiveness — — — — 2,582 _______________________ (1) Includes net interest settlements. (2) Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019. Table 11.2 - Net Gains (Losses) on Fair Value and Cash Flow Hedging Relationships (dollars in thousands) For the Six Months Ended June 30, 2019 Interest Income/Expense Advances Available-for-sale Securities Consolidated Obligation Bonds Other Comprehensive Income (Loss) Total interest income (expense) in the statements of operations $ 471,746 $ 42,946 $ (305,532 ) Gains (losses) on fair-value hedging relationships Interest rate contracts Derivatives (1) $ (44,769 ) $ (64,699 ) $ 53,863 $ — Hedged items 73,272 50,385 (69,276 ) — Net gains (losses) on fair value hedging relationships $ 28,503 $ (14,314 ) $ (15,413 ) $ — Gains (losses) on cash-flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,917 ) $ — Recognized in other comprehensive loss — — — (5,822 ) For the Six Months Ended June 30, 2018 (2) Interest Income/Expense Net Gains (Losses) on Derivatives and Hedging Activities Other Comprehensive Income (Loss) Advances Available-for-sale Securities Consolidated Obligation Bonds Total income (expense) in the statements of operations $ 391,370 $ 77,999 $ (255,757 ) $ 1,598 Gains (losses) on fair value hedging relationships Interest rate contracts Derivatives (1) $ 20,232 $ (13,775 ) $ (11,530 ) $ 50,257 $ — Hedged items — — — (48,674 ) — Net gains (losses) on fair value hedging relationships $ 20,232 $ (13,775 ) $ (11,530 ) $ 1,583 $ — Gains (losses) on cash flow hedging relationships Interest rate contracts Reclassified from accumulated other comprehensive loss into interest expense $ — $ — $ (1,948 ) $ — $ — Recognized in income for hedge ineffectiveness — — — 161 — Recognized in other comprehensive loss for hedge effectiveness — — — — 11,748 _______________________ (1) Includes net interest settlements. (2) Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019. Table 11.4 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Derivatives designated as hedging instruments: Total net gains related to fair-value hedges (1) $ 475 $ 1,583 Total net gains related to cash-flow hedges (2) 85 161 Total net gains related to derivatives designated as hedging instruments 560 1,744 Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps $ (1,427 ) 98 $ (1,487 ) 722 Mortgage-delivery commitments 462 51 1,070 (467 ) Total net (losses) gains related to derivatives not designated as hedging instruments (965 ) 149 (417 ) 255 Other (3) 3 (251 ) 3 (401 ) Net (losses) gains on derivatives and hedging activities $ (962 ) $ 458 $ (414 ) $ 1,598 ______________________ (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.
Gains (Losses) By Type of Hedged Item [Table Text Block]	Table 11.3 - Cumulative Basis Adjustments for Fair-Value Hedges (dollars in thousands) June 30, 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 $ 5,312,448 $ 43,634 $ 10,335 $ 53,969 Available-for-sale securities 1,157,556 252,353 — 252,353 Consolidated bonds (4,775,299 ) (9,638 ) (37,111 ) (46,749 ) _______________________ (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 11.4 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Derivatives designated as hedging instruments: Total net gains related to fair-value hedges (1) $ 475 $ 1,583 Total net gains related to cash-flow hedges (2) 85 161 Total net gains related to derivatives designated as hedging instruments 560 1,744 Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps $ (1,427 ) 98 $ (1,487 ) 722 Mortgage-delivery commitments 462 51 1,070 (467 ) Total net (losses) gains related to derivatives not designated as hedging instruments (965 ) 149 (417 ) 255 Other (3) 3 (251 ) 3 (401 ) Net (losses) gains on derivatives and hedging activities $ (962 ) $ 458 $ (414 ) $ 1,598 ______________________ (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 11.5 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 June 30, 2019 . Table 11.5 - Post Haircut Value of Incremental Collateral to be Delivered as of June 30, 2019 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 370 AA- A+, A or A- — A- below A- 7,372 _______________________ (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 11.6 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 June 30, 2019 , and December 31, 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 11.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) June 30, 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 $ 7,875 $ (5,897 ) $ 200 $ 2,178 $ (1,171 ) $ — $ 1,007 Cleared 2,332 63,251 65,583 — — 65,583 Total $ 67,761 $ 66,590 Derivative Liabilities Uncleared $ (52,883 ) $ 41,177 $ (8 ) $ (11,714 ) $ 700 $ 9,762 $ (1,252 ) Cleared (320 ) 320 — — — — Total $ (11,714 ) $ (1,252 ) _______________________ (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 June 30, 2019 , we had additional net credit exposure of $371 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 $ 12,861 $ (11,885 ) $ 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 11.6 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 June 30, 2019 , and December 31, 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 11.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) June 30, 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 $ 7,875 $ (5,897 ) $ 200 $ 2,178 $ (1,171 ) $ — $ 1,007 Cleared 2,332 63,251 65,583 — — 65,583 Total $ 67,761 $ 66,590 Derivative Liabilities Uncleared $ (52,883 ) $ 41,177 $ (8 ) $ (11,714 ) $ 700 $ 9,762 $ (1,252 ) Cleared (320 ) 320 — — — — Total $ (11,714 ) $ (1,252 ) _______________________ (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 June 30, 2019 , we had additional net credit exposure of $371 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 $ 12,861 $ (11,885 ) $ 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)	6 Months Ended
	Jun. 30, 2019
Deposits [Abstract]
Interest-bearing and Non-interest-bearing Deposits [Table Text Block]	Table 12.1 - Deposits (dollars in thousands) June 30, 2019 December 31, 2018 Interest-bearing Demand and overnight $ 558,060 $ 444,486 Term 1,303 800 Other 2,524 2,961 Noninterest-bearing Other 32,961 26,631 Total deposits $ 594,848 $ 474,878

Consolidated Obligations (Table

Consolidated Obligations (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
CO Bonds by Year of Contractual Maturity [Table Text Block]	Table 13.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) June 30, 2019 December 31, 2018 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 9,921,050 2.27 % $ 9,638,270 2.01 % Due after one year through two years 5,117,975 2.16 5,375,845 2.24 Due after two years through three years 3,190,500 2.21 3,864,560 2.17 Due after three years through four years 1,903,105 2.28 1,891,975 2.20 Due after four years through five years 1,061,715 2.50 1,338,515 2.39 Thereafter 4,021,335 3.21 3,792,150 3.25 Total par value 25,215,680 2.40 % 25,901,315 2.30 % Premiums 82,048 88,434 Discounts (14,876 ) (16,133 ) Hedging adjustments 9,638 (60,932 ) $ 25,292,490 $ 25,912,684 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Table 13.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date June 30, 2019 December 31, 2018 Due in one year or less $ 13,328,050 $ 13,435,270 Due after one year through two years 5,004,975 5,602,845 Due after two years through three years 2,583,500 2,802,560 Due after three years through four years 1,648,105 1,366,975 Due after four years through five years 804,715 1,156,515 Thereafter 1,846,335 1,537,150 Total par value $ 25,215,680 $ 25,901,315
CO Bonds Long-term Debt Instruments [Table Text Block]	Table 13.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds June 30, 2019 December 31, 2018 Fixed-rate $ 20,017,680 $ 21,216,315 Simple variable-rate 3,741,000 2,853,000 Step-up 1,457,000 1,832,000 Total par value $ 25,215,680 $ 25,901,315 Table 13.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds June 30, 2019 December 31, 2018 Noncallable and nonputable $ 20,558,680 $ 20,419,315 Callable 4,657,000 5,482,000 Total par value $ 25,215,680 $ 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 13.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) June 30, 2019 $ 26,424,978 $ 26,499,124 2.31 % 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)	6 Months Ended
	Jun. 30, 2019
Affordable Housing Program [Abstract]
Roll-forward of the AHP Liability[Table Text Block]	Table 14.1 - AHP Liability (dollars in thousands) June 30, 2019 December 31, 2018 Balance at beginning of period $ 83,965 $ 81,600 AHP expense for the period 10,072 24,299 AHP direct grant disbursements (6,454 ) (17,729 ) AHP subsidy for AHP advance disbursements (1,598 ) (4,360 ) Return of previously disbursed grants and subsidies 6 155 Balance at end of period $ 85,991 $ 83,965

Capital (Tables)

Capital (Tables)	6 Months Ended
	Jun. 30, 2019
Stockholders' Equity Note [Abstract]
Compliance with Regulatory Capital Requirements [Table Text Block]	Table 15.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements June 30, December 31, Permanent capital Class B capital stock $ 1,995,252 $ 2,528,854 Mandatorily redeemable capital stock 17,107 31,868 Retained earnings 1,416,326 1,395,012 Total permanent capital $ 3,428,685 $ 3,955,734 Risk-based capital requirement Credit-risk capital $ 265,041 $ 289,080 Market-risk capital 162,581 187,183 Operations-risk capital 128,287 142,879 Total risk-based capital requirement $ 555,909 $ 619,142 Permanent capital in excess of risk-based capital requirement $ 2,872,776 $ 3,336,592 June 30, 2019 December 31, 2018 Required Actual Required Actual Capital Ratio Risk-based capital $ 555,909 $ 3,428,685 $ 619,142 $ 3,955,734 Total regulatory capital $ 2,231,181 $ 3,428,685 $ 2,543,733 $ 3,955,734 Total capital-to-asset ratio 4.0 % 6.1 % 4.0 % 6.2 % Leverage Ratio Leverage capital $ 2,788,977 $ 5,143,028 $ 3,179,666 $ 5,933,601 Leverage capital-to-assets ratio 5.0 % 9.2 % 5.0 % 9.3 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2019
AOCI Attributable to Parent [Abstract]
Schedule of Accumulated Other Comprehensive Loss [Table Text Block]	Table 16.1 - 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 Gain (Loss) Relating to Hedging Activities Pension and Postretirement Benefits Total Balance, March 31, 2018 $ (153,953 ) $ (150,790 ) $ (30,332 ) $ (5,770 ) $ (340,845 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (13,968 ) — 2,582 — (11,386 ) Accretion of noncredit loss — 7,462 — — 7,462 Net actuarial loss — — — (1,460 ) (1,460 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 132 — — 132 Amortization - hedging activities (2) — — 1,017 — 1,017 Amortization - pension and postretirement benefits (3) — — — 490 490 Other comprehensive (loss) income (13,968 ) 7,594 3,599 (970 ) (3,745 ) Balance, June 30, 2018 $ (167,921 ) $ (143,196 ) $ (26,733 ) $ (6,740 ) $ (344,590 ) Balance, March 31, 2019 $ (118,893 ) $ (122,913 ) $ (31,887 ) $ (5,115 ) $ (278,808 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 36,293 — (2,443 ) — 33,850 Noncredit other-than-temporary impairment losses — (101 ) — — (101 ) Accretion of noncredit loss — 6,188 — — 6,188 Net actuarial gain — — — 19 19 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 188 — — 188 Amortization - hedging activities (4) — — 1,131 — 1,131 Amortization - pension and postretirement benefits (3) — — — 171 171 Other comprehensive income (loss) 36,293 6,275 (1,312 ) 190 41,446 Balance, June 30, 2019 $ (82,600 ) $ (116,638 ) $ (33,199 ) $ (4,925 ) $ (237,362 ) _______________________ (1) Recorded in net other-than-temporary impairment losses in investment securities, credit portion in the statement of operations. (2) Amortization of hedging activities includes $1.0 million recorded in CO bond interest expense and $3 thousand recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Recorded in CO bond interest expense. Table 16.1 - 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 Gain (Loss) Relating to Hedging Activities Pension and Postretirement Benefits Total Balance, December 31, 2017 $ (122,331 ) $ (158,218 ) $ (40,436 ) $ (5,955 ) $ (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (45,590 ) — 11,748 — (33,842 ) Accretion of noncredit loss — 14,818 — — 14,818 Net actuarial loss — — — (1,460 ) (1,460 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 204 — — 204 Amortization - hedging activities (2) — — 1,955 — 1,955 Amortization - pension and postretirement benefits (3) — — — 675 675 Other comprehensive (loss) income (45,590 ) 15,022 13,703 (785 ) (17,650 ) Balance, June 30, 2018 $ (167,921 ) $ (143,196 ) $ (26,733 ) $ (6,740 ) $ (344,590 ) 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) 70,358 — (5,822 ) — 64,536 Noncredit other-than-temporary impairment losses — (181 ) — — (181 ) Accretion of noncredit loss — 12,479 — — 12,479 Net actuarial gain — — — 19 19 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 218 — — 218 Amortization - hedging activities (4) — — 1,917 — 1,917 Amortization - pension and postretirement benefits (3) — — — 332 332 Other comprehensive income (loss) 70,358 12,516 (3,905 ) 351 79,320 Balance, June 30, 2019 $ (82,600 ) $ (116,638 ) $ (33,199 ) $ (4,925 ) $ (237,362 ) _______________________ (1) Recorded in net other-than-temporary impairment losses in investment securities, credit portion in the statement of operations. (2) Amortization of hedging activities includes $1.9 million recorded in CO bond interest expense and $7 thousand recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Recorded in CO bond interest expense.

Fair Values (Tables)

Fair Values (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments [Table Text Block]	Table 17.1 - Fair Value Summary (dollars in thousands) June 30, 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 $ 28,739 $ 28,739 $ 28,739 $ — $ — $ — Interest-bearing deposits 1,146,961 1,146,961 1,146,961 — — — Securities purchased under agreements to resell 5,000,000 5,000,054 — 5,000,054 — — Federal funds sold 250,000 250,000 — 250,000 — — Trading securities (1) 1,097,963 1,097,963 — 1,097,963 — — Available-for-sale securities (1) 5,281,570 5,281,570 — 5,230,010 51,560 — Held-to-maturity securities 1,186,937 1,409,594 — 581,591 828,003 — Advances 37,096,797 37,208,993 — 37,208,993 — — Mortgage loans, net 4,421,028 4,508,857 — 4,488,116 20,741 — Accrued interest receivable 117,793 117,793 — 117,793 — — Derivative assets (1) 67,761 67,761 — 10,408 — 57,353 Other assets (1) 30,746 30,746 12,200 18,546 — — Liabilities: Deposits (594,848 ) (594,831 ) — (594,831 ) — — COs: Bonds (25,292,490 ) (25,565,210 ) — (25,565,210 ) — — Discount notes (26,424,978 ) (26,426,741 ) — (26,426,741 ) — — Mandatorily redeemable capital stock (17,107 ) (17,107 ) (17,107 ) — — — Accrued interest payable (119,293 ) (119,293 ) — (119,293 ) — — Derivative liabilities (1) (11,714 ) (11,714 ) — (53,211 ) — 41,497 Other: Commitments to extend credit for advances — (2,946 ) — (2,946 ) — — Standby letters of credit (1,746 ) (1,746 ) — (1,746 ) — — _______________________ (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. 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 17.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (dollars in thousands) June 30, 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 $ — $ 6,208 $ — $ — $ 6,208 U.S. Treasury obligations — 1,003,118 — — 1,003,118 U.S. government-guaranteed – single-family MBS — 4,701 — — 4,701 GSEs – single-family MBS — 107 — — 107 GSEs – multifamily MBS — 83,829 — — 83,829 Total trading securities — 1,097,963 — — 1,097,963 Available-for-sale securities: State or local HFA securities — — 51,560 — 51,560 Supranational institutions — 419,185 — — 419,185 U.S. government-owned corporations — 290,058 — — 290,058 GSEs — 121,897 — — 121,897 U.S. government guaranteed – single-family MBS — 66,558 — — 66,558 U.S. government guaranteed – multifamily MBS — 337,450 — — 337,450 GSEs – single-family MBS — 3,165,003 — — 3,165,003 GSEs – multifamily MBS — 829,859 — — 829,859 Total available-for-sale securities — 5,230,010 51,560 — 5,281,570 Derivative assets: Interest-rate-exchange agreements — 10,208 — 57,353 67,561 Mortgage delivery commitments — 200 — — 200 Total derivative assets — 10,408 — 57,353 67,761 Other assets 12,200 18,546 — — 30,746 Total assets carried at fair value on a recurring basis $ 12,200 $ 6,356,927 $ 51,560 $ 57,353 $ 6,478,040 Carried at fair value on a nonrecurring basis (2) Held-to-maturity securities: Private-label residential MBS $ — $ — $ 7,048 $ — $ 7,048 Mortgage loans held for portfolio — — 472 — 472 REO — — 5 — 5 Total assets carried at fair value on a nonrecurring basis $ — $ — $ 7,525 $ — $ 7,525 Liabilities: Carried at fair value on a recurring basis Derivative liabilities Interest-rate-exchange agreements $ — $ (53,203 ) $ — $ 41,497 $ (11,706 ) Mortgage delivery commitments — (8 ) — — (8 ) Total liabilities carried at fair value on a recurring basis $ — $ (53,211 ) $ — $ 41,497 $ (11,714 ) _______________________ (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 real estate owned property (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. 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 GSEs – single-family MBS — 148 — — 148 GSEs – multifamily MBS — 151,444 — — 151,444 Total trading securities — 163,038 — — 163,038 Available-for-sale securities: State or local HFA securities — — 49,601 — 49,601 Supranational institutions — 405,155 — — 405,155 U.S. government-owned corporations — 273,169 — — 273,169 GSEs — 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 GSEs – single-family MBS — 3,562,159 — — 3,562,159 GSEs – 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 residential 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 17.3 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 three and six months ended June 30, 2019 and 2018 . Table 17.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Balance at beginning of period $ 50,348 $ 37,495 $ 49,601 $ 37,683 Unrealized gains (losses) included in other comprehensive income 1,212 105 1,959 (83 ) Balance at end of period $ 51,560 $ 37,600 $ 51,560 $ 37,600

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	Table 18.1 - Off-Balance Sheet Commitments (dollars in thousands) June 30, 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) $ 7,850,041 $ 282,032 $ 8,132,073 $ 6,028,851 $ 226,438 $ 6,255,289 Commitments for unused lines of credit - advances (2) 1,162,632 — 1,162,632 1,177,377 — 1,177,377 Commitments to make additional advances 122,330 60,310 182,640 159,401 59,894 219,295 Commitments to invest in mortgage loans 53,555 — 53,555 50,773 — 50,773 Unsettled CO bonds, at par 23,000 — 23,000 105,400 — 105,400 Unsettled CO discount notes, at par — — — 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 June 30, 2019 , and December 31, 2018 , these amounts totaled $ 27.0 million and $32.6 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $675 thousand at December 31, 2018 . (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)	6 Months Ended
	Jun. 30, 2019
Transactions with Shareholders [Abstract]
Schedule of Transactions with Shareholders [Table Text Block]	Table 19.1 - 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 June 30, 2019 Citizens Bank, N.A. $ 121,572 6.0 % $ 2,555,961 6.9 % $ 1,855 3.2 % 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 19.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Three Months Ended June 30, For the Six Months Ended June 30, Citizens Bank, N.A. 2019 2018 2019 2018 Interest income on advances $ 21,958 $ 29,192 $ 61,071 $ 56,084 Fees on letters of credit 1,641 984 3,519 2,081
Schedule of Transactions with Shareholders, Transactions with Directors' Financial Institutions [Table Text Block]	Table 19.3 - 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 June 30, 2019 $ 86,052 4.3 % $ 1,728,192 4.7 % $ 3,234 5.5 % As of December 31, 2018 113,337 4.4 2,147,602 5.0 3,576 6.0

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Narratives (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jan. 01, 2019
Accounting Policies [Line Items]
Cost of operating lease	$ 646,000	$ 1,300,000
Minimum [Member]
Accounting Policies [Line Items]
Premises, software, and equipment, useful life		3 years
Maximum [Member]
Accounting Policies [Line Items]
Premises, software, and equipment, useful life		10 years
Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
Operating lease, right-of-use asset	10,800,000	$ 10,800,000	$ 11,900,000
Operating lease, liability	$ 11,300,000	$ 11,300,000	$ 12,500,000

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Guidance Operating Leases (Details) - Accounting Standards Update 2016-02 [Member] - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right-of-use asset	$ 10.8	$ 11.9
Operating lease, liability	$ 11.3	$ 12.5

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 1,097,963	$ 163,038
Corporate bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	6,208	6,102
U.S. Treasury obligations [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	1,003,118	0
Other Than Mortgage-backed Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	1,009,326	6,102
U.S. government-guaranteed - single-family MBS [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	4,701	5,344
MBS [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	88,637	156,936
GSEs - single-family [Member] | Government Sponsored Enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	107	148
GSEs - multifamily [Member] | Government Sponsored Enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 83,829	$ 151,444

Trading Securities - Net Unreal

Trading Securities - Net Unrealized (Losses) Gains (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Securities, Trading, Gain (Loss) [Abstract]
Net unrealized gains or (losses) on trading securities	$ 1,328	$ (1,024)	$ 1,054	$ (2,988)

Available-for-Sale Securities M

Available-for-Sale Securities Major Security Types (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	$ 5,364,170	$ 6,002,902
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		4,563	869
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(87,163)	(153,827)
Available-for-sale securities Fair Value		5,281,570	5,849,944
States or local housing-finance-agency obligations (HFA securities) [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	55,500	55,500
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(3,940)	(5,899)
Available-for-sale securities Fair Value		51,560	49,601
Supranational institutions [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	434,918	419,222
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(15,733)	(14,067)
Available-for-sale securities Fair Value		419,185	405,155
U.S. government-owned corporations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	322,295	297,729
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(32,237)	(24,560)
Available-for-sale securities Fair Value		290,058	273,169
GSEs [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	131,096	122,423
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(9,199)	(6,796)
Available-for-sale securities Fair Value		121,897	115,627
Other Than Mortgage-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	943,809	894,874
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(61,109)	(51,322)
Available-for-sale securities Fair Value		882,700	843,552
U.S. government-guaranteed - single-family MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	68,392	79,075
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		7	20
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(1,841)	(3,437)
Available-for-sale securities Fair Value		66,558	75,658
U.S. government guaranteed - multifamily MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	339,951	368,103
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(2,501)	(6,969)
Available-for-sale securities Fair Value		337,450	361,134
MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	4,420,361	5,108,028
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		4,563	869
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(26,054)	(102,505)
Available-for-sale securities Fair Value		4,398,870	5,006,392
Single Family [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	3,181,514	3,649,964
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		4,011	681
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(20,522)	(88,486)
Available-for-sale securities Fair Value		3,165,003	3,562,159
Multifamily [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	830,504	1,010,886
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		545	168
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(1,190)	(3,613)
Available-for-sale securities Fair Value		$ 829,859	$ 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	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	$ 708,234	$ 967,090
Less than 12 Months, Unrealized Losses	(2,483)	(5,683)
12 Months or More, Fair Value	3,547,795	4,668,323
12 Months or More, Unrealized Losses	(84,680)	(148,144)
Total Fair Value	4,256,029	5,635,413
Total Unrealized Losses	(87,163)	(153,827)
HFA securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	11,552	11,118
Less than 12 Months, Unrealized Losses	(1,248)	(1,682)
12 Months or More, Fair Value	40,008	38,483
12 Months or More, Unrealized Losses	(2,692)	(4,217)
Total Fair Value	51,560	49,601
Total Unrealized Losses	(3,940)	(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	419,185	405,155
12 Months or More, Unrealized Losses	(15,733)	(14,067)
Total Fair Value	419,185	405,155
Total Unrealized Losses	(15,733)	(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	290,058	273,169
12 Months or More, Unrealized Losses	(32,237)	(24,560)
Total Fair Value	290,058	273,169
Total Unrealized Losses	(32,237)	(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	121,897	115,627
12 Months or More, Unrealized Losses	(9,199)	(6,796)
Total Fair Value	121,897	115,627
Total Unrealized Losses	(9,199)	(6,796)
Other Than Mortgage-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	11,552	11,118
Less than 12 Months, Unrealized Losses	(1,248)	(1,682)
12 Months or More, Fair Value	871,148	832,434
12 Months or More, Unrealized Losses	(59,861)	(49,640)
Total Fair Value	882,700	843,552
Total Unrealized Losses	(61,109)	(51,322)
U.S. government-guaranteed - single-family MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	13,578	0
Less than 12 Months, Unrealized Losses	(1)	0
12 Months or More, Fair Value	51,504	57,679
12 Months or More, Unrealized Losses	(1,840)	(3,437)
Total Fair Value	65,082	57,679
Total Unrealized Losses	(1,841)	(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	337,450	361,134
12 Months or More, Unrealized Losses	(2,501)	(6,969)
Total Fair Value	337,450	361,134
Total Unrealized Losses	(2,501)	(6,969)
MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	696,682	955,972
Less than 12 Months, Unrealized Losses	(1,235)	(4,001)
12 Months or More, Fair Value	2,676,647	3,835,889
12 Months or More, Unrealized Losses	(24,819)	(98,504)
Total Fair Value	3,373,329	4,791,861
Total Unrealized Losses	(26,054)	(102,505)
GSEs - single-family [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	22,012	53,122
Less than 12 Months, Unrealized Losses	(44)	(388)
12 Months or More, Fair Value	2,287,693	3,417,076
12 Months or More, Unrealized Losses	(20,478)	(88,098)
Total Fair Value	2,309,705	3,470,198
Total Unrealized Losses	(20,522)	(88,486)
GSEs - multifamily [Member] | GSEs – MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Fair Value	661,092	902,850
Less than 12 Months, Unrealized Losses	(1,190)	(3,613)
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Losses	0	0
Total Fair Value	661,092	902,850
Total Unrealized Losses	$ (1,190)	$ (3,613)

Available-for-Sale Securities R

Available-for-Sale Securities Redemption Terms (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	$ 5,364,170	$ 6,002,902
Fair Value		5,281,570	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		7,457	0
Due after one year through five years, amortized cost		47,900	55,500
Due after one year through five years, fair value		44,104	49,601
Due after five years through 10 years, amortized cost		483,205	465,248
Due after five years through 10 years, fair value		466,369	450,102
Due after 10 years, amortized cost		405,104	374,126
Due after 10 years, fair value		364,770	343,849
Amortized Cost	[1]	943,809	894,874
Fair Value		882,700	843,552
MBS [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	4,420,361	5,108,028
Fair Value		4,398,870	5,006,392
Amortized Cost MBS	[2]	4,420,361	5,108,028
Fair Value MBS	[2]	$ 4,398,870	$ 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		Jun. 30, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 1,303,574	$ 1,424,176
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(116,637)	(129,153)
Carrying Value	[1],[2]	1,186,937	1,295,023
Gross Unrecognized Holding Gains		229,370	242,834
Gross Unrecognized Holding Losses		(6,713)	(8,928)
Held-to-maturity securities Fair Value		1,409,594	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		101,005	104,465
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		101,005	104,465
Gross Unrecognized Holding Gains		4	4
Gross Unrecognized Holding Losses		(4,608)	(4,612)
Held-to-maturity securities Fair Value		96,401	99,857
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		101,005	104,673
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss			0
Carrying Value	[1]	101,005	104,673
Gross Unrecognized Holding Gains			4
Gross Unrecognized Holding Losses			(4,612)
Held-to-maturity securities Fair Value		96,401	100,065
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		7,609	8,173
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		7,609	8,173
Gross Unrecognized Holding Gains		148	158
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		7,757	8,331
GSEs – MBS [Member] | GSEs - single-family [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		358,498	412,639
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		358,498	412,639
Gross Unrecognized Holding Gains		6,406	6,861
Gross Unrecognized Holding Losses		(313)	(1,389)
Held-to-maturity securities Fair Value		364,591	418,111
GSEs – MBS [Member] | GSEs - multifamily [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		207,120	209,786
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		207,120	209,786
Gross Unrecognized Holding Gains		2,123	1,728
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		209,243	211,514
Asset-backed securities (ABS) backed by home equity loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		6,399	6,781
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(15)	(18)
Carrying Value		6,384	6,763
Gross Unrecognized Holding Gains		16	20
Gross Unrecognized Holding Losses		(233)	(256)
Held-to-maturity securities Fair Value		6,167	6,527
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	1,202,569	1,319,503
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(116,637)	(129,153)
Carrying Value	[1],[3]	1,085,932	1,190,350
Gross Unrecognized Holding Gains		229,366	242,830
Gross Unrecognized Holding Losses		(2,105)	(4,316)
Held-to-maturity securities Fair Value	[3]	1,313,193	1,428,864
Residential Mortgage Backed Securities [Member] | Private-label residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		622,943	682,124
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(116,622)	(129,135)
Carrying Value		506,321	552,989
Gross Unrecognized Holding Gains		220,673	234,063
Gross Unrecognized Holding Losses		(1,559)	(2,671)
Held-to-maturity securities Fair Value		$ 725,435	$ 784,381
[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 $ 1,409,594 and $1,528,929 at June 30, 2019 , and December 31, 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	Jun. 30, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	$ 31,587	$ 101,253
Less than 12 Months, Unrealized Losses	(361)	(920)
12 Months or More, Fair Value	231,490	259,996
12 Months or More, Unrealized Losses	(7,919)	(9,999)
Total Fair Value	263,077	361,249
Total Unrealized Losses	(8,280)	(10,919)
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	6,197	6,196
Less than 12 Months, Unrealized Losses	(7)	(9)
12 Months or More, Fair Value	89,364	92,822
12 Months or More, Unrealized Losses	(4,601)	(4,603)
Total Fair Value	95,561	99,018
Total Unrealized Losses	(4,608)	(4,612)
GSEs – MBS [Member] | Single Family [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	892	69,377
Less than 12 Months, Unrealized Losses	(8)	(580)
12 Months or More, Fair Value	46,957	52,237
12 Months or More, Unrealized Losses	(305)	(809)
Total Fair Value	47,849	121,614
Total Unrealized Losses	(313)	(1,389)
ABS backed by home equity loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	670	759
Less than 12 Months, Unrealized Losses	(5)	(5)
12 Months or More, Fair Value	5,375	5,641
12 Months or More, Unrealized Losses	(228)	(251)
Total Fair Value	6,045	6,400
Total Unrealized Losses	(233)	(256)
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	25,390	95,057
Less than 12 Months, Unrealized Losses	(354)	(911)
12 Months or More, Fair Value	142,126	167,174
12 Months or More, Unrealized Losses	(3,318)	(5,396)
Total Fair Value	167,516	262,231
Total Unrealized Losses	(3,672)	(6,307)
Residential Mortgage Backed Securities [Member] | Private-label residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	23,828	24,921
Less than 12 Months, Unrealized Losses	(341)	(326)
12 Months or More, Fair Value	89,794	109,296
12 Months or More, Unrealized Losses	(2,785)	(4,336)
Total Fair Value	113,622	134,217
Total Unrealized Losses	$ (3,126)	$ (4,662)

Held-to-Maturity Securities Red

Held-to-Maturity Securities Redemption Terms (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 1,303,574	$ 1,424,176
Carrying Value	[1],[2]	1,186,937	1,295,023
Fair Value		1,409,594	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		835	1,043
Due in one year or less, Carrying Value	[1]	835	1,043
Due in one year or less, Fair Value		839	1,047
Due after one year through five years, Amortized Cost		6,205	6,205
Due after one year through five years, Carrying Value	[1]	6,205	6,205
Due after one year through five years, Fair Value		6,197	6,196
Due after five years through 10 years, Amortized Cost		16,145	16,865
Due after five years through 10 years, Carrying Value	[1]	16,145	16,865
Due after five years through 10 years, Fair Value		15,982	16,639
Due after 10 years, Amortized Cost		77,820	80,560
Due after 10 years, Carrying Value	[1]	77,820	80,560
Due after 10 years, Fair Value		73,383	76,183
Amortized Cost		101,005	104,673
Carrying Value	[1]	101,005	104,673
Fair Value		96,401	100,065
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	1,202,569	1,319,503
Carrying Value	[1],[3]	1,085,932	1,190,350
Fair Value	[3]	$ 1,313,193	$ 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 $ 1,409,594 and $1,528,929 at June 30, 2019 , and December 31, 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.

Other-Than-Temporary Impairme_3

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	6 Months Ended
	Jun. 30, 2019USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 42,077
Project Prepayment Rates - Weighted Average Percent	11.60%
Projected Default Rates, Weighted Average Percent	22.70%
Projected Loss Severities, Weighted Average Percent	52.50%
Current Credit Enhancement, Weighted Average Percent	8.20%
[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_4

Other-Than-Temporary Impairment OTTI Credit Losses Recognized During Life of Security (Details) - Held-to-maturity Securities [Member] $ in Thousands	Jun. 30, 2019USD ($)	[1]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	$ 767,076
Amortized Cost	552,584
Carrying Value	435,947
Fair Value	656,582
Asset-backed securities (ABS) backed by home equity loans [Member] | Subprime [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	146
Amortized Cost	138
Carrying Value	123
Fair Value	139
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Prime [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	22,079
Amortized Cost	18,795
Carrying Value	14,894
Fair Value	20,597
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Alt-A [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	744,851
Amortized Cost	533,651
Carrying Value	420,930
Fair Value	$ 635,846
[1]	Securities are classified based on the classifications of their underlying loan composition at the time of issuance. We have instituted 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_5

Other-Than-Temporary Impairment Roll-forward of Amounts Related to Credit Losses Recognized in Earnings (Details) - Held-to-maturity Securities [Member] - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at beginning of period		$ 414,595,000	$ 445,286,000	$ 422,035,000	$ 452,523,000
Credit losses for which other-than-temporary impairment was not previously recognized		93,000	0	102,000	0
Additional credit losses for which an other-than-temporary impairment charge was previously recognized		221,000	257,000	315,000	336,000
Securities matured during the period		0	0	(485,000)	0
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	[1]	(6,962,000)	(8,228,000)	(14,020,000)	(15,544,000)
Balance at end of period		407,947,000	$ 437,315,000	407,947,000	$ 437,315,000
Recoveries of losses received from (OTTI) securities paid off and recognized in earnings		$ 15,000		$ 263,000
[1]	For the three and six months ended June 30, 2019 , the amount excludes an additional $15 thousand and $263 thousand , respectively, for bonds previously paid off.

Advances - Outstanding by Year

Advances - Outstanding by Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Maturity, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts		$ 446	$ 12,332
Due in one year or less		24,192,583	24,029,592
Due after one year through two years		5,600,803	11,413,640
Due after two years through three years		2,782,869	2,832,290
Due after three years through four years		2,073,720	1,648,076
Due after four years through five years		1,363,453	1,980,468
Thereafter		1,062,673	1,351,987
Total par value		$ 37,076,547	$ 43,268,385
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Rolling Year [Abstract]
Overdrawn demand-deposit accounts, Weighted average rate		2.67%	2.88%
Due in one year or less, Weighted average rate		2.44%	2.48%
Due after one year through two years, Weighted average rate		2.42%	2.55%
Due after two years through three years, Weighted average rate		2.54%	2.47%
Due after three years through four years, Weighted average rate		2.65%	2.37%
Due after four years through five years, Weighted average rate		2.40%	2.24%
Thereafter, Weighted average rate		2.88%	2.99%
Total Weighted average rate		2.47%	2.50%
Premiums		$ 14,661	$ 13,347
Discounts		(38,045)	(38,036)
Fair value of bifurcated derivatives	[1]	33,837	13,051
Hedging adjustments		9,797	(64,525)
Total Advances		$ 37,096,797	$ 43,192,222
[1]	At June 30, 2019 , and December 31, 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	Jun. 30, 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	$ 446	$ 12,332
Due in one year or less	27,543,358	32,748,467
Due after one year through two years	3,350,803	3,913,640
Due after two years through three years	2,571,269	2,672,290
Due after three years through four years	1,538,520	1,261,176
Due after four years through five years	1,063,453	1,362,468
Thereafter	1,008,698	1,298,012
Total par value	$ 37,076,547	$ 43,268,385

Advances - Outstanding by the E

Advances - Outstanding by the Earlier of Contractual Maturity or Next Put Date (Details) - USD ($) $ in Thousands	Jun. 30, 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	$ 446	$ 12,332
Due in one year or less	25,312,183	25,199,892
Due after one year through two years	5,776,703	11,652,840
Due after two years through three years	2,762,369	2,834,790
Due after three years through four years	1,261,620	1,367,576
Due after four years through five years	1,060,053	1,152,468
Thereafter	903,173	1,048,487
Total par value	$ 37,076,547	$ 43,268,385

Advances - Interest-Rate-Paymen

Advances - Interest-Rate-Payment Terms (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Fixed Rate [Abstract]
Fixed-rate	$ 33,080,226	$ 33,570,278
Federal Home Loan Bank, Advances, Floating Rate [Abstract]
Variable-rate	3,996,321	9,698,107
Total par value	$ 37,076,547	$ 43,268,385

Advances - Narratives (Details)

Advances - Narratives (Details) $ in Billions	Jun. 30, 2019USD ($)Borrowers	Dec. 31, 2018USD ($)Borrowers
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount	$ 12.2	$ 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	6	6
Total outstanding advances greater than $1.0 billion per borrower as a percentage of advances outstanding	32.90%	37.90%
Minimum [Member]
Federal Home Loan Bank, Advances [Line Items]
Interest rates of advances outstanding	0.00%	0.00%
Maximum [Member]
Federal Home Loan Bank, Advances [Line Items]
Interest rates of advances outstanding	7.72%	7.72%

Advances Advances - Prepayment

Advances Advances - Prepayment Fees (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Federal Home Loan Bank Advances Prepayment Fees [Abstract]
Prepayment fees received from borrowers	$ 2,669	$ 5	$ 28,855	$ 65
Hedging fair-value adjustments on prepaid advances	1,399	2	1,926	98
Net (premiums) discounts associated with prepaid advances	(61)	0	157	0
Deferred recognition of prepayment fees received from borrowers on advance prepayments deemed to be loan modifications	(201)	0	(201)	0
Advance prepayment fees recognized in income, net	$ 3,806	$ 7	$ 30,737	$ 163

Mortgage Loans Held for Portf_3

Mortgage Loans Held for Portfolio (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Par Value	$ 4,351,723		$ 4,231,206
Premiums	67,790		67,671
Discounts	(1,762)		(1,800)
Deferred derivative gains, net	3,777		2,825
Total mortgage loans held for portfolio	4,421,528		4,299,902
Less: allowance for credit losses	(500)		(500)
Total mortgage loans, net of allowance for credit losses	$ 4,421,028		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	$ 314,749		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	362,600		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	3,989,123		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	4,036,974		3,902,555
Less: allowance for credit losses	$ (500)	$ (500)	$ (500)	$ (500)	$ (500)	$ (500)

Allowance for credit losses - C

Allowance for credit losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Dec. 31, 2018
Mortgage Loans Past Due [Line Items]
Total past due		$ 61,649	$ 58,346
Total current loans		4,382,641	4,263,381
Total mortgage loans		4,444,290	4,321,727
In process of foreclosure, included above	[1]	$ 6,880	$ 5,553
Serious delinquency rate	[2]	0.37%	0.34%
Past due 90 days or more still accruing interest		$ 5,664	$ 6,670
Loans on nonaccrual status	[3]	$ 10,951	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		$ 20,822	20,898
Total current loans		301,961	316,285
Total mortgage loans		322,783	337,183
In process of foreclosure, included above	[1]	$ 2,721	$ 2,086
Serious delinquency rate	[2]	1.75%	1.98%
Past due 90 days or more still accruing interest		$ 5,664	$ 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		40,827	37,448
Total current loans		4,080,680	3,947,096
Total mortgage loans		4,121,507	3,984,544
In process of foreclosure, included above	[1]	$ 4,159	$ 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]	10,951	7,975
Past due 30-59 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		37,825	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		11,736	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		26,089	23,045
Past due 60-89 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		7,944	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		3,422	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		4,522	7,019
Past due 90 days or more delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		15,880	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		5,664	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		$ 10,216	$ 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 - A

Allowance for credit losses - Allowance Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				$ 500
Provision for (reduction of) credit losses		$ 12	$ (3)	15	$ 6
Balance, end of period		500		500
Conventional Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period		500	500	500	500
(Charge-offs) recoveries		(12)	3	(15)	(6)
Provision for (reduction of) credit losses		12	(3)	15	6
Balance, end of period		500	500	500	500
Ending balance, individually evaluated for impairment		0	0	0	0
Ending balance, collectively evaluated for impairment		500	500	500	500
Recorded Investment Individually evaluated for impairment	[1]	14,447	15,653	14,447	15,653
Recorded Investment Collectively evaluated for impairment	[1]	$ 4,107,060	$ 3,725,529	$ 4,107,060	$ 3,725,529
[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 ($)		Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		$ 12,812,299,000	$ 13,241,272,000
Derivative Assets, before netting and collateral adjustments		10,408,000	13,832,000
Derivative Liabilities, before netting and collateral adjustments		(53,211,000)	(309,552,000)
Derivative Asset, netting adjustments and cash collateral including related accrued interest	[1],[2],[3]	57,353,000	8,571,000
Derivative Liability, netting adjustments and cash collateral including related accrued interest	[1],[2],[3]	41,497,000	53,752,000
Derivative assets		67,761,000	22,403,000
Derivative liabilities		(11,714,000)	(255,800,000)
Cash collateral and related accrued interest posted		99,300,000	62,800,000
Cash collateral and related accrued interest received		401,000	471,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		10,951,944,000	12,262,699,000
Derivative Assets, before netting and collateral adjustments		9,639,000	12,811,000
Derivative Liabilities, before netting and collateral adjustments		(19,731,000)	(297,077,000)
Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		10,858,944,000	11,980,699,000
Derivative Assets, before netting and collateral adjustments		9,625,000	12,811,000
Derivative Liabilities, before netting and collateral adjustments		(19,724,000)	(296,324,000)
Designated as Hedging Instrument [Member] | Forward-start interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		93,000,000	282,000,000
Derivative Assets, before netting and collateral adjustments		14,000	0
Derivative Liabilities, before netting and collateral adjustments		(7,000)	(753,000)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,860,355,000	978,573,000
Derivative Assets, before netting and collateral adjustments		769,000	1,021,000
Derivative Liabilities, before netting and collateral adjustments		(33,480,000)	(12,475,000)
Not Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,806,800,000	927,800,000
Derivative Assets, before netting and collateral adjustments		569,000	682,000
Derivative Liabilities, before netting and collateral adjustments		(33,472,000)	(12,475,000)
Mortgage Receivable [Member] | Not Designated as Hedging Instrument [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	[4]	53,555,000	50,773,000
Derivative Assets, before netting and collateral adjustments	[4]	200,000	339,000
Derivative Liabilities, before netting and collateral adjustments	[4]	$ (8,000)	$ 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 $99.3 million and $62.8 million at June 30, 2019 , and December 31, 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 $401 thousand and $471 thousand at June 30, 2019 , and December 31, 2018 , respectively.
[2]	Carried at fair value and measured on a recurring basis.
[3]	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.
[4]	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		3 Months Ended			6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Interest income on advances		$ 223,869	$ 213,920	[1]	$ 471,746	$ 391,370	[1]
Interest income on available-for-sale securities		21,655	37,221	[1]	42,946	77,999	[1]
Interest expense on consolidated obligations bonds		(150,715)	(136,556)	[1]	(305,532)	(255,757)	[1]
Net gains on derivatives and hedging activities	[1]		458			1,598
Gain (Loss) on Derivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains on derivatives and hedging activities			458			1,598
Net gains (losses) on fair value hedging relationships	[2]		475			1,583
Recognize in income for hedge ineffectiveness	[3]		85			161
Gain (Loss) on Derivative Instruments [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives	[1],[4]		13,385			50,257
Hedged items	[1]		(12,910)			(48,674)
Net gains (losses) on fair value hedging relationships	[1]		475			1,583
Recognize in income for hedge ineffectiveness	[1]		85			161
Advances [Member] | Interest Income [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives	[4]	(36,409)			(44,769)
Hedged items		48,044			73,272
Net gains (losses) on fair value hedging relationships		11,635			28,503
Derivatives		11,635			28,503
Advances [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) on fair value hedging relationships	[1],[4]		14,537			20,232
Derivatives	[1],[4]		14,537			20,232
Reclassified from accumulated other comprehensive loss into interest expense		0			0
Net gains (losses) on fair value hedging relationships	[1]		14,537			20,232
Available-for-sale Securities [Member] | Interest Income [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives	[4]	(35,719)			(64,699)
Hedged items		31,270			50,385
Net gains (losses) on fair value hedging relationships		(4,449)			(14,314)
Derivatives		(4,449)			(14,314)
Available-for-sale Securities [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) on fair value hedging relationships	[1],[4]		(6,464)			(13,775)
Derivatives	[1],[4]		(6,464)			(13,775)
Reclassified from accumulated other comprehensive loss into interest expense		0			0
Net gains (losses) on fair value hedging relationships	[1]		(6,464)			(13,775)
COs - bonds [Member] | Interest Expense [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives	[4]	29,302			53,863
Hedged items		(34,568)			(69,276)
Net gains (losses) on fair value hedging relationships		(5,266)			(15,413)
Derivatives		(5,266)			(15,413)
COs - bonds [Member] | Interest Expense [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) on fair value hedging relationships	[1],[4]		(8,513)			(11,530)
Derivatives	[1],[4]		(8,513)			(11,530)
Reclassified from accumulated other comprehensive loss into interest expense		(1,131)			(1,917)
Net gains (losses) on fair value hedging relationships	[1]		(8,513)			(11,530)
Other Comprehensive Income (Loss) [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Recognize in other comprehensive loss		$ (2,443)			$ (5,822)
Cash Flow Hedging [Member] | Advances [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Reclassified from accumulated other comprehensive loss into interest expense	[1]		0			0
Cash Flow Hedging [Member] | Available-for-sale Securities [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Reclassified from accumulated other comprehensive loss into interest expense	[1]		0			0
Cash Flow Hedging [Member] | COs - bonds [Member] | Interest Expense [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Reclassified from accumulated other comprehensive loss into interest expense	[1]		(1,014)			(1,948)
Cash Flow Hedging [Member] | Other Comprehensive Income (Loss) [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Recognized in other comprehensive loss for hedge effectiveness	[1]		$ 2,582			$ 11,748
[1]	Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019.
[2]	Consists of interest-rate swaps
[3]	Consists of forward-start interest-rate swaps
[4]	Includes net interest settlements.

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities Basis Adjustments for Fair Value Hedges (Details) $ in Thousands	Jun. 30, 2019USD ($)
Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amortized Cost of Hedged Asset/(Liability)	$ 5,312,448	[1]
Basis Adjustments for Active Hedging Relationships Included in Amortized Cost	43,634
Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost	10,335
Cumulative Amount of Fair Value Hedging Basis Adjustments	53,969
Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amortized Cost of Hedged Asset/(Liability)	1,157,556	[1]
Basis Adjustments for Active Hedging Relationships Included in Amortized Cost	252,353
Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost	0
Cumulative Amount of Fair Value Hedging Basis Adjustments	252,353
COs - bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amortized Cost of Hedged Asset/(Liability)	(4,775,299)	[1]
Basis Adjustments for Active Hedging Relationships Included in Amortized Cost Basis	(9,638)
Basis Adjustments for Discontinued Hedging Relationships Included in Amortized Cost Basis	(37,111)
Cumulative Amount of Fair Value Hedging Basis Adjustments	$ (46,749)
[1]	Includes only the portion of amortized cost representing the hedged items in fair-value hedging relationships.

Derivatives and Hedging Activ_6

Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Other Income/Loss (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative [Line Items]
Total net (losses) gains related to derivatives not designated as hedging instruments		$ (962)		$ (414)
Net (losses) gains on derivatives and hedging activities	[1]		$ 458		$ 1,598
Gain (Loss) on Derivative Instruments [Member]
Derivative [Line Items]
Total net gains related to fair value hedges	[2]		475		1,583
Total net gains related to cash flow hedges	[3]		85		161
Total net gains related to derivatives designated as hedging instruments			560		1,744
Total net (losses) gains related to derivatives not designated as hedging instruments		(965)	149	(417)	255
Other	[4]		(251)		(401)
Net (losses) gains on derivatives and hedging activities			458		1,598
Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative [Line Items]
Other	[4]	3		3
Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest-rate swaps [Member]
Derivative [Line Items]
Total net (losses) gains related to derivatives not designated as hedging instruments		(1,427)	98	(1,487)	722
Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Net (losses) gains on derivatives and hedging activities		(962)		(414)
Mortgage Receivable [Member] | Gain (Loss) on Derivative Instruments [Member] | Mortgage-delivery commitments [Member]
Derivative [Line Items]
Total net (losses) gains related to derivatives not designated as hedging instruments		$ 462	$ 51	$ 1,070	$ (467)
[1]	Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019.
[2]	Consists of interest-rate swaps
[3]	Consists of forward-start interest-rate swaps
[4]	Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount.

Derivatives and Hedging Activ_7

Derivatives and Hedging Activities Narratives (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Mar. 28, 2019
Derivative [Line Items]
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 derivative accumulated in other comprehensive loss related to cash-flow hedges expected to be reclassified to earnings during the next 12 months		$ 6,800
Aggregate fair value of all uncleared derivative instruments with credit-risk-related contingent features that were in a net liability position		46,700
Post-haircut value of collateral already posted		46,200
Rating Downgrade from AAPlus to AA or AAMinus [Member]
Derivative [Line Items]
Incremental collateral	[1]	370
Rating Downgrade From AAMinus to APlus, A or AMinus [Member]
Derivative [Line Items]
Incremental collateral	[1]	0
Rating Downgrade From AMinus to below AMinus [Member]
Derivative [Line Items]
Incremental collateral	[1]	$ 7,372
Terminated Derivatives [Member]
Derivative [Line Items]
Terminated derivatives notional amount			$ 611,900
Terminated derivatives settlement amount			(251,500)
Replacement Derivatives [Member]
Derivative [Line Items]
Replacement derivatives notional amount			611,900
Replacement derivatives settlement amount			$ 251,500
[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_8

Derivatives and Hedging Activities Fair Value of Derivative Instruments With or Without Legal Rights of Offset (Details) - USD ($)		Jun. 30, 2019		Dec. 31, 2018
Derivative [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2],[3]	$ 57,353,000		$ 8,571,000
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2],[3]	41,497,000		53,752,000
Derivative assets		67,761,000		22,403,000
Derivative liabilities		(11,714,000)		(255,800,000)
Derivative Asset, Fair value, amount offset against collateral		66,590,000		22,007,000
Derivative Liability, Fair value, amount offset against collateral		(1,252,000)		(12,642,000)
Derivative Liabilities, additional net exposure, collateral pledged to counterparties in excess of net liabilities		371,000		639,000
Uncleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		7,875,000		12,861,000
Derivative Liability, total gross recognized amount		(52,883,000)		(306,848,000)
Derivative Assets, Netting Adjustments and Cash Collateral		(5,897,000)	[4]	(11,885,000)	[5]
Derivative liability, Netting Adjustments and Cash Collateral		41,177,000	[4]	51,048,000	[5]
Derivative assets		2,178,000		1,315,000
Derivative liabilities		(11,714,000)		(255,800,000)
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		(1,171,000)	[6]	(396,000)	[7]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		700,000	[6]	6,104,000	[7]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[6]	0	[7]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		9,762,000	[6]	237,054,000	[7]
Derivative Asset, Fair value, amount offset against collateral		1,007,000		919,000
Derivative Liability, Fair value, amount offset against collateral		(1,252,000)		(12,642,000)
Cleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		2,332,000		631,000
Derivative Liability, total gross recognized amount		(320,000)		(2,704,000)
Derivative Assets, Netting Adjustments and Cash Collateral		63,251,000	[4]	20,457,000	[5]
Derivative liability, Netting Adjustments and Cash Collateral		320,000	[4]	2,704,000	[5]
Derivative assets		65,583,000		21,088,000
Derivative liabilities		0		0
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	[6]	0	[7]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		0	[6]	0	[7]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[6]	0	[7]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		0	[6]	0	[7]
Derivative Asset, Fair value, amount offset against collateral		65,583,000		21,088,000
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		200,000		339,000
Derivative Liabilities, Mortgage delivery commitments		$ (8,000)		$ 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 $99.3 million and $62.8 million at June 30, 2019 , and December 31, 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 $401 thousand and $471 thousand at June 30, 2019 , and December 31, 2018 , respectively.
[2]	Carried at fair value and measured on a recurring basis.
[3]	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.
[4]	Includes gross amounts of netting adjustments and cash collateral.
[5]	Includes gross amounts of netting adjustments and cash collateral.
[6]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At June 30, 2019 , we had additional net credit exposure of $371 thousand due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.
[7]	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	Jun. 30, 2019	Dec. 31, 2018
Deposits [Abstract]
Interest-bearing deposit demand and overnight	$ 558,060	$ 444,486
Interest-bearing deposit term	1,303	800
Interest-bearing deposit other	2,524	2,961
Non-interest bearing deposits other	32,961	26,631
Total deposits	$ 594,848	$ 474,878

Consolidated Obligations CO Bon

Consolidated Obligations CO Bonds - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Schedule of Short-term and Long-term Debt [Line Items]
Due in one year or less		$ 9,921,050	$ 9,638,270
Due in one year or less, weighted average rate	[1]	2.27%	2.01%
Due after one year through two years		$ 5,117,975	$ 5,375,845
Due after one year through two years, weighted average rate	[1]	2.16%	2.24%
Due after two years through three years		$ 3,190,500	$ 3,864,560
Due after two years through three years, weighted average rate	[1]	2.21%	2.17%
Due after three years through four years		$ 1,903,105	$ 1,891,975
Due after three years through four years, weighted average rate	[1]	2.28%	2.20%
Due after four years through five years		$ 1,061,715	$ 1,338,515
Due after four years through five years, weighted average rate	[1]	2.50%	2.39%
Thereafter		$ 4,021,335	$ 3,792,150
Thereafter, weighted average rate	[1]	3.21%	3.25%
Total par value		$ 25,215,680	$ 25,901,315
Total par value, weighted average rate	[1]	2.40%	2.30%
Hedging adjustments		$ 9,638	$ (60,932)
Total		25,292,490	25,912,684
COs - bonds [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Premiums		82,048	88,434
Discounts		$ (14,876)	$ (16,133)
[1]	The CO bonds' weighted-average rate excludes concession fees.

Consolidated Obligations CO B_2

Consolidated Obligations CO Bonds - Outstanding By Call Features (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 25,215,680	$ 25,901,315
Noncallable and nonputable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	20,558,680	20,419,315
Callable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 4,657,000	$ 5,482,000

Consolidated Obligations CO B_3

Consolidated Obligations CO Bonds - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Due in one year or less	$ 13,328,050	$ 13,435,270
Due after one year through two years	5,004,975	5,602,845
Due after two years through three years	2,583,500	2,802,560
Due after three years through four years	1,648,105	1,366,975
Due after four years through five years	804,715	1,156,515
Thereafter	1,846,335	1,537,150
Total par value	$ 25,215,680	$ 25,901,315

Consolidated Obligations CO B_4

Consolidated Obligations CO Bonds - Interest-Rate-Payment Type (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Fixed-rate	$ 20,017,680	$ 21,216,315
Simple variable-rate	3,741,000	2,853,000
Step-up	1,457,000	1,832,000
Total par value	$ 25,215,680	$ 25,901,315

Consolidated Obligations CO - D

Consolidated Obligations CO - Discount Notes (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Federal Home Loan Bank, Consolidated Obligations, Discount Notes		$ 26,424,978	$ 33,065,822
Par value		$ 26,499,124	$ 33,147,065
Weighted Average Rate	[1]	2.31%	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	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Affordable Housing Program [Roll Forward]
Balance at beginning of period			$ 83,965	$ 81,600	$ 81,600
AHP expense for the period	$ 3,987	$ 5,978	10,072	12,149	24,299
AHP direct grant disbursements			(6,454)	$ (10,308)	(17,729)
AHP subsidy for AHP advance disbursements			(1,598)		(4,360)
Return of previously disbursed grants and subsidies			6		155
Balance at end of period	$ 85,991		$ 85,991		$ 83,965

Capital Requirements (Details)

Capital Requirements (Details) $ in Thousands	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)
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	$ 1,995,252	$ 2,528,854
Mandatorily redeemable capital stock	17,107	31,868
Retained earnings	1,416,326	1,395,012
Total permanent capital	3,428,685	3,955,734
Credit-risk capital	265,041	289,080
Market-risk capital	162,581	187,183
Operations-risk capital	128,287	142,879
Total risk-based capital requirement	555,909	619,142
Permanent capital in excess of risk-based capital requirement	2,872,776	3,336,592
Regulatory capital, Required	2,231,181	2,543,733
Leverage capital, Required	2,788,977	3,179,666
Risk-based capital, Actual	3,428,685	3,955,734
Regulatory capital, Actual	$ 3,428,685	$ 3,955,734
Capital-to-asset ratio, Actual	6.10%	6.20%
Leverage capital, Actual	$ 5,143,028	$ 5,933,601
Leverage capital-to-assets ratio, Actual	9.20%	9.30%

Capital Narratives (Details)

Capital Narratives (Details) - $ / shares	Jun. 30, 2019	Jan. 16, 2019	Dec. 31, 2018
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 eligible 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

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended				6 Months Ended
		Jun. 30, 2019		Jun. 30, 2018		Jun. 30, 2019		Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		$ 150,715,000		$ 136,556,000	[1]	$ 305,532,000		$ 255,757,000	[1]
Amortization of hedging activities recorded in net gains (losses) on derivatives and hedging activities	[1]			458,000				1,598,000
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		2,963,804,000		3,318,568,000		3,607,359,000		3,265,130,000
Other comprehensive income (loss)		41,446,000		(3,745,000)		79,320,000		(17,650,000)
Period end		3,174,216,000		3,492,457,000		3,174,216,000		3,492,457,000
Net Unrealized Gain (Loss) Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(31,887,000)		(30,332,000)		(29,119,000)		(40,436,000)
Cumulative effect of change in accounting principle		(175,000)				(175,000)
Net Unrealized Gains (Losses)		(2,443,000)		2,582,000		(5,822,000)		11,748,000
Amortization - hedging activities		1,131,000	[2]	1,017,000	[3]	1,917,000	[2]	1,955,000	[4]
Other comprehensive income (loss)		(1,312,000)		3,599,000		(3,905,000)		13,703,000
Period end		(33,199,000)		(26,733,000)		(33,199,000)		(26,733,000)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(5,115,000)		(5,770,000)		(5,276,000)		(5,955,000)
Net actuarial loss		19,000		(1,460,000)		19,000		(1,460,000)
Amortization - pension and postretirement benefits	[5]	171,000		490,000		332,000		675,000
Other comprehensive income (loss)		190,000		(970,000)		351,000		(785,000)
Period end		(4,925,000)		(6,740,000)		(4,925,000)		(6,740,000)
Total [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(278,808,000)		(340,845,000)		(316,507,000)		(326,940,000)
Cumulative effect of change in accounting principle		(175,000)				(175,000)
Net Unrealized Gains (Losses)		33,850,000		(11,386,000)		64,536,000		(33,842,000)
Noncredit other-than-temporary impairment losses		(101,000)				(181,000)
Accretion of noncredit loss		6,188,000		7,462,000		12,479,000		14,818,000
Net actuarial loss		19,000		(1,460,000)		19,000		(1,460,000)
Noncredit other-than-temporary impairment losses reclassified to credit loss	[6]	188,000		132,000		218,000		204,000
Amortization - hedging activities		1,131,000	[2]	1,017,000	[3]	1,917,000	[2]	1,955,000	[4]
Amortization - pension and postretirement benefits	[5]	171,000		490,000		332,000		675,000
Other comprehensive income (loss)		41,446,000		(3,745,000)		79,320,000		(17,650,000)
Period end		(237,362,000)		(344,590,000)		(237,362,000)		(344,590,000)
Held-to-maturity Securities [Member] | Noncredit Portion of Other-Than-Temporary Impairment Losses on Held-to-Maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(122,913,000)		(150,790,000)		(129,154,000)		(158,218,000)
Noncredit other-than-temporary impairment losses		(101,000)				(181,000)
Accretion of noncredit loss		6,188,000		7,462,000		12,479,000		14,818,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[6]	188,000		132,000		218,000		204,000
Other comprehensive income (loss)		6,275,000		7,594,000		12,516,000		15,022,000
Period end		(116,638,000)		(143,196,000)		(116,638,000)		(143,196,000)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Unrealized Gain (Loss) Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds				1,000,000				1,900,000
Amortization of hedging activities recorded in net gains (losses) on derivatives and hedging activities				3,000				7,000
Available-for-sale Securities [Member] | Net Unrealized Loss on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(118,893,000)		(153,953,000)		(152,958,000)		(122,331,000)
Net Unrealized Gains (Losses)		36,293,000		(13,968,000)		70,358,000		(45,590,000)
Other comprehensive income (loss)		36,293,000		(13,968,000)		70,358,000		(45,590,000)
Period end		$ (82,600,000)		$ (167,921,000)		$ (82,600,000)		$ (167,921,000)
[1]	Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019.
[2]	Recorded in CO bond interest expense.
[3]	Amortization of hedging activities includes $1.0 million recorded in CO bond interest expense and $3 thousand recorded in net gains (losses) on derivatives and hedging activities in the statement of operations.
[4]	Amortization of hedging activities includes $1.9 million recorded in CO bond interest expense and $7 thousand recorded in net gains (losses) on derivatives and hedging activities in the statement of operations.
[5]	Recorded in other operating expenses in the statement of operations.
[6]	Recorded in net other-than-temporary impairment losses in investment securities, credit portion in the statement of operations.

Carrying Value and Fair Value o

Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 28,739	$ 10,431
Trading securities		1,097,963	163,038
Available-for-sale securities Fair Value		5,281,570	5,849,944
Held-to-maturity securities	[1],[2]	1,186,937	1,295,023
Held-to-maturity securities Fair Value		1,409,594	1,528,929
Accrued interest receivable		117,793	112,751
Derivative assets		67,761	22,403
Derivative Assets, Netting Adjustments and Cash Collateral	[3],[4],[5]	57,353	8,571
Mandatorily redeemable capital stock		(17,107)	(31,868)
Accrued interest payable		(119,293)	(112,043)
Derivative liabilities		(11,714)	(255,800)
Derivative liability, Netting Adjustments and Cash Collateral	[3],[4],[5]	41,497	53,752
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		28,739	10,431
Interest-bearing deposits		1,146,961	593,199
Securities purchased under agreements to resell		0	0
Federal funds sold		0	0
Trading securities	[4]	0	0
Available-for-sale securities Fair Value	[4]	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	[4]	0	0
Other assets	[4]	12,200	9,988
Deposits		0	0
Mandatorily redeemable capital stock		(17,107)	(31,868)
Accrued interest payable		0	0
Derivative liabilities	[4]	0	0
Level 1 [Member] | Commitments to extend credt for advances
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		5,000,054	6,499,078
Federal funds sold		250,000	1,500,002
Trading securities	[4]	1,097,963	163,038
Available-for-sale securities Fair Value	[4]	5,230,010	5,800,343
Held-to-maturity securities Fair Value		581,591	638,164
Advances		37,208,993	43,167,700
Mortgage loans, net		4,488,116	4,217,487
Accrued interest receivable		117,793	112,751
Derivative assets	[4]	10,408	13,832
Other assets	[4]	18,546	15,071
Deposits		(594,831)	(474,848)
Mandatorily redeemable capital stock		0	0
Accrued interest payable		(119,293)	(112,043)
Derivative liabilities	[4]	(53,211)	(309,552)
Level 2 [Member] | Commitments to extend credt for advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(2,946)	(4,164)
Level 2 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,746)	(1,257)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(26,426,741)	(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	[4]	0	0
Available-for-sale securities Fair Value	[4]	51,560	49,601
Held-to-maturity securities Fair Value		828,003	890,765
Advances		0	0
Mortgage loans, net		20,741	20,600
Accrued interest receivable		0	0
Derivative assets	[4]	0	0
Other assets	[4]	0	0
Deposits		0	0
Mandatorily redeemable capital stock		0	0
Accrued interest payable		0	0
Derivative liabilities	[4]	0	0
Level 3 [Member] | Commitments to extend credt for advances
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		28,739	10,431
Interest-bearing deposits		1,146,961	593,199
Securities purchased under agreements to resell		5,000,000	6,499,000
Federal funds sold		250,000	1,500,000
Trading securities	[4]	1,097,963	163,038
Available-for-sale securities Fair Value	[4]	5,281,570	5,849,944
Held-to-maturity securities		1,186,937	1,295,023
Advances		37,096,797	43,192,222
Mortgage loans, net		4,421,028	4,299,402
Accrued interest receivable		117,793	112,751
Derivative assets	[4]	67,761	22,403
Other assets	[4]	30,746	25,059
Deposits		(594,848)	(474,878)
Mandatorily redeemable capital stock		(17,107)	(31,868)
Accrued interest payable		(119,293)	(112,043)
Derivative liabilities	[4]	(11,714)	(255,800)
Carrying Value [Member] | Commitments to extend credt for advances
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		(1,746)	(1,257)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(26,424,978)	(33,065,822)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		28,739	10,431
Interest-bearing deposits		1,146,961	593,199
Securities purchased under agreements to resell		5,000,054	6,499,078
Federal funds sold		250,000	1,500,002
Trading securities	[4]	1,097,963	163,038
Available-for-sale securities Fair Value	[4]	5,281,570	5,849,944
Held-to-maturity securities Fair Value		1,409,594	1,528,929
Advances		37,208,993	43,167,700
Mortgage loans, net		4,508,857	4,238,087
Accrued interest receivable		117,793	112,751
Derivative assets	[4]	67,761	22,403
Other assets	[4]	30,746	25,059
Deposits		(594,831)	(474,848)
Mandatorily redeemable capital stock		(17,107)	(31,868)
Accrued interest payable		(119,293)	(112,043)
Derivative liabilities	[4]	(11,714)	(255,800)
Total Fair Value [Member] | Commitments to extend credt for advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(2,946)	(4,164)
Total Fair Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,746)	(1,257)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(26,426,741)	(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		(25,565,210)	(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		(25,292,490)	(25,912,684)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (25,565,210)	$ (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 $ 1,409,594 and $1,528,929 at June 30, 2019 , and December 31, 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 $99.3 million and $62.8 million at June 30, 2019 , and December 31, 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 $401 thousand and $471 thousand at June 30, 2019 , and December 31, 2018 , respectively.
[4]	Carried at fair value and measured on a recurring basis.
[5]	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 of Assets and Liabil

Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		$ 1,097,963	$ 163,038
Available-for-sale securities Fair Value		5,281,570	5,849,944
Derivative assets		67,761	22,403
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2],[3]	57,353	8,571
Fair value of held-to-maturity securities		1,409,594	1,528,929
Derivative liabilities		(11,714)	(255,800)
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2],[3]	41,497	53,752
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	0	0
Available-for-sale securities Fair Value	[2]	0	0
Derivative assets	[2]	0	0
Other assets	[2]	12,200	9,988
Fair value of held-to-maturity securities		0	0
Mortgage loans held for portfolio		0	0
Derivative liabilities	[2]	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	1,097,963	163,038
Available-for-sale securities Fair Value	[2]	5,230,010	5,800,343
Derivative assets	[2]	10,408	13,832
Other assets	[2]	18,546	15,071
Fair value of held-to-maturity securities		581,591	638,164
Mortgage loans held for portfolio		4,488,116	4,217,487
Derivative liabilities	[2]	(53,211)	(309,552)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	0	0
Available-for-sale securities Fair Value	[2]	51,560	49,601
Derivative assets	[2]	0	0
Other assets	[2]	0	0
Fair value of held-to-maturity securities		828,003	890,765
Mortgage loans held for portfolio		20,741	20,600
Derivative liabilities	[2]	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]	57,353	8,571
Derivative liability, Netting Adjustments and Cash Collateral	[4]	41,497	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]	57,353	8,571
Derivative liability, Netting Adjustments and Cash Collateral	[4]	41,497	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		12,200	9,988
Total assets carried at fair value		12,200	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		1,097,963	163,038
Available-for-sale securities Fair Value		5,230,010	5,800,343
Derivative assets		10,408	13,832
Other assets		18,546	15,071
Total assets carried at fair value		6,356,927	5,992,284
Total liabilities carried at fair value		(53,211)	(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		10,208	13,493
Derivative liabilities		(53,203)	(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		51,560	49,601
Derivative assets		0	0
Other assets		0	0
Total assets carried at fair value		51,560	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		0	0
Mortgage loans held for portfolio		0	0
REO		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		0	0
Mortgage loans held for portfolio		0	0
REO		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]	7,525	3,173
Mortgage loans held for portfolio	[5]	472	1,144
REO	[5]	5	361
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	1,097,963	163,038
Available-for-sale securities Fair Value	[2]	5,281,570	5,849,944
Derivative assets	[2]	67,761	22,403
Other assets	[2]	30,746	25,059
Fair value of held-to-maturity securities		1,409,594	1,528,929
Mortgage loans held for portfolio		4,508,857	4,238,087
Derivative liabilities	[2]	(11,714)	(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		1,097,963	163,038
Available-for-sale securities Fair Value		5,281,570	5,849,944
Derivative assets		67,761	22,403
Other assets		30,746	25,059
Total assets carried at fair value		6,478,040	6,060,444
Total liabilities carried at fair value		(11,714)	(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		67,561	22,064
Derivative liabilities		(11,706)	(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]	7,525	3,173
Mortgage loans held for portfolio	[5]	472	1,144
REO	[5]	5	361
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		6,208	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		6,208	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		6,208	6,102
U.S. Treasury obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		1,003,118	0
U.S. Treasury obligations [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
U.S. Treasury obligations [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		1,003,118
U.S. Treasury obligations [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
U.S. Treasury obligations [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		1,003,118
U.S. government-guaranteed - single-family MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		4,701	5,344
Available-for-sale securities Fair Value		66,558	75,658
Fair value of held-to-maturity securities		7,757	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		4,701	5,344
Available-for-sale securities Fair Value		66,558	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		4,701	5,344
Available-for-sale securities Fair Value		66,558	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		337,450	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		337,450	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		337,450	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
Derivative liabilities		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		200	339
Derivative liabilities		(8)
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
Derivative liabilities		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		200	339
Derivative liabilities		(8)
HFA securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		51,560	49,601
Fair value of held-to-maturity securities		96,401	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		51,560	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		51,560	49,601
Supranational institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		419,185	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		419,185	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		419,185	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		290,058	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		290,058	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		290,058	273,169
GSEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		121,897	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		121,897	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		121,897	115,627
Single Family [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		107	148
Available-for-sale securities Fair Value		3,165,003	3,562,159
Fair value of held-to-maturity securities		364,591	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		107	148
Available-for-sale securities Fair Value		3,165,003	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		107	148
Available-for-sale securities Fair Value		3,165,003	3,562,159
Multifamily [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		83,829	151,444
Available-for-sale securities Fair Value		829,859	1,007,441
Fair value of held-to-maturity securities		209,243	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	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		83,829	151,444
Available-for-sale securities Fair Value		829,859	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	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		83,829	151,444
Available-for-sale securities Fair Value		829,859	1,007,441
Residential Mortgage Backed Securities [Member] | 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		725,435	784,381
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		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		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]	7,048	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]	$ 7,048	$ 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 $99.3 million and $62.8 million at June 30, 2019 , and December 31, 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 $401 thousand and $471 thousand at June 30, 2019 , and December 31, 2018 , respectively.
[2]	Carried at fair value and measured on a recurring basis.
[3]	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.
[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 real estate owned property (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	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 50,348	$ 37,495	$ 49,601	$ 37,683
Unrealized gains (losses) included in other comprehensive income	1,212	105	1,959	(83)
Balance at end of period	$ 51,560	$ 37,600	$ 51,560	$ 37,600

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($)		6 Months Ended
		Jun. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Value of the guarantees related to standby letters of credit		$ 58,895,000	$ 48,898,000
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		$ 996,700,000,000	972,600,000,000
Standby Letters of Credit Issuance Commitments [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 27,000,000	32,600,000
Off-balance-sheet Commitments Expiring After One Year			675,000
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]	$ 7,850,041,000	6,028,851,000
Off-balance-sheet Commitments Expiring After One Year	[1]	282,032,000	226,438,000
Total Off-balance Sheet Commitments	[1]	8,132,073,000	6,255,289,000
Value of the guarantees related to standby letters of credit		1,700,000	1,300,000
Commitments of unused lines of credit - advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[2]	1,162,632,000	1,177,377,000
Off-balance-sheet Commitments Expiring After One Year	[2]	0	0
Total Off-balance Sheet Commitments	[2]	$ 1,162,632,000	1,177,377,000
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		$ 122,330,000	159,401,000
Off-balance-sheet Commitments Expiring After One Year		60,310,000	59,894,000
Total Off-balance Sheet Commitments		182,640,000	219,295,000
Unsettled CO bonds, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		23,000,000	105,400,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		23,000,000	105,400,000
Unsettled CO discount notes, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		0	600,000,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		0	600,000,000
Mortgage Receivable [Member] | Commitments to Invest in Mortgage Loans [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		53,555,000	50,773,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		$ 53,555,000	$ 50,773,000
[1]	The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At June 30, 2019 , and December 31, 2018 , these amounts totaled $ 27.0 million and $32.6 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $675 thousand at December 31, 2018 .
[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 ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018		Dec. 31, 2018
Schedule of Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 1,995,252			$ 1,995,252			$ 2,528,854
Par Value of Advances	37,076,547			37,076,547			43,268,385
Total Accrued Interest Receivable	117,793			117,793			112,751
Interest income on advances	223,869	$ 213,920	[1]	471,746	$ 391,370	[1]
Fees on letters of credit	3,329	2,463		6,293	4,819
Citizens Bank N.A. [Member]
Schedule of Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 121,572			$ 121,572			$ 339,003
Percent of Total Capital Stock Outstanding	6.00%			6.00%			13.20%
Par Value of Advances	$ 2,555,961			$ 2,555,961			$ 7,656,146
Percentage of Total Par Value of Advances	6.90%			6.90%			17.70%
Total Accrued Interest Receivable	$ 1,855			$ 1,855			$ 5,005
Percent of Total Accrued Interest Receivable on Advances	3.20%			3.20%			8.30%
Interest income on advances	$ 21,958	29,192		$ 61,071	56,084
Fees on letters of credit	1,641	$ 984		3,519	$ 2,081
Directors' Financial Institutions [Member]
Schedule of Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 86,052			$ 86,052			$ 113,337
Percent of Total Capital Stock Outstanding	4.30%			4.30%			4.40%
Par Value of Advances	$ 1,728,192			$ 1,728,192			$ 2,147,602
Percentage of Total Par Value of Advances	4.70%			4.70%			5.00%
Total Accrued Interest Receivable	$ 3,234			$ 3,234			$ 3,576
Percent of Total Accrued Interest Receivable on Advances	5.50%			5.50%			6.00%
Minimum [Member]
Schedule of Transactions with Shareholders [Line Items]
Definition of shareholder concentration, minimum percent	10.00%			10.00%
[1]	Prior period amounts were not revised to conform with new hedge accounting guidance adopted January 1, 2019.

Subsequent Events (Details)

Subsequent Events (Details) - Common Class B [Member] - Subsequent Event [Member] - USD ($) $ in Millions	Aug. 02, 2019	Jul. 26, 2019
Subsequent Event [Line Items]
Annualized rate of cash dividend		6.04%
Dividend, including dividends on mandatorily redeemable capital stock	$ 28.1