Federal Home Loan Bank of Boston 10-Q 8 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Entity Registrant Name	FEDERAL HOME LOAN BANK OF BOSTON
Entity Central Index Key	1,331,463
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Current Reporting Status	Yes
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		24,751,377

Statements of Condition (unaudi

Statements of Condition (unaudited) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks		$ 45,614	$ 261,673
Interest-bearing deposits		397,203	246
Securities purchased under agreements to resell		5,499,000	5,349,000
Federal funds sold		5,650,000	3,450,000
Investment securities:
Trading securities		176,113	191,510
Available-for-sale securities - includes $4,734 and $1,414 pledged as collateral at September 30, 2018 and December 31, 2017, respectively that may be repledged		6,227,080	7,324,736
Held-to-maturity securities - includes $7,100 and $6,444 pledged as collateral at September 30, 2018 and December 31, 2017, respectively that may be repledged	[1]	1,372,299	1,626,122
Total investment securities		7,775,492	9,142,368
Advances		40,927,639	37,565,967
Mortgage loans held for portfolio, net of allowance for credit losses of $500 at September 30, 2018. and December 31, 2017		4,192,425	4,004,737
Loans to other Federal Home Loan Banks (FHLBanks)		0	400,000
Accrued interest receivable		102,466	94,100
Derivative assets, net		21,956	34,786
Other assets		82,008	59,069
Total Assets		64,693,803	60,361,946
Deposits
Interest-bearing		463,349	450,922
Non-interest-bearing		21,412	26,147
Total deposits		484,761	477,069
Consolidated obligations (COs):
Bonds		26,741,036	28,344,623
Discount notes		33,431,980	27,720,906
Total consolidated obligations		60,173,016	56,065,529
Mandatorily redeemable capital stock		31,868	35,923
Accrued interest payable		119,242	90,626
Affordable Housing Program (AHP) payable		83,982	81,600
Derivative liabilities, net		228,127	300,450
Other liabilities		52,478	45,619
Total liabilities		61,173,474	57,096,816
Commitments and contingencies (Note 17)
Capital
Capital stock – Class B – putable ($100 par value), 24,769 shares and 22,837 shares issued and outstanding at September 30, 2018, and December 31, 2017, respectively		2,476,876	2,283,721
Retained earnings:
Unrestricted		1,084,538	1,041,033
Restricted		301,928	267,316
Total retained earnings		1,386,466	1,308,349
Accumulated other comprehensive loss		(343,013)	(326,940)
Total capital		3,520,329	3,265,130
Total Liabilities and Capital		$ 64,693,803	$ 60,361,946
[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.

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Available-for-sale securities pledged as collateral that may be repledged	$ 4,734	$ 1,414
Held-to-maturity securities pledged as collateral that may be repledged (a)	7,100	6,444
Allowance for credit losses	500	500
Fair value of held-to-maturity securities	$ 1,638,491	$ 1,903,227
Common Class B [Member]
Common Stock, Class B, putable shares issued	24,769	22,837
Common Stock, Class B, putable par value per share	$ 100	$ 100
Common Stock, Class B, putable shares outstanding	24,769	22,837

Statements of Operations (unaud

Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
INTEREST INCOME
Advances	$ 226,544	$ 136,462	$ 618,077	$ 371,075
Securities purchased under agreements to resell	20,865	8,074	44,494	18,822
Federal funds sold	29,329	16,622	81,126	39,614
Investment securities:
Trading securities	1,934	2,809	6,947	8,200
Available-for-sale securities	35,532	30,625	113,531	78,161
Held-to-maturity securities	19,525	19,754	57,622	60,129
Total investment securities	56,991	53,188	178,100	146,490
Mortgage loans held for portfolio	33,967	31,656	100,774	92,592
Other	1,122	822	2,270	1,549
Total interest income	368,818	246,824	1,024,841	670,142
Consolidated obligations:
Bonds	142,086	109,052	397,843	311,395
Discount notes	147,463	65,120	385,804	157,767
Total consolidated obligations	289,549	174,172	783,647	469,162
Deposits	1,337	1,144	3,600	2,434
Mandatorily redeemable capital stock	472	399	1,427	1,105
Other borrowings	0	0	38	8
Total interest expense	291,358	175,715	788,712	472,709
NET INTEREST INCOME	77,460	71,109	236,129	197,433
Provision (reduction of provision) for credit losses	0	28	6	(148)
NET INTEREST INCOME AFTER PROVISION (REDUCTION OF PROVISION) FOR CREDIT LOSSES	77,460	71,081	236,123	197,581
OTHER INCOME (LOSS)
Total other-than-temporary impairment losses on investment securities	(65)	(12)	(197)	(102)
Net amount of impairment losses reclassified from accumulated other comprehensive loss	(6)	(420)	(210)	(1,316)
Net other-than-temporary impairment losses on investment securities, credit portion	(71)	(432)	(407)	(1,418)
Litigation settlements	12,769	0	12,769	0
Service fees	2,719	2,228	7,538	6,362
Net unrealized losses on trading securities	(714)	(1,591)	(3,702)	(3,857)
Net gains (losses) on derivatives and hedging activities	487	(6)	2,085	(388)
Other	(82)	397	340	358
Total other income	15,108	596	18,623	1,057
OTHER EXPENSE
Compensation and benefits	10,309	11,111	31,085	31,065
Other operating expenses	5,818	5,749	17,992	17,704
Federal Housing Finance Agency (the FHFA)	832	934	2,593	2,870
Office of Finance	911	734	2,538	2,321
Other	2,788	2,444	8,090	8,583
Total other expense	20,658	20,972	62,298	62,543
INCOME BEFORE ASSESSMENTS	71,910	50,705	192,448	136,095
AHP assessments	7,238	5,110	19,387	13,720
NET INCOME	$ 64,672	$ 45,595	$ 173,061	$ 122,375

Statements of Comprehensive Inc

Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 64,672	$ 45,595	$ 173,061	$ 122,375
Other comprehensive income:
Net unrealized (losses) gains on available-for-sale securities	(8,690)	(61)	(54,280)	42,439
Net noncredit portion of other-than-temporary impairment losses on held-to-maturity securities	7,133	8,598	22,155	25,909
Net unrealized gains relating to hedging activities	3,526	1,305	17,229	3,938
Pension and postretirement benefits	(392)	305	(1,177)	914
Total other comprehensive income (loss)	1,577	10,147	(16,073)	73,200
Comprehensive income	$ 66,249	$ 55,742	$ 156,988	$ 195,575

Statements of Capital (unaudite

Statements of Capital (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			$ 3,265,130	$ 3,244,778
Comprehensive income	$ 66,249	$ 55,742	156,988	195,575
Proceeds from sale of capital stock			1,311,464	731,366
Repurchase of capital stock			(1,118,018)	(861,354)
Shares reclassified to mandatorily redeemable capital stock			(291)	(8,670)
Cash dividends on capital stock			(94,944)	(74,079)
Period end	3,520,329	3,227,616	3,520,329	3,227,616
Retained Earnings, Unrestricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			1,041,033	987,711
Comprehensive income			138,449	97,900
Cash dividends on capital stock			(94,944)	(74,079)
Period end	1,084,538	1,011,532	1,084,538	1,011,532
Retained Earnings, Restricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			267,316	229,275
Comprehensive income			34,612	24,475
Period end	301,928	253,750	301,928	253,750
Retained Earnings, Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			1,308,349	1,216,986
Comprehensive income			173,061	122,375
Cash dividends on capital stock			(94,944)	(74,079)
Period end	1,386,466	1,265,282	1,386,466	1,265,282
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	(344,590)	(320,461)	(326,940)	(383,514)
Comprehensive income			(16,073)	73,200
Period end	$ (343,013)	$ (310,314)	$ (343,013)	$ (310,314)
Common Class B [Member] | Capital Stock Class B - Putable
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period, shares			22,837	24,113
Beginning of period			$ 2,283,721	$ 2,411,306
Proceeds from sale of capital stock, shares			13,115	7,314
Proceeds from sale of capital stock			$ 1,311,464	$ 731,366
Repurchase of capital stock, shares			(11,180)	(8,614)
Repurchase of capital stock			$ (1,118,018)	$ (861,354)
Shares reclassified to mandatorily redeemable capital stock, shares			(3)	(87)
Shares reclassified to mandatorily redeemable capital stock			$ (291)	$ (8,670)
Period end, shares	24,769	22,726	24,769	22,726
Period end	$ 2,476,876	$ 2,272,648	$ 2,476,876	$ 2,272,648

Statements of Cash Flows (unaud

Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
OPERATING ACTIVITIES
Net Income			$ 173,061	$ 122,375
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			(5,205)	(5,690)
Provision (reduction of provision) for credit losses	$ 0	$ 28	6	(148)
Change in net fair-value adjustments on derivatives and hedging activities			62,198	(10,293)
Net other-than-temporary impairment losses on investment securities, credit portion	71	432	407	1,418
Other adjustments			4,057	3,741
Net change in:
Market value of trading securities			3,702	3,857
Accrued interest receivable			(8,366)	(238)
Other assets			(19,509)	(1,522)
Accrued interest payable			28,618	19,326
Other liabilities			9,183	(1,343)
Total adjustments			75,091	9,108
Net cash provided by operating activities			248,152	131,483
INVESTING ACTIVITIES
Interest-bearing deposits			(442,598)	(195,156)
Securities purchased under agreements to resell			(150,000)	3,000,000
Federal funds sold			(2,200,000)	(3,550,000)
Premises, software, and equipment			(533)	(1,901)
Loans to other FHLBanks			400,000	0
Trading securities:
Proceeds			767,897	717,022
Purchases			(749,072)	(618,051)
Available-for-sale securities:
Proceeds from long-term			979,365	902,513
Purchases of long-term			(3,150)	(1,710,033)
Held-to-maturity securities:
Proceeds from long-term			283,819	376,797
Advances to members:
Repaid			508,490,355	361,435,261
Originated			(511,902,406)	(359,828,724)
Mortgage loans held for portfolio:
Proceeds			320,586	352,393
Purchases			(517,010)	(608,887)
Proceeds from sale of foreclosed assets			2,440	3,239
Net cash (used in) provided by investing activities			(4,720,307)	274,473
FINANCING ACTIVITIES
Net change in deposits			9,013	10,348
Net payments on derivatives with a financing element			0	(4,100)
Net proceeds from issuance of consolidated obligations:
Discount notes			149,554,769	125,580,345
Bonds			8,128,518	7,821,400
Payments for maturing and retiring consolidated obligations:
Discount notes			(143,869,342)	(127,600,947)
Bonds			(9,661,015)	(6,491,880)
Proceeds from issuance of capital stock			1,311,464	731,366
Payments for repurchase of capital stock			(1,118,018)	(861,354)
Payments for redemption of mandatorily redeemable capital stock			(4,346)	(5,315)
Cash dividends paid			(94,947)	(74,076)
Net cash provided by (used in) financing activities			4,256,096	(894,213)
Net decrease in cash and due from banks			(216,059)	(488,257)
Cash and due from banks at beginning of the period			261,673	520,031	$ 520,031
Cash and due from banks at end of the period	$ 45,614	$ 31,774	45,614	31,774	261,673
Supplemental disclosures:
Interest paid			754,566	471,076
AHP payments			13,384	16,217	$ 18,628
Noncash receipt of trading securities			7,130	0
Noncash transfers of mortgage loans held for portfolio to other assets			$ 1,413	$ 1,588

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation [Text Block]	Basis of Presentation

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	9 Months Ended
	Sep. 30, 2018
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, 2018 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. On March 10, 2017, the Financial Accounting Standards Board (FASB) issued amended guidance to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The amendments require that employers disaggregate the service cost component from the other components of net benefit cost. The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This guidance resulted in the reclassification of $352,000 and $1.1 million , respectively, of non-service cost components of net benefit cost from compensation and benefits expense to other non-interest expense in the statements of operations for the three and nine months ended September 30, 2017. Recognition and Measurement of Financial Assets and Financial Liabilities. On January 5, 2016, the FASB issued amended guidance on certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. This guidance requires, among other things, that we: • Present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when we elect to measure the liability at fair value in accordance with the fair value option for financial instruments. • Present separately financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the statement of condition or the accompanying notes to the financial statements. • Discontinue the disclosure of the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the statement of condition. This guidance did not have any effect on our financial condition, results of operations, or cash flows. In accordance with the updated guidance, we have made insignificant revisions to Note 16 — Fair Values to specify the measurement category for each form of financial asset (that is, securities or loans and receivables). Becoming effective January 1, 2019 Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes. On October 25, 2018, the FASB issued amended guidance to permit use of the OIS rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815. This guidance is effective for us for interim and annual periods beginning on January 1, 2019, and while early adoption is permitted, we do not intend to adopt this guidance early. We are currently evaluating the effect this guidance may have on our financial condition, results of operations, and cash flows. 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 only how changes in the benchmark interest rate affect a decision to settle a prepayable instrument before its scheduled maturity in calculating the change in the fair value of the hedged item attributable to interest-rate risk; • For a cash flow hedge of interest-rate risk of a variable-rate financial instrument, an entity could designate as the hedged risk the variability in cash flows attributable to the contractually specified interest-rate; • 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; • An entity can perform subsequent assessments of hedge effectiveness qualitatively in instances where initial quantitative testing is required; and • For financial instruments eligible to be designated as a hedged item under the last-of-layer method, a one-time reclassification of prepayable financial instruments from held-to-maturity to available-for-sale at the date of adoption is permitted. This guidance becomes effective for us for interim and annual periods beginning on January 1, 2019, and while early adoption is permitted, we do not intend to adopt this guidance early. For all cash flow hedges existing on the date of adoption, this guidance will be 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 is required only prospectively. We have evaluated this guidance and it is not expected to affect our application of hedge accounting for existing hedge strategies, with the exception of designation of a fallback long-haul effectiveness testing method for our short-cut hedge strategies. Upon adoption, this guidance will prospectively affect our presentation of fair value hedge relationships on the statement of operations and will require certain new disclosures. We will continue to assess the new strategies and opportunities enabled by this guidance to expand our risk management strategies. We do not anticipate the adoption of this guidance will have a material effect on our financial condition, results of operations, or cash flows. Premium Amortization on Purchased Callable Debt Securities. On March 30, 2017, the FASB issued amended guidance to shorten the amortization period for certain purchased callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. This guidance affects all entities that hold investments in callable debt securities that have an amortized cost basis in excess of the amount that is repayable by the issuer at the earliest call date (that is, at a premium). This guidance is effective for us for interim and annual periods beginning on January 1, 2019, and while early adoption is permitted, we do not intend to adopt this guidance early. This guidance will be applied using a modified retrospective method through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. We currently do not have any assets that are in scope to be evaluated under the updated guidance. As such, adoption of this guidance is not expected to have a material effect on our financial condition, results of operations, or cash flows. 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 becomes effective for us for the interim and annual periods beginning on January 1, 2019, and while early application is permitted, we do not intend to adopt the new guidance early. Upon adoption of the new guidance, we currently estimate that we will recognize right-of-use assets and lease liabilities for our operating leases of approximately $11.8 million and $12.3 million , respectively, on the statement of condition. We do not anticipate the adoption of this guidance will have a material effect on our results of operations or cash flows. 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.

Trading Securities

Trading Securities	9 Months Ended
	Sep. 30, 2018
Trading Securities [Abstract]
Trading Securities (and Certain Trading Assets) Disclosure [Text Block]	Trading Securities Table 3.1 - Trading Securities by Major Security Type (dollars in thousands) September 30, 2018 December 31, 2017 Corporate bonds $ 6,774 $ — Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 5,684 6,807 Government-sponsored enterprise (GSE)s – single-family 180 346 GSEs – multifamily 163,475 184,357 169,339 191,510 Total $ 176,113 $ 191,510 Net unrealized losses on trading securities for the nine months ended September 30, 2018 and 2017 , amounted to $3.7 million and $3.9 million , respectively.

Available-for-Sale Securities

Available-for-Sale Securities	9 Months Ended
	Sep. 30, 2018
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Disclosure [Text Block]	Available-for-Sale Securities Table 4.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) September 30, 2018 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) $ 45,850 $ — $ (5,513 ) $ 40,337 Supranational institutions 409,784 — (14,606 ) 395,178 U.S. government-owned corporations 286,169 — (17,545 ) 268,624 GSEs 118,173 — (4,748 ) 113,425 859,976 — (42,412 ) 817,564 MBS U.S. government guaranteed – single-family 84,742 41 (3,746 ) 81,037 U.S. government guaranteed – multifamily 374,986 — (7,471 ) 367,515 GSEs – single-family 3,856,145 962 (125,102 ) 3,732,005 GSEs – multifamily 1,227,842 1,444 (327 ) 1,228,959 5,543,715 2,447 (136,646 ) 5,409,516 Total $ 6,403,691 $ 2,447 $ (179,058 ) $ 6,227,080 _______________________ (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, 2017 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 42,700 $ — $ (5,017 ) $ 37,683 Supranational institutions 438,667 — (20,382 ) 418,285 U.S. government-owned corporations 313,985 — (21,908 ) 292,077 GSEs 128,744 — (7,401 ) 121,343 924,096 — (54,708 ) 869,388 MBS U.S. government guaranteed – single-family 98,720 55 (2,998 ) 95,777 U.S. government guaranteed – multifamily 447,975 — (4,602 ) 443,373 GSEs – single-family 4,625,333 1,194 (63,535 ) 4,562,992 GSEs – multifamily 1,350,943 2,263 — 1,353,206 6,522,971 3,512 (71,135 ) 6,455,348 Total $ 7,447,067 $ 3,512 $ (125,843 ) $ 7,324,736 _______________________ (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 4.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position by Major Security Type (dollars in thousands) September 30, 2018 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 21,793 $ (3,587 ) $ 18,544 $ (1,926 ) $ 40,337 $ (5,513 ) Supranational institutions — — 395,178 (14,606 ) 395,178 (14,606 ) U.S. government-owned corporations — — 268,624 (17,545 ) 268,624 (17,545 ) GSEs — — 113,425 (4,748 ) 113,425 (4,748 ) 21,793 (3,587 ) 795,771 (38,825 ) 817,564 (42,412 ) MBS U.S. government guaranteed – single-family — — 61,434 (3,746 ) 61,434 (3,746 ) U.S. government guaranteed – multifamily — — 367,515 (7,471 ) 367,515 (7,471 ) GSEs – single-family 1,175,912 (32,577 ) 2,439,363 (92,525 ) 3,615,275 (125,102 ) GSEs – multifamily 339,153 (327 ) — — 339,153 (327 ) 1,515,065 (32,904 ) 2,868,312 (103,742 ) 4,383,377 (136,646 ) Total temporarily impaired $ 1,536,858 $ (36,491 ) $ 3,664,083 $ (142,567 ) $ 5,200,941 $ (179,058 ) December 31, 2017 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 29,345 $ (4,005 ) $ 8,338 $ (1,012 ) $ 37,683 $ (5,017 ) Supranational institutions — — 418,285 (20,382 ) 418,285 (20,382 ) U.S. government-owned corporations — — 292,077 (21,908 ) 292,077 (21,908 ) GSEs — — 121,343 (7,401 ) 121,343 (7,401 ) 29,345 (4,005 ) 840,043 (50,703 ) 869,388 (54,708 ) MBS U.S. government guaranteed – single-family — — 70,877 (2,998 ) 70,877 (2,998 ) U.S. government guaranteed – multifamily 64,219 (571 ) 379,154 (4,031 ) 443,373 (4,602 ) GSEs – single-family 1,853,323 (12,661 ) 2,540,006 (50,874 ) 4,393,329 (63,535 ) 1,917,542 (13,232 ) 2,990,037 (57,903 ) 4,907,579 (71,135 ) Total temporarily impaired $ 1,946,887 $ (17,237 ) $ 3,830,080 $ (108,606 ) $ 5,776,967 $ (125,843 ) Table 4.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Year of Contractual Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ — $ — $ — $ — Due after one year through five years 42,700 37,640 42,700 37,683 Due after five years through 10 years 457,717 441,968 438,667 418,285 Due after 10 years 359,559 337,956 442,729 413,420 859,976 817,564 924,096 869,388 MBS (1) 5,543,715 5,409,516 6,522,971 6,455,348 Total $ 6,403,691 $ 6,227,080 $ 7,447,067 $ 7,324,736 _______________________ (1)

Held-to-Maturity Securities

Held-to-Maturity Securities	9 Months Ended
	Sep. 30, 2018
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity Securities Disclosure [Text Block]	Held-to-Maturity Securities Table 5.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) September 30, 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 $ 416 $ — $ 416 $ 1 $ — $ 417 HFA securities 124,560 — 124,560 6 (3,542 ) 121,024 124,976 — 124,976 7 (3,542 ) 121,441 MBS U.S. government guaranteed – single-family 8,647 — 8,647 170 — 8,817 GSEs – single-family 444,076 — 444,076 7,369 (2,140 ) 449,305 GSEs – multifamily 211,476 — 211,476 1,511 — 212,987 Private-label – residential 712,078 (136,043 ) 576,035 264,618 (1,648 ) 839,005 Asset-backed securities (ABS) backed by home equity loans 7,108 (19 ) 7,089 24 (177 ) 6,936 1,383,385 (136,062 ) 1,247,323 273,692 (3,965 ) 1,517,050 Total $ 1,508,361 $ (136,062 ) $ 1,372,299 $ 273,699 $ (7,507 ) $ 1,638,491 December 31, 2017 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 $ 1,042 $ — $ 1,042 $ 10 $ — $ 1,052 HFA securities 146,410 — 146,410 26 (14,372 ) 132,064 147,452 — 147,452 36 (14,372 ) 133,116 MBS U.S. government guaranteed – single-family 10,097 — 10,097 190 — 10,287 U.S. government guaranteed – multifamily 280 — 280 — — 280 GSEs – single-family 568,948 — 568,948 10,410 (310 ) 579,048 GSEs – multifamily 214,641 — 214,641 6,451 — 221,092 Private-label – residential 835,070 (158,194 ) 676,876 278,217 (3,195 ) 951,898 ABS backed by home equity loans 7,851 (23 ) 7,828 27 (349 ) 7,506 1,636,887 (158,217 ) 1,478,670 295,295 (3,854 ) 1,770,111 Total $ 1,784,339 $ (158,217 ) $ 1,626,122 $ 295,331 $ (18,226 ) $ 1,903,227 Table 5.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position by Major Security Type (dollars in thousands) September 30, 2018 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 110,953 $ (3,542 ) $ 110,953 $ (3,542 ) MBS GSEs – single-family 106,028 (1,650 ) 22,748 (490 ) 128,776 (2,140 ) Private-label – residential — — 117,245 (2,555 ) 117,245 (2,555 ) ABS backed by home equity loans — — 5,869 (177 ) 5,869 (177 ) 106,028 (1,650 ) 145,862 (3,222 ) 251,890 (4,872 ) Total $ 106,028 $ (1,650 ) $ 256,815 $ (6,764 ) $ 362,843 $ (8,414 ) December 31, 2017 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 121,203 $ (14,372 ) $ 121,203 $ (14,372 ) MBS GSEs – single-family 44,759 (52 ) 28,771 (258 ) 73,530 (310 ) Private-label – residential — — 158,963 (5,558 ) 158,963 (5,558 ) ABS backed by home equity loans — — 7,371 (350 ) 7,371 (350 ) 44,759 (52 ) 195,105 (6,166 ) 239,864 (6,218 ) Total $ 44,759 $ (52 ) $ 316,308 $ (20,538 ) $ 361,067 $ (20,590 ) Table 5.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 1,251 $ 1,251 $ 1,256 $ 264 $ 264 $ 267 Due after one year through five years 9,230 9,230 9,232 11,613 11,613 11,645 Due after five years through 10 years 17,565 17,565 17,458 18,245 18,245 18,226 Due after 10 years 96,930 96,930 93,495 117,330 117,330 102,978 124,976 124,976 121,441 147,452 147,452 133,116 MBS (2) 1,383,385 1,247,323 1,517,050 1,636,887 1,478,670 1,770,111 Total $ 1,508,361 $ 1,372,299 $ 1,638,491 $ 1,784,339 $ 1,626,122 $ 1,903,227 _______________________ (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)

Other-Than-Temporary Impairment

Other-Than-Temporary Impairment	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 . At September 30, 2018 , 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. We do not consider these investments to be other-than-temporarily impaired at September 30, 2018 . Private-Label Residential MBS and ABS Backed by Home Equity Loans. For those securities for which a credit loss was recognized during the nine months ended September 30, 2018 , Table 6.1 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 6.1 - 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 Alt-A - Private-label residential MBS (1) $ 6,230 12.6 % 18.5 % 27.3 % 23.6 % _______________________ (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 6.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) September 30, 2018 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 25,864 $ 22,026 $ 17,295 $ 24,484 Private-label residential MBS – Alt-A 831,215 597,346 466,033 721,713 ABS backed by home equity loans – Subprime 161 150 132 155 Total other-than-temporarily impaired securities $ 857,240 $ 619,522 $ 483,460 $ 746,352 _______________________ (1) Securities are classified based on their classifications 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 6.3 presents a roll forward of the amounts related to credit losses recognized in earnings. The roll forward is the amount of credit losses on investment securities for which we recognized a portion of other-than-temporary impairment charges into accumulated other comprehensive loss. Table 6.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Balance at beginning of period $ 437,315 $ 468,706 $ 452,523 $ 490,404 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 71 432 407 1,418 Reductions: Securities matured during the period (2) — — — (5,565 ) 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 (7,997 ) (8,356 ) (23,541 ) (25,475 ) Balance at end of period $ 429,389 $ 460,782 $ 429,389 $ 460,782 _______________________ (1) For the three months ended September 30, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to July 1, 2018 and 2017 . For the nine months ended September 30, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to January 1, 2018 and 2017 . (2)

Advances

Advances	9 Months Ended
	Sep. 30, 2018
Advances [Abstract]
Federal Home Loan Bank, Advances [Text Block]	Advances General Terms. At both September 30, 2018 , and December 31, 2017 , we had advances outstanding with interest rates ranging from zero percent to 7.72 percent . Table 7.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 7,887 2.63 % $ 5,698 1.70 % Due in one year or less 20,964,860 2.20 21,501,397 1.56 Due after one year through two years 12,202,282 2.30 7,462,785 1.65 Due after two years through three years 2,171,439 2.28 2,709,951 1.85 Due after three years through four years 2,130,610 2.32 2,084,105 2.03 Due after four years through five years 2,466,375 2.10 2,071,989 1.56 Thereafter 1,115,924 2.85 1,811,241 2.23 Total par value 41,059,377 2.25 % 37,647,166 1.66 % Premiums 14,394 17,931 Discounts (36,356 ) (32,757 ) Fair value of bifurcated derivatives (1) (221 ) (1,591 ) Hedging adjustments (109,555 ) (64,782 ) Total $ 40,927,639 $ 37,565,967 _________________________ (1) At September 30, 2018 , and December 31, 2017 , 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 7.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (1) (dollars in thousands) September 30, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,887 $ 5,698 Due in one year or less 30,153,735 25,842,572 Due after one year through two years 4,202,282 3,722,785 Due after two years through three years 2,161,439 2,709,951 Due after three years through four years 1,968,910 1,924,105 Due after four years through five years 1,503,175 1,684,789 Thereafter 1,061,949 1,757,266 Total par value $ 41,059,377 $ 37,647,166 _______________________ (1) Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees. Table 7.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value September 30, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,887 $ 5,698 Due in one year or less 22,282,660 22,828,547 Due after one year through two years 12,426,982 7,921,035 Due after two years through three years 2,211,439 2,686,951 Due after three years through four years 1,807,610 1,984,705 Due after four years through five years 1,518,375 1,216,989 Thereafter 804,424 1,003,241 Total par value $ 41,059,377 $ 37,647,166 Table 7.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances September 30, 2018 December 31, 2017 Fixed-rate $ 30,882,215 $ 31,658,293 Variable-rate 10,177,162 5,988,873 Total par value $ 41,059,377 $ 37,647,166 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 September 30, 2018 , and December 31, 2017 , we had $14.3 billion and $12.1 billion , respectively, of advances issued to members with at least $1.0 billion of advances outstanding. These advances were made to five and six borrowers at September 30, 2018 , and December 31, 2017 , representing 34.8 percent and 32.3 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 9 — Allowance for Credit Losses

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	9 Months Ended
	Sep. 30, 2018
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portofolio [Text Block]	Mortgage Loans Held for Portfolio We invest in mortgage loans through the Mortgage Partnership Finance® program (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 8.1 - Mortgage Loans Held for Portfolio (dollars in thousands) September 30, 2018 December 31, 2017 Real estate Fixed-rate 15-year single-family mortgages $ 410,019 $ 466,952 Fixed-rate 20- and 30-year single-family mortgages 3,714,114 3,466,752 Premiums 67,957 70,074 Discounts (1,730 ) (1,541 ) Deferred derivative gains, net 2,565 3,000 Total mortgage loans held for portfolio 4,192,925 4,005,237 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,192,425 $ 4,004,737 Table 8.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) September 30, 2018 December 31, 2017 Conventional mortgage loans $ 3,787,412 $ 3,568,473 Government mortgage loans 336,721 365,231 Total par value $ 4,124,133 $ 3,933,704 See Note 9 — Allowance for Credit Losses for information related to our credit risk from our investments in mortgage loans and allowance for credit losses based on these investments.

Allowance for Credit Losses

Allowance for Credit Losses	9 Months Ended
	Sep. 30, 2018
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 10 — Allowance for Credit Losses in the 2017 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 September 30, 2018 , and December 31, 2017 , none of our secured member credit products outstanding were past due, on nonaccrual status, or considered impaired. In addition, there were no troubled debt restructurings related to credit products during the nine months ended September 30, 2018 , and 2017 . 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 September 30, 2018 , and December 31, 2017 . At September 30, 2018 , and December 31, 2017 , no liability to reflect an allowance for credit losses for off-balance-sheet credit exposures was recorded. See Note 17 — 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 September 30, 2018 , and December 31, 2017 . 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 10 — Allowance for Credit Losses in the 2017 Annual Report. Conventional Mortgage Loans Held for Portfolio For information on our conventional mortgage loans held for portfolio see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2017 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 9.1 sets forth certain key credit quality indicators for our investments in mortgage loans at September 30, 2018 , and December 31, 2017 (dollars in thousands): Table 9.1 - Recorded Investment in Delinquent Mortgage Loans (dollars in thousands) September 30, 2018 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 24,591 $ 10,264 $ 34,855 Past due 60-89 days delinquent 4,963 3,742 8,705 Past due 90 days or more delinquent 9,813 4,849 14,662 Total past due 39,367 18,855 58,222 Total current loans 3,828,656 326,644 4,155,300 Total mortgage loans $ 3,868,023 $ 345,499 $ 4,213,522 Other delinquency statistics In process of foreclosure, included above (1) $ 4,223 $ 1,446 $ 5,669 Serious delinquency rate (2) 0.28 % 1.40 % 0.37 % Past due 90 days or more still accruing interest $ — $ 4,849 $ 4,849 Loans on nonaccrual status (3) $ 10,138 $ — $ 10,138 _______________________ (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, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 28,622 $ 13,862 $ 42,484 Past due 60-89 days delinquent 6,617 4,142 10,759 Past due 90 days or more delinquent 13,310 4,831 18,141 Total past due 48,549 22,835 71,384 Total current loans 3,601,952 352,249 3,954,201 Total mortgage loans $ 3,650,501 $ 375,084 $ 4,025,585 Other delinquency statistics In process of foreclosure, included above (1) $ 6,389 $ 1,306 $ 7,695 Serious delinquency rate (2) 0.38 % 1.29 % 0.46 % Past due 90 days or more still accruing interest $ — $ 4,831 $ 4,831 Loans on nonaccrual status (3) $ 13,598 $ — $ 13,598 _______________________ (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. Individually Evaluated Impaired Loans. Table 9.2 - Individually Evaluated Impaired Conventional Mortgage Loans (dollars in thousands) September 30, 2018 December 31, 2017 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 15,671 $ 15,632 $ 17,668 $ 17,630 Table 9.3 - Average Recorded Investment of Individually Evaluated Impaired Mortgage Loans and Related Interest Income (dollars in thousands) For the Three Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 15,641 $ 116 $ 18,645 $ 91 Table 9.3 - Average Recorded Investment of Individually Evaluated Impaired Mortgage Loans and Related Interest Income (dollars in thousands) For the Nine Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 16,226 $ 334 $ 19,614 $ 314 Credit Enhancements. For information on our credit enhancements held for portfolio see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2017 Annual Report. Roll-Forward of Allowance for Credit Losses on Mortgage Loans. Table 9.4 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the three and nine months ended September 30, 2018 and 2017 , as well as the recorded investment in mortgage loans by impairment methodology at September 30, 2018 and 2017 . The recorded investment in a loan is the par amount of the loan, adjusted for accrued interest, unamortized premiums or discounts, deferred derivative gains and losses, and direct write-downs. The recorded investment is net of any valuation allowance. Table 9.4 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Allowance for credit losses Balance, beginning of period $ 500 $ 500 $ 500 $ 650 Charge-offs, net of recoveries — (28 ) (6 ) (2 ) Provision (reduction of provision) for credit losses — 28 6 (148 ) 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 $ 15,671 $ 18,786 $ 15,671 $ 18,786 Collectively evaluated for impairment $ 3,852,352 $ 3,562,789 $ 3,852,352 $ 3,562,789 _________________________ (1)

Derivatives and Hedging Activit

Derivatives and Hedging Activities	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities Table 10.1 - Fair Value of Derivative Instruments (dollars in thousands) September 30, 2018 December 31, 2017 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 12,340,429 $ 15,169 $ (291,922 ) $ 14,118,994 $ 52,557 $ (332,830 ) Forward-start interest-rate swaps 376,200 — (403 ) 481,200 — (9,807 ) Total derivatives designated as hedging instruments 12,716,629 15,169 (292,325 ) 14,600,194 52,557 (342,637 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,164,300 2,753 (1,536 ) 1,166,900 3,512 (4,688 ) Mortgage-delivery commitments (1) 41,397 27 (80 ) 42,918 169 (27 ) Total derivatives not designated as hedging instruments 1,205,697 2,780 (1,616 ) 1,209,818 3,681 (4,715 ) Total notional amount of derivatives $ 13,922,326 $ 15,810,012 Total derivatives before netting and collateral adjustments 17,949 (293,941 ) 56,238 (347,352 ) Netting adjustments and cash collateral, including related accrued interest (2) 4,007 65,814 (21,452 ) 46,902 Derivative assets and derivative liabilities $ 21,956 $ (228,127 ) $ 34,786 $ (300,450 ) _______________________ (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 $71.5 million and $25.8 million at September 30, 2018 , and December 31, 2017 , 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 $1.7 million and $350,000 at September 30, 2018 , and December 31, 2017 . Table 10.2 - Net Gains and Losses on Derivatives and Hedging Activities Recorded in Other Income (Loss) (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Derivatives designated as hedging instruments Interest-rate swaps $ 557 $ (876 ) $ 2,140 $ (2,287 ) Forward-start interest-rate swaps 83 (18 ) 244 213 Total net gains (losses) related to derivatives designated as hedging instruments 640 (894 ) 2,384 (2,074 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps 7 14 729 (208 ) CO Bond firm commitments — 56 — 56 Mortgage-delivery commitments 131 692 (336 ) 1,556 Total net gains related to derivatives not designated as hedging instruments 138 762 393 1,404 Other (1) (291 ) 126 (692 ) 282 Net gains (losses) on derivatives and hedging activities $ 487 $ (6 ) $ 2,085 $ (388 ) ______________ (1) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount. Table 10.3 - Effect of Fair Value Hedge Relationships (dollars in thousands) For the Three Months Ended September 30, 2018 Gain/(Loss) on Derivative (Loss)/Gain on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (1,975 ) $ 1,667 $ (308 ) $ 15,769 Investments 19,287 (18,832 ) 455 (6,200 ) COs – bonds (3,069 ) 3,479 410 (8,787 ) Total $ 14,243 $ (13,686 ) $ 557 $ 782 For the Three Months Ended September 30, 2017 Gain/(Loss) on Derivative (Loss)/Gain on Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 9,382 $ (8,881 ) $ 501 $ (2,878 ) Investments 5,007 (4,503 ) 504 (7,879 ) COs – bonds 2,018 (3,899 ) (1,881 ) 242 Total $ 16,407 $ (17,283 ) $ (876 ) $ (10,515 ) ______________ (1) The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item. For the Nine Months Ended September 30, 2018 Gain/(Loss) on Derivative (Loss)/Gain on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 46,793 $ (44,773 ) $ 2,020 $ 36,001 Investments 68,878 (67,270 ) 1,608 (19,975 ) COs – bonds (51,171 ) 49,683 (1,488 ) (20,317 ) Total $ 64,500 $ (62,360 ) $ 2,140 $ (4,291 ) For the Nine Months Ended September 30, 2017 Gain/(Loss) on Derivative (Loss)/Gain on Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 19,150 $ (18,780 ) $ 370 $ (24,566 ) Investments 8,412 (7,047 ) 1,365 (24,319 ) COs – bonds 19,813 (23,835 ) (4,022 ) 6,965 Total $ 47,375 $ (49,662 ) $ (2,287 ) $ (41,920 ) ______________ (1) The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item. Table 10.4 - Effect of Cash Flow Hedge Relationships (dollars in thousands) Derivatives and Hedged Items in Cash Flow Hedging Relationships Gains (Losses) Recognized in Other Comprehensive Loss on Derivatives (Effective Portion) Location of Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Gains (Losses) Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion) Forward-start Interest-rate swaps - CO bonds For the Three Months Ended September 30, 2018 $ 2,985 Interest expense $ (537 ) $ 83 For the Three Months Ended September 30, 2017 (856 ) Interest expense (2,158 ) (18 ) For the Nine Months Ended September 30, 2018 14,733 Interest expense (2,485 ) 244 For the Nine Months Ended September 30, 2017 (5,937 ) Interest expense (9,865 ) 213 For the nine months ended September 30, 2018 and 2017 , there were no reclassifications from accumulated other comprehensive loss into earnings as a result of the discontinuance of cash-flow hedges because the original forecasted transactions were not expected to occur by the end of the originally specified time period or within a two-month period thereafter. As of September 30, 2018 , the maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions is three years . As of September 30, 2018 , 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 $3.5 million . 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 or 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 September 30, 2018 , was $276.8 million for which we had delivered collateral with a post-haircut value of $258.0 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 10.5 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 September 30, 2018 . Table 10.5 - Post Haircut Value of Incremental Collateral to be Delivered as of September 30, 2018 (dollars in thousands) Ratings Downgrade (1) Incremental From To Collateral AA+ AA or AA- $ 1,142 AA- A+, A or A- 13,584 A- below A- 14,723 _______________________ (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 certain amendments, effective January 3, 2017, made by CME Inc. to its rulebook, we began to characterize variation margin payments related to CME Inc. contracts as daily settlement payments, rather than collateral. However, throughout 2017, we continued to characterize our variation margin related to LCH Ltd. contracts as cash collateral. We began to characterize variation margin payments related to LCH Ltd. contracts as daily settlement payments, rather than cash collateral, based upon a change effective January 16, 2018, to LCH Ltd.’s rulebook. At both DCOs, initial margin has been, and continues to be, considered cash collateral. We post initial margin and exchange variation margin through a clearing member who acts as our agent to the DCO and who guarantees our performance to the DCO, subject to the terms of relevant agreements. These arrangements expose us to credit risk in the event that one of our clearing members or one of the DCOs fails to meet its obligations. The use of cleared derivatives is intended to mitigate credit risk exposure because the DCO, which is fully secured at all times through margin received from its clearing members, is substituted for the credit risk exposure of individual counterparties in uncleared derivatives, and collateral is posted at least once daily for changes in the fair value of cleared derivatives through a clearing member. For cleared derivatives, the DCO determines initial margin requirements. We clear our trades via clearing members of the DCOs. These clearing members who act as our agent to the DCOs are CFTC-registered futures commission merchants. Our clearing members may require us to post margin in excess of DCO requirements based on our credit or other considerations, including but not limited to, credit rating downgrades. We were not required to post any such excess margin by our clearing members based on credit considerations at September 30, 2018 . Offsetting of Certain Derivatives. We present derivatives, any related cash collateral, including initial and certain variation margin, 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 10.6 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 September 30, 2018 , and December 31, 2017 , 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 10.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) September 30, 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 $ 17,319 $ (15,542 ) $ 27 $ 1,804 $ — $ — $ 1,804 Cleared 603 19,549 20,152 — — 20,152 Total $ 21,956 $ 21,956 Derivative Liabilities Uncleared $ (292,034 ) $ 63,987 $ (80 ) $ (228,127 ) $ 10,809 $ 206,680 $ (10,638 ) Cleared (1,828 ) 1,828 — — — — Total $ (228,127 ) $ (10,638 ) _______________________ (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 September 30, 2018 , we had additional net credit exposure of $220,000 due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2017 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 $ 15,587 $ (13,481 ) $ 169 $ 2,275 $ — $ — $ 2,275 Cleared 40,482 (7,971 ) 32,511 — — 32,511 Total $ 34,786 $ 34,786 Derivative Liabilities Uncleared $ (335,289 ) $ 34,866 $ (27 ) $ (300,450 ) $ 7,627 $ 280,486 $ (12,337 ) Cleared (12,036 ) 12,036 — — — — Total $ (300,450 ) $ (12,337 ) _______________________ (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, 2017 , we had additional net credit exposure of $502,000

Deposits

Deposits	9 Months Ended
	Sep. 30, 2018
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 11.1 - Deposits (dollars in thousands) September 30, 2018 December 31, 2017 Interest-bearing Demand and overnight $ 460,636 $ 447,700 Term 800 — Other 1,913 3,222 Noninterest-bearing Other 21,412 26,147 Total deposits $ 484,761 $ 477,069 The aggregate amount of time deposits with a denomination of $100,000 or more was $800,000 as of September 30, 2018

Consolidated Obligations

Consolidated Obligations	9 Months Ended
	Sep. 30, 2018
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 12.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 10,123,250 1.80 % $ 12,186,510 1.35 % Due after one year through two years 6,283,295 2.15 5,288,470 1.63 Due after two years through three years 3,073,605 2.19 3,128,240 1.81 Due after three years through four years 2,395,865 1.98 2,759,460 1.74 Due after four years through five years 1,410,655 2.30 1,572,775 2.00 Thereafter 3,482,710 3.06 3,389,695 2.76 Total par value 26,769,380 2.13 % 28,325,150 1.70 % Premiums 92,653 90,836 Discounts (15,637 ) (15,685 ) Hedging adjustments (105,360 ) (55,678 ) $ 26,741,036 $ 28,344,623 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Table 12.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds September 30, 2018 December 31, 2017 Noncallable and nonputable $ 21,867,380 $ 23,931,150 Callable 4,902,000 4,394,000 Total par value $ 26,769,380 $ 28,325,150 Table 12.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date September 30, 2018 December 31, 2017 Due in one year or less $ 13,698,250 $ 15,309,510 Due after one year through two years 6,392,295 5,580,470 Due after two years through three years 2,491,605 3,020,240 Due after three years through four years 1,485,865 1,542,460 Due after four years through five years 1,140,655 1,107,775 Thereafter 1,560,710 1,764,695 Total par value $ 26,769,380 $ 28,325,150 Table 12.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds September 30, 2018 December 31, 2017 Fixed-rate $ 20,954,380 $ 21,416,150 Simple variable-rate 3,983,000 5,432,000 Step-up 1,832,000 1,477,000 Total par value $ 26,769,380 $ 28,325,150 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 12.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) September 30, 2018 $ 33,431,980 $ 33,501,223 2.07 % December 31, 2017 $ 27,720,906 $ 27,752,860 1.25 % _______________________ (1)

Affordable Housing Program

Affordable Housing Program	9 Months Ended
	Sep. 30, 2018
Affordable Housing Program [Abstract]
Affordable Housing Program [Text Block]	Affordable Housing Program Table 13.1 - AHP Liability (dollars in thousands) September 30, 2018 December 31, 2017 Balance at beginning of year $ 81,600 $ 81,627 AHP expense for the period 19,387 21,307 AHP direct grant disbursements (13,384 ) (18,628 ) AHP subsidy for AHP advance disbursements (3,707 ) (2,782 ) Return of previously disbursed grants and subsidies 86 76 Balance at end of period $ 83,982 $ 81,600

Capital

Capital	9 Months Ended
	Sep. 30, 2018
Capital [Abstract]
Capital [Text Block]	Capital We are subject to capital requirements under our capital plan, the Federal Home Loan Bank Act of 1932, as amended (the FHLBank Act), and FHFA regulations: 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 may require us to maintain a greater amount of permanent capital than is required as defined by the risk-based capital requirements. Table 14.1 demonstrates our compliance with our regulatory capital requirements at September 30, 2018 , and December 31, 2017 . Table 14.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements September 30, 2018 December 31, 2017 Permanent capital Class B capital stock $ 2,476,876 $ 2,283,721 Mandatorily redeemable capital stock 31,868 35,923 Retained earnings 1,386,466 1,308,349 Total permanent capital $ 3,895,210 $ 3,627,993 Risk-based capital requirement Credit-risk capital $ 320,819 $ 328,557 Market-risk capital 253,082 170,102 Operations-risk capital 172,170 149,598 Total risk-based capital requirement $ 746,071 $ 648,257 Permanent capital in excess of risk-based capital requirement $ 3,149,139 $ 2,979,736 September 30, 2018 December 31, 2017 Required Actual Required Actual Capital Ratio Risk-based capital $ 746,071 $ 3,895,210 $ 648,257 $ 3,627,993 Total regulatory capital $ 2,587,752 $ 3,895,210 $ 2,414,478 $ 3,627,993 Total capital-to-asset ratio 4.0 % 6.0 % 4.0 % 6.0 % Leverage Ratio Leverage capital $ 3,234,690 $ 5,842,815 $ 3,018,097 $ 5,441,990 Leverage capital-to-assets ratio 5.0 % 9.0 % 5.0 % 9.0 %

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2018
AOCI Attributable to Parent [Abstract]
Accumulated Other Comprehensive Loss [Text Block]	Accumulated Other Comprehensive Loss Table 15.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Accumulated Other Comprehensive Loss Balance, June 30, 2017 $ (94,309 ) $ (175,068 ) $ (45,554 ) $ (5,530 ) $ (320,461 ) Other comprehensive income (loss) before reclassifications: Net unrealized losses (61 ) — (856 ) — (917 ) Accretion of noncredit loss — 8,178 — — 8,178 Net actuarial gain — — — 112 112 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 420 — — 420 Amortization - hedging activities (2) — — 2,161 — 2,161 Amortization - pension and postretirement benefits (3) — — — 193 193 Other comprehensive (loss) income (61 ) 8,598 1,305 305 10,147 Balance, September 30, 2017 $ (94,370 ) $ (166,470 ) $ (44,249 ) $ (5,225 ) $ (310,314 ) Balance, June 30, 2018 $ (167,921 ) $ (143,196 ) $ (26,733 ) $ (6,740 ) $ (344,590 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (8,690 ) — 2,985 — (5,705 ) Accretion of noncredit loss — 7,127 — — 7,127 Net actuarial loss — — — (729 ) (729 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 6 — — 6 Amortization - hedging activities (4) — — 541 — 541 Amortization - pension and postretirement benefits (3) — — — 337 337 Other comprehensive (loss) income (8,690 ) 7,133 3,526 (392 ) 1,577 Balance, September 30, 2018 $ (176,611 ) $ (136,063 ) $ (23,207 ) $ (7,132 ) $ (343,013 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $2.2 million recorded in CO bond interest expense and $4,000 recorded in net losses on derivatives and hedging activities in the statement of operations. (3) Recorded in other non-interest expenses in the statement of operations. (4) Amortization of hedging activities includes $537,000 recorded in CO bond interest expense and $4,000 recorded in net losses on derivatives and hedging activities in the statement of operations. Table 15.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Accumulated Other Comprehensive Loss Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 42,439 — (5,937 ) — 36,502 Accretion of noncredit loss — 24,593 — — 24,593 Net actuarial gain — — — 336 336 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 1,316 — — 1,316 Amortization - hedging activities (2) — — 9,875 — 9,875 Amortization - pension and postretirement benefits (3) — — — 578 578 Other comprehensive income 42,439 25,909 3,938 914 73,200 Balance, September 30, 2017 $ (94,370 ) $ (166,470 ) $ (44,249 ) $ (5,225 ) $ (310,314 ) Balance, December 31, 2017 $ (122,331 ) $ (158,218 ) $ (40,436 ) $ (5,955 ) $ (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (54,280 ) — 14,733 — (39,547 ) Accretion of noncredit loss — 21,945 — — 21,945 Net actuarial loss — — — (2,189 ) (2,189 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 210 — — 210 Amortization - hedging activities (4) — — 2,496 — 2,496 Amortization - pension and postretirement benefits (3) — — — 1,012 1,012 Other comprehensive (loss) income (54,280 ) 22,155 17,229 (1,177 ) (16,073 ) Balance, September 30, 2018 $ (176,611 ) $ (136,063 ) $ (23,207 ) $ (7,132 ) $ (343,013 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $9.9 million recorded in CO bond interest expense and $11,000 recorded in net losses on derivatives and hedging activities in the statement of operations. (3) Recorded in other non-interest expenses in the statement of operations. (4) Amortization of hedging activities includes $2.5 million recorded in CO bond interest expense and $11,000

Fair Values

Fair Values	9 Months Ended
	Sep. 30, 2018
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 18 — Fair Values in the 2017 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 nine months ended September 30, 2018 . Table 16.1 - Fair Value Summary (dollars in thousands) September 30, 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 $ 45,614 $ 45,614 $ 45,614 $ — $ — $ — Interest-bearing deposits 397,203 397,203 397,203 — — — Securities purchased under agreements to resell 5,499,000 5,498,962 — 5,498,962 — — Federal funds sold 5,650,000 5,650,001 — 5,650,001 — — Trading securities (1) 176,113 176,113 — 176,113 — — Available-for-sale securities (1) 6,227,080 6,227,080 — 6,186,743 40,337 — Held-to-maturity securities 1,372,299 1,638,491 — 671,526 966,965 — Advances 40,927,639 40,880,159 — 40,880,159 — — Mortgage loans, net 4,192,425 4,076,278 — 4,056,143 20,135 — Accrued interest receivable 102,466 102,466 — 102,466 — — Derivative assets (1) 21,956 21,956 — 17,949 — 4,007 Other assets (1) 26,036 26,036 11,189 14,847 — — Liabilities: Deposits (484,761 ) (484,750 ) — (484,750 ) — — COs: Bonds (26,741,036 ) (26,508,907 ) — (26,508,907 ) — — Discount notes (33,431,980 ) (33,428,979 ) — (33,428,979 ) — — Mandatorily redeemable capital stock (31,868 ) (31,868 ) (31,868 ) — — — Accrued interest payable (119,242 ) (119,242 ) — (119,242 ) — — Derivative liabilities (1) (228,127 ) (228,127 ) — (293,941 ) — 65,814 Other: Commitments to extend credit for advances — (4,946 ) — (4,946 ) — — Standby letters of credit (1,179 ) (1,179 ) — (1,179 ) — — _______________________ (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, 2017 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 $ 261,673 $ 261,673 $ 261,673 $ — $ — $ — Interest-bearing deposits 246 246 246 — — — Securities purchased under agreements to resell 5,349,000 5,348,898 — 5,348,898 — — Federal funds sold 3,450,000 3,449,981 — 3,449,981 — — Trading securities (1) 191,510 191,510 — 191,510 — — Available-for-sale securities (1) 7,324,736 7,324,736 — 7,287,053 37,683 — Held-to-maturity securities 1,626,122 1,903,227 — 811,759 1,091,468 — Advances 37,565,967 37,591,048 — 37,591,048 — — Mortgage loans, net 4,004,737 4,035,928 — 4,013,704 22,224 — Loans to other FHLBanks (3) 400,000 399,997 — 399,997 — — Accrued interest receivable 94,100 94,100 — 94,100 — — Derivative assets (1) 34,786 34,786 — 56,238 — (21,452 ) Other assets (1) 22,351 22,351 9,726 12,625 — — Liabilities: Deposits (477,069 ) (477,060 ) — (477,060 ) — — COs: Bonds (28,344,623 ) (28,353,945 ) — (28,353,945 ) — — Discount notes (27,720,906 ) (27,719,598 ) — (27,719,598 ) — — Mandatorily redeemable capital stock (35,923 ) (35,923 ) (35,923 ) — — — Accrued interest payable (90,626 ) (90,626 ) — (90,626 ) — — Derivative liabilities (1) (300,450 ) (300,450 ) — (347,352 ) — 46,902 Other: Commitments to extend credit for advances — (3,817 ) — (3,817 ) — — Standby letters of credit (1,100 ) (1,100 ) — (1,100 ) — — _______________________ (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. (3) The Fair Value Summary table for December 31, 2017, has been revised to correct the omission of Loans to Other FHLBanks. This revision had no impact on the Statements of Condition, Statements of Operations, or Statements of Cash Flows. Fair Value Measured on a Recurring Basis. Table 16.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (dollars in thousands) September 30, 2018 Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (1) Total Assets: Trading securities: Corporate bonds $ — $ 6,774 $ — $ — $ 6,774 U.S. government-guaranteed – single-family MBS — 5,684 — — 5,684 GSEs – single-family MBS — 180 — — 180 GSEs – multifamily MBS — 163,475 — — 163,475 Total trading securities — 176,113 — — 176,113 Available-for-sale securities: State or local HFA securities — — 40,337 — 40,337 Supranational institutions — 395,178 — — 395,178 U.S. government-owned corporations — 268,624 — — 268,624 GSEs — 113,425 — — 113,425 U.S. government guaranteed – single-family MBS — 81,037 — — 81,037 U.S. government guaranteed – multifamily MBS — 367,515 — — 367,515 GSEs – single-family MBS — 3,732,005 — — 3,732,005 GSEs – multifamily — 1,228,959 — — 1,228,959 Total available-for-sale securities — 6,186,743 40,337 — 6,227,080 Derivative assets: Interest-rate-exchange agreements — 17,922 — 4,007 21,929 Mortgage delivery commitments — 27 — — 27 Total derivative assets — 17,949 — 4,007 21,956 Other assets 11,189 14,847 — — 26,036 Total assets at fair value $ 11,189 $ 6,395,652 $ 40,337 $ 4,007 $ 6,451,185 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (293,861 ) $ — $ 65,814 $ (228,047 ) Mortgage delivery commitments — (80 ) — — (80 ) Total liabilities at fair value $ — $ (293,941 ) $ — $ 65,814 $ (228,127 ) _______________________ (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. December 31, 2017 Level 1 Level 2 Level 3 Netting (1) Total Assets: Trading securities: U.S. government-guaranteed – single-family MBS $ — $ 6,807 $ — $ — $ 6,807 GSEs – single-family MBS — 346 — — 346 GSEs – multifamily MBS — 184,357 — — 184,357 Total trading securities — 191,510 — — 191,510 Available-for-sale securities: State or local HFA securities — — 37,683 — 37,683 Supranational institutions — 418,285 — — 418,285 U.S. government-owned corporations — 292,077 — — 292,077 GSEs — 121,343 — — 121,343 U.S. government guaranteed – single-family MBS — 95,777 — — 95,777 U.S. government guaranteed – multifamily MBS — 443,373 — — 443,373 GSEs – single-family MBS — 4,562,992 — — 4,562,992 GSEs – multifamily MBS — 1,353,206 — — 1,353,206 Total available-for-sale securities — 7,287,053 37,683 — 7,324,736 Derivative assets: Interest-rate-exchange agreements — 56,069 — (21,452 ) 34,617 Mortgage delivery commitments — 169 — — 169 Total derivative assets — 56,238 — (21,452 ) 34,786 Other assets 9,726 12,625 — — 22,351 Total assets at fair value $ 9,726 $ 7,547,426 $ 37,683 $ (21,452 ) $ 7,573,383 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (347,325 ) $ — $ 46,902 $ (300,423 ) Mortgage delivery commitments — (27 ) — — (27 ) Total liabilities at fair value $ — $ (347,352 ) $ — $ 46,902 $ (300,450 ) _______________________ (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. Table 16.3 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 nine months ended September 30, 2018 and 2017 . Table 16.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Balance at beginning of period $ 37,600 $ 15,414 $ 37,683 $ 8,146 Purchases 3,150 3,520 3,150 11,120 Unrealized gains (losses) included in other comprehensive income (413 ) (391 ) (496 ) (723 ) Balance at end of period $ 40,337 $ 18,543 $ 40,337 $ 18,543 Fair Value on a Nonrecurring Basis 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). Table 16.4 - Fair Value of Assets Measured at Fair Value on a Nonrecurring Basis (1) (dollars in thousands) September 30, 2018 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,736 $ 1,736 Mortgage loans held for portfolio — — 1,122 1,122 REO — — 361 361 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 3,219 $ 3,219 December 31, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,970 $ 1,970 Mortgage loans held for portfolio — — 4,608 4,608 REO — — 784 784 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 7,362 $ 7,362 _______________________ (1) The fair values presented are as of the date the fair value adjustment was recorded during the nine months ended September 30, 2018 , and year ended December 31, 2017

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 , and through the filing of this report, we believe that the likelihood is only remote 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 September 30, 2018 , and December 31, 2017 . The par amounts of other FHLBanks' outstanding COs for which we are jointly and severally liable totaled $ 958.8 billion and $978.2 billion at September 30, 2018 , and December 31, 2017 , respectively. See Note 12 — Consolidated Obligations for additional information. Off-Balance-Sheet Commitments Table 17.1 - Off-Balance Sheet Commitments (dollars in thousands) September 30, 2018 December 31, 2017 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 6,086,259 $ 231,611 $ 6,317,870 $ 5,034,725 $ 223,167 $ 5,257,892 Commitments for unused lines of credit - advances (2) 1,213,453 — 1,213,453 1,216,592 — 1,216,592 Commitments to make additional advances 20,880 37,527 58,407 18,851 63,488 82,339 Commitments to invest in mortgage loans 41,397 — 41,397 42,918 — 42,918 Unsettled CO bonds, at par 138,800 — 138,800 52,550 — 52,550 __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At September 30, 2018 , and December 31, 2017 , these amounts totaled $ 29.3 million and $1.4 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $543,000 at December 31, 2017 . (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 security for deposits from federal, state, and municipal 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 original 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 . Our unearned fees for the value of the guarantees related to standby letters of credit are recorded in other liabilities and totaled $1.2 million and $1.1 million , respectively, at September 30, 2018 , and December 31, 2017 . 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 10 — Derivatives and Hedging Activities for additional information about our pledged collateral and other credit-risk-related contingent features. Legal Proceedings

Transactions with Shareholders

Transactions with Shareholders	9 Months Ended
	Sep. 30, 2018
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 year. Table 18.1 - Shareholder Concentrations, Balance Sheet (dollars in thousands) Capital Stock Outstanding Percent of Total 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 September 30, 2018 Citizens Bank, N.A. $ 354,645 14.1 % $ 8,009,938 19.5 % $ 5,692 10.0 % As of December 31, 2017 Citizens Bank, N.A. $ 227,287 9.8 % $ 4,858,592 12.9 % $ 2,558 6.0 % 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. We recognized interest income on outstanding advances and fees on letters of credit from Citizens Bank, N.A. during the three and nine months ended September 30, 2018 , and 2017 , as follows (dollars in thousands): Table 18.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, Citizens Bank, N.A. 2018 2017 2018 2017 Interest income on advances $ 33,144 $ 14,316 $ 89,228 $ 46,968 Fees on letters of credit 1,257 1,002 3,338 2,448 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 18.3 presents the outstanding balances of capital stock, advances, and accrued interest receivable with members whose officers or directors serve on our board of directors, and those balances as a percentage of our total balance as reported on our statement of condition: Table 18.3 - Transactions with Directors' Institutions (dollars in thousands) Capital Stock Outstanding Percent of Total 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 September 30, 2018 $ 106,932 4.3 % $ 2,002,884 4.9 % $ 2,960 5.2 % As of December 31, 2017 114,498 4.9 2,133,374 5.7 2,466 5.8

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On October 19, 2018 , the board of directors declared a cash dividend at an annualized rate of 5.87 percent based on capital stock balances outstanding during the third quarter of 2018. The dividend, including dividends classified as interest on mandatorily redeemable capital stock, amounted to $35.6 million and was paid on November 2, 2018

Basis of Presentation Summary o

Basis of Presentation Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Investment, Policy	We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter.
Derivatives, Policy	We utilize two DCOs for all cleared derivative transactions, CME Inc. and LCH Ltd. Based upon certain amendments, effective January 3, 2017, made by CME Inc. to its rulebook, we began to characterize variation margin payments related to CME Inc. contracts as daily settlement payments, rather than collateral. However, throughout 2017, we continued to characterize our variation margin related to LCH Ltd. contracts as cash collateral. We began to characterize variation margin payments related to LCH Ltd. contracts as daily settlement payments, rather than cash collateral, based upon a change effective January 16, 2018, to LCH Ltd.’s rulebook. At both DCOs, initial margin has been, and continues to be, considered cash collateral.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.
Fair Value of Financial Instruments, Policy	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).
Joint and Several Liability, Policy	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)	9 Months Ended
	Sep. 30, 2018
Trading Securities [Abstract]
Trading Securities by Major Security Type [Table Text Block]	Table 3.1 - Trading Securities by Major Security Type (dollars in thousands) September 30, 2018 December 31, 2017 Corporate bonds $ 6,774 $ — Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 5,684 6,807 Government-sponsored enterprise (GSE)s – single-family 180 346 GSEs – multifamily 163,475 184,357 169,339 191,510 Total $ 176,113 $ 191,510

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale (AFS) Securities by Major Security Type [Table Text Block]	Table 4.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) September 30, 2018 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) $ 45,850 $ — $ (5,513 ) $ 40,337 Supranational institutions 409,784 — (14,606 ) 395,178 U.S. government-owned corporations 286,169 — (17,545 ) 268,624 GSEs 118,173 — (4,748 ) 113,425 859,976 — (42,412 ) 817,564 MBS U.S. government guaranteed – single-family 84,742 41 (3,746 ) 81,037 U.S. government guaranteed – multifamily 374,986 — (7,471 ) 367,515 GSEs – single-family 3,856,145 962 (125,102 ) 3,732,005 GSEs – multifamily 1,227,842 1,444 (327 ) 1,228,959 5,543,715 2,447 (136,646 ) 5,409,516 Total $ 6,403,691 $ 2,447 $ (179,058 ) $ 6,227,080 _______________________ (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, 2017 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 42,700 $ — $ (5,017 ) $ 37,683 Supranational institutions 438,667 — (20,382 ) 418,285 U.S. government-owned corporations 313,985 — (21,908 ) 292,077 GSEs 128,744 — (7,401 ) 121,343 924,096 — (54,708 ) 869,388 MBS U.S. government guaranteed – single-family 98,720 55 (2,998 ) 95,777 U.S. government guaranteed – multifamily 447,975 — (4,602 ) 443,373 GSEs – single-family 4,625,333 1,194 (63,535 ) 4,562,992 GSEs – multifamily 1,350,943 2,263 — 1,353,206 6,522,971 3,512 (71,135 ) 6,455,348 Total $ 7,447,067 $ 3,512 $ (125,843 ) $ 7,324,736 _______________________ (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]
Schedule of Available-for-sale Securities [Line Items]
AFS Securities in a Continuous Unrealized Loss Position [Table Text Block]	Table 4.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position by Major Security Type (dollars in thousands) September 30, 2018 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 21,793 $ (3,587 ) $ 18,544 $ (1,926 ) $ 40,337 $ (5,513 ) Supranational institutions — — 395,178 (14,606 ) 395,178 (14,606 ) U.S. government-owned corporations — — 268,624 (17,545 ) 268,624 (17,545 ) GSEs — — 113,425 (4,748 ) 113,425 (4,748 ) 21,793 (3,587 ) 795,771 (38,825 ) 817,564 (42,412 ) MBS U.S. government guaranteed – single-family — — 61,434 (3,746 ) 61,434 (3,746 ) U.S. government guaranteed – multifamily — — 367,515 (7,471 ) 367,515 (7,471 ) GSEs – single-family 1,175,912 (32,577 ) 2,439,363 (92,525 ) 3,615,275 (125,102 ) GSEs – multifamily 339,153 (327 ) — — 339,153 (327 ) 1,515,065 (32,904 ) 2,868,312 (103,742 ) 4,383,377 (136,646 ) Total temporarily impaired $ 1,536,858 $ (36,491 ) $ 3,664,083 $ (142,567 ) $ 5,200,941 $ (179,058 ) December 31, 2017 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 29,345 $ (4,005 ) $ 8,338 $ (1,012 ) $ 37,683 $ (5,017 ) Supranational institutions — — 418,285 (20,382 ) 418,285 (20,382 ) U.S. government-owned corporations — — 292,077 (21,908 ) 292,077 (21,908 ) GSEs — — 121,343 (7,401 ) 121,343 (7,401 ) 29,345 (4,005 ) 840,043 (50,703 ) 869,388 (54,708 ) MBS U.S. government guaranteed – single-family — — 70,877 (2,998 ) 70,877 (2,998 ) U.S. government guaranteed – multifamily 64,219 (571 ) 379,154 (4,031 ) 443,373 (4,602 ) GSEs – single-family 1,853,323 (12,661 ) 2,540,006 (50,874 ) 4,393,329 (63,535 ) 1,917,542 (13,232 ) 2,990,037 (57,903 ) 4,907,579 (71,135 ) Total temporarily impaired $ 1,946,887 $ (17,237 ) $ 3,830,080 $ (108,606 ) $ 5,776,967 $ (125,843 )
Investments Classified by Contractual Maturity Date [Table Text Block]	Table 4.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Year of Contractual Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ — $ — $ — $ — Due after one year through five years 42,700 37,640 42,700 37,683 Due after five years through 10 years 457,717 441,968 438,667 418,285 Due after 10 years 359,559 337,956 442,729 413,420 859,976 817,564 924,096 869,388 MBS (1) 5,543,715 5,409,516 6,522,971 6,455,348 Total $ 6,403,691 $ 6,227,080 $ 7,447,067 $ 7,324,736 _______________________ (1)

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities by Major Security Type [Table Text Block]	Table 5.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) September 30, 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 $ 416 $ — $ 416 $ 1 $ — $ 417 HFA securities 124,560 — 124,560 6 (3,542 ) 121,024 124,976 — 124,976 7 (3,542 ) 121,441 MBS U.S. government guaranteed – single-family 8,647 — 8,647 170 — 8,817 GSEs – single-family 444,076 — 444,076 7,369 (2,140 ) 449,305 GSEs – multifamily 211,476 — 211,476 1,511 — 212,987 Private-label – residential 712,078 (136,043 ) 576,035 264,618 (1,648 ) 839,005 Asset-backed securities (ABS) backed by home equity loans 7,108 (19 ) 7,089 24 (177 ) 6,936 1,383,385 (136,062 ) 1,247,323 273,692 (3,965 ) 1,517,050 Total $ 1,508,361 $ (136,062 ) $ 1,372,299 $ 273,699 $ (7,507 ) $ 1,638,491 December 31, 2017 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 $ 1,042 $ — $ 1,042 $ 10 $ — $ 1,052 HFA securities 146,410 — 146,410 26 (14,372 ) 132,064 147,452 — 147,452 36 (14,372 ) 133,116 MBS U.S. government guaranteed – single-family 10,097 — 10,097 190 — 10,287 U.S. government guaranteed – multifamily 280 — 280 — — 280 GSEs – single-family 568,948 — 568,948 10,410 (310 ) 579,048 GSEs – multifamily 214,641 — 214,641 6,451 — 221,092 Private-label – residential 835,070 (158,194 ) 676,876 278,217 (3,195 ) 951,898 ABS backed by home equity loans 7,851 (23 ) 7,828 27 (349 ) 7,506 1,636,887 (158,217 ) 1,478,670 295,295 (3,854 ) 1,770,111 Total $ 1,784,339 $ (158,217 ) $ 1,626,122 $ 295,331 $ (18,226 ) $ 1,903,227
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 5.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position by Major Security Type (dollars in thousands) September 30, 2018 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 110,953 $ (3,542 ) $ 110,953 $ (3,542 ) MBS GSEs – single-family 106,028 (1,650 ) 22,748 (490 ) 128,776 (2,140 ) Private-label – residential — — 117,245 (2,555 ) 117,245 (2,555 ) ABS backed by home equity loans — — 5,869 (177 ) 5,869 (177 ) 106,028 (1,650 ) 145,862 (3,222 ) 251,890 (4,872 ) Total $ 106,028 $ (1,650 ) $ 256,815 $ (6,764 ) $ 362,843 $ (8,414 ) December 31, 2017 Length of Continuous Unrealized Loss Less than 12 Months Length of Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 121,203 $ (14,372 ) $ 121,203 $ (14,372 ) MBS GSEs – single-family 44,759 (52 ) 28,771 (258 ) 73,530 (310 ) Private-label – residential — — 158,963 (5,558 ) 158,963 (5,558 ) ABS backed by home equity loans — — 7,371 (350 ) 7,371 (350 ) 44,759 (52 ) 195,105 (6,166 ) 239,864 (6,218 ) Total $ 44,759 $ (52 ) $ 316,308 $ (20,538 ) $ 361,067 $ (20,590 )
HTM Securities by Contractual Maturity [Table Text Block]	Table 5.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 1,251 $ 1,251 $ 1,256 $ 264 $ 264 $ 267 Due after one year through five years 9,230 9,230 9,232 11,613 11,613 11,645 Due after five years through 10 years 17,565 17,565 17,458 18,245 18,245 18,226 Due after 10 years 96,930 96,930 93,495 117,330 117,330 102,978 124,976 124,976 121,441 147,452 147,452 133,116 MBS (2) 1,383,385 1,247,323 1,517,050 1,636,887 1,478,670 1,770,111 Total $ 1,508,361 $ 1,372,299 $ 1,638,491 $ 1,784,339 $ 1,626,122 $ 1,903,227 _______________________ (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)

Other-Than-Temporary Impairme_2

Other-Than-Temporary Impairment (Tables)	9 Months Ended
	Sep. 30, 2018
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 nine months ended September 30, 2018 , Table 6.1 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 6.1 - 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 Alt-A - Private-label residential MBS (1) $ 6,230 12.6 % 18.5 % 27.3 % 23.6 % _______________________ (1)
Total Securities Other-than-Temporarily Impaired during the Life of the Security [Table Text Block]	Table 6.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) September 30, 2018 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 25,864 $ 22,026 $ 17,295 $ 24,484 Private-label residential MBS – Alt-A 831,215 597,346 466,033 721,713 ABS backed by home equity loans – Subprime 161 150 132 155 Total other-than-temporarily impaired securities $ 857,240 $ 619,522 $ 483,460 $ 746,352 _______________________ (1)
Rollforward of the Amounts Related to Credit Losses Recognized into Earnings [Table Text Block]	Table 6.3 presents a roll forward of the amounts related to credit losses recognized in earnings. The roll forward is the amount of credit losses on investment securities for which we recognized a portion of other-than-temporary impairment charges into accumulated other comprehensive loss. Table 6.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Balance at beginning of period $ 437,315 $ 468,706 $ 452,523 $ 490,404 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 71 432 407 1,418 Reductions: Securities matured during the period (2) — — — (5,565 ) 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 (7,997 ) (8,356 ) (23,541 ) (25,475 ) Balance at end of period $ 429,389 $ 460,782 $ 429,389 $ 460,782 _______________________ (1) For the three months ended September 30, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to July 1, 2018 and 2017 . For the nine months ended September 30, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to January 1, 2018 and 2017 . (2)

Advances (Tables)

Advances (Tables)	9 Months Ended
	Sep. 30, 2018
Advances [Abstract]
Advances [Table Text Block]	Table 7.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 7,887 2.63 % $ 5,698 1.70 % Due in one year or less 20,964,860 2.20 21,501,397 1.56 Due after one year through two years 12,202,282 2.30 7,462,785 1.65 Due after two years through three years 2,171,439 2.28 2,709,951 1.85 Due after three years through four years 2,130,610 2.32 2,084,105 2.03 Due after four years through five years 2,466,375 2.10 2,071,989 1.56 Thereafter 1,115,924 2.85 1,811,241 2.23 Total par value 41,059,377 2.25 % 37,647,166 1.66 % Premiums 14,394 17,931 Discounts (36,356 ) (32,757 ) Fair value of bifurcated derivatives (1) (221 ) (1,591 ) Hedging adjustments (109,555 ) (64,782 ) Total $ 40,927,639 $ 37,565,967 _________________________ (1) At September 30, 2018 , and December 31, 2017 Table 7.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances September 30, 2018 December 31, 2017 Fixed-rate $ 30,882,215 $ 31,658,293 Variable-rate 10,177,162 5,988,873 Total par value $ 41,059,377 $ 37,647,166 Table 7.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value September 30, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,887 $ 5,698 Due in one year or less 22,282,660 22,828,547 Due after one year through two years 12,426,982 7,921,035 Due after two years through three years 2,211,439 2,686,951 Due after three years through four years 1,807,610 1,984,705 Due after four years through five years 1,518,375 1,216,989 Thereafter 804,424 1,003,241 Total par value $ 41,059,377 $ 37,647,166 Table 7.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (1) (dollars in thousands) September 30, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,887 $ 5,698 Due in one year or less 30,153,735 25,842,572 Due after one year through two years 4,202,282 3,722,785 Due after two years through three years 2,161,439 2,709,951 Due after three years through four years 1,968,910 1,924,105 Due after four years through five years 1,503,175 1,684,789 Thereafter 1,061,949 1,757,266 Total par value $ 41,059,377 $ 37,647,166 _______________________ (1)

Mortgage Loans Held for Portf_2

Mortgage Loans Held for Portfolio (Tables)	9 Months Ended
	Sep. 30, 2018
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	Table 8.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) September 30, 2018 December 31, 2017 Conventional mortgage loans $ 3,787,412 $ 3,568,473 Government mortgage loans 336,721 365,231 Total par value $ 4,124,133 $ 3,933,704 Table 8.1 - Mortgage Loans Held for Portfolio (dollars in thousands) September 30, 2018 December 31, 2017 Real estate Fixed-rate 15-year single-family mortgages $ 410,019 $ 466,952 Fixed-rate 20- and 30-year single-family mortgages 3,714,114 3,466,752 Premiums 67,957 70,074 Discounts (1,730 ) (1,541 ) Deferred derivative gains, net 2,565 3,000 Total mortgage loans held for portfolio 4,192,925 4,005,237 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,192,425 $ 4,004,737

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Recorded Investment in Delinquent Mortgage Loans [Table Text Block]	Table 9.1 sets forth certain key credit quality indicators for our investments in mortgage loans at September 30, 2018 , and December 31, 2017 (dollars in thousands): Table 9.1 - Recorded Investment in Delinquent Mortgage Loans (dollars in thousands) September 30, 2018 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 24,591 $ 10,264 $ 34,855 Past due 60-89 days delinquent 4,963 3,742 8,705 Past due 90 days or more delinquent 9,813 4,849 14,662 Total past due 39,367 18,855 58,222 Total current loans 3,828,656 326,644 4,155,300 Total mortgage loans $ 3,868,023 $ 345,499 $ 4,213,522 Other delinquency statistics In process of foreclosure, included above (1) $ 4,223 $ 1,446 $ 5,669 Serious delinquency rate (2) 0.28 % 1.40 % 0.37 % Past due 90 days or more still accruing interest $ — $ 4,849 $ 4,849 Loans on nonaccrual status (3) $ 10,138 $ — $ 10,138 _______________________ (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, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 28,622 $ 13,862 $ 42,484 Past due 60-89 days delinquent 6,617 4,142 10,759 Past due 90 days or more delinquent 13,310 4,831 18,141 Total past due 48,549 22,835 71,384 Total current loans 3,601,952 352,249 3,954,201 Total mortgage loans $ 3,650,501 $ 375,084 $ 4,025,585 Other delinquency statistics In process of foreclosure, included above (1) $ 6,389 $ 1,306 $ 7,695 Serious delinquency rate (2) 0.38 % 1.29 % 0.46 % Past due 90 days or more still accruing interest $ — $ 4,831 $ 4,831 Loans on nonaccrual status (3) $ 13,598 $ — $ 13,598 _______________________ (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.
Individually Evaluated Impaired Loans, Average Recorded Investment and Interest Income Recognized [Table Text Block]	Table 9.2 - Individually Evaluated Impaired Conventional Mortgage Loans (dollars in thousands) September 30, 2018 December 31, 2017 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 15,671 $ 15,632 $ 17,668 $ 17,630 Table 9.3 - Average Recorded Investment of Individually Evaluated Impaired Mortgage Loans and Related Interest Income (dollars in thousands) For the Three Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 15,641 $ 116 $ 18,645 $ 91 Table 9.3 - Average Recorded Investment of Individually Evaluated Impaired Mortgage Loans and Related Interest Income (dollars in thousands) For the Nine Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 16,226 $ 334 $ 19,614 $ 314
Rollforward of Allowance for Credit Losses on Mortgage Loans [Table Text Block]	Table 9.4 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the three and nine months ended September 30, 2018 and 2017 , as well as the recorded investment in mortgage loans by impairment methodology at September 30, 2018 and 2017 . The recorded investment in a loan is the par amount of the loan, adjusted for accrued interest, unamortized premiums or discounts, deferred derivative gains and losses, and direct write-downs. The recorded investment is net of any valuation allowance. Table 9.4 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Allowance for credit losses Balance, beginning of period $ 500 $ 500 $ 500 $ 650 Charge-offs, net of recoveries — (28 ) (6 ) (2 ) Provision (reduction of provision) for credit losses — 28 6 (148 ) 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 $ 15,671 $ 18,786 $ 15,671 $ 18,786 Collectively evaluated for impairment $ 3,852,352 $ 3,562,789 $ 3,852,352 $ 3,562,789 _________________________ (1)

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments [Table Text Block]	Table 10.1 - Fair Value of Derivative Instruments (dollars in thousands) September 30, 2018 December 31, 2017 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 12,340,429 $ 15,169 $ (291,922 ) $ 14,118,994 $ 52,557 $ (332,830 ) Forward-start interest-rate swaps 376,200 — (403 ) 481,200 — (9,807 ) Total derivatives designated as hedging instruments 12,716,629 15,169 (292,325 ) 14,600,194 52,557 (342,637 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,164,300 2,753 (1,536 ) 1,166,900 3,512 (4,688 ) Mortgage-delivery commitments (1) 41,397 27 (80 ) 42,918 169 (27 ) Total derivatives not designated as hedging instruments 1,205,697 2,780 (1,616 ) 1,209,818 3,681 (4,715 ) Total notional amount of derivatives $ 13,922,326 $ 15,810,012 Total derivatives before netting and collateral adjustments 17,949 (293,941 ) 56,238 (347,352 ) Netting adjustments and cash collateral, including related accrued interest (2) 4,007 65,814 (21,452 ) 46,902 Derivative assets and derivative liabilities $ 21,956 $ (228,127 ) $ 34,786 $ (300,450 ) _______________________ (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 $71.5 million and $25.8 million at September 30, 2018 , and December 31, 2017 , 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 $1.7 million and $350,000 at September 30, 2018 , and December 31, 2017 .
Net Gains (Losses) on Derivatives and Hedging Activities [Table Text Block]	Table 10.2 - Net Gains and Losses on Derivatives and Hedging Activities Recorded in Other Income (Loss) (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Derivatives designated as hedging instruments Interest-rate swaps $ 557 $ (876 ) $ 2,140 $ (2,287 ) Forward-start interest-rate swaps 83 (18 ) 244 213 Total net gains (losses) related to derivatives designated as hedging instruments 640 (894 ) 2,384 (2,074 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps 7 14 729 (208 ) CO Bond firm commitments — 56 — 56 Mortgage-delivery commitments 131 692 (336 ) 1,556 Total net gains related to derivatives not designated as hedging instruments 138 762 393 1,404 Other (1) (291 ) 126 (692 ) 282 Net gains (losses) on derivatives and hedging activities $ 487 $ (6 ) $ 2,085 $ (388 ) ______________
Gains (Losses) By Type of Hedged Item [Table Text Block]	Table 10.3 - Effect of Fair Value Hedge Relationships (dollars in thousands) For the Three Months Ended September 30, 2018 Gain/(Loss) on Derivative (Loss)/Gain on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (1,975 ) $ 1,667 $ (308 ) $ 15,769 Investments 19,287 (18,832 ) 455 (6,200 ) COs – bonds (3,069 ) 3,479 410 (8,787 ) Total $ 14,243 $ (13,686 ) $ 557 $ 782 For the Three Months Ended September 30, 2017 Gain/(Loss) on Derivative (Loss)/Gain on Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 9,382 $ (8,881 ) $ 501 $ (2,878 ) Investments 5,007 (4,503 ) 504 (7,879 ) COs – bonds 2,018 (3,899 ) (1,881 ) 242 Total $ 16,407 $ (17,283 ) $ (876 ) $ (10,515 ) ______________ (1) The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item. For the Nine Months Ended September 30, 2018 Gain/(Loss) on Derivative (Loss)/Gain on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 46,793 $ (44,773 ) $ 2,020 $ 36,001 Investments 68,878 (67,270 ) 1,608 (19,975 ) COs – bonds (51,171 ) 49,683 (1,488 ) (20,317 ) Total $ 64,500 $ (62,360 ) $ 2,140 $ (4,291 ) For the Nine Months Ended September 30, 2017 Gain/(Loss) on Derivative (Loss)/Gain on Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 19,150 $ (18,780 ) $ 370 $ (24,566 ) Investments 8,412 (7,047 ) 1,365 (24,319 ) COs – bonds 19,813 (23,835 ) (4,022 ) 6,965 Total $ 47,375 $ (49,662 ) $ (2,287 ) $ (41,920 ) ______________ (1) The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item.
Effect of Cash Flow Hedge-Related Derivative Instruments [Table Text Block]	Table 10.4 - Effect of Cash Flow Hedge Relationships (dollars in thousands) Derivatives and Hedged Items in Cash Flow Hedging Relationships Gains (Losses) Recognized in Other Comprehensive Loss on Derivatives (Effective Portion) Location of Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Gains (Losses) Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion) Forward-start Interest-rate swaps - CO bonds For the Three Months Ended September 30, 2018 $ 2,985 Interest expense $ (537 ) $ 83 For the Three Months Ended September 30, 2017 (856 ) Interest expense (2,158 ) (18 ) For the Nine Months Ended September 30, 2018 14,733 Interest expense (2,485 ) 244 For the Nine Months Ended September 30, 2017 (5,937 ) Interest expense (9,865 ) 213
Post-haircut Value of Incremental Collateral Based on Incremental Credit Rating Downgrades [Table Text Block]	Table 10.5 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 September 30, 2018 . Table 10.5 - Post Haircut Value of Incremental Collateral to be Delivered as of September 30, 2018 (dollars in thousands) Ratings Downgrade (1) Incremental From To Collateral AA+ AA or AA- $ 1,142 AA- A+, A or A- 13,584 A- below A- 14,723 _______________________ (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 10.6 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 September 30, 2018 , and December 31, 2017 , 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 10.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) September 30, 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 $ 17,319 $ (15,542 ) $ 27 $ 1,804 $ — $ — $ 1,804 Cleared 603 19,549 20,152 — — 20,152 Total $ 21,956 $ 21,956 Derivative Liabilities Uncleared $ (292,034 ) $ 63,987 $ (80 ) $ (228,127 ) $ 10,809 $ 206,680 $ (10,638 ) Cleared (1,828 ) 1,828 — — — — Total $ (228,127 ) $ (10,638 ) _______________________ (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 September 30, 2018 , we had additional net credit exposure of $220,000 due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2017 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 $ 15,587 $ (13,481 ) $ 169 $ 2,275 $ — $ — $ 2,275 Cleared 40,482 (7,971 ) 32,511 — — 32,511 Total $ 34,786 $ 34,786 Derivative Liabilities Uncleared $ (335,289 ) $ 34,866 $ (27 ) $ (300,450 ) $ 7,627 $ 280,486 $ (12,337 ) Cleared (12,036 ) 12,036 — — — — Total $ (300,450 ) $ (12,337 ) _______________________ (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, 2017 , we had additional net credit exposure of $502,000
Offsetting Liabilities [Table Text Block]	Table 10.6 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 September 30, 2018 , and December 31, 2017 , 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 10.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) September 30, 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 $ 17,319 $ (15,542 ) $ 27 $ 1,804 $ — $ — $ 1,804 Cleared 603 19,549 20,152 — — 20,152 Total $ 21,956 $ 21,956 Derivative Liabilities Uncleared $ (292,034 ) $ 63,987 $ (80 ) $ (228,127 ) $ 10,809 $ 206,680 $ (10,638 ) Cleared (1,828 ) 1,828 — — — — Total $ (228,127 ) $ (10,638 ) _______________________ (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 September 30, 2018 , we had additional net credit exposure of $220,000 due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2017 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 $ 15,587 $ (13,481 ) $ 169 $ 2,275 $ — $ — $ 2,275 Cleared 40,482 (7,971 ) 32,511 — — 32,511 Total $ 34,786 $ 34,786 Derivative Liabilities Uncleared $ (335,289 ) $ 34,866 $ (27 ) $ (300,450 ) $ 7,627 $ 280,486 $ (12,337 ) Cleared (12,036 ) 12,036 — — — — Total $ (300,450 ) $ (12,337 ) _______________________ (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, 2017 , we had additional net credit exposure of $502,000

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2018
Deposits [Abstract]
Interest-bearing and Non-interest-bearing Deposits [Table Text Block]	Table 11.1 - Deposits (dollars in thousands) September 30, 2018 December 31, 2017 Interest-bearing Demand and overnight $ 460,636 $ 447,700 Term 800 — Other 1,913 3,222 Noninterest-bearing Other 21,412 26,147 Total deposits $ 484,761 $ 477,069

Consolidated Obligations (Table

Consolidated Obligations (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
CO Bonds by Year of Contractual Maturity [Table Text Block]	Table 12.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date September 30, 2018 December 31, 2017 Due in one year or less $ 13,698,250 $ 15,309,510 Due after one year through two years 6,392,295 5,580,470 Due after two years through three years 2,491,605 3,020,240 Due after three years through four years 1,485,865 1,542,460 Due after four years through five years 1,140,655 1,107,775 Thereafter 1,560,710 1,764,695 Total par value $ 26,769,380 $ 28,325,150 Table 12.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) September 30, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 10,123,250 1.80 % $ 12,186,510 1.35 % Due after one year through two years 6,283,295 2.15 5,288,470 1.63 Due after two years through three years 3,073,605 2.19 3,128,240 1.81 Due after three years through four years 2,395,865 1.98 2,759,460 1.74 Due after four years through five years 1,410,655 2.30 1,572,775 2.00 Thereafter 3,482,710 3.06 3,389,695 2.76 Total par value 26,769,380 2.13 % 28,325,150 1.70 % Premiums 92,653 90,836 Discounts (15,637 ) (15,685 ) Hedging adjustments (105,360 ) (55,678 ) $ 26,741,036 $ 28,344,623 _______________________ (1)
CO Bonds Long-term Debt Instruments [Table Text Block]	Table 12.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds September 30, 2018 December 31, 2017 Noncallable and nonputable $ 21,867,380 $ 23,931,150 Callable 4,902,000 4,394,000 Total par value $ 26,769,380 $ 28,325,150 Table 12.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds September 30, 2018 December 31, 2017 Fixed-rate $ 20,954,380 $ 21,416,150 Simple variable-rate 3,983,000 5,432,000 Step-up 1,832,000 1,477,000 Total par value $ 26,769,380 $ 28,325,150
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 12.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) September 30, 2018 $ 33,431,980 $ 33,501,223 2.07 % December 31, 2017 $ 27,720,906 $ 27,752,860 1.25 % _______________________ (1)

Affordable Housing Program (Tab

Affordable Housing Program (Tables)	9 Months Ended
	Sep. 30, 2018
Affordable Housing Program [Abstract]
Roll-forward of the AHP Liability[Table Text Block]	Table 13.1 - AHP Liability (dollars in thousands) September 30, 2018 December 31, 2017 Balance at beginning of year $ 81,600 $ 81,627 AHP expense for the period 19,387 21,307 AHP direct grant disbursements (13,384 ) (18,628 ) AHP subsidy for AHP advance disbursements (3,707 ) (2,782 ) Return of previously disbursed grants and subsidies 86 76 Balance at end of period $ 83,982 $ 81,600

Capital (Tables)

Capital (Tables)	9 Months Ended
	Sep. 30, 2018
Capital [Abstract]
Compliance with Regulatory Capital Requirements [Table Text Block]	Table 14.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements September 30, 2018 December 31, 2017 Permanent capital Class B capital stock $ 2,476,876 $ 2,283,721 Mandatorily redeemable capital stock 31,868 35,923 Retained earnings 1,386,466 1,308,349 Total permanent capital $ 3,895,210 $ 3,627,993 Risk-based capital requirement Credit-risk capital $ 320,819 $ 328,557 Market-risk capital 253,082 170,102 Operations-risk capital 172,170 149,598 Total risk-based capital requirement $ 746,071 $ 648,257 Permanent capital in excess of risk-based capital requirement $ 3,149,139 $ 2,979,736 September 30, 2018 December 31, 2017 Required Actual Required Actual Capital Ratio Risk-based capital $ 746,071 $ 3,895,210 $ 648,257 $ 3,627,993 Total regulatory capital $ 2,587,752 $ 3,895,210 $ 2,414,478 $ 3,627,993 Total capital-to-asset ratio 4.0 % 6.0 % 4.0 % 6.0 % Leverage Ratio Leverage capital $ 3,234,690 $ 5,842,815 $ 3,018,097 $ 5,441,990 Leverage capital-to-assets ratio 5.0 % 9.0 % 5.0 % 9.0 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2018
AOCI Attributable to Parent [Abstract]
Schedule of Accumulated Other Comprehensive Loss [Table Text Block]	Accumulated Other Comprehensive Loss Table 15.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Accumulated Other Comprehensive Loss Balance, June 30, 2017 $ (94,309 ) $ (175,068 ) $ (45,554 ) $ (5,530 ) $ (320,461 ) Other comprehensive income (loss) before reclassifications: Net unrealized losses (61 ) — (856 ) — (917 ) Accretion of noncredit loss — 8,178 — — 8,178 Net actuarial gain — — — 112 112 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 420 — — 420 Amortization - hedging activities (2) — — 2,161 — 2,161 Amortization - pension and postretirement benefits (3) — — — 193 193 Other comprehensive (loss) income (61 ) 8,598 1,305 305 10,147 Balance, September 30, 2017 $ (94,370 ) $ (166,470 ) $ (44,249 ) $ (5,225 ) $ (310,314 ) Balance, June 30, 2018 $ (167,921 ) $ (143,196 ) $ (26,733 ) $ (6,740 ) $ (344,590 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (8,690 ) — 2,985 — (5,705 ) Accretion of noncredit loss — 7,127 — — 7,127 Net actuarial loss — — — (729 ) (729 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 6 — — 6 Amortization - hedging activities (4) — — 541 — 541 Amortization - pension and postretirement benefits (3) — — — 337 337 Other comprehensive (loss) income (8,690 ) 7,133 3,526 (392 ) 1,577 Balance, September 30, 2018 $ (176,611 ) $ (136,063 ) $ (23,207 ) $ (7,132 ) $ (343,013 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $2.2 million recorded in CO bond interest expense and $4,000 recorded in net losses on derivatives and hedging activities in the statement of operations. (3) Recorded in other non-interest expenses in the statement of operations. (4) Amortization of hedging activities includes $537,000 recorded in CO bond interest expense and $4,000 recorded in net losses on derivatives and hedging activities in the statement of operations. Table 15.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Accumulated Other Comprehensive Loss Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 42,439 — (5,937 ) — 36,502 Accretion of noncredit loss — 24,593 — — 24,593 Net actuarial gain — — — 336 336 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 1,316 — — 1,316 Amortization - hedging activities (2) — — 9,875 — 9,875 Amortization - pension and postretirement benefits (3) — — — 578 578 Other comprehensive income 42,439 25,909 3,938 914 73,200 Balance, September 30, 2017 $ (94,370 ) $ (166,470 ) $ (44,249 ) $ (5,225 ) $ (310,314 ) Balance, December 31, 2017 $ (122,331 ) $ (158,218 ) $ (40,436 ) $ (5,955 ) $ (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (54,280 ) — 14,733 — (39,547 ) Accretion of noncredit loss — 21,945 — — 21,945 Net actuarial loss — — — (2,189 ) (2,189 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 210 — — 210 Amortization - hedging activities (4) — — 2,496 — 2,496 Amortization - pension and postretirement benefits (3) — — — 1,012 1,012 Other comprehensive (loss) income (54,280 ) 22,155 17,229 (1,177 ) (16,073 ) Balance, September 30, 2018 $ (176,611 ) $ (136,063 ) $ (23,207 ) $ (7,132 ) $ (343,013 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $9.9 million recorded in CO bond interest expense and $11,000 recorded in net losses on derivatives and hedging activities in the statement of operations. (3) Recorded in other non-interest expenses in the statement of operations. (4) Amortization of hedging activities includes $2.5 million recorded in CO bond interest expense and $11,000

Fair Values (Tables)

Fair Values (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments [Table Text Block]	Table 16.1 - Fair Value Summary (dollars in thousands) September 30, 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 $ 45,614 $ 45,614 $ 45,614 $ — $ — $ — Interest-bearing deposits 397,203 397,203 397,203 — — — Securities purchased under agreements to resell 5,499,000 5,498,962 — 5,498,962 — — Federal funds sold 5,650,000 5,650,001 — 5,650,001 — — Trading securities (1) 176,113 176,113 — 176,113 — — Available-for-sale securities (1) 6,227,080 6,227,080 — 6,186,743 40,337 — Held-to-maturity securities 1,372,299 1,638,491 — 671,526 966,965 — Advances 40,927,639 40,880,159 — 40,880,159 — — Mortgage loans, net 4,192,425 4,076,278 — 4,056,143 20,135 — Accrued interest receivable 102,466 102,466 — 102,466 — — Derivative assets (1) 21,956 21,956 — 17,949 — 4,007 Other assets (1) 26,036 26,036 11,189 14,847 — — Liabilities: Deposits (484,761 ) (484,750 ) — (484,750 ) — — COs: Bonds (26,741,036 ) (26,508,907 ) — (26,508,907 ) — — Discount notes (33,431,980 ) (33,428,979 ) — (33,428,979 ) — — Mandatorily redeemable capital stock (31,868 ) (31,868 ) (31,868 ) — — — Accrued interest payable (119,242 ) (119,242 ) — (119,242 ) — — Derivative liabilities (1) (228,127 ) (228,127 ) — (293,941 ) — 65,814 Other: Commitments to extend credit for advances — (4,946 ) — (4,946 ) — — Standby letters of credit (1,179 ) (1,179 ) — (1,179 ) — — _______________________ (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, 2017 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 $ 261,673 $ 261,673 $ 261,673 $ — $ — $ — Interest-bearing deposits 246 246 246 — — — Securities purchased under agreements to resell 5,349,000 5,348,898 — 5,348,898 — — Federal funds sold 3,450,000 3,449,981 — 3,449,981 — — Trading securities (1) 191,510 191,510 — 191,510 — — Available-for-sale securities (1) 7,324,736 7,324,736 — 7,287,053 37,683 — Held-to-maturity securities 1,626,122 1,903,227 — 811,759 1,091,468 — Advances 37,565,967 37,591,048 — 37,591,048 — — Mortgage loans, net 4,004,737 4,035,928 — 4,013,704 22,224 — Loans to other FHLBanks (3) 400,000 399,997 — 399,997 — — Accrued interest receivable 94,100 94,100 — 94,100 — — Derivative assets (1) 34,786 34,786 — 56,238 — (21,452 ) Other assets (1) 22,351 22,351 9,726 12,625 — — Liabilities: Deposits (477,069 ) (477,060 ) — (477,060 ) — — COs: Bonds (28,344,623 ) (28,353,945 ) — (28,353,945 ) — — Discount notes (27,720,906 ) (27,719,598 ) — (27,719,598 ) — — Mandatorily redeemable capital stock (35,923 ) (35,923 ) (35,923 ) — — — Accrued interest payable (90,626 ) (90,626 ) — (90,626 ) — — Derivative liabilities (1) (300,450 ) (300,450 ) — (347,352 ) — 46,902 Other: Commitments to extend credit for advances — (3,817 ) — (3,817 ) — — Standby letters of credit (1,100 ) (1,100 ) — (1,100 ) — — _______________________ (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. (3)
Fair Value Measured on Recurring Basis [Table Text Block]	Table 16.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (dollars in thousands) September 30, 2018 Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (1) Total Assets: Trading securities: Corporate bonds $ — $ 6,774 $ — $ — $ 6,774 U.S. government-guaranteed – single-family MBS — 5,684 — — 5,684 GSEs – single-family MBS — 180 — — 180 GSEs – multifamily MBS — 163,475 — — 163,475 Total trading securities — 176,113 — — 176,113 Available-for-sale securities: State or local HFA securities — — 40,337 — 40,337 Supranational institutions — 395,178 — — 395,178 U.S. government-owned corporations — 268,624 — — 268,624 GSEs — 113,425 — — 113,425 U.S. government guaranteed – single-family MBS — 81,037 — — 81,037 U.S. government guaranteed – multifamily MBS — 367,515 — — 367,515 GSEs – single-family MBS — 3,732,005 — — 3,732,005 GSEs – multifamily — 1,228,959 — — 1,228,959 Total available-for-sale securities — 6,186,743 40,337 — 6,227,080 Derivative assets: Interest-rate-exchange agreements — 17,922 — 4,007 21,929 Mortgage delivery commitments — 27 — — 27 Total derivative assets — 17,949 — 4,007 21,956 Other assets 11,189 14,847 — — 26,036 Total assets at fair value $ 11,189 $ 6,395,652 $ 40,337 $ 4,007 $ 6,451,185 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (293,861 ) $ — $ 65,814 $ (228,047 ) Mortgage delivery commitments — (80 ) — — (80 ) Total liabilities at fair value $ — $ (293,941 ) $ — $ 65,814 $ (228,127 ) _______________________ (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. December 31, 2017 Level 1 Level 2 Level 3 Netting (1) Total Assets: Trading securities: U.S. government-guaranteed – single-family MBS $ — $ 6,807 $ — $ — $ 6,807 GSEs – single-family MBS — 346 — — 346 GSEs – multifamily MBS — 184,357 — — 184,357 Total trading securities — 191,510 — — 191,510 Available-for-sale securities: State or local HFA securities — — 37,683 — 37,683 Supranational institutions — 418,285 — — 418,285 U.S. government-owned corporations — 292,077 — — 292,077 GSEs — 121,343 — — 121,343 U.S. government guaranteed – single-family MBS — 95,777 — — 95,777 U.S. government guaranteed – multifamily MBS — 443,373 — — 443,373 GSEs – single-family MBS — 4,562,992 — — 4,562,992 GSEs – multifamily MBS — 1,353,206 — — 1,353,206 Total available-for-sale securities — 7,287,053 37,683 — 7,324,736 Derivative assets: Interest-rate-exchange agreements — 56,069 — (21,452 ) 34,617 Mortgage delivery commitments — 169 — — 169 Total derivative assets — 56,238 — (21,452 ) 34,786 Other assets 9,726 12,625 — — 22,351 Total assets at fair value $ 9,726 $ 7,547,426 $ 37,683 $ (21,452 ) $ 7,573,383 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (347,325 ) $ — $ 46,902 $ (300,423 ) Mortgage delivery commitments — (27 ) — — (27 ) Total liabilities at fair value $ — $ (347,352 ) $ — $ 46,902 $ (300,450 ) _______________________ (1)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Table 16.3 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 nine months ended September 30, 2018 and 2017 . Table 16.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Balance at beginning of period $ 37,600 $ 15,414 $ 37,683 $ 8,146 Purchases 3,150 3,520 3,150 11,120 Unrealized gains (losses) included in other comprehensive income (413 ) (391 ) (496 ) (723 ) Balance at end of period $ 40,337 $ 18,543 $ 40,337 $ 18,543
Fair Value on a Nonrecurring Basis [Table Text Block]	Table 16.4 - Fair Value of Assets Measured at Fair Value on a Nonrecurring Basis (1) (dollars in thousands) September 30, 2018 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,736 $ 1,736 Mortgage loans held for portfolio — — 1,122 1,122 REO — — 361 361 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 3,219 $ 3,219 December 31, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,970 $ 1,970 Mortgage loans held for portfolio — — 4,608 4,608 REO — — 784 784 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 7,362 $ 7,362 _______________________ (1) The fair values presented are as of the date the fair value adjustment was recorded during the nine months ended September 30, 2018 , and year ended December 31, 2017

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	Table 17.1 - Off-Balance Sheet Commitments (dollars in thousands) September 30, 2018 December 31, 2017 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 6,086,259 $ 231,611 $ 6,317,870 $ 5,034,725 $ 223,167 $ 5,257,892 Commitments for unused lines of credit - advances (2) 1,213,453 — 1,213,453 1,216,592 — 1,216,592 Commitments to make additional advances 20,880 37,527 58,407 18,851 63,488 82,339 Commitments to invest in mortgage loans 41,397 — 41,397 42,918 — 42,918 Unsettled CO bonds, at par 138,800 — 138,800 52,550 — 52,550 __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At September 30, 2018 , and December 31, 2017 , these amounts totaled $ 29.3 million and $1.4 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $543,000 at December 31, 2017 . (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)	9 Months Ended
	Sep. 30, 2018
Transactions with Shareholders [Abstract]
Schedule of Transactions with Shareholders [Table Text Block]	Table 18.1 - Shareholder Concentrations, Balance Sheet (dollars in thousands) Capital Stock Outstanding Percent of Total 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 September 30, 2018 Citizens Bank, N.A. $ 354,645 14.1 % $ 8,009,938 19.5 % $ 5,692 10.0 % As of December 31, 2017 Citizens Bank, N.A. $ 227,287 9.8 % $ 4,858,592 12.9 % $ 2,558 6.0 %
Schedule of Transactions with Shareholders, Interest Income [Table Text Block]	Table 18.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Three Months Ended September 30, For the Nine Months Ended September 30, Citizens Bank, N.A. 2018 2017 2018 2017 Interest income on advances $ 33,144 $ 14,316 $ 89,228 $ 46,968 Fees on letters of credit 1,257 1,002 3,338 2,448
Schedule of Transactions with Shareholders, Transactions with Directors' Financial Institutions [Table Text Block]	Table 18.3 presents the outstanding balances of capital stock, advances, and accrued interest receivable with members whose officers or directors serve on our board of directors, and those balances as a percentage of our total balance as reported on our statement of condition: Table 18.3 - Transactions with Directors' Institutions (dollars in thousands) Capital Stock Outstanding Percent of Total 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 September 30, 2018 $ 106,932 4.3 % $ 2,002,884 4.9 % $ 2,960 5.2 % As of December 31, 2017 114,498 4.9 2,133,374 5.7 2,466 5.8

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Guidance Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Accounting Standards Update 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost	$ 352,000	$ 1,100,000

Recently Issued and Adopted A_3

Recently Issued and Adopted Accounting Guidance Leases (Details) - Scenario, Forecast [Member] - Accounting Standards Update 2016-02 [Member] $ in Millions	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right-of-use assets	$ 11.8
Operating lease, liability	$ 12.3

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 176,113	$ 191,510
Corporate bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	6,774	0
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	5,684	6,807
MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	169,339	191,510
GSEs - single-family [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	180	346
GSEs - multifamily [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 163,475	$ 184,357

Trading Securities - Net Unreal

Trading Securities - Net Unrealized (Losses) Gains (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Trading Securities [Abstract]
Net unrealized losses on trading securities	$ (714)	$ (1,591)	$ (3,702)	$ (3,857)

Available-for-Sale Securities M

Available-for-Sale Securities Major Security Types (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 6,403,691	$ 7,447,067
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		2,447	3,512
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(179,058)	(125,843)
Available-for-sale securities Fair Value		6,227,080	7,324,736
States or local housing-finance-agency obligations (HFA securities) [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	45,850	42,700
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(5,513)	(5,017)
Available-for-sale securities Fair Value		40,337	37,683
Supranational institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	409,784	438,667
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(14,606)	(20,382)
Available-for-sale securities Fair Value		395,178	418,285
U.S. government-owned corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	286,169	313,985
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(17,545)	(21,908)
Available-for-sale securities Fair Value		268,624	292,077
GSEs [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	118,173	128,744
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(4,748)	(7,401)
Available-for-sale securities Fair Value		113,425	121,343
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	859,976	924,096
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(42,412)	(54,708)
Available-for-sale securities Fair Value		817,564	869,388
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	84,742	98,720
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		41	55
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(3,746)	(2,998)
Available-for-sale securities Fair Value		81,037	95,777
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	374,986	447,975
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(7,471)	(4,602)
Available-for-sale securities Fair Value		367,515	443,373
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	5,543,715	6,522,971
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		2,447	3,512
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(136,646)	(71,135)
Available-for-sale securities Fair Value	[2]	5,409,516	6,455,348
Single Family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	3,856,145	4,625,333
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		962	1,194
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(125,102)	(63,535)
Available-for-sale securities Fair Value		3,732,005	4,562,992
Multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	1,227,842	1,350,943
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		1,444	2,263
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(327)	0
Available-for-sale securities Fair Value		$ 1,228,959	$ 1,353,206
[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.

Available-for-Sale Securities S

Available-for-Sale Securities Securities with Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 1,536,858	$ 1,946,887
Less than 12 Months, Unrealized Losses	(36,491)	(17,237)
12 Months or More, Fair Value	3,664,083	3,830,080
12 Months or More, Unrealized Losses	(142,567)	(108,606)
Total Fair Value	5,200,941	5,776,967
Total Unrealized Losses	(179,058)	(125,843)
HFA securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	21,793	29,345
Less than 12 Months, Unrealized Losses	(3,587)	(4,005)
12 Months or More, Fair Value	18,544	8,338
12 Months or More, Unrealized Losses	(1,926)	(1,012)
Total Fair Value	40,337	37,683
Total Unrealized Losses	(5,513)	(5,017)
Supranational institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	395,178	418,285
12 Months or More, Unrealized Losses	(14,606)	(20,382)
Total Fair Value	395,178	418,285
Total Unrealized Losses	(14,606)	(20,382)
U.S. government-owned corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	268,624	292,077
12 Months or More, Unrealized Losses	(17,545)	(21,908)
Total Fair Value	268,624	292,077
Total Unrealized Losses	(17,545)	(21,908)
GSEs [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	113,425	121,343
12 Months or More, Unrealized Losses	(4,748)	(7,401)
Total Fair Value	113,425	121,343
Total Unrealized Losses	(4,748)	(7,401)
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	21,793	29,345
Less than 12 Months, Unrealized Losses	(3,587)	(4,005)
12 Months or More, Fair Value	795,771	840,043
12 Months or More, Unrealized Losses	(38,825)	(50,703)
Total Fair Value	817,564	869,388
Total Unrealized Losses	(42,412)	(54,708)
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	61,434	70,877
12 Months or More, Unrealized Losses	(3,746)	(2,998)
Total Fair Value	61,434	70,877
Total Unrealized Losses	(3,746)	(2,998)
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	64,219
Less than 12 Months, Unrealized Losses	0	(571)
12 Months or More, Fair Value	367,515	379,154
12 Months or More, Unrealized Losses	(7,471)	(4,031)
Total Fair Value	367,515	443,373
Total Unrealized Losses	(7,471)	(4,602)
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,515,065	1,917,542
Less than 12 Months, Unrealized Losses	(32,904)	(13,232)
12 Months or More, Fair Value	2,868,312	2,990,037
12 Months or More, Unrealized Losses	(103,742)	(57,903)
Total Fair Value	4,383,377	4,907,579
Total Unrealized Losses	(136,646)	(71,135)
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,175,912	1,853,323
Less than 12 Months, Unrealized Losses	(32,577)	(12,661)
12 Months or More, Fair Value	2,439,363	2,540,006
12 Months or More, Unrealized Losses	(92,525)	(50,874)
Total Fair Value	3,615,275	4,393,329
Total Unrealized Losses	(125,102)	$ (63,535)
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	339,153
Less than 12 Months, Unrealized Losses	(327)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	339,153
Total Unrealized Losses	$ (327)

Available-for-Sale Securities R

Available-for-Sale Securities Redemption Terms (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 6,403,691	$ 7,447,067
Fair Value		6,227,080	7,324,736
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, amortized cost		0	0
Due in one year or less, fair value		0	0
Due after one year through five years, amortized cost		42,700	42,700
Due after one year through five years, fair value		37,640	37,683
Due after five years through 10 years, amortized cost		457,717	438,667
Due after five years through 10 years, fair value		441,968	418,285
Due after 10 years, amortized cost		359,559	442,729
Due after 10 years, fair value		337,956	413,420
Amortized Cost	[1]	859,976	924,096
Fair Value		817,564	869,388
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	5,543,715	6,522,971
Fair Value	[2]	$ 5,409,516	$ 6,455,348
[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		Sep. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 1,508,361	$ 1,784,339
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(136,062)	(158,217)
Carrying Value	[1]	1,372,299	1,626,122
Gross Unrecognized Holding Gains		273,699	295,331
Gross Unrecognized Holding Losses		(7,507)	(18,226)
Held-to-maturity securities Fair Value		1,638,491	1,903,227
U.S. agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		416	1,042
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		416	1,042
Gross Unrecognized Holding Gains		1	10
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		417	1,052
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		124,560	146,410
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		124,560	146,410
Gross Unrecognized Holding Gains		6	26
Gross Unrecognized Holding Losses		(3,542)	(14,372)
Held-to-maturity securities Fair Value		121,024	132,064
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		124,976	147,452
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value	[1]	124,976	147,452
Gross Unrecognized Holding Gains		7	36
Gross Unrecognized Holding Losses		(3,542)	(14,372)
Held-to-maturity securities Fair Value		121,441	133,116
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		8,647	10,097
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		8,647	10,097
Gross Unrecognized Holding Gains		170	190
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		8,817	10,287
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost			280
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss			0
Carrying Value			280
Gross Unrecognized Holding Gains			0
Gross Unrecognized Holding Losses			0
Held-to-maturity securities Fair Value			280
Asset Backed Securities Backed by Home Equity Loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		7,108	7,851
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(19)	(23)
Carrying Value		7,089	7,828
Gross Unrecognized Holding Gains		24	27
Gross Unrecognized Holding Losses		(177)	(349)
Held-to-maturity securities Fair Value		6,936	7,506
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[2]	1,383,385	1,636,887
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(136,062)	(158,217)
Carrying Value	[1],[2]	1,247,323	1,478,670
Gross Unrecognized Holding Gains		273,692	295,295
Gross Unrecognized Holding Losses		(3,965)	(3,854)
Held-to-maturity securities Fair Value	[2]	1,517,050	1,770,111
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		444,076	568,948
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		444,076	568,948
Gross Unrecognized Holding Gains		7,369	10,410
Gross Unrecognized Holding Losses		(2,140)	(310)
Held-to-maturity securities Fair Value		449,305	579,048
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		211,476	214,641
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		211,476	214,641
Gross Unrecognized Holding Gains		1,511	6,451
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		212,987	221,092
Private-label - residential MBS [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		712,078	835,070
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(136,043)	(158,194)
Carrying Value		576,035	676,876
Gross Unrecognized Holding Gains		264,618	278,217
Gross Unrecognized Holding Losses		(1,648)	(3,195)
Held-to-maturity securities Fair Value		$ 839,005	$ 951,898
[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.

Held-to-Maturity Securities Fai

Held-to-Maturity Securities Fair Value and Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	$ 106,028	$ 44,759
Less than 12 Months, Unrealized Losses	(1,650)	(52)
12 Months or More, Fair Value	256,815	316,308
12 Months or More, Unrealized Losses	(6,764)	(20,538)
Total Fair Value	362,843	361,067
Total Unrealized Losses	(8,414)	(20,590)
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	110,953	121,203
12 Months or More, Unrealized Losses	(3,542)	(14,372)
Total Fair Value	110,953	121,203
Total Unrealized Losses	(3,542)	(14,372)
Asset Backed Securities Backed by Home Equity Loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	5,869	7,371
12 Months or More, Unrealized Losses	(177)	(350)
Total Fair Value	5,869	7,371
Total Unrealized Losses	(177)	(350)
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	106,028	44,759
Less than 12 Months, Unrealized Losses	(1,650)	(52)
12 Months or More, Fair Value	145,862	195,105
12 Months or More, Unrealized Losses	(3,222)	(6,166)
Total Fair Value	251,890	239,864
Total Unrealized Losses	(4,872)	(6,218)
Single Family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	106,028	44,759
Less than 12 Months, Unrealized Losses	(1,650)	(52)
12 Months or More, Fair Value	22,748	28,771
12 Months or More, Unrealized Losses	(490)	(258)
Total Fair Value	128,776	73,530
Total Unrealized Losses	(2,140)	(310)
Private-label - residential MBS [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	117,245	158,963
12 Months or More, Unrealized Losses	(2,555)	(5,558)
Total Fair Value	117,245	158,963
Total Unrealized Losses	$ (2,555)	$ (5,558)

Held-to-Maturity Securities Red

Held-to-Maturity Securities Redemption Terms (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 1,508,361	$ 1,784,339
Carrying Value	[1]	1,372,299	1,626,122
Fair Value		1,638,491	1,903,227
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Due in one year or less, Amortized Cost		1,251	264
Due in one year or less, Carrying Value	[1]	1,251	264
Due in one year or less, Fair Value		1,256	267
Due after one year through five years, Amortized Cost		9,230	11,613
Due after one year through five years, Carrying Value	[1]	9,230	11,613
Due after one year through five years, Fair Value		9,232	11,645
Due after five years through 10 years, Amortized Cost		17,565	18,245
Due after five years through 10 years, Carrying Value	[1]	17,565	18,245
Due after five years through 10 years, Fair Value		17,458	18,226
Due after 10 years, Amortized Cost		96,930	117,330
Due after 10 years, Carrying Value	[1]	96,930	117,330
Due after 10 years, Fair Value		93,495	102,978
Amortized Cost		124,976	147,452
Carrying Value	[1]	124,976	147,452
Fair Value		121,441	133,116
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[2]	1,383,385	1,636,887
Carrying Value	[1],[2]	1,247,323	1,478,670
Fair Value	[2]	$ 1,517,050	$ 1,770,111
[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_3

Other-Than-Temporary Impairment Significant Inputs (Details) - Alt-A [Member] - Mortgage-backed Securities, Issued by Private Enterprises [Member] - Residential Mortgage Backed Securities [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 6,230
Project Prepayment Rates - Weighted Average Percent	12.60%
Projected Default Rates, Weighted Average Percent	18.50%
Projected Loss Severities, Weighted Average Percent	27.30%
Current Credit Enhancement, Weighted Average Percent	23.60%
[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	Sep. 30, 2018USD ($)	[1]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	$ 857,240
Amortized Cost	619,522
Carrying Value	483,460
Fair Value	746,352
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Prime [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	25,864
Amortized Cost	22,026
Carrying Value	17,295
Fair Value	24,484
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Alt-A [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	831,215
Amortized Cost	597,346
Carrying Value	466,033
Fair Value	721,713
Asset Backed Securities Backed by Home Equity Loans [Member] | Subprime [Member]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	161
Amortized Cost	150
Carrying Value	132
Fair Value	$ 155
[1]	Securities are classified based on their classifications 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 ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at beginning of period		$ 437,315	$ 468,706	$ 452,523	$ 490,404
Additional credit losses for which an other-than-temporary impairment charge was previously recognized	[1]	71	432	407	1,418
Securities matured during the period	[2]	0	0	0	(5,565)
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		(7,997)	(8,356)	(23,541)	(25,475)
Balance at end of period		$ 429,389	$ 460,782	$ 429,389	$ 460,782
[1]	For the three months ended September 30, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to July 1, 2018 and 2017 . For the nine months ended September 30, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to January 1, 2018 and 2017
[2]	Represents reductions related to securities having reached final maturity during the period and, therefore, are no longer held by us at the end of the period.

Advances - Year of Contractual

Advances - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Maturity, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	[1]	$ 7,887	$ 5,698
Due in one year or less		20,964,860	21,501,397
Due after one year through two years		12,202,282	7,462,785
Due after two years through three years		2,171,439	2,709,951
Due after three years through four years		2,130,610	2,084,105
Due after four years through five years		2,466,375	2,071,989
Thereafter		1,115,924	1,811,241
Total par value	[1]	$ 41,059,377	$ 37,647,166
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Rolling Year [Abstract]
Overdrawn demand-deposit accounts, Weighted average rate		2.63%	1.70%
Due in one year or less, Weighted average rate		2.20%	1.56%
Due after one year through two years, Weighted average rate		2.30%	1.65%
Due after two years through three years, Weighted average rate		2.28%	1.85%
Due after three years through four years, Weighted average rate		2.32%	2.03%
Due after four years through five years, Weighted average rate		2.10%	1.56%
Thereafter, Weighted average rate		2.85%	2.23%
Total Weighted average rate		2.25%	1.66%
Premiums		$ 14,394	$ 17,931
Discounts		(36,356)	(32,757)
Fair value of bifurcated derivatives	[2]	(221)	(1,591)
Hedging adjustments		(109,555)	(64,782)
Total Advances		$ 40,927,639	$ 37,565,967
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.
[2]	At September 30, 2018 , and December 31, 2017

Advances Advances - Year of Con

Advances Advances - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	[1]	$ 7,887	$ 5,698
Due in one year or less	[1]	30,153,735	25,842,572
Due after one year through two years	[1]	4,202,282	3,722,785
Due after two years through three years	[1]	2,161,439	2,709,951
Due after three years through four years	[1]	1,968,910	1,924,105
Due after four years through five years	[1]	1,503,175	1,684,789
Thereafter	[1]	1,061,949	1,757,266
Total par value	[1]	$ 41,059,377	$ 37,647,166
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Advances - Outstanding by the E

Advances - Outstanding by the Earlier of Contractual Maturity or Next Put Date (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	[1]	$ 7,887	$ 5,698
Due in one year or less		22,282,660	22,828,547
Due after one year through two years		12,426,982	7,921,035
Due after two years through three years		2,211,439	2,686,951
Due after three years through four years		1,807,610	1,984,705
Due after four years through five years		1,518,375	1,216,989
Thereafter		804,424	1,003,241
Total par value	[1]	$ 41,059,377	$ 37,647,166
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Advances - Interest-Rate-Paymen

Advances - Interest-Rate-Payment Terms (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, by Interest Rate Type [Abstract]
Fixed-rate		$ 30,882,215	$ 31,658,293
Variable-rate		10,177,162	5,988,873
Total par value	[1]	$ 41,059,377	$ 37,647,166
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Advances - Narratives (Details)

Advances - Narratives (Details) $ in Billions	Sep. 30, 2018USD ($)Borrowers	Dec. 31, 2017USD ($)Borrowers
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount	$ 14.3	$ 12.1
Minimum amount of advances outstanding per borrower	$ 1
Federal Home Loan Bank Advances [Member]
Credit Risk Exposure and Security Terms [Abstract]
Number of financial institutions with more than $1.0 billion advances borrowing | Borrowers	5	6
Total outstanding advances greater than $1.0 billion per borrower as a percentage of advances outstanding	34.80%	32.30%
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%

Mortgage Loans Held for Portf_3

Mortgage Loans Held for Portfolio (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 4,124,133	$ 3,933,704
Premiums	67,957	70,074
Discounts	(1,730)	(1,541)
Deferred derivative gains, net	2,565	3,000
Total mortgage loans held for portfolio	4,192,925	4,005,237
Allowance for credit losses	(500)	(500)
Total mortgage loans, net of allowance for credit losses	$ 4,192,425	4,004,737
Fixed-rate 15-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Original contractual terms	15 years
Conventional Mortgage Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,787,412	3,568,473
Minimum [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Original contractual terms	20 years
Maximum [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Original contractual terms	30 years
Government Mortgage Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 336,721	365,231
Single Family [Member] | Fixed-rate 15-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	410,019	466,952
Single Family [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,714,114	$ 3,466,752

Allowance for credit losses - C

Allowance for credit losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
Mortgage Loans Past Due [Line Items]
Total past due		$ 58,222	$ 71,384
Total current loans		4,155,300	3,954,201
Total mortgage loans		4,213,522	4,025,585
In process of foreclosure, included above	[1]	$ 5,669	$ 7,695
Serious delinquency rate	[2]	0.37%	0.46%
Past due 90 days or more still accruing interest		$ 4,849	$ 4,831
Loans on nonaccrual status	[3]	$ 10,138	13,598
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		$ 18,855	22,835
Total current loans		326,644	352,249
Total mortgage loans		345,499	375,084
In process of foreclosure, included above	[1]	$ 1,446	$ 1,306
Serious delinquency rate	[2]	1.40%	1.29%
Past due 90 days or more still accruing interest		$ 4,849	$ 4,831
Loans on nonaccrual status	[3]	0	0
Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		39,367	48,549
Total current loans		3,828,656	3,601,952
Total mortgage loans		3,868,023	3,650,501
In process of foreclosure, included above	[1]	$ 4,223	$ 6,389
Serious delinquency rate	[2]	0.28%	0.38%
Past due 90 days or more still accruing interest		$ 0	$ 0
Loans on nonaccrual status	[3]	10,138	13,598
Past due 30-59 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		34,855	42,484
Past due 30-59 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		10,264	13,862
Past due 30-59 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		24,591	28,622
Past due 60-89 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		8,705	10,759
Past due 60-89 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		3,742	4,142
Past due 60-89 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		4,963	6,617
Past due 90 days or more delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		14,662	18,141
Past due 90 days or more delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		4,849	4,831
Past due 90 days or more delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		$ 9,813	$ 13,310
[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
[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 - I

Allowance for credit losses - Individually Evaluated Impaired Loans (Details) - Conventional Mortgage Loans [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired mortgage loans with no related allowance - Recorded Investment	$ 15,671		$ 15,671		$ 17,668
Individually evaluated impaired mortgage loans with no related allowance - Par Value	15,632		15,632		$ 17,630
Individually evaluated impaired mortgage loans with no related allowance - Average Recorded Investment	15,641	$ 18,645	16,226	$ 19,614
Individually evaluated impaired mortgage loans with no related allowance - Interest Income recognized	$ 116	$ 91	$ 334	$ 314

Allowance for credit losses - A

Allowance for credit losses - Allowance Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				$ 500
Provision (reduction of provision) for credit losses		$ 0	$ 28	6	$ (148)
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	650
Charge-offs, net of recoveries		0	(28)	(6)	(2)
Provision (reduction of provision) for credit losses		0	28	6	(148)
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]	15,671	18,786	15,671	18,786
Recorded Investment Collectively evaluated for impairment	[1]	$ 3,852,352	$ 3,562,789	$ 3,852,352	$ 3,562,789
[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 ($)		Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		$ 13,922,326,000	$ 15,810,012,000
Derivative Assets, before netting and collateral adjustments		17,949,000	56,238,000
Derivative Liabilities, before netting and collateral adjustments		(293,941,000)	(347,352,000)
Derivative Asset, netting adjustments and cash collateral including related accrued interest	[1],[2]	4,007,000	(21,452,000)
Derivative Liability, netting adjustments and cash collateral including related accrued interest	[1],[2]	65,814,000	46,902,000
Derivative assets		21,956,000	34,786,000
Derivative liabilities		(228,127,000)	(300,450,000)
Cash collateral and related accrued interest posted		71,500,000	25,800,000
Cash collateral and related accrued interest received		1,700,000	350,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		12,716,629,000	14,600,194,000
Derivative Assets, before netting and collateral adjustments		15,169,000	52,557,000
Derivative Liabilities, before netting and collateral adjustments		(292,325,000)	(342,637,000)
Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		12,340,429,000	14,118,994,000
Derivative Assets, before netting and collateral adjustments		15,169,000	52,557,000
Derivative Liabilities, before netting and collateral adjustments		(291,922,000)	(332,830,000)
Designated as Hedging Instrument [Member] | Forward-start interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		376,200,000	481,200,000
Derivative Assets, before netting and collateral adjustments		0	0
Derivative Liabilities, before netting and collateral adjustments		(403,000)	(9,807,000)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,205,697,000	1,209,818,000
Derivative Assets, before netting and collateral adjustments		2,780,000	3,681,000
Derivative Liabilities, before netting and collateral adjustments		(1,616,000)	(4,715,000)
Not Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,164,300,000	1,166,900,000
Derivative Assets, before netting and collateral adjustments		2,753,000	3,512,000
Derivative Liabilities, before netting and collateral adjustments		(1,536,000)	(4,688,000)
Mortgage-delivery commitments [Member] | Not Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	[3]	41,397,000	42,918,000
Derivative Assets, before netting and collateral adjustments	[3]	27,000	169,000
Derivative Liabilities, before netting and collateral adjustments	[3]	$ (80,000)	$ (27,000)
[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 $71.5 million and $25.8 million at September 30, 2018 , and December 31, 2017 , 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 $1.7 million and $350,000 at September 30, 2018 , and December 31, 2017 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income.

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities Derivatives in Statement of Income (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		$ 557	$ (876)	$ 2,140	$ (2,287)
Total net gains (losses) related to derivatives designated as hedging instruments		640	(894)	2,384	(2,074)
Total net gains related to derivatives not designated as hedging instruments		138	762	393	1,404
Other	[1]	(291)	126	(692)	282
Net gains (losses) on derivatives and hedging activities		487	(6)	2,085	(388)
Interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		557	(876)	2,140	(2,287)
Forward-start interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge ineffectiveness		83	(18)	244	213
Mortgage-delivery commitments [Member] | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		131	692	(336)	1,556
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		7	14	729	(208)
COs - bonds [Member] | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		$ 0	$ 56	$ 0	$ 56
[1]	Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount.

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Interest (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		$ 14,243	$ 16,407	$ 64,500	$ 47,375
(Loss)/Gain on Hedged Item		(13,686)	(17,283)	(62,360)	(49,662)
Net Fair-Value Hedge Ineffectiveness		557	(876)	2,140	(2,287)
Effect of Derivatives on Net Interest Income	[1]	782	(10,515)	(4,291)	(41,920)
Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		(1,975)	9,382	46,793	19,150
(Loss)/Gain on Hedged Item		1,667	(8,881)	(44,773)	(18,780)
Net Fair-Value Hedge Ineffectiveness		(308)	501	2,020	370
Effect of Derivatives on Net Interest Income	[1]	15,769	(2,878)	36,001	(24,566)
Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		19,287	5,007	68,878	8,412
(Loss)/Gain on Hedged Item		(18,832)	(4,503)	(67,270)	(7,047)
Net Fair-Value Hedge Ineffectiveness		455	504	1,608	1,365
Effect of Derivatives on Net Interest Income	[1]	(6,200)	(7,879)	(19,975)	(24,319)
COs - bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		(3,069)	2,018	(51,171)	19,813
(Loss)/Gain on Hedged Item		3,479	(3,899)	49,683	(23,835)
Net Fair-Value Hedge Ineffectiveness		410	(1,881)	(1,488)	(4,022)
Effect of Derivatives on Net Interest Income	[1]	$ (8,787)	$ 242	$ (20,317)	$ 6,965
[1]	The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item.

Derivatives and Hedging Activ_6

Derivatives and Hedging Activities Cash Flow Hedge Activity (Details) - COs - bonds [Member] - Interest-rate swaps [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Gains (Losses) Recognized in Other Comprehensive Loss on Derivatives (Effective Portion)	$ 2,985	$ (856)	$ 14,733	$ (5,937)
Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion)	(537)	(2,158)	(2,485)	(9,865)
Gains (Losses) Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion)	$ 83	$ (18)	$ 244	$ 213

Derivatives and Hedging Activ_7

Derivatives and Hedging Activities Narratives (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Derivative [Line Items]
Maximum length of time which we are hedging our exposure to the variability in future cash flows for forecasted transactions	3 years
Deferred net losses on derivative accumulated in other comprehensive loss expected to be reclassified to earnings during the next 12 months	$ 3,500
Aggregate fair value of all uncleared derivative instruments with credit-risk-related contingent features that were in a net liability position	276,800
Post-haircut value of collateral already posted	258,000
Rating Downgrade from AAPlus to AA or AAMinus [Member]
Derivative [Line Items]
Incremental collateral	1,142	[1]
Rating Downgrade From AAMinus to APlus, A or AMinus [Member]
Derivative [Line Items]
Incremental collateral	13,584	[1]
Rating Downgrade From AMinus to below AMinus [Member]
Derivative [Line Items]
Incremental collateral	$ 14,723	[1]
[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 ($)		Sep. 30, 2018		Dec. 31, 2017
Derivative [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	$ 4,007,000		$ (21,452,000)
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2]	65,814,000		46,902,000
Derivative assets		21,956,000		34,786,000
Derivative liabilities		(228,127,000)		(300,450,000)
Derivative Asset, Fair value, amount offset against collateral		21,956,000		34,786,000
Derivative Liability, Fair value, amount offset against collateral		(10,638,000)		(12,337,000)
Derivative Liabilities, additional net exposure, collateral pledged to counterparties in excess of net liabilities		220,000		502,000
Uncleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		17,319,000		15,587,000
Derivative Liability, total gross recognized amount		(292,034,000)		(335,289,000)
Derivative Assets, Netting Adjustments and Cash Collateral		(15,542,000)	[3]	(13,481,000)	[4]
Derivative liability, Netting Adjustments and Cash Collateral		63,987,000	[3]	34,866,000	[4]
Derivative assets		1,804,000		2,275,000
Derivative liabilities		(228,127,000)		(300,450,000)
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		10,809,000	[5]	7,627,000	[6]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		206,680,000	[5]	280,486,000	[6]
Derivative Asset, Fair value, amount offset against collateral		1,804,000		2,275,000
Derivative Liability, Fair value, amount offset against collateral		(10,638,000)		(12,337,000)
Uncleared derivatives [Member] | Mortgage-delivery commitments [Member] | Forward Contracts [Member]
Derivative [Line Items]
Derivative Asset, Mortgage delivery commitments		27,000		169,000
Derivative Liabilities, Mortgage delivery commitments		(80,000)		(27,000)
Cleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		603,000		40,482,000
Derivative Liability, total gross recognized amount		(1,828,000)		(12,036,000)
Derivative Assets, Netting Adjustments and Cash Collateral		19,549,000	[3]	(7,971,000)	[4]
Derivative liability, Netting Adjustments and Cash Collateral		1,828,000	[3]	12,036,000	[4]
Derivative assets		20,152,000		32,511,000
Derivative liabilities		0		0
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		0	[5]	0	[6]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Asset, Fair value, amount offset against collateral		20,152,000		32,511,000
Derivative Liability, Fair value, amount offset against collateral		$ 0		$ 0
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $71.5 million and $25.8 million at September 30, 2018 , and December 31, 2017 , 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 $1.7 million and $350,000 at September 30, 2018 , and December 31, 2017 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Includes gross amounts of netting adjustments and cash collateral.
[4]	Includes gross amounts of netting adjustments and cash collateral.
[5]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At September 30, 2018 , we had additional net credit exposure of $220,000
[6]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2017 , we had additional net credit exposure of $502,000

Deposits Narratives (Details)

Deposits Narratives (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Interest-bearing deposits demand and overnight	$ 460,636,000	$ 447,700,000
Interest-bearing deposits term	800,000	0
Interest-bearing deposits other	1,913,000	3,222,000
Noninterest-bearing deposits other	21,412,000	26,147,000
Total deposits	484,761,000	$ 477,069,000
Aggregate amount of time deposits with a denomination of $100,000 or more	$ 800,000

Consolidated Obligations CO Bon

Consolidated Obligations CO Bonds - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Schedule of Short-term and Long-term Debt [Line Items]
Due in one year or less		$ 10,123,250	$ 12,186,510
Due in one year or less, weighted average rate	[1]	1.80%	1.35%
Due after one year through two years		$ 6,283,295	$ 5,288,470
Due after one year through two years, weighted average rate	[1]	2.15%	1.63%
Due after two years through three years		$ 3,073,605	$ 3,128,240
Due after two years through three years, weighted average rate	[1]	2.19%	1.81%
Due after three years through four years		$ 2,395,865	$ 2,759,460
Due after three years through four years, weighted average rate	[1]	1.98%	1.74%
Due after four years through five years		$ 1,410,655	$ 1,572,775
Due after four years through five years, weighted average rate	[1]	2.30%	2.00%
Thereafter		$ 3,482,710	$ 3,389,695
Thereafter, weighted average rate	[1]	3.06%	2.76%
Total par value		$ 26,769,380	$ 28,325,150
Total par value, weighted average rate	[1]	2.13%	1.70%
Hedging adjustments		$ (105,360)	$ (55,678)
Total		26,741,036	28,344,623
COs - bonds [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Premiums		92,653	90,836
Discounts		$ (15,637)	$ (15,685)
[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	Sep. 30, 2018	Dec. 31, 2017
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 26,769,380	$ 28,325,150
Noncallable and nonputable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	21,867,380	23,931,150
Callable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 4,902,000	$ 4,394,000

Consolidated Obligations CO B_3

Consolidated Obligations CO Bonds - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Due in one year or less	$ 13,698,250	$ 15,309,510
Due after one year through two years	6,392,295	5,580,470
Due after two years through three years	2,491,605	3,020,240
Due after three years through four years	1,485,865	1,542,460
Due after four years through five years	1,140,655	1,107,775
Thereafter	1,560,710	1,764,695
Total par value	$ 26,769,380	$ 28,325,150

Consolidated Obligations CO B_4

Consolidated Obligations CO Bonds - Interest-Rate-Payment Type (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Fixed-rate	$ 20,954,380	$ 21,416,150
Simple variable-rate	3,983,000	5,432,000
Step-up	1,832,000	1,477,000
Total par value	$ 26,769,380	$ 28,325,150

Consolidated Obligations CO - D

Consolidated Obligations CO - Discount Notes (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Federal Home Loan Bank, Consolidated Obligations, Discount Notes		$ 33,431,980	$ 27,720,906
Par value		$ 33,501,223	$ 27,752,860
Weighted Average Rate	[1]	2.07%	1.25%
[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		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Affordable Housing Program [Roll Forward]
Balance at beginning of year			$ 81,600	$ 81,627	$ 81,627
AHP expense for the period	$ 7,238	$ 5,110	19,387	13,720	21,307
AHP direct grant disbursements			(13,384)	$ (16,217)	(18,628)
AHP subsidy for AHP advance disbursements			(3,707)		(2,782)
Return of previously disbursed grants and subsidies			86		76
Balance at end of period	$ 83,982		$ 83,982		$ 81,600

Capital Requirements (Details)

Capital Requirements (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Capital [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	$ 2,476,876	$ 2,283,721
Mandatorily redeemable capital stock	31,868	35,923
Retained earnings	1,386,466	1,308,349
Total permanent capital	3,895,210	3,627,993
Credit-risk capital	320,819	328,557
Market-risk capital	253,082	170,102
Operations-risk capital	172,170	149,598
Total risk-based capital requirement	746,071	648,257
Permanent capital in excess of risk-based capital requirement	3,149,139	2,979,736
Regulatory capital, Required	2,587,752	2,414,478
Leverage capital, Required	3,234,690	3,018,097
Risk-based capital, Actual	3,895,210	3,627,993
Regulatory capital, Actual	$ 3,895,210	$ 3,627,993
Capital-to-asset ratio, Actual	6.00%	6.00%
Leverage capital, Actual	$ 5,842,815	$ 5,441,990
Leverage capital-to-assets ratio, Actual	9.00%	9.00%

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended				9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2018		Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		$ 142,086,000		$ 109,052,000		$ 397,843,000		$ 311,395,000
Amortization of hedging activities recorded in net losses on derivatives and hedging activities		487,000		(6,000)		2,085,000		(388,000)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period						3,265,130,000		3,244,778,000
Total other comprehensive income (loss)		1,577,000		10,147,000		(16,073,000)		73,200,000
Period end		3,520,329,000		3,227,616,000		3,520,329,000		3,227,616,000
Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(26,733,000)		(45,554,000)		(40,436,000)		(48,187,000)
Net unrealized gains (losses)		2,985,000		(856,000)		14,733,000		(5,937,000)
Amortization - hedging activities		541,000	[1]	2,161,000	[2]	2,496,000	[3]	9,875,000	[4]
Total other comprehensive income (loss)		3,526,000		1,305,000		17,229,000		3,938,000
Period end		(23,207,000)		(44,249,000)		(23,207,000)		(44,249,000)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(6,740,000)		(5,530,000)		(5,955,000)		(6,139,000)
Net actuarial gain (loss)		(729,000)		112,000		(2,189,000)		336,000
Amortization - pension and postretirement benefits	[5]	337,000		193,000		1,012,000		578,000
Total other comprehensive income (loss)		(392,000)		305,000		(1,177,000)		914,000
Period end		(7,132,000)		(5,225,000)		(7,132,000)		(5,225,000)
Total Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(344,590,000)		(320,461,000)		(326,940,000)		(383,514,000)
Net unrealized gains (losses)		(5,705,000)		(917,000)		(39,547,000)		36,502,000
Accretion of noncredit loss		7,127,000		8,178,000		21,945,000		24,593,000
Net actuarial gain (loss)		(729,000)		112,000		(2,189,000)		336,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[6]	6,000		420,000		210,000		1,316,000
Amortization - hedging activities		541,000	[1]	2,161,000	[2]	2,496,000	[3]	9,875,000	[4]
Amortization - pension and postretirement benefits	[5]	337,000		193,000		1,012,000		578,000
Total other comprehensive income (loss)		1,577,000		10,147,000		(16,073,000)		73,200,000
Period end		(343,013,000)		(310,314,000)		(343,013,000)		(310,314,000)
Available-for-sale Securities [Member] | Net Unrealized Loss on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(167,921,000)		(94,309,000)		(122,331,000)		(136,809,000)
Net unrealized gains (losses)		(8,690,000)		(61,000)		(54,280,000)		42,439,000
Total other comprehensive income (loss)		(8,690,000)		(61,000)		(54,280,000)		42,439,000
Period end		(176,611,000)		(94,370,000)		(176,611,000)		(94,370,000)
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		(143,196,000)		(175,068,000)		(158,218,000)		(192,379,000)
Accretion of noncredit loss		7,127,000		8,178,000		21,945,000		24,593,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[6]	6,000		420,000		210,000		1,316,000
Total other comprehensive income (loss)		7,133,000		8,598,000		22,155,000		25,909,000
Period end		(136,063,000)		(166,470,000)		(136,063,000)		(166,470,000)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		537,000		2,200,000		2,500,000		9,900,000
Amortization of hedging activities recorded in net losses on derivatives and hedging activities		$ 4,000		$ 4,000		$ 11,000		$ 11,000
[1]	Amortization of hedging activities includes $537,000 recorded in CO bond interest expense and $4,000
[2]	Amortization of hedging activities includes $2.2 million recorded in CO bond interest expense and $4,000
[3]	Amortization of hedging activities includes $2.5 million recorded in CO bond interest expense and $11,000
[4]	Amortization of hedging activities includes $9.9 million recorded in CO bond interest expense and $11,000
[5]	Recorded in other non-interest expenses in the statement of operations.
[6]	Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations.

Fair Values Carrying Value and

Fair Values Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 45,614	$ 261,673
Trading securities		176,113	191,510
Available-for-sale securities Fair Value		6,227,080	7,324,736
Held-to-maturity securities	[1]	1,372,299	1,626,122
Held-to-maturity securities Fair Value		1,638,491	1,903,227
Loans to other FHLBanks		0	400,000
Accrued interest receivable		102,466	94,100
Derivative assets		21,956	34,786
Derivative Assets, Netting Adjustments and Cash Collateral	[2],[3]	4,007	(21,452)
Mandatorily redeemable capital stock		(31,868)	(35,923)
Accrued interest payable		(119,242)	(90,626)
Derivative liabilities		(228,127)	(300,450)
Derivative liability, Netting Adjustments and Cash Collateral	[2],[3]	65,814	46,902
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		45,614	261,673
Interest-bearing deposits		397,203	246
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
Loans to other FHLBanks	[5]		0
Accrued interest receivable		0	0
Derivative assets	[4]	0	0
Other assets	[4]	11,189	9,726
Deposits		0	0
Mandatorily redeemable capital stock		(31,868)	(35,923)
Accrued interest payable		0	0
Derivative liabilities	[4]	0	0
Level 1 [Member] | Commitments to extend credit 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		5,498,962	5,348,898
Federal funds sold		5,650,001	3,449,981
Trading securities	[4]	176,113	191,510
Available-for-sale securities Fair Value	[4]	6,186,743	7,287,053
Held-to-maturity securities Fair Value		671,526	811,759
Advances		40,880,159	37,591,048
Mortgage loans, net		4,056,143	4,013,704
Loans to other FHLBanks	[5]		399,997
Accrued interest receivable		102,466	94,100
Derivative assets	[4]	17,949	56,238
Other assets	[4]	14,847	12,625
Deposits		(484,750)	(477,060)
Mandatorily redeemable capital stock		0	0
Accrued interest payable		(119,242)	(90,626)
Derivative liabilities	[4]	(293,941)	(347,352)
Level 2 [Member] | Commitments to extend credit for advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(4,946)	(3,817)
Level 2 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,179)	(1,100)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(33,428,979)	(27,719,598)
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]	40,337	37,683
Held-to-maturity securities Fair Value		966,965	1,091,468
Advances		0	0
Mortgage loans, net		20,135	22,224
Loans to other FHLBanks	[5]		0
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 credit 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		45,614	261,673
Interest-bearing deposits		397,203	246
Securities purchased under agreements to resell		5,499,000	5,349,000
Federal funds sold		5,650,000	3,450,000
Trading securities	[4]	176,113	191,510
Available-for-sale securities Fair Value	[4]	6,227,080	7,324,736
Held-to-maturity securities		1,372,299	1,626,122
Advances		40,927,639	37,565,967
Mortgage loans, net		4,192,425	4,004,737
Loans to other FHLBanks	[5]		400,000
Accrued interest receivable		102,466	94,100
Derivative assets	[4]	21,956	34,786
Other assets	[4]	26,036	22,351
Deposits		(484,761)	(477,069)
Mandatorily redeemable capital stock		(31,868)	(35,923)
Accrued interest payable		(119,242)	(90,626)
Derivative liabilities	[4]	(228,127)	(300,450)
Carrying Value [Member] | Commitments to extend credit 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		(1,179)	(1,100)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(33,431,980)	(27,720,906)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		45,614	261,673
Interest-bearing deposits		397,203	246
Securities purchased under agreements to resell		5,498,962	5,348,898
Federal funds sold		5,650,001	3,449,981
Trading securities	[4]	176,113	191,510
Available-for-sale securities Fair Value	[4]	6,227,080	7,324,736
Held-to-maturity securities Fair Value		1,638,491	1,903,227
Advances		40,880,159	37,591,048
Mortgage loans, net		4,076,278	4,035,928
Loans to other FHLBanks	[5]		399,997
Accrued interest receivable		102,466	94,100
Derivative assets	[4]	21,956	34,786
Other assets	[4]	26,036	22,351
Deposits		(484,750)	(477,060)
Mandatorily redeemable capital stock		(31,868)	(35,923)
Accrued interest payable		(119,242)	(90,626)
Derivative liabilities	[4]	(228,127)	(300,450)
Total Fair Value [Member] | Commitments to extend credit for advances
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(4,946)	(3,817)
Total Fair Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,179)	(1,100)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(33,428,979)	(27,719,598)
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		(26,508,907)	(28,353,945)
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		(26,741,036)	(28,344,623)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (26,508,907)	$ (28,353,945)
[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]	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 $71.5 million and $25.8 million at September 30, 2018 , and December 31, 2017 , 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 $1.7 million and $350,000 at September 30, 2018 , and December 31, 2017 .
[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]	Carried at fair value and measured on a recurring basis.
[5]	The Fair Value Summary table for December 31, 2017, has been revised to correct the omission of Loans to Other FHLBanks. This revision had no impact on the Statements of Condition, Statements of Operations, or Statements of Cash Flows.

Fair Values Fair Value of Asset

Fair Values Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		$ 176,113	$ 191,510
Available-for-sale securities Fair Value		6,227,080	7,324,736
Derivative assets		21,956	34,786
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	4,007	(21,452)
Derivative liabilities		(228,127)	(300,450)
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2]	65,814	46,902
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	0	0
Available-for-sale securities Fair Value	[3]	0	0
Derivative assets	[3]	0	0
Other assets	[3]	11,189	9,726
Derivative liabilities	[3]	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	176,113	191,510
Available-for-sale securities Fair Value	[3]	6,186,743	7,287,053
Derivative assets	[3]	17,949	56,238
Other assets	[3]	14,847	12,625
Derivative liabilities	[3]	(293,941)	(347,352)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	0	0
Available-for-sale securities Fair Value	[3]	40,337	37,683
Derivative assets	[3]	0	0
Other assets	[3]	0	0
Derivative liabilities	[3]	0	0
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[2]	4,007	(21,452)
Derivative liability, Netting Adjustments and Cash Collateral	[2]	65,814	46,902
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	[2]	4,007	(21,452)
Derivative liability, Netting Adjustments and Cash Collateral	[2]	65,814	46,902
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		11,189	9,726
Total assets at fair value		11,189	9,726
Total liabilities 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		176,113	191,510
Available-for-sale securities Fair Value		6,186,743	7,287,053
Derivative assets		17,949	56,238
Other assets		14,847	12,625
Total assets at fair value		6,395,652	7,547,426
Total liabilities at fair value		(293,941)	(347,352)
Recurring [Member] | Level 2 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		17,922	56,069
Derivative liabilities		(293,861)	(347,325)
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		40,337	37,683
Derivative assets		0	0
Other assets		0	0
Total assets at fair value		40,337	37,683
Total liabilities 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
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	176,113	191,510
Available-for-sale securities Fair Value	[3]	6,227,080	7,324,736
Derivative assets	[3]	21,956	34,786
Other assets	[3]	26,036	22,351
Derivative liabilities	[3]	(228,127)	(300,450)
Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		176,113	191,510
Available-for-sale securities Fair Value		6,227,080	7,324,736
Derivative assets		21,956	34,786
Other assets		26,036	22,351
Total assets at fair value		6,451,185	7,573,383
Total liabilities at fair value		(228,127)	(300,450)
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		21,929	34,617
Derivative liabilities		(228,047)	(300,423)
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		6,774	0
Corporate bonds [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
Corporate bonds [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		6,774
Corporate bonds [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		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		6,774
U.S. government-guaranteed - single-family MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		5,684	6,807
Available-for-sale securities Fair Value		81,037	95,777
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		5,684	6,807
Available-for-sale securities Fair Value		81,037	95,777
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		5,684	6,807
Available-for-sale securities Fair Value		81,037	95,777
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		367,515	443,373
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		367,515	443,373
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		367,515	443,373
HFA securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		40,337	37,683
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		40,337	37,683
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		40,337	37,683
Supranational institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		395,178	418,285
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		395,178	418,285
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		395,178	418,285
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		268,624	292,077
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		268,624	292,077
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		268,624	292,077
GSEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		113,425	121,343
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		113,425	121,343
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		113,425	121,343
Single Family [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		180	346
Available-for-sale securities Fair Value		3,732,005	4,562,992
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		180	346
Available-for-sale securities Fair Value		3,732,005	4,562,992
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		180	346
Available-for-sale securities Fair Value		3,732,005	4,562,992
Multifamily [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		163,475	184,357
Available-for-sale securities Fair Value		1,228,959	1,353,206
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		163,475	184,357
Available-for-sale securities Fair Value		1,228,959	1,353,206
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		163,475	184,357
Available-for-sale securities Fair Value		1,228,959	1,353,206
Mortgage-delivery commitments [Member] | Recurring [Member] | Level 1 [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Mortgage-delivery commitments [Member] | Recurring [Member] | Level 2 [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		27	169
Derivative liabilities		(80)	(27)
Mortgage-delivery commitments [Member] | Recurring [Member] | Level 3 [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Mortgage-delivery commitments [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		27	169
Derivative liabilities		$ (80)	$ (27)
[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 $71.5 million and $25.8 million at September 30, 2018 , and December 31, 2017 , 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 $1.7 million and $350,000 at September 30, 2018 , and December 31, 2017 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Carried at fair value and measured on a recurring basis.

Estimated Fair Value Level 3 Re

Estimated Fair Value Level 3 Reconciliation - Roll Forward (Details) - Level 3 [Member] - Recurring [Member] - Available-for-sale Securities [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 37,600	$ 15,414	$ 37,683	$ 8,146
Purchases	3,150	3,520	3,150	11,120
Unrealized gains (losses) included in other comprehensive income	(413)	(391)	(496)	(723)
Balance at end of period	$ 40,337	$ 18,543	$ 40,337	$ 18,543

Fair Value of Assets Measured a

Fair Value of Assets Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		$ 1,638,491	$ 1,903,227
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
Mortgage loans held for portfolio		0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		671,526	811,759
Mortgage loans held for portfolio		4,056,143	4,013,704
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		966,965	1,091,468
Mortgage loans held for portfolio		20,135	22,224
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	0	0
REO	[1]	0	0
Total assets recorded at fair value on a nonrecurring basis	[1]	0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	0	0
REO	[1]	0	0
Total assets recorded at fair value on a nonrecurring basis	[1]	0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	1,122	4,608
REO	[1]	361	784
Total assets recorded at fair value on a nonrecurring basis	[1]	3,219	7,362
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		1,638,491	1,903,227
Mortgage loans held for portfolio		4,076,278	4,035,928
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	1,122	4,608
REO	[1]	361	784
Total assets recorded at fair value on a nonrecurring basis	[1]	3,219	7,362
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		839,005	951,898
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, 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	[1]	0	0
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, 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	[1]	0	0
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, 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	[1]	1,736	1,970
Residential Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[1]	$ 1,736	$ 1,970
[1]	The fair values presented are as of the date the fair value adjustment was recorded during the nine months ended September 30, 2018 , and year ended December 31, 2017

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($)		9 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Value of the guarantees related to standby letters of credit		$ 52,478,000	$ 45,619,000
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		$ 958,800,000,000	978,200,000,000
Standby Letters of Credit Issuance Commitments [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 29,300,000	1,400,000
Off-balance-sheet Commitments Expiring After One Year			543,000
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 outstanding [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[1]	$ 6,086,259,000	5,034,725,000
Off-balance-sheet Commitments Expiring After One Year	[1]	231,611,000	223,167,000
Total Off-balance Sheet Commitments	[1]	6,317,870,000	5,257,892,000
Value of the guarantees related to standby letters of credit		1,200,000	1,100,000
Commitments of unused lines of credit - advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[2]	1,213,453,000	1,216,592,000
Off-balance-sheet Commitments Expiring After One Year	[2]	0	0
Total Off-balance Sheet Commitments	[2]	$ 1,213,453,000	1,216,592,000
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		$ 20,880,000	18,851,000
Off-balance-sheet Commitments Expiring After One Year		37,527,000	63,488,000
Total Off-balance Sheet Commitments		58,407,000	82,339,000
Unsettled CO bonds, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		138,800,000	52,550,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		138,800,000	52,550,000
Mortgages [Member] | Commitments to invest in mortgage loans [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		41,397,000	42,918,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		$ 41,397,000	$ 42,918,000
[1]	The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At September 30, 2018 , and December 31, 2017 , these amounts totaled $ 29.3 million and $1.4 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $543,000 at December 31, 2017
[2]	Commitments for unused line-of-credit advances are generally for periods of up to 12 months

Transactions with Shareholder_2

Transactions with Shareholders (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Transactions with Shareholders [Line Items]
Capital Stock Outstanding		$ 2,476,876		$ 2,476,876		$ 2,283,721
Par Value of Advances	[1]	41,059,377		41,059,377		37,647,166
Total Accrued Interest Receivable		102,466		102,466		94,100
Interest income on advances		226,544	$ 136,462	618,077	$ 371,075
Fees on letters of credit		2,719	2,228	7,538	6,362
Citizens Bank, N.A. [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding		$ 354,645		$ 354,645		$ 227,287
Percent of Total Capital Stock Outstanding		14.10%		14.10%		9.80%
Par Value of Advances		$ 8,009,938		$ 8,009,938		$ 4,858,592
Percentage of Total Par Value of Advances		19.50%		19.50%		12.90%
Total Accrued Interest Receivable		$ 5,692		$ 5,692		$ 2,558
Percent of Total Accrued Interest Receivable on Advances		10.00%		10.00%		6.00%
Interest income on advances		$ 33,144	14,316	$ 89,228	46,968
Fees on letters of credit		1,257	$ 1,002	3,338	$ 2,448
Directors' Financial Institutions [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding		$ 106,932		$ 106,932		$ 114,498
Percent of Total Capital Stock Outstanding		4.30%		4.30%		4.90%
Par Value of Advances		$ 2,002,884		$ 2,002,884		$ 2,133,374
Percentage of Total Par Value of Advances		4.90%		4.90%		5.70%
Total Accrued Interest Receivable		$ 2,960		$ 2,960		$ 2,466
Percent of Total Accrued Interest Receivable on Advances		5.20%		5.20%		5.80%
Minimum [Member]
Transactions with Shareholders [Line Items]
Definition of shareholder concentration, minimum percent		10.00%		10.00%
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Subsequent Events (Details)

Subsequent Events (Details) - Common Class B [Member] - Subsequent Event [Member] - USD ($) $ in Millions	Nov. 02, 2018	Oct. 19, 2018
Subsequent Event [Line Items]
Annualized rate of cash dividend		5.87%
Dividend, including dividends on mandatorily redeemable capital stock	$ 35.6