Federal Home Loan Bank of Boston 10-Q 10 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 31, 2017
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
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	2,017
Document Fiscal Period Focus	Q2
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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		23,286,595

Statements of Condition (unaudi

Statements of Condition (unaudited) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
ASSETS
Cash and due from banks		$ 176,852	$ 520,031
Interest-bearing deposits		279,046	278
Securities purchased under agreements to resell		4,349,000	5,999,000
Federal funds sold		4,460,000	2,700,000
Investment securities:
Trading securities		514,313	612,622
Available-for-sale securities - includes $1,917 and $7,968 pledged as collateral at June 30, 2017, and December 31, 2016, respectively that may be repledged		6,641,796	6,588,664
Held-to-maturity securities - includes $9,945 and $23,618 pledged as collateral at June 30, 2017, and December 31, 2016, respectively that may be repledged	[1],[2]	1,898,097	2,130,767
Total investment securities		9,054,206	9,332,053
Advances		38,427,616	39,099,339
Mortgage loans held for portfolio, net of allowance for credit losses of $500 and $650 at June 30, 2017, and December 31, 2016, respectively		3,804,581	3,693,894
Accrued interest receivable		85,997	84,653
Premises, software, and equipment, net		5,940	5,211
Derivative assets, net		56,623	61,598
Other assets		54,386	49,529
Total Assets		60,754,247	61,545,586
Deposits
Interest-bearing		441,310	444,897
Non-interest-bearing		27,863	37,266
Total deposits		469,173	482,163
Consolidated obligations (COs):
Bonds		28,518,424	27,171,434
Discount notes		27,865,529	30,053,964
Total consolidated obligations		56,383,953	57,225,398
Mandatorily redeemable capital stock		37,380	32,687
Accrued interest payable		84,093	80,822
Affordable Housing Program (AHP) payable		78,344	81,627
Derivative liabilities, net		329,229	357,876
Other liabilities		38,564	40,235
Total liabilities		57,420,736	58,300,808
Commitments and contingencies (Note 18)
Capital
Capital stock – Class B – putable ($100 par value), 24,086 shares and 24,113 shares issued and outstanding at June 30, 2017, and December 31, 2016, respectively		2,408,647	2,411,306
Retained earnings:
Unrestricted		1,000,694	987,711
Restricted		244,631	229,275
Total retained earnings		1,245,325	1,216,986
Accumulated other comprehensive loss		(320,461)	(383,514)
Total capital		3,333,511	3,244,778
Total Liabilities and Capital		$ 60,754,247	$ 61,545,586
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 2,160,053 and $2,372,290 at June 30, 2017 , and December 31, 2016

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Available-for-sale securities pledged as collateral that may be repledged	$ 1,917	$ 7,968
Held-to-maturity securities pledged as collateral that may be repledged (a)	9,945	23,618
Allowance for credit losses	500	650
Fair value of held-to-maturity securities	$ 2,160,053	$ 2,372,290
Common Class B [Member]
Common Stock, Class B, putable shares issued	24,086	24,113
Common Stock, Class B, putable par value per share	$ 100	$ 100
Common Stock, Class B, putable shares outstanding	24,086	24,113

Statements of Operations (unaud

Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
INTEREST INCOME
Advances	$ 127,736	$ 81,011	$ 234,319	$ 159,230
Prepayment fees on advances, net	130	863	294	2,932
Securities purchased under agreements to resell	6,330	2,713	10,748	5,906
Federal funds sold	12,708	5,176	22,992	10,792
Investment securities:
Trading securities	2,757	2,205	5,310	4,441
Available-for-sale securities	22,872	23,170	47,536	48,315
Held-to-maturity securities	20,021	22,218	40,375	44,388
Prepayment fees on investments	16	6	81	331
Total investment securities	45,666	47,599	93,302	97,475
Mortgage loans held for portfolio	30,989	29,906	60,936	60,982
Other	668	136	727	243
Total interest income	224,227	167,404	423,318	337,560
Consolidated obligations:
Bonds	104,168	89,780	202,343	180,640
Discount notes	55,068	22,579	92,647	45,276
Total consolidated obligations	159,236	112,359	294,990	225,916
Deposits	788	146	1,290	261
Mandatorily redeemable capital stock	377	319	706	698
Other borrowings	6	1	8	2
Total interest expense	160,407	112,825	296,994	226,877
NET INTEREST INCOME	63,820	54,579	126,324	110,683
Reduction of provision for credit losses	(125)	(111)	(176)	(100)
NET INTEREST INCOME AFTER REDUCTION OF PROVISION FOR CREDIT LOSSES	63,945	54,690	126,500	110,783
OTHER INCOME (LOSS)
Total other-than-temporary impairment losses on investment securities	(37)	(643)	(90)	(1,085)
Net amount of impairment losses reclassified from accumulated other comprehensive loss	(531)	(360)	(896)	(1,265)
Net other-than-temporary impairment losses on investment securities, credit portion	(568)	(1,003)	(986)	(2,350)
Litigation settlements	0	19,584	0	19,584
Loss on early extinguishment of debt	0	(742)	0	(1,300)
Service fees	2,122	1,934	4,134	3,902
Net unrealized (losses) gains on trading securities	(852)	84	(2,266)	1,957
Net losses on derivatives and hedging activities	(418)	(2,963)	(382)	(9,198)
Other	168	(100)	(39)	(138)
Total other income	452	16,794	461	12,457
OTHER EXPENSE
Compensation and benefits	9,819	10,023	20,657	20,350
Other operating expenses	6,071	5,895	11,955	11,147
Federal Housing Finance Agency (the FHFA)	934	818	1,936	1,821
Office of Finance	745	726	1,587	1,542
Other	3,028	1,226	5,436	2,762
Total other expense	20,597	18,688	41,571	37,622
INCOME BEFORE ASSESSMENTS	43,800	52,796	85,390	85,618
AHP	4,418	5,312	8,610	8,632
NET INCOME	$ 39,382	$ 47,484	$ 76,780	$ 76,986

Statements of Comprehensive Inc

Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 39,382	$ 47,484	$ 76,780	$ 76,986
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent [Abstract]
Net unrealized gains on available-for-sale securities	15,594	27,941	42,500	79,771
Net noncredit portion of other-than-temporary impairment losses on held-to-maturity securities
Net amount of impairment losses reclassified to non-interest income	531	359	896	1,264
Accretion of noncredit portion	8,119	9,211	16,415	18,352
Total net noncredit portion of other-than-temporary impairment losses on held-to-maturity securities	8,650	9,570	17,311	19,616
Net unrealized (losses) gains relating to hedging activities
Unrealized losses	(4,943)	(9,731)	(5,081)	(26,770)
Reclassification adjustment for previously deferred hedging gains and losses included in net income	3,395	6,893	7,714	14,104
Total net unrealized (losses) gains relating to hedging activities	(1,548)	(2,838)	2,633	(12,666)
Pension and postretirement benefits	415	(2,585)	609	(2,466)
Total other comprehensive income	23,111	32,088	63,053	84,255
Comprehensive income	$ 62,493	$ 79,572	$ 139,833	$ 161,241

Statements of Capital (unaudite

Statements of Capital (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			$ 3,244,778	$ 3,022,913
Comprehensive income	$ 62,493	$ 79,572	139,833	161,241
Proceeds from sale of capital stock			523,765	225,813
Repurchase of capital stock			(517,754)	(208,737)
Shares reclassified to mandatorily redeemable capital stock			(8,670)	(40)
Cash dividends on capital stock			(48,441)	(40,677)
Period end	3,333,511	3,160,513	3,333,511	3,160,513
Retained Earnings, Unrestricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			987,711	934,214
Comprehensive income			61,424	61,589
Cash dividends on capital stock			(48,441)	(40,677)
Period end	1,000,694	955,126	1,000,694	955,126
Retained Earnings, Restricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			229,275	194,634
Comprehensive income			15,356	15,397
Period end	244,631	210,031	244,631	210,031
Retained Earnings, Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			1,216,986	1,128,848
Comprehensive income			76,780	76,986
Cash dividends on capital stock			(48,441)	(40,677)
Period end	1,245,325	1,165,157	1,245,325	1,165,157
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period			(383,514)	(442,597)
Comprehensive income			63,053	84,255
Period end	$ (320,461)	$ (358,342)	$ (320,461)	$ (358,342)
Common Class B [Member] | Capital Stock Class B - Putable
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period, shares			24,113	23,367
Beginning of period			$ 2,411,306	$ 2,336,662
Proceeds from sale of capital stock, shares			5,238	2,258
Proceeds from sale of capital stock			$ 523,765	$ 225,813
Repurchase of capital stock, shares			(5,178)	(2,087)
Repurchase of capital stock			$ (517,754)	$ (208,737)
Shares reclassified to mandatorily redeemable capital stock, shares			(87)	(1)
Shares reclassified to mandatorily redeemable capital stock			$ (8,670)	$ (40)
Period end, shares	24,086	23,537	24,086	23,537
Period end	$ 2,408,647	$ 2,353,698	$ 2,408,647	$ 2,353,698

Statements of Cash Flows (unaud

Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
OPERATING ACTIVITIES
Net income	$ 39,382	$ 47,484	$ 76,780	$ 76,986
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			737	(10,722)
Reduction of provision for credit losses	(125)	(111)	(176)	(100)
Change in net fair-value adjustments on derivatives and hedging activities			(2,207)	23,851
Net other-than-temporary impairment losses on investment securities, credit portion	568	1,003	986	2,350
Loss on early extinguishment of debt	0	742	0	1,300
Other adjustments			3,749	1,018
Net change in:
Market value of trading securities			2,266	(1,957)
Accrued interest receivable			(1,349)	1,447
Other assets			(2,875)	(15)
Accrued interest payable			3,271	(5,170)
Other liabilities			(4,273)	(2,278)
Total adjustments			129	9,724
Net cash provided by operating activities			76,909	86,710
INVESTING ACTIVITIES
Interest-bearing deposits			(262,731)	(150,602)
Securities purchased under agreements to resell			1,650,000	901,000
Federal funds sold			(1,760,000)	(1,720,000)
Premises, software, and equipment			(1,524)	(848)
Trading securities:
Proceeds			404,995	5,461
Purchases			(308,671)	0
Available-for-sale securities:
Proceeds from long-term			587,243	530,343
Purchases of long-term			(617,156)	(1,501,952)
Held-to-maturity securities:
Proceeds from long-term			263,081	294,084
Advances to members:
Proceeds			253,472,443	173,556,118
Disbursements			(252,817,444)	(175,623,844)
Mortgage loans held for portfolio:
Proceeds			223,635	248,017
Purchases			(339,310)	(300,648)
Proceeds from sale of foreclosed assets			1,711	3,078
Net cash provided by (used in) investing activities			496,272	(3,759,793)
FINANCING ACTIVITIES
Net change in deposits			(13,239)	151,644
Net payments on derivatives with a financing element			(3,388)	(6,707)
Net proceeds from issuance of consolidated obligations:
Discount notes			84,129,002	76,298,504
Bonds			5,376,043	9,716,022
Payments for maturing and retiring consolidated obligations:
Discount notes			(86,331,088)	(74,297,930)
Bonds			(4,027,290)	(7,998,206)
Proceeds from issuance of capital stock			523,765	225,813
Payments for redemption of mandatorily redeemable capital stock			(3,977)	(6,953)
Payments for repurchase of capital stock			(517,754)	(208,737)
Cash dividends paid			(48,434)	(40,677)
Net cash (used in) provided by financing activities			(916,360)	3,832,773
Net (decrease) increase in cash and due from banks			(343,179)	159,690
Cash and due from banks at beginning of the period			520,031	254,218	$ 254,218
Cash and due from banks at end of the period	$ 176,852	$ 413,908	176,852	413,908	520,031
Supplemental disclosures:
Interest paid			300,048	254,901
AHP payments			10,491	7,025	$ 18,575
Noncash transfers of mortgage loans held for portfolio to other assets			$ 1,230	$ 1,604

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation [Text Block]	Basis of Presentation

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies As of June 30, 2017 , we have not made any significant changes to the summary of significant accounting policies described in Item 8 — Financial Statements and Supplementary Data — Note 18 — Fair Values in the 2016 Annual Report other than described below.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	6 Months Ended
	Jun. 30, 2017
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 Premium Amortization on Purchased Callable Debt Securities. On March 30, 2017, the Financial Accounting Standards Board (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 early adoption is permitted. This guidance should be applied using a modified retrospective method through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Adoption of this guidance is not expected to have a material effect on our financial condition, results of operations, or cash flows. Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. On March 10, 2017, the 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 is effective for us for interim and annual periods beginning on January 1, 2018, and early adoption is permitted. This guidance should be applied retrospectively for the presentation of the service cost component and the other components of net periodic pension cost and net periodic postretirement benefit cost in the income statement and prospectively, on and after the effective date, for the capitalization of the service cost component of net periodic pension cost and net periodic postretirement benefit in assets. Adoption of this guidance is not expected to have a material effect on our financial condition, results of operations, or cash flows. 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, the following: • The statement of income reflects the measurement of credit losses for newly recognized financial assets, as well as the expected increases or decreases of expected credit losses that have taken place during the period. • Entities 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. • Entities 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. • Public entities further disaggregate the current disclosure of credit quality indicators in relation to the amortized cost of financing receivables by the year of origination. This guidance is effective for us for interim and annual periods beginning on January 1, 2020. Early application is permitted as of the interim and annual reporting periods beginning after December 15, 2018. This guidance is required to be applied using a modified-retrospective approach, through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. In addition, entities are required to use a prospective transition approach for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination and for debt securities for which an other-than-temporary impairment had been recognized before the effective date. We do not intend to adopt the new guidance early. While we are in the process of evaluating this guidance, we expect the adoption of the guidance will result in an increase in the allowance for credit losses given the requirement to assess losses for the entire estimated life of the financial asset. The effect on our financial condition, results of operations, and cash flows will depend upon the composition of our financial assets held at the adoption date as well as the economic conditions and forecasts at that time. Contingent Put and Call Options in Debt Instruments. On March 14, 2016, the FASB issued amendments to clarify the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. Specifically, the updated guidance clarifies what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts, which is one of the criteria for bifurcating an embedded derivative. Consequently, when a call (put) option is contingently exercisable, an entity does not have to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. We adopted this guidance on January 1, 2017. The adoption of this guidance did not have any effect on our financial condition, results of operations, or cash flows. 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 includes, but is not limited to, the following: • Requires equity investments (with certain exceptions) to be measured at fair value with changes in fair value recognized in net income; • Requires an entity to 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 the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; • Requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the statement of condition or the accompanying notes to the financial statements; and • Eliminates the requirement for public entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the statement of condition. This guidance becomes effective for us for the interim and annual periods beginning on January 1, 2018, and early adoption is only permitted for certain provisions. The amendments, in general, are required to be applied by means of a cumulative-effect adjustment on the statement of condition as of the beginning of the period of adoption. We do not invest in equity securities and we have not previously elected the fair value option for our own debt securities. Accordingly, adoption of this guidance is not

Trading Securities

Trading Securities	6 Months Ended
	Jun. 30, 2017
Trading Securities [Abstract]
Trading Securities (and Certain Trading Assets) Disclosure [Text Block]	Trading Securities Major Security Types . Our trading securities as of June 30, 2017 , and December 31, 2016 , were (dollars in thousands): June 30, 2017 December 31, 2016 U.S. Treasury obligations $ 309,332 $ 399,521 Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 7,634 8,494 Government-sponsored enterprise (GSE)s – single-family 534 768 GSEs – multifamily 196,813 203,839 204,981 213,101 Total $ 514,313 $ 612,622 Net unrealized losses or gains on trading securities for the six months ended June 30, 2017 , and 2016 , amounted to net losses of $2.3 million and net gains of $2.0 million for securities held on June 30, 2017 , and 2016 , respectively.

Available-for-Sale Securities

Available-for-Sale Securities	6 Months Ended
	Jun. 30, 2017
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Disclosure [Text Block]	Available-for-Sale Securities Major Security Types . Our available-for-sale securities as of June 30, 2017 , were (dollars in thousands): 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) $ 16,950 $ — $ (1,536 ) $ 15,414 Supranational institutions 448,953 — (26,775 ) 422,178 U.S. government-owned corporations 318,140 — (32,368 ) 285,772 GSEs 130,770 — (10,417 ) 120,353 914,813 — (71,096 ) 843,717 MBS U.S. government guaranteed – single-family 112,759 55 (2,367 ) 110,447 U.S. government guaranteed – multifamily 493,695 — (2,458 ) 491,237 GSEs – single-family 4,169,847 6,711 (27,861 ) 4,148,697 GSEs – multifamily 1,044,991 3,882 (1,175 ) 1,047,698 5,821,292 10,648 (33,861 ) 5,798,079 Total $ 6,736,105 $ 10,648 $ (104,957 ) $ 6,641,796 _______________________ (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. Our available-for-sale securities as of December 31, 2016 , were (dollars in thousands): Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 9,350 $ — $ (1,204 ) $ 8,146 Supranational institutions 452,021 — (29,401 ) 422,620 U.S. government-owned corporations 317,588 — (45,631 ) 271,957 GSEs 130,798 — (13,330 ) 117,468 909,757 — (89,566 ) 820,191 MBS U.S. government guaranteed – single-family 127,032 16 (2,321 ) 124,727 U.S. government guaranteed – multifamily 565,593 45 (2,277 ) 563,361 GSEs – single-family 4,447,803 1,765 (45,713 ) 4,403,855 GSEs – multifamily 675,288 1,242 — 676,530 5,815,716 3,068 (50,311 ) 5,768,473 Total $ 6,725,473 $ 3,068 $ (139,877 ) $ 6,588,664 _______________________ (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. The following table summarizes our available-for-sale securities with unrealized losses as of June 30, 2017 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands): Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 15,414 $ (1,536 ) $ — $ — $ 15,414 $ (1,536 ) Supranational institutions — — 422,178 (26,775 ) 422,178 (26,775 ) U.S. government-owned corporations — — 285,772 (32,368 ) 285,772 (32,368 ) GSEs — — 120,353 (10,417 ) 120,353 (10,417 ) 15,414 (1,536 ) 828,303 (69,560 ) 843,717 (71,096 ) MBS U.S. government guaranteed – single-family — — 81,466 (2,367 ) 81,466 (2,367 ) U.S. government guaranteed – multifamily 353,041 (1,479 ) 138,196 (979 ) 491,237 (2,458 ) GSEs – single-family 2,777,084 (21,541 ) 361,515 (6,320 ) 3,138,599 (27,861 ) GSEs – multifamily 394,996 (1,175 ) — — 394,996 (1,175 ) 3,525,121 (24,195 ) 581,177 (9,666 ) 4,106,298 (33,861 ) Total temporarily impaired $ 3,540,535 $ (25,731 ) $ 1,409,480 $ (79,226 ) $ 4,950,015 $ (104,957 ) The following table summarizes our available-for-sale securities with unrealized losses as of December 31, 2016 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands): Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 8,146 $ (1,204 ) $ — $ — $ 8,146 $ (1,204 ) Supranational institutions — — 422,620 (29,401 ) 422,620 (29,401 ) U.S. government-owned corporations — — 271,957 (45,631 ) 271,957 (45,631 ) GSEs — — 117,468 (13,330 ) 117,468 (13,330 ) 8,146 (1,204 ) 812,045 (88,362 ) 820,191 (89,566 ) MBS U.S. government guaranteed – single-family 31,606 (4 ) 90,854 (2,317 ) 122,460 (2,321 ) U.S. government guaranteed – multifamily 326,126 (1,261 ) 165,246 (1,016 ) 491,372 (2,277 ) GSEs – single-family 3,517,094 (39,181 ) 351,331 (6,532 ) 3,868,425 (45,713 ) 3,874,826 (40,446 ) 607,431 (9,865 ) 4,482,257 (50,311 ) Total temporarily impaired $ 3,882,972 $ (41,650 ) $ 1,419,476 $ (98,227 ) $ 5,302,448 $ (139,877 ) Redemption Terms. The amortized cost and fair value of our available-for-sale securities by contractual maturity at June 30, 2017 , and December 31, 2016 , were (dollars in thousands): June 30, 2017 December 31, 2016 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ — $ — $ — $ — Due after one year through five years 16,950 15,414 9,350 8,146 Due after five years through 10 years 170,161 159,254 171,589 161,746 Due after 10 years 727,702 669,049 728,818 650,299 914,813 843,717 909,757 820,191 MBS (1) 5,821,292 5,798,079 5,815,716 5,768,473 Total $ 6,736,105 $ 6,641,796 $ 6,725,473 $ 6,588,664 _______________________ (1)

Held-to-Maturity Securities

Held-to-Maturity Securities	6 Months Ended
	Jun. 30, 2017
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity Securities Disclosure [Text Block]	Held-to-Maturity Securities Major Security Types . Our held-to-maturity securities as of June 30, 2017 , were (dollars in thousands): 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 $ 1,602 $ — $ 1,602 $ 29 $ — $ 1,631 HFA securities 159,689 — 159,689 10 (15,856 ) 143,843 161,291 — 161,291 39 (15,856 ) 145,474 MBS U.S. government guaranteed – single-family 11,427 — 11,427 243 — 11,670 U.S. government guaranteed – multifamily 800 — 800 — (1 ) 799 GSEs – single-family 678,107 — 678,107 14,115 (292 ) 691,930 GSEs – multifamily 295,130 — 295,130 10,271 — 305,401 Private-label – residential 913,841 (174,537 ) 739,304 259,043 (5,702 ) 992,645 Asset-backed securities (ABS) backed by home equity loans 12,568 (530 ) 12,038 581 (485 ) 12,134 1,911,873 (175,067 ) 1,736,806 284,253 (6,480 ) 2,014,579 Total $ 2,073,164 $ (175,067 ) $ 1,898,097 $ 284,292 $ (22,336 ) $ 2,160,053 Our held-to-maturity securities as of December 31, 2016 , were (dollars in thousands): 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 $ 2,159 $ — $ 2,159 $ 56 $ — $ 2,215 HFA securities 162,568 — 162,568 11 (19,291 ) 143,288 164,727 — 164,727 67 (19,291 ) 145,503 MBS U.S. government guaranteed – single-family 12,719 — 12,719 246 — 12,965 U.S. government guaranteed – multifamily 1,532 — 1,532 — — 1,532 GSEs – single-family 812,836 — 812,836 16,881 (519 ) 829,198 GSEs – multifamily 318,667 — 318,667 11,692 — 330,359 Private-label – residential 999,149 (191,804 ) 807,345 240,818 (8,373 ) 1,039,790 ABS backed by home equity loans 13,515 (574 ) 12,941 602 (600 ) 12,943 2,158,418 (192,378 ) 1,966,040 270,239 (9,492 ) 2,226,787 Total $ 2,323,145 $ (192,378 ) $ 2,130,767 $ 270,306 $ (28,783 ) $ 2,372,290 The following table summarizes our held-to-maturity securities with unrealized losses as of June 30, 2017 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands). Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 141,514 $ (15,856 ) $ 141,514 $ (15,856 ) MBS U.S. government guaranteed - multifamily 799 (1 ) — — 799 (1 ) GSEs – single-family 15,928 (191 ) 17,590 (101 ) 33,518 (292 ) Private-label – residential — — 284,674 (15,614 ) 284,674 (15,614 ) ABS backed by home equity loans — — 11,143 (601 ) 11,143 (601 ) 16,727 (192 ) 313,407 (16,316 ) 330,134 (16,508 ) Total $ 16,727 $ (192 ) $ 454,921 $ (32,172 ) $ 471,648 $ (32,364 ) The following table summarizes our held-to-maturity securities with unrealized losses as of December 31, 2016 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands). Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 140,959 $ (19,291 ) $ 140,959 $ (19,291 ) MBS GSEs – single-family 83,291 (393 ) 13,405 (126 ) 96,696 (519 ) Private-label – residential 16,915 (128 ) 397,407 (28,781 ) 414,322 (28,909 ) ABS backed by home equity loans — — 11,898 (720 ) 11,898 (720 ) 100,206 (521 ) 422,710 (29,627 ) 522,916 (30,148 ) Total $ 100,206 $ (521 ) $ 563,669 $ (48,918 ) $ 663,875 $ (49,439 ) Redemption Terms. The amortized cost, carrying value, and fair value of our held-to-maturity securities by contractual maturity at June 30, 2017 , and December 31, 2016 , are shown below (dollars in thousands). Expected maturities of some securities and MBS may 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. June 30, 2017 December 31, 2016 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 109 $ 109 $ 111 $ — $ — $ — Due after one year through five years 15,972 15,972 15,974 16,637 16,637 16,663 Due after five years through 10 years — — — — — — Due after 10 years 145,210 145,210 129,389 148,090 148,090 128,840 161,291 161,291 145,474 164,727 164,727 145,503 MBS (2) 1,911,873 1,736,806 2,014,579 2,158,418 1,966,040 2,226,787 Total $ 2,073,164 $ 1,898,097 $ 2,160,053 $ 2,323,145 $ 2,130,767 $ 2,372,290 _______________________ (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	6 Months Ended
	Jun. 30, 2017
Other than Temporary Impairment Losses, Investments [Abstract]
Other-than-Temporary Impairment [Text Block]	Other-Than-Temporary Impairment We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter. Available-for-Sale Securities We determined that none of our available-for-sale securities were other-than-temporarily impaired at June 30, 2017 . At June 30, 2017 , 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 June 30, 2017 . Private-Label Residential MBS and ABS Backed by Home Equity Loans. For those securities for which a credit loss was recognized during the six months ended June 30, 2017 , the following table 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 (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) $ 66,522 8.4 % 26.8 % 35.5 % 11.1 % _______________________ (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. The following table sets forth our securities for which other-than-temporary impairment credit losses were recognized during the life of the security through June 30, 2017 (dollars in thousands). Securities are classified in the table below based on their classifications at the time of issuance. June 30, 2017 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 34,924 $ 30,001 $ 23,642 $ 31,335 Private-label residential MBS – Alt-A 1,018,372 753,997 585,819 837,054 ABS backed by home equity loans – Subprime 3,556 3,259 2,729 3,310 Total other-than-temporarily impaired securities $ 1,056,852 $ 787,257 $ 612,190 $ 871,699 _______________________ (1) 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. The following table 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 (dollars in thousands). For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 Balance at beginning of period $ 482,221 $ 525,809 $ 490,404 $ 533,888 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 568 1,003 986 2,350 Reductions: Securities matured during the period (2) (5,565 ) — (5,565 ) — Increase in cash flows expected to be collected which are recognized over the remaining life of the security (3) (8,518 ) (9,890 ) (17,119 ) (19,316 ) Balance at end of period $ 468,706 $ 516,922 $ 468,706 $ 516,922 _______________________ (1) For the three months ended June 30, 2017 and 2016 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to April 1, 2017 and 2016 , respectively. For the six months ended June 30, 2017 and 2016 , 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, 2017 and 2016 , respectively. (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. (3)

Advances

Advances	6 Months Ended
	Jun. 30, 2017
Advances [Abstract]
Federal Home Loan Bank, Advances [Text Block]	Advances General Terms. At both June 30, 2017 , and December 31, 2016 , we had advances outstanding with interest rates ranging from zero percent to 7.72 percent as summarized below (dollars in thousands). June 30, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 3,046 1.45 % $ 3,780 0.92 % Due in one year or less 20,369,559 1.35 18,783,802 1.05 Due after one year through two years 8,740,980 1.50 10,966,780 1.15 Due after two years through three years 3,005,963 1.78 2,508,459 1.67 Due after three years through four years 2,034,081 1.75 2,177,432 1.64 Due after four years through five years 1,931,339 1.97 2,041,269 1.80 Thereafter 2,375,221 1.81 2,633,333 1.70 Total par value 38,460,189 1.50 % 39,114,855 1.23 % Premiums 19,735 22,633 Discounts (30,900 ) (25,847 ) Fair value of bifurcated derivatives (1) 640 (153 ) Hedging adjustments (22,048 ) (12,149 ) Total $ 38,427,616 $ 39,099,339 _________________________ (1) At June 30, 2017 , and December 31, 2016 , we had certain advances with embedded features that met the requirements to be separated from the host contract and designated as stand-alone derivatives. At June 30, 2017 , and December 31, 2016 , we had callable advances and floating-rate advances that may be prepaid on a floating-rate reset date without prepayment or termination fees outstanding totaling $ 5.7 billion and $7.9 billion , respectively. The following table sets forth our advances outstanding by the year of contractual maturity or next call date for callable advances (dollars in thousands): Year of Contractual Maturity or Next Call Date (1) , Par Value June 30, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 3,046 $ 3,780 Due in one year or less 25,883,734 26,447,977 Due after one year through two years 3,627,980 3,693,780 Due after two years through three years 3,005,963 2,508,459 Due after three years through four years 1,848,881 2,002,232 Due after four years through five years 1,769,339 1,891,269 Thereafter 2,321,246 2,567,358 Total par value $ 38,460,189 $ 39,114,855 _______________________ (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. At June 30, 2017 , and December 31, 2016 , we had putable advances outstanding totaling $ 2.6 billion and $3.4 billion , respectively. The following table sets forth our advances outstanding by the year of contractual maturity or next put date for putable advances (dollars in thousands): Year of Contractual Maturity or Next Put Date, Par Value June 30, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 3,046 $ 3,780 Due in one year or less 22,092,559 20,788,552 Due after one year through two years 8,946,230 10,946,530 Due after two years through three years 2,922,963 2,455,709 Due after three years through four years 1,847,081 1,974,932 Due after four years through five years 1,631,339 1,736,769 Thereafter 1,016,971 1,208,583 Total par value $ 38,460,189 $ 39,114,855 Interest-Rate-Payment Terms. The following table details interest-rate-payment types for our outstanding advances (dollars in thousands): Par value of advances June 30, 2017 December 31, 2016 Fixed-rate $ 32,303,868 $ 30,526,192 Variable-rate 6,156,321 8,588,663 Total par value $ 38,460,189 $ 39,114,855 Credit-Risk Exposure and Security Terms . At June 30, 2017 , and December 31, 2016 , we had $12.2 billion and $16.2 billion , respectively, of advances issued to members with at least $1.0 billion of advances outstanding. These advances were made to five borrowers and six borrowers, respectively, as of June 30, 2017 , and December 31, 2016 , representing 31.7 percent and 41.5 percent

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	6 Months Ended
	Jun. 30, 2017
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 ® (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 by the related entity that sold the loan (a participating financial institution), as is the case with conventional mortgage loans. All such investments are held for portfolio. The following table presents certain characteristics of these investments (dollars in thousands): June 30, 2017 December 31, 2016 Real estate Fixed-rate 15-year single-family mortgages $ 500,527 $ 528,486 Fixed-rate 20- and 30-year single-family mortgages 3,235,321 3,098,476 Premiums 68,395 67,523 Discounts (1,613 ) (1,696 ) Deferred derivative gains, net 2,451 1,755 Total mortgage loans held for portfolio 3,805,081 3,694,544 Less: allowance for credit losses (500 ) (650 ) Total mortgage loans, net of allowance for credit losses $ 3,804,581 $ 3,693,894 The following table details the par value of mortgage loans held for portfolio (dollars in thousands): June 30, 2017 December 31, 2016 Conventional mortgage loans $ 3,357,891 $ 3,235,835 Government mortgage loans 377,957 391,127 Total par value $ 3,735,848 $ 3,626,962 See Note 10 — Allowance for Credit Losses for information related to our credit risk from our investments in mortgage loans and allowance for credit losses based on these investments.

Allowance for Credit Losses

Allowance for Credit Losses	6 Months Ended
	Jun. 30, 2017
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 2016 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, an ongoing review of each borrower's financial condition, and collateral and lending policies that are intended to limit risk of loss while balancing borrowers' needs for a reliable source of funding. At June 30, 2017 , and December 31, 2016 , 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 six months ended June 30, 2017 and 2016 . Based upon the collateral held as security, our credit extension and collateral policies, management's credit analysis, and the repayment history on secured member credit products, we have not recorded any allowance for credit losses on our secured member credit products at June 30, 2017 , and December 31, 2016 . At June 30, 2017 , and December 31, 2016 , no liability to reflect an allowance for credit losses for off-balance-sheet credit exposures was recorded. See Note 18 — Commitments and Contingencies for additional information on our off-balance-sheet credit exposure. For additional information see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2016 Annual Report. Government Mortgage Loans Held for Portfolio Based on our assessment of our servicers for our government loans, there is no allowance for credit losses for the government mortgage loan portfolio as of June 30, 2017 , and December 31, 2016 . In addition, 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 2016 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 2016 Annual Report. Credit Quality Indicators. Key credit quality indicators for mortgage loans include the migration of past due loans, nonaccrual loans, loans in process of foreclosure, and impaired loans. The tables below set forth certain key credit quality indicators for our investments in mortgage loans at June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 23,951 $ 11,324 $ 35,275 Past due 60-89 days delinquent 6,401 3,642 10,043 Past due 90 days or more delinquent 12,727 4,985 17,712 Total past due 43,079 19,951 63,030 Total current loans 3,392,655 368,309 3,760,964 Total mortgage loans $ 3,435,734 $ 388,260 $ 3,823,994 Other delinquency statistics In process of foreclosure, included above (1) $ 6,031 $ 1,297 $ 7,328 Serious delinquency rate (2) 0.39 % 1.28 % 0.48 % Past due 90 days or more still accruing interest $ — $ 4,985 $ 4,985 Loans on nonaccrual status (3) $ 13,006 $ — $ 13,006 _______________________ (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, 2016 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 26,757 $ 14,878 $ 41,635 Past due 60-89 days delinquent 5,508 3,846 9,354 Past due 90 days or more delinquent 16,379 5,807 22,186 Total past due 48,644 24,531 73,175 Total current loans 3,262,671 377,438 3,640,109 Total mortgage loans $ 3,311,315 $ 401,969 $ 3,713,284 Other delinquency statistics In process of foreclosure, included above (1) $ 7,495 $ 1,502 $ 8,997 Serious delinquency rate (2) 0.53 % 1.44 % 0.63 % Past due 90 days or more still accruing interest $ — $ 5,807 $ 5,807 Loans on nonaccrual status (3) $ 16,940 $ — $ 16,940 _______________________ (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. For information on how we collectively and individually evaluate mortgage loans for impairment see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2016 Annual Report. Individually Evaluated Impaired Loans. The following tables present the recorded investment, par value and any related allowance for impaired loans individually assessed for impairment at June 30, 2017 , and December 31, 2016 , and the average recorded investment and interest income recognized on these loans during the three and six months ended June 30, 2017 and 2016 (dollars in thousands). As of June 30, 2017 As of December 31, 2016 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 18,709 $ 18,672 $ 22,945 $ 22,905 For the Three Months Ended June 30, 2017 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 19,367 $ 107 $ 24,770 $ 102 For the Six Months Ended June 30, 2017 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 20,324 $ 223 $ 25,217 $ 182 Credit Enhancements. Our allowance for credit losses factors in the credit enhancements associated with conventional mortgage loans under the MPF program. These credit enhancements apply after the homeowner's equity is exhausted and can include primary and/or supplemental mortgage insurance or other kinds of credit enhancement. The credit-enhancement amounts estimated to protect us against credit losses are determined through the use of a model. Any incurred losses that would be recovered from the credit enhancements are not reserved as part of our allowance for loan losses. In such cases, a receivable is generally established to reflect the expected recovery from credit-enhancement arrangements. Previously, conventional mortgage loans were required to be credit enhanced so that the risk of loss was limited to the losses equivalent to an investment in a double-A rated MBS at the time of purchase. The FHFA final rule on acquired member assets (AMA) went into effect on January 18, 2017, allowing each FHLBank to utilize its own model to determine the credit enhancement for AMA loan assets and pool loans in lieu of a nationally recognized statistical ratings organization (NRSRO) ratings model. Upon effectiveness of the final AMA rule, we determined that assets delivered to us must be credit enhanced at our determined “AMA investment grade” of a double-A rated MBS. In March 2017, we determined that assets delivered to us must be credit enhanced at our revised determination of “AMA investment grade” of a single-A-minus rated MBS. This revision had no impact on the June 30, 2017 , allowance for credit losses. We share the risk of credit losses on our investments in mortgage loans with the related participating financial institution by structuring potential losses on these investments into layers with respect to each master commitment. We analyze the risk characteristics of our mortgage loans using a third-party model to determine the credit enhancement amount at the time of purchase. This credit-enhancement amount is broken into a first-loss account and a credit-enhancement obligation of each participating financial institution, which may be calculated based on the risk analysis to equal the difference between the amounts needed for the master commitment to have a rating equivalent to a single-A-minus rated MBS and our initial first-loss account exposure. Roll-Forward of Allowance for Credit Losses on Mortgage Loans. The following table presents a roll-forward of the allowance for credit losses on conventional mortgage loans for the three and six months ended June 30, 2017 and 2016 , as well as the recorded investment in mortgage loans by impairment methodology at June 30, 2017 and 2016 (dollars in thousands). 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. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 Allowance for credit losses Balance, beginning of period $ 625 $ 1,025 $ 650 $ 1,025 Recoveries (charge-offs) — (14 ) 26 (25 ) Reduction of provision for credit losses (125 ) (111 ) (176 ) (100 ) Balance, end of period $ 500 $ 900 $ 500 $ 900 Ending balance, individually evaluated for impairment $ — $ — $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 900 $ 500 $ 900 Recorded investment, end of period (1) Individually evaluated for impairment $ 18,709 $ 24,583 $ 18,709 $ 24,583 Collectively evaluated for impairment $ 3,417,025 $ 3,208,989 $ 3,417,025 $ 3,208,989 _________________________ (1)

Derivatives and Hedging Activit

Derivatives and Hedging Activities	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities The following table presents the notional amount and fair value of derivatives (excluding fair value adjustments related to variation margin for daily settled contracts) and total derivatives assets and liabilities. Total derivative asset and liabilities include the effect of netting adjustments, cash collateral, and variation margin for daily settled contracts as of June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 16,212,840 $ 41,631 $ (369,601 ) $ 18,215,809 $ 52,715 $ (413,026 ) Forward-start interest-rate swaps 527,800 — (41,099 ) 527,800 — (36,250 ) Total derivatives designated as hedging instruments 16,740,640 41,631 (410,700 ) 18,743,609 52,715 (449,276 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,050,900 1,132 (8,589 ) 1,199,000 2,293 (10,840 ) Mortgage-delivery commitments (1) 71,314 99 (197 ) 22,524 70 (171 ) Total derivatives not designated as hedging instruments 1,122,214 1,231 (8,786 ) 1,221,524 2,363 (11,011 ) Total notional amount of derivatives $ 17,862,854 $ 19,965,133 Total derivatives before netting and collateral adjustments 42,862 (419,486 ) 55,078 (460,287 ) Netting adjustments, cash collateral, and variation margin for daily settled contracts including related accrued interest (2) 13,761 90,257 6,520 102,411 Derivative assets and derivative liabilities $ 56,623 $ (329,229 ) $ 61,598 $ (357,876 ) _______________________ (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 $62.0 million and $109.8 million at June 30, 2017 , and December 31, 2016 , 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 $601,000 and $850,000 at June 30, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $42.6 million at June 30, 2017 . Net (losses) gains on derivatives and hedging activities recorded in Other Income (Loss) for the three and six months ended June 30, 2017 and 2016 , were as follows (dollars in thousands): For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 Derivatives designated as hedging instruments Interest-rate swaps $ (752 ) $ (2,218 ) $ (1,411 ) $ (5,251 ) Forward-start interest-rate swaps 97 (190 ) 231 (536 ) Total net losses related to derivatives designated as hedging instruments (655 ) (2,408 ) (1,180 ) (5,787 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps (375 ) (1,245 ) (222 ) (4,717 ) Mortgage-delivery commitments 507 690 864 1,306 Total net gains (losses) related to derivatives not designated as hedging instruments 132 (555 ) 642 (3,411 ) Other (1) 105 — 156 — Net losses on derivatives and hedging activities $ (418 ) $ (2,963 ) $ (382 ) $ (9,198 ) ______________ (1) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount. The following tables present, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair-value hedge relationships and the impact of those derivatives on our net interest income for the three and six months ended June 30, 2017 and 2016 (dollars in thousands): For the Three Months Ended June 30, 2017 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (11,327 ) $ 10,554 $ (773 ) $ (8,283 ) Investments (6,863 ) 7,264 401 (8,099 ) COs – bonds 17,719 (18,099 ) (380 ) 2,082 Total $ (471 ) $ (281 ) $ (752 ) $ (14,300 ) For the Three Months Ended June 30, 2016 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (25,621 ) $ 24,655 $ (966 ) $ (26,128 ) Investments (26,830 ) 27,186 356 (8,883 ) COs – bonds 564 (2,172 ) (1,608 ) 7,158 Total $ (51,887 ) $ 49,669 $ (2,218 ) $ (27,853 ) For the Six Months Ended June 30, 2017 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 9,768 $ (9,899 ) $ (131 ) $ (21,688 ) Investments 3,405 (2,544 ) 861 (16,440 ) COs – bonds 17,795 (19,936 ) (2,141 ) 6,723 Total $ 30,968 $ (32,379 ) $ (1,411 ) $ (31,405 ) For the Six Months Ended June 30, 2016 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (94,077 ) $ 92,888 $ (1,189 ) $ (56,252 ) Investments (76,285 ) 77,025 740 (17,894 ) COs – bonds 10,831 (15,633 ) (4,802 ) 15,230 Total $ (159,531 ) $ 154,280 $ (5,251 ) $ (58,916 ) ______________ (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. The following table presents the losses recognized in accumulated other comprehensive loss, the losses reclassified from accumulated other comprehensive loss into income, and the effect of our hedging activities on our net losses on derivatives and hedging activities in the statement of income for our forward-start interest-rate swaps associated with hedged CO bonds in cash-flow hedge relationships (dollars in thousands). Derivatives and Hedged Items in Cash Flow Hedging Relationships 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) Interest-rate swaps - CO bonds For the Three Months Ended June 30, 2017 $ (4,943 ) Interest expense $ (3,392 ) $ 97 For the Three Months Ended June 30, 2016 (9,731 ) Interest expense (6,889 ) (190 ) For the Six Months Ended June 30, 2017 (5,081 ) Interest expense (7,707 ) 231 For the Six Months Ended June 30, 2016 (26,770 ) Interest expense (14,097 ) (536 ) For the six months ended June 30, 2017 and 2016 , there were no reclassifications from accumulated other comprehensive loss into earnings as a result of the discontinuance of cash-flow hedges because the original forecasted transactions were not expected to occur by the end of the originally specified time period or within a two-month period thereafter. As of June 30, 2017 , the maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions is seven years . As of June 30, 2017 , 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 $4.9 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 Investors Services (Moody's) or Standard & Poor's Rating Service (S&P) to a certain level, we are required to deliver additional collateral on uncleared derivatives in a net liability position. In the event of a split between such credit ratings, the lower rating governs. The aggregate fair value of all uncleared derivatives with these provisions that were in a net-liability position (before cash collateral and related accrued interest) at June 30, 2017 , was $351.4 million for which we had delivered collateral with a post-haircut value of $326.5 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. The following table sets forth the post-haircut value of incremental collateral that certain uncleared derivatives counterparties could have required us to deliver in case of an incremental credit rating downgrades at June 30, 2017 . Post Haircut Value of Incremental Collateral to be Delivered as of June 30, 2017 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 9,858 AA- A+, A or A- 6,250 A- below A- 22,670 _______________________ (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. 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. Effective January 3, 2017, CME Clearing made certain amendments to its rulebook, changing the legal characterization of variation margin payments to be daily settlement payments, rather than collateral. We continue to characterize our variation margin related to LCH Ltd. contracts as cash collateral. At both DCOs, initial margin is 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. 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. For cleared derivatives, the DCO determines initial margin requirements. We clear our trades via clearing members of the DCOs. The clearing members who act as our agent to the DCOs are U.S. Commodity Futures Trading Commission (the CFTC) registered futures commission merchants. Our clearing members may require us to post margin in excess of DCO requirements based on our credit or other considerations, including but not limited to, credit rating downgrades. We were not required to post any such excess margin by our clearing members based on credit considerations at June 30, 2017 . 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. The following table presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of June 30, 2017 , and December 31, 2016 and the fair value of derivatives that are not subject to such netting (dollars in thousands). Such netting includes any related cash collateral received from or pledged to counterparties and variation margin for daily settled contracts. June 30, 2017 December 31, 2016 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Derivatives meeting netting requirements Gross recognized amount Uncleared derivatives $ 9,168 $ (359,879 ) $ 12,594 $ (405,310 ) Cleared derivatives 33,595 (59,410 ) 42,414 (54,806 ) Total gross recognized amount 42,763 (419,289 ) 55,008 (460,116 ) Gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives (8,377 ) 30,847 (12,028 ) 47,605 Cleared derivatives 22,138 59,410 18,548 54,806 Total gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts 13,761 90,257 6,520 102,411 Net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives 791 (329,032 ) 566 (357,705 ) Cleared derivatives 55,733 — 60,962 — Total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts 56,524 (329,032 ) 61,528 (357,705 ) Derivatives not meeting netting requirements Mortgage delivery commitments 99 (197 ) 70 (171 ) Total derivative assets and total derivative liabilities Uncleared derivatives 791 (329,032 ) 566 (357,705 ) Cleared derivatives 55,733 — 60,962 — Mortgage delivery commitments 99 (197 ) 70 (171 ) Total derivative assets and total derivative liabilities presented in the statement of condition 56,623 (329,229 ) 61,598 (357,876 ) Non-cash collateral received or pledged not offset (1) Can be sold or repledged Uncleared derivatives — 11,933 — 30,306 Cannot be sold or repledged Uncleared derivatives — 297,802 — 290,444 Total non-cash collateral received or pledged, not offset — 309,735 — 320,750 Net amount Uncleared derivatives 791 (19,297 ) 566 (36,955 ) Cleared derivatives 55,733 — 60,962 — Mortgage delivery commitments 99 (197 ) 70 (171 ) Total net amount $ 56,623 $ (19,494 ) $ 61,598 $ (37,126 ) _______________________ (1) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At June 30, 2017 , and December 31, 2016 , we had additional net credit exposure of $118,000 and $2.0 million

Deposits

Deposits	6 Months Ended
	Jun. 30, 2017
Deposits [Abstract]
Deposits [Text Block]	Deposits We offer demand and overnight deposits for members and qualifying nonmembers. In addition, we offer short-term interest-bearing deposit programs to members. We classify these items as "other" in the following table. The following table details interest- and noninterest-bearing deposits (dollars in thousands): June 30, 2017 December 31, 2016 Interest-bearing Demand and overnight $ 436,800 $ 440,731 Other 4,510 4,166 Noninterest-bearing Other 27,863 37,266 Total deposits $ 469,173 $ 482,163

Consolidated Obligations

Consolidated Obligations	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Consolidated Obligations [Text Block]	Consolidated Obligations COs - Bonds. The following table sets forth the outstanding CO bonds for which we were primarily liable at June 30, 2017 , and December 31, 2016 , by year of contractual maturity (dollars in thousands): June 30, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 12,230,385 1.33 % $ 8,734,955 1.43 % Due after one year through two years 6,320,065 1.36 7,752,420 1.19 Due after two years through three years 3,080,645 1.86 3,297,120 1.63 Due after three years through four years 1,817,190 1.79 1,637,335 1.87 Due after four years through five years 1,965,545 1.77 2,574,375 1.65 Thereafter 3,060,590 2.70 3,135,745 2.70 Total par value 28,474,420 1.60 % 27,131,950 1.58 % Premiums 101,843 118,145 Discounts (14,020 ) (14,906 ) Hedging adjustments (43,819 ) (63,755 ) $ 28,518,424 $ 27,171,434 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Our CO bonds outstanding at June 30, 2017 , and December 31, 2016 , included (dollars in thousands): June 30, 2017 December 31, 2016 Par value of CO bonds Noncallable and nonputable $ 24,456,420 $ 22,388,950 Callable 4,018,000 4,743,000 Total par value $ 28,474,420 $ 27,131,950 The following is a summary of the CO bonds for which we were primarily liable at June 30, 2017 , and December 31, 2016 , by year of contractual maturity or next call date for callable CO bonds (dollars in thousands): Year of Contractual Maturity or Next Call Date June 30, 2017 December 31, 2016 Due in one year or less $ 15,325,385 $ 12,858,955 Due after one year through two years 6,170,065 7,013,420 Due after two years through three years 2,952,645 2,904,120 Due after three years through four years 1,254,190 1,289,335 Due after four years through five years 1,003,545 1,242,375 Thereafter 1,768,590 1,823,745 Total par value $ 28,474,420 $ 27,131,950 The following table sets forth the CO bonds for which we were primarily liable by interest-rate-payment type at June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Par value of CO bonds Fixed-rate $ 20,357,420 $ 20,289,950 Simple variable-rate 6,665,000 5,300,000 Step-up 1,452,000 1,542,000 Total par value $ 28,474,420 $ 27,131,950 COs – Discount Notes. Outstanding CO discount notes for which we were primarily liable, all of which are due within one year, were as follows (dollars in thousands): Book Value Par Value Weighted Average Rate (1) June 30, 2017 $ 27,865,529 $ 27,892,943 0.95 % December 31, 2016 $ 30,053,964 $ 30,070,103 0.47 % _______________________ (1)

Affordable Housing Program

Affordable Housing Program	6 Months Ended
	Jun. 30, 2017
Affordable Housing Program [Abstract]
Affordable Housing Program [Text Block]	Affordable Housing Program The following table presents a roll-forward of the AHP liability for the six months ended June 30, 2017 , and year ended December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Balance at beginning of period $ 81,627 $ 82,081 AHP expense for the period 8,610 19,397 AHP direct grant disbursements (10,491 ) (18,575 ) AHP subsidy for AHP advance disbursements (1,416 ) (1,378 ) Return of previously disbursed grants and subsidies 14 102 Balance at end of period $ 78,344 $ 81,627

Capital

Capital	6 Months Ended
	Jun. 30, 2017
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. The following tables demonstrate our compliance with our regulatory capital requirements at June 30, 2017 , and December 31, 2016 (dollars in thousands): Risk-Based Capital Requirements June 30, December 31, Permanent capital Class B capital stock $ 2,408,647 $ 2,411,306 Mandatorily redeemable capital stock 37,380 32,687 Retained earnings 1,245,325 1,216,986 Total permanent capital $ 3,691,352 $ 3,660,979 Risk-based capital requirement Credit-risk capital $ 344,501 $ 355,182 Market-risk capital 152,177 118,765 Operations-risk capital 149,003 142,184 Total risk-based capital requirement $ 645,681 $ 616,131 Permanent capital in excess of risk-based capital requirement $ 3,045,671 $ 3,044,848 June 30, 2017 December 31, 2016 Required Actual Required Actual Capital Ratio Risk-based capital $ 645,681 $ 3,691,352 $ 616,131 $ 3,660,979 Total regulatory capital $ 2,430,170 $ 3,691,352 $ 2,461,823 $ 3,660,979 Total capital-to-asset ratio 4.0 % 6.1 % 4.0 % 5.9 % Leverage Ratio Leverage capital $ 3,037,712 $ 5,537,028 $ 3,077,279 $ 5,491,469 Leverage capital-to-assets ratio 5.0 % 9.1 % 5.0 % 8.9 %

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2017
AOCI Attributable to Parent [Abstract]
Accumulated Other Comprehensive Loss [Text Block]	Accumulated Other Comprehensive Loss The following table presents a summary of changes in accumulated other comprehensive loss for the three and six months ended June 30, 2017 and 2016 (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, March 31, 2016 $ (85,888 ) $ (219,739 ) $ (81,065 ) $ (3,738 ) $ (390,430 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 27,941 — (9,731 ) — 18,210 Noncredit other-than-temporary impairment losses — (420 ) — — (420 ) Accretion of noncredit loss — 9,211 — — 9,211 Net actuarial loss — — — (2,918 ) (2,918 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 779 — — 779 Amortization - hedging activities (2) — — 6,893 — 6,893 Amortization - pension and postretirement benefits (3) — — — 333 333 Other comprehensive income (loss) 27,941 9,570 (2,838 ) (2,585 ) 32,088 Balance, June 30, 2016 $ (57,947 ) $ (210,169 ) $ (83,903 ) $ (6,323 ) $ (358,342 ) Balance, March 31, 2017 $ (109,903 ) $ (183,718 ) $ (44,006 ) $ (5,945 ) $ (343,572 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 15,594 — (4,943 ) — 10,651 Accretion of noncredit loss — 8,119 — — 8,119 Net actuarial gain — — — 224 224 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 531 — — 531 Amortization - hedging activities (4) — — 3,395 — 3,395 Amortization - pension and postretirement benefits (3) — — — 191 191 Other comprehensive income (loss) 15,594 8,650 (1,548 ) 415 23,111 Balance, June 30, 2017 $ (94,309 ) $ (175,068 ) $ (45,554 ) $ (5,530 ) $ (320,461 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to (from) accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $6.9 million recorded in CO bond interest expense and $4,000 recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Amortization of hedging activities includes $3.4 million recorded in CO bond interest expense and $4,000 recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. 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, 2015 $ (137,718 ) $ (229,785 ) $ (71,237 ) $ (3,857 ) $ (442,597 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 79,771 — (26,770 ) — 53,001 Noncredit other-than-temporary impairment losses — (656 ) — — (656 ) Accretion of noncredit loss — 18,352 — — 18,352 Net actuarial loss — — — (2,917 ) (2,917 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 1,920 — — 1,920 Amortization - hedging activities (2) — — 14,104 — 14,104 Amortization - pension and postretirement benefits (3) — — — 451 451 Other comprehensive income (loss) 79,771 19,616 (12,666 ) (2,466 ) 84,255 Balance, June 30, 2016 $ (57,947 ) $ (210,169 ) $ (83,903 ) $ (6,323 ) $ (358,342 ) Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 42,500 — (5,081 ) — 37,419 Accretion of noncredit loss — 16,415 — — 16,415 Net actuarial gain — — — 224 224 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 896 — — 896 Amortization - hedging activities (4) — — 7,714 — 7,714 Amortization - pension and postretirement benefits (3) — — — 385 385 Other comprehensive income 42,500 17,311 2,633 609 63,053 Balance, June 30, 2017 $ (94,309 ) $ (175,068 ) $ (45,554 ) $ (5,530 ) $ (320,461 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to (from) accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $14.1 million recorded in CO bond interest expense and $7,000 recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Amortization of hedging activities includes $7.7 million recorded in CO bond interest expense and $7,000

Fair Values

Fair Values	6 Months Ended
	Jun. 30, 2017
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 2016 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 six months ended June 30, 2017 . The carrying values, fair values, and fair-value hierarchy of our financial instruments at June 30, 2017 , and December 31, 2016 , were as follows (dollars in thousands). These fair values do not represent an estimate of our overall market value as a going concern, which would take into account, among other things, our future business opportunities and the net profitability of our assets and liabilities. June 30, 2017 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral Financial instruments Assets: Cash and due from banks $ 176,852 $ 176,852 $ 176,852 $ — $ — $ — Interest-bearing deposits 279,046 279,046 279,046 — — — Securities purchased under agreements to resell 4,349,000 4,348,852 — 4,348,852 — — Federal funds sold 4,460,000 4,459,941 — 4,459,941 — — Trading securities (1) 514,313 514,313 — 514,313 — — Available-for-sale securities (1) 6,641,796 6,641,796 — 6,626,382 15,414 — Held-to-maturity securities 1,898,097 2,160,053 — 1,011,431 1,148,622 — Advances 38,427,616 38,572,842 — 38,572,842 — — Mortgage loans, net 3,804,581 3,848,195 — 3,824,845 23,350 — Accrued interest receivable 85,997 85,997 — 85,997 — — Derivative assets (1) 56,623 56,623 — 42,862 — 13,761 Other assets (1) 21,703 21,703 10,336 11,367 — — Liabilities: Deposits (469,173 ) (469,169 ) — (469,169 ) — — COs: Bonds (28,518,424 ) (28,645,061 ) — (28,645,061 ) — — Discount notes (27,865,529 ) (27,864,927 ) — (27,864,927 ) — — Mandatorily redeemable capital stock (37,380 ) (37,380 ) (37,380 ) — — — Accrued interest payable (84,093 ) (84,093 ) — (84,093 ) — — Derivative liabilities (1) (329,229 ) (329,229 ) — (419,486 ) — 90,257 Other: Commitments to extend credit for advances — (4,377 ) — (4,377 ) — — Standby letters of credit (763 ) (763 ) — (763 ) — — _______________________ (1) Carried at fair value on a recurring basis. December 31, 2016 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral Financial instruments Assets: Cash and due from banks $ 520,031 $ 520,031 $ 520,031 $ — $ — $ — Interest-bearing deposits 278 278 278 — — — Securities purchased under agreements to resell 5,999,000 5,998,799 — 5,998,799 — — Federal funds sold 2,700,000 2,699,949 — 2,699,949 — — Trading securities (1) 612,622 612,622 — 612,622 — — Available-for-sale securities (1) 6,588,664 6,588,664 — 6,580,518 8,146 — Held-to-maturity securities 2,130,767 2,372,290 — 1,176,269 1,196,021 — Advances 39,099,339 39,273,044 — 39,273,044 — — Mortgage loans, net 3,693,894 3,736,548 — 3,708,123 28,425 — Accrued interest receivable 84,653 84,653 — 84,653 — — Derivative assets (1) 61,598 61,598 — 55,078 — 6,520 Other assets (1) 17,779 17,779 8,394 9,385 — — Liabilities: Deposits (482,163 ) (482,158 ) — (482,158 ) — — COs: Bonds (27,171,434 ) (27,298,499 ) — (27,298,499 ) — — Discount notes (30,053,964 ) (30,054,085 ) — (30,054,085 ) — — Mandatorily redeemable capital stock (32,687 ) (32,687 ) (32,687 ) — — — Accrued interest payable (80,822 ) (80,822 ) — (80,822 ) — — Derivative liabilities (1) (357,876 ) (357,876 ) — (460,287 ) — 102,411 Other: Commitments to extend credit for advances — (4,412 ) — (4,412 ) — — Standby letters of credit (1,064 ) (1,064 ) — (1,064 ) — — _______________________ (1) Carried at fair value on a recurring basis. Fair Value Measured on a Recurring Basis. The following tables present our assets and liabilities that are measured at fair value on the statement of condition, which are recorded on a recurring basis at June 30, 2017 , and December 31, 2016 , by fair-value hierarchy level (dollars in thousands): June 30, 2017 Level 1 Level 2 Level 3 Netting Adjustment (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 309,332 $ — $ — $ 309,332 U.S. government-guaranteed – single-family MBS — 7,634 — — 7,634 GSEs – single-family MBS — 534 — — 534 GSEs – multifamily MBS — 196,813 — — 196,813 Total trading securities — 514,313 — — 514,313 Available-for-sale securities: State or local HFA securities — — 15,414 — 15,414 Supranational institutions — 422,178 — — 422,178 U.S. government-owned corporations — 285,772 — — 285,772 GSEs — 120,353 — — 120,353 U.S. government guaranteed – single-family MBS — 110,447 — — 110,447 U.S. government guaranteed – multifamily MBS — 491,237 — — 491,237 GSEs – single-family MBS — 4,148,697 — — 4,148,697 GSEs – multifamily MBS — 1,047,698 — — 1,047,698 Total available-for-sale securities — 6,626,382 15,414 — 6,641,796 Derivative assets: Interest-rate-exchange agreements — 42,763 — 13,761 56,524 Mortgage delivery commitments — 99 — — 99 Total derivative assets — 42,862 — 13,761 56,623 Other assets 10,336 11,367 — — 21,703 Total assets at fair value $ 10,336 $ 7,194,924 $ 15,414 $ 13,761 $ 7,234,435 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (419,289 ) $ — $ 90,257 $ (329,032 ) Mortgage delivery commitments — (197 ) — — (197 ) Total liabilities at fair value $ — $ (419,486 ) $ — $ 90,257 $ (329,229 ) _______________________ (1) These amounts represent the application of the netting requirements which 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, 2016 Level 1 Level 2 Level 3 Netting Adjustment (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 399,521 $ — $ — $ 399,521 U.S. government-guaranteed – single-family MBS — 8,494 — — 8,494 GSEs – single-family MBS — 768 — — 768 GSEs – multifamily MBS — 203,839 — — 203,839 Total trading securities — 612,622 — — 612,622 Available-for-sale securities: State or local HFA securities — — 8,146 — 8,146 Supranational institutions — 422,620 — — 422,620 U.S. government-owned corporations — 271,957 — — 271,957 GSEs — 117,468 — — 117,468 U.S. government guaranteed – single-family MBS — 124,727 — — 124,727 U.S. government guaranteed – multifamily MBS — 563,361 — — 563,361 GSEs – single-family MBS — 4,403,855 — — 4,403,855 GSEs – multifamily MBS — 676,530 — — 676,530 Total available-for-sale securities — 6,580,518 8,146 — 6,588,664 Derivative assets: Interest-rate-exchange agreements — 55,008 — 6,520 61,528 Mortgage delivery commitments — 70 — — 70 Total derivative assets — 55,078 — 6,520 61,598 Other assets 8,394 9,385 — — 17,779 Total assets at fair value $ 8,394 $ 7,257,603 $ 8,146 $ 6,520 $ 7,280,663 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (460,116 ) $ — $ 102,411 $ (357,705 ) Mortgage delivery commitments — (171 ) — — (171 ) Total liabilities at fair value $ — $ (460,287 ) $ — $ 102,411 $ (357,876 ) _______________________ (1) These amounts represent the application of the netting requirements which 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. The following table presents a reconciliation of available-for-sale securities that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the three and six months ended June 30, 2017 . There were no Level 3 available-for-sale securities during the six months ended June 30, 2016 (dollars in thousands). For the Three Months Ended For the Six Months Ended June 30, 2017 June 30, 2017 Balance at beginning of period $ 8,184 $ 8,146 Purchases 7,600 7,600 Unrealized losses included in other comprehensive income (370 ) (332 ) Balance at end of period $ 15,414 $ 15,414 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). The following tables present financial assets by level within the fair-value hierarchy which were recorded at fair value on a nonrecurring basis. The fair values presented are as of the date the fair value adjustment was recorded (dollars in thousands). June 30, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 2,077 $ 2,077 Mortgage loans held for portfolio — — 4,745 4,745 REO — — 654 654 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 7,476 $ 7,476 December 31, 2016 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 8,498 $ 8,498 Mortgage loans held for portfolio — — 5,618 5,618 REO — — 786 786 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 14,902 $ 14,902

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies Joint and Several Liability. COs are backed by the financial resources of the FHLBanks. The FHFA has authority to require any FHLBank to repay all or a portion of the principal and interest on COs for which another FHLBank is the primary obligor. No FHLBank has ever been asked or required to repay the principal or interest on any CO on behalf of another FHLBank. We evaluate the financial condition of the other FHLBanks primarily based on known regulatory actions, publicly available financial information, and individual long-term credit-rating action as of each period-end presented. Based on this evaluation, as of June 30, 2017 , and through the filing of this report, we believe there is a remote likelihood that we will be required to repay the principal or interest on any CO on behalf of another FHLBank. We have considered applicable FASB guidance and determined it is not necessary to recognize a liability for the fair value of our joint and several liability for all of the COs. The joint and several obligation is mandated by the FHLBank Act, as implemented by FHFA regulations, and is not the result of an arms-length transaction among the FHLBanks. The FHLBanks have no control over the amount of the guaranty or the determination of how each FHLBank would perform under the joint and several obligation. Because the FHLBanks are subject to the authority of the FHFA as it relates to decisions involving the allocation of the joint and several liability for the FHLBanks' COs, the FHLBanks' joint and several obligation is excluded from the initial recognition and measurement provisions. Accordingly, we have not recognized a liability for our joint and several obligation related to other FHLBanks' COs at June 30, 2017 , and December 31, 2016 . The par amounts of other FHLBanks' outstanding COs for which we are jointly and severally liable totaled $ 955.2 billion and $932.1 billion at June 30, 2017 , and December 31, 2016 , respectively. See Note 13 — Consolidated Obligations for additional information. Off-Balance-Sheet Commitments The following table sets forth our off-balance-sheet commitments as of June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 4,042,006 $ 205,432 $ 4,247,438 $ 4,050,447 $ 179,632 $ 4,230,079 Commitments for unused lines of credit - advances (2) 1,274,172 — 1,274,172 1,255,140 — 1,255,140 Commitments to make additional advances 151,874 54,241 206,115 44,865 65,972 110,837 Commitments to invest in mortgage loans 71,314 — 71,314 22,524 — 22,524 Unsettled CO bonds, at par 107,745 — 107,745 — — — __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At June 30, 2017 , and December 31, 2016 , these amounts totaled $ 7.3 million and $2.7 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $285,000 at December 31, 2016 . (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. A standby letter of credit is a financing arrangement pursuant to which we agree for a fee to fund the associated obligation to a third-party beneficiary should the primary obligor fail to fund such obligation. 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. The original terms of these standby letters of credit have original expiration periods of up to 20 years , currently expiring no later than 2026 . Our unearned fees for the value of the guarantees related to standby letters of credit are recorded in other liabilities and totaled $763,000 and $1.1 million at June 30, 2017 , and December 31, 2016 , respectively. Commitments to Invest in Mortgage Loans. Commitments to invest in mortgage loans are generally for periods not to exceed 45 business days. Such commitments are recorded as derivatives at their fair values on the statement of condition. Pledged Collateral. We have pledged securities, as collateral, related to derivatives. See Note 11 — Derivatives and Hedging Activities for additional information about our pledged collateral and other credit-risk-related contingent features. Legal Proceedings

Transactions with Shareholders

Transactions with Shareholders	6 Months Ended
	Jun. 30, 2017
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. The following tables present transactions with shareholders whose holdings of capital stock exceed 10 percent or more of total capital stock outstanding at June 30, 2017 , and December 31, 2016 (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 June 30, 2017 Citizens Bank, N.A. $ 245,034 10.0 % $ 5,108,880 13.3 % $ 1,661 4.4 % As of December 31, 2016 Citizens Bank, N.A. $ 357,508 14.6 % $ 7,260,446 18.6 % $ 2,625 7.3 % We held sufficient collateral to support the advances to the above institution such that we do not expect to incur any credit losses on these advances. We recognized interest income on outstanding advances and fees on letters of credit from Citizens Bank, N.A. during the three and six months ended June 30, 2017 and 2016 , as follows (dollars in thousands): For the Three Months Ended June 30, For the Six Months Ended June 30, Citizens Bank, N.A. 2017 2016 2017 2016 Interest income on advances $ 18,541 $ 8,082 $ 32,652 $ 16,286 Fees on letters of credit 701 779 1,446 1,619 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. The following table 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 (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 June 30, 2017 $ 78,430 3.2 % $ 1,416,338 3.7 % $ 1,541 4.1 % As of December 31, 2016 91,374 3.7 1,554,753 4.0 1,631 4.5

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On July 21, 2017 , the board of directors declared a cash dividend at an annualized rate of 4.22 percent based on capital stock balances outstanding during the second quarter of 2017. The dividend, including dividends on mandatorily redeemable capital stock, amounted to $26.0 million and was paid on August 2, 2017

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
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 derivatives clearing organizations (DCOs), for all cleared derivative transactions, Chicago Mercantile Exchange, Inc. (CME Inc.) and LCH Limited (LCH Ltd.). Effective January 3, 2017, CME Inc. made certain amendments to its rulebook changing the legal characterization of variation margin payments to be daily settlement payments, rather than collateral transfers. We continue to characterize our variation margin related at LCH Ltd. contracts as cash collateral. At both DCOs, initial margin is 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-
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)	6 Months Ended
	Jun. 30, 2017
Trading Securities [Abstract]
Trading Securities by Major Security Type [Table Text Block]	Our trading securities as of June 30, 2017 , and December 31, 2016 , were (dollars in thousands): June 30, 2017 December 31, 2016 U.S. Treasury obligations $ 309,332 $ 399,521 Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 7,634 8,494 Government-sponsored enterprise (GSE)s – single-family 534 768 GSEs – multifamily 196,813 203,839 204,981 213,101 Total $ 514,313 $ 612,622

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	6 Months Ended
	Jun. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale (AFS) Securities by Major Security Type [Table Text Block]	Our available-for-sale securities as of June 30, 2017 , were (dollars in thousands): 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) $ 16,950 $ — $ (1,536 ) $ 15,414 Supranational institutions 448,953 — (26,775 ) 422,178 U.S. government-owned corporations 318,140 — (32,368 ) 285,772 GSEs 130,770 — (10,417 ) 120,353 914,813 — (71,096 ) 843,717 MBS U.S. government guaranteed – single-family 112,759 55 (2,367 ) 110,447 U.S. government guaranteed – multifamily 493,695 — (2,458 ) 491,237 GSEs – single-family 4,169,847 6,711 (27,861 ) 4,148,697 GSEs – multifamily 1,044,991 3,882 (1,175 ) 1,047,698 5,821,292 10,648 (33,861 ) 5,798,079 Total $ 6,736,105 $ 10,648 $ (104,957 ) $ 6,641,796 _______________________ (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. Our available-for-sale securities as of December 31, 2016 , were (dollars in thousands): Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 9,350 $ — $ (1,204 ) $ 8,146 Supranational institutions 452,021 — (29,401 ) 422,620 U.S. government-owned corporations 317,588 — (45,631 ) 271,957 GSEs 130,798 — (13,330 ) 117,468 909,757 — (89,566 ) 820,191 MBS U.S. government guaranteed – single-family 127,032 16 (2,321 ) 124,727 U.S. government guaranteed – multifamily 565,593 45 (2,277 ) 563,361 GSEs – single-family 4,447,803 1,765 (45,713 ) 4,403,855 GSEs – multifamily 675,288 1,242 — 676,530 5,815,716 3,068 (50,311 ) 5,768,473 Total $ 6,725,473 $ 3,068 $ (139,877 ) $ 6,588,664 _______________________ (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.
Categories of Investments, Marketable Securities, Available-for-Sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
AFS Securities in a Continuous Unrealized Loss Position [Table Text Block]	The following table summarizes our available-for-sale securities with unrealized losses as of June 30, 2017 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands): Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 15,414 $ (1,536 ) $ — $ — $ 15,414 $ (1,536 ) Supranational institutions — — 422,178 (26,775 ) 422,178 (26,775 ) U.S. government-owned corporations — — 285,772 (32,368 ) 285,772 (32,368 ) GSEs — — 120,353 (10,417 ) 120,353 (10,417 ) 15,414 (1,536 ) 828,303 (69,560 ) 843,717 (71,096 ) MBS U.S. government guaranteed – single-family — — 81,466 (2,367 ) 81,466 (2,367 ) U.S. government guaranteed – multifamily 353,041 (1,479 ) 138,196 (979 ) 491,237 (2,458 ) GSEs – single-family 2,777,084 (21,541 ) 361,515 (6,320 ) 3,138,599 (27,861 ) GSEs – multifamily 394,996 (1,175 ) — — 394,996 (1,175 ) 3,525,121 (24,195 ) 581,177 (9,666 ) 4,106,298 (33,861 ) Total temporarily impaired $ 3,540,535 $ (25,731 ) $ 1,409,480 $ (79,226 ) $ 4,950,015 $ (104,957 ) The following table summarizes our available-for-sale securities with unrealized losses as of December 31, 2016 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands): Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 8,146 $ (1,204 ) $ — $ — $ 8,146 $ (1,204 ) Supranational institutions — — 422,620 (29,401 ) 422,620 (29,401 ) U.S. government-owned corporations — — 271,957 (45,631 ) 271,957 (45,631 ) GSEs — — 117,468 (13,330 ) 117,468 (13,330 ) 8,146 (1,204 ) 812,045 (88,362 ) 820,191 (89,566 ) MBS U.S. government guaranteed – single-family 31,606 (4 ) 90,854 (2,317 ) 122,460 (2,321 ) U.S. government guaranteed – multifamily 326,126 (1,261 ) 165,246 (1,016 ) 491,372 (2,277 ) GSEs – single-family 3,517,094 (39,181 ) 351,331 (6,532 ) 3,868,425 (45,713 ) 3,874,826 (40,446 ) 607,431 (9,865 ) 4,482,257 (50,311 ) Total temporarily impaired $ 3,882,972 $ (41,650 ) $ 1,419,476 $ (98,227 ) $ 5,302,448 $ (139,877 )
Investments Classified by Contractual Maturity Date [Table Text Block]	The amortized cost and fair value of our available-for-sale securities by contractual maturity at June 30, 2017 , and December 31, 2016 , were (dollars in thousands): June 30, 2017 December 31, 2016 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ — $ — $ — $ — Due after one year through five years 16,950 15,414 9,350 8,146 Due after five years through 10 years 170,161 159,254 171,589 161,746 Due after 10 years 727,702 669,049 728,818 650,299 914,813 843,717 909,757 820,191 MBS (1) 5,821,292 5,798,079 5,815,716 5,768,473 Total $ 6,736,105 $ 6,641,796 $ 6,725,473 $ 6,588,664 _______________________ (1)

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	6 Months Ended
	Jun. 30, 2017
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities by Major Security Type [Table Text Block]	Our held-to-maturity securities as of June 30, 2017 , were (dollars in thousands): 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 $ 1,602 $ — $ 1,602 $ 29 $ — $ 1,631 HFA securities 159,689 — 159,689 10 (15,856 ) 143,843 161,291 — 161,291 39 (15,856 ) 145,474 MBS U.S. government guaranteed – single-family 11,427 — 11,427 243 — 11,670 U.S. government guaranteed – multifamily 800 — 800 — (1 ) 799 GSEs – single-family 678,107 — 678,107 14,115 (292 ) 691,930 GSEs – multifamily 295,130 — 295,130 10,271 — 305,401 Private-label – residential 913,841 (174,537 ) 739,304 259,043 (5,702 ) 992,645 Asset-backed securities (ABS) backed by home equity loans 12,568 (530 ) 12,038 581 (485 ) 12,134 1,911,873 (175,067 ) 1,736,806 284,253 (6,480 ) 2,014,579 Total $ 2,073,164 $ (175,067 ) $ 1,898,097 $ 284,292 $ (22,336 ) $ 2,160,053 Our held-to-maturity securities as of December 31, 2016 , were (dollars in thousands): 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 $ 2,159 $ — $ 2,159 $ 56 $ — $ 2,215 HFA securities 162,568 — 162,568 11 (19,291 ) 143,288 164,727 — 164,727 67 (19,291 ) 145,503 MBS U.S. government guaranteed – single-family 12,719 — 12,719 246 — 12,965 U.S. government guaranteed – multifamily 1,532 — 1,532 — — 1,532 GSEs – single-family 812,836 — 812,836 16,881 (519 ) 829,198 GSEs – multifamily 318,667 — 318,667 11,692 — 330,359 Private-label – residential 999,149 (191,804 ) 807,345 240,818 (8,373 ) 1,039,790 ABS backed by home equity loans 13,515 (574 ) 12,941 602 (600 ) 12,943 2,158,418 (192,378 ) 1,966,040 270,239 (9,492 ) 2,226,787 Total $ 2,323,145 $ (192,378 ) $ 2,130,767 $ 270,306 $ (28,783 ) $ 2,372,290
Categories of Investments, Marketable Securities, Held-to-maturity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities in a Continuous Unrealized Loss Position [Table Text Block]	The following table summarizes our held-to-maturity securities with unrealized losses as of June 30, 2017 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands). Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 141,514 $ (15,856 ) $ 141,514 $ (15,856 ) MBS U.S. government guaranteed - multifamily 799 (1 ) — — 799 (1 ) GSEs – single-family 15,928 (191 ) 17,590 (101 ) 33,518 (292 ) Private-label – residential — — 284,674 (15,614 ) 284,674 (15,614 ) ABS backed by home equity loans — — 11,143 (601 ) 11,143 (601 ) 16,727 (192 ) 313,407 (16,316 ) 330,134 (16,508 ) Total $ 16,727 $ (192 ) $ 454,921 $ (32,172 ) $ 471,648 $ (32,364 ) The following table summarizes our held-to-maturity securities with unrealized losses as of December 31, 2016 , which are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands). Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 140,959 $ (19,291 ) $ 140,959 $ (19,291 ) MBS GSEs – single-family 83,291 (393 ) 13,405 (126 ) 96,696 (519 ) Private-label – residential 16,915 (128 ) 397,407 (28,781 ) 414,322 (28,909 ) ABS backed by home equity loans — — 11,898 (720 ) 11,898 (720 ) 100,206 (521 ) 422,710 (29,627 ) 522,916 (30,148 ) Total $ 100,206 $ (521 ) $ 563,669 $ (48,918 ) $ 663,875 $ (49,439 )
HTM Securities by Contractual Maturity [Table Text Block]	The amortized cost, carrying value, and fair value of our held-to-maturity securities by contractual maturity at June 30, 2017 , and December 31, 2016 , are shown below (dollars in thousands). Expected maturities of some securities and MBS may 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. June 30, 2017 December 31, 2016 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 109 $ 109 $ 111 $ — $ — $ — Due after one year through five years 15,972 15,972 15,974 16,637 16,637 16,663 Due after five years through 10 years — — — — — — Due after 10 years 145,210 145,210 129,389 148,090 148,090 128,840 161,291 161,291 145,474 164,727 164,727 145,503 MBS (2) 1,911,873 1,736,806 2,014,579 2,158,418 1,966,040 2,226,787 Total $ 2,073,164 $ 1,898,097 $ 2,160,053 $ 2,323,145 $ 2,130,767 $ 2,372,290 _______________________ (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 Impairme32

Other-Than-Temporary Impairment (Tables)	6 Months Ended
	Jun. 30, 2017
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 six months ended June 30, 2017 , the following table 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 (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) $ 66,522 8.4 % 26.8 % 35.5 % 11.1 % _______________________ (1)
Total Securities Other-than-Temporarily Impaired during the Life of the Security [Table Text Block]	The following table sets forth our securities for which other-than-temporary impairment credit losses were recognized during the life of the security through June 30, 2017 (dollars in thousands). Securities are classified in the table below based on their classifications at the time of issuance. June 30, 2017 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 34,924 $ 30,001 $ 23,642 $ 31,335 Private-label residential MBS – Alt-A 1,018,372 753,997 585,819 837,054 ABS backed by home equity loans – Subprime 3,556 3,259 2,729 3,310 Total other-than-temporarily impaired securities $ 1,056,852 $ 787,257 $ 612,190 $ 871,699 _______________________ (1)
Rollforward of the Amounts Related to Credit Losses Recognized into Earnings [Table Text Block]	The following table 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 (dollars in thousands). For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 Balance at beginning of period $ 482,221 $ 525,809 $ 490,404 $ 533,888 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 568 1,003 986 2,350 Reductions: Securities matured during the period (2) (5,565 ) — (5,565 ) — Increase in cash flows expected to be collected which are recognized over the remaining life of the security (3) (8,518 ) (9,890 ) (17,119 ) (19,316 ) Balance at end of period $ 468,706 $ 516,922 $ 468,706 $ 516,922 _______________________ (1) For the three months ended June 30, 2017 and 2016 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to April 1, 2017 and 2016 , respectively. For the six months ended June 30, 2017 and 2016 , 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, 2017 and 2016 , respectively. (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. (3)

Advances (Tables)

Advances (Tables)	6 Months Ended
	Jun. 30, 2017
Advances [Abstract]
Advances [Table Text Block]	The following table details interest-rate-payment types for our outstanding advances (dollars in thousands): Par value of advances June 30, 2017 December 31, 2016 Fixed-rate $ 32,303,868 $ 30,526,192 Variable-rate 6,156,321 8,588,663 Total par value $ 38,460,189 $ 39,114,855 Year of Contractual Maturity or Next Put Date, Par Value June 30, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 3,046 $ 3,780 Due in one year or less 22,092,559 20,788,552 Due after one year through two years 8,946,230 10,946,530 Due after two years through three years 2,922,963 2,455,709 Due after three years through four years 1,847,081 1,974,932 Due after four years through five years 1,631,339 1,736,769 Thereafter 1,016,971 1,208,583 Total par value $ 38,460,189 $ 39,114,855 At both June 30, 2017 , and December 31, 2016 , we had advances outstanding with interest rates ranging from zero percent to 7.72 percent as summarized below (dollars in thousands). June 30, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 3,046 1.45 % $ 3,780 0.92 % Due in one year or less 20,369,559 1.35 18,783,802 1.05 Due after one year through two years 8,740,980 1.50 10,966,780 1.15 Due after two years through three years 3,005,963 1.78 2,508,459 1.67 Due after three years through four years 2,034,081 1.75 2,177,432 1.64 Due after four years through five years 1,931,339 1.97 2,041,269 1.80 Thereafter 2,375,221 1.81 2,633,333 1.70 Total par value 38,460,189 1.50 % 39,114,855 1.23 % Premiums 19,735 22,633 Discounts (30,900 ) (25,847 ) Fair value of bifurcated derivatives (1) 640 (153 ) Hedging adjustments (22,048 ) (12,149 ) Total $ 38,427,616 $ 39,099,339 _________________________ (1) At June 30, 2017 , and December 31, 2016 Year of Contractual Maturity or Next Call Date (1) , Par Value June 30, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 3,046 $ 3,780 Due in one year or less 25,883,734 26,447,977 Due after one year through two years 3,627,980 3,693,780 Due after two years through three years 3,005,963 2,508,459 Due after three years through four years 1,848,881 2,002,232 Due after four years through five years 1,769,339 1,891,269 Thereafter 2,321,246 2,567,358 Total par value $ 38,460,189 $ 39,114,855 _______________________ (1)

Mortgage Loans Held for Portf34

Mortgage Loans Held for Portfolio (Tables)	6 Months Ended
	Jun. 30, 2017
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	The following table presents certain characteristics of these investments (dollars in thousands): June 30, 2017 December 31, 2016 Real estate Fixed-rate 15-year single-family mortgages $ 500,527 $ 528,486 Fixed-rate 20- and 30-year single-family mortgages 3,235,321 3,098,476 Premiums 68,395 67,523 Discounts (1,613 ) (1,696 ) Deferred derivative gains, net 2,451 1,755 Total mortgage loans held for portfolio 3,805,081 3,694,544 Less: allowance for credit losses (500 ) (650 ) Total mortgage loans, net of allowance for credit losses $ 3,804,581 $ 3,693,894 June 30, 2017 December 31, 2016 Conventional mortgage loans $ 3,357,891 $ 3,235,835 Government mortgage loans 377,957 391,127 Total par value $ 3,735,848 $ 3,626,962

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Recorded Investment in Delinquent Mortgage Loans [Table Text Block]	The tables below set forth certain key credit quality indicators for our investments in mortgage loans at June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 23,951 $ 11,324 $ 35,275 Past due 60-89 days delinquent 6,401 3,642 10,043 Past due 90 days or more delinquent 12,727 4,985 17,712 Total past due 43,079 19,951 63,030 Total current loans 3,392,655 368,309 3,760,964 Total mortgage loans $ 3,435,734 $ 388,260 $ 3,823,994 Other delinquency statistics In process of foreclosure, included above (1) $ 6,031 $ 1,297 $ 7,328 Serious delinquency rate (2) 0.39 % 1.28 % 0.48 % Past due 90 days or more still accruing interest $ — $ 4,985 $ 4,985 Loans on nonaccrual status (3) $ 13,006 $ — $ 13,006 _______________________ (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, 2016 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 26,757 $ 14,878 $ 41,635 Past due 60-89 days delinquent 5,508 3,846 9,354 Past due 90 days or more delinquent 16,379 5,807 22,186 Total past due 48,644 24,531 73,175 Total current loans 3,262,671 377,438 3,640,109 Total mortgage loans $ 3,311,315 $ 401,969 $ 3,713,284 Other delinquency statistics In process of foreclosure, included above (1) $ 7,495 $ 1,502 $ 8,997 Serious delinquency rate (2) 0.53 % 1.44 % 0.63 % Past due 90 days or more still accruing interest $ — $ 5,807 $ 5,807 Loans on nonaccrual status (3) $ 16,940 $ — $ 16,940 _______________________ (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, Recorded Investment [Table Text Block]	The following tables present the recorded investment, par value and any related allowance for impaired loans individually assessed for impairment at June 30, 2017 , and December 31, 2016 , and the average recorded investment and interest income recognized on these loans during the three and six months ended June 30, 2017 and 2016 (dollars in thousands). As of June 30, 2017 As of December 31, 2016 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 18,709 $ 18,672 $ 22,945 $ 22,905
Individually Evaluated Impaired Loans, Average Recorded Investment and Interest Income Recognized [Table Text Block]	For the Three Months Ended June 30, 2017 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 19,367 $ 107 $ 24,770 $ 102 For the Six Months Ended June 30, 2017 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 20,324 $ 223 $ 25,217 $ 182
Rollforward of Allowance for Credit Losses on Mortgage Loans [Table Text Block]	The following table presents a roll-forward of the allowance for credit losses on conventional mortgage loans for the three and six months ended June 30, 2017 and 2016 , as well as the recorded investment in mortgage loans by impairment methodology at June 30, 2017 and 2016 (dollars in thousands). 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. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 Allowance for credit losses Balance, beginning of period $ 625 $ 1,025 $ 650 $ 1,025 Recoveries (charge-offs) — (14 ) 26 (25 ) Reduction of provision for credit losses (125 ) (111 ) (176 ) (100 ) Balance, end of period $ 500 $ 900 $ 500 $ 900 Ending balance, individually evaluated for impairment $ — $ — $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 900 $ 500 $ 900 Recorded investment, end of period (1) Individually evaluated for impairment $ 18,709 $ 24,583 $ 18,709 $ 24,583 Collectively evaluated for impairment $ 3,417,025 $ 3,208,989 $ 3,417,025 $ 3,208,989 _________________________ (1)

Derivatives and Hedging Activ36

Derivatives and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments [Table Text Block]	The following table presents the notional amount and fair value of derivatives (excluding fair value adjustments related to variation margin for daily settled contracts) and total derivatives assets and liabilities. Total derivative asset and liabilities include the effect of netting adjustments, cash collateral, and variation margin for daily settled contracts as of June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 16,212,840 $ 41,631 $ (369,601 ) $ 18,215,809 $ 52,715 $ (413,026 ) Forward-start interest-rate swaps 527,800 — (41,099 ) 527,800 — (36,250 ) Total derivatives designated as hedging instruments 16,740,640 41,631 (410,700 ) 18,743,609 52,715 (449,276 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,050,900 1,132 (8,589 ) 1,199,000 2,293 (10,840 ) Mortgage-delivery commitments (1) 71,314 99 (197 ) 22,524 70 (171 ) Total derivatives not designated as hedging instruments 1,122,214 1,231 (8,786 ) 1,221,524 2,363 (11,011 ) Total notional amount of derivatives $ 17,862,854 $ 19,965,133 Total derivatives before netting and collateral adjustments 42,862 (419,486 ) 55,078 (460,287 ) Netting adjustments, cash collateral, and variation margin for daily settled contracts including related accrued interest (2) 13,761 90,257 6,520 102,411 Derivative assets and derivative liabilities $ 56,623 $ (329,229 ) $ 61,598 $ (357,876 ) _______________________ (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 $62.0 million and $109.8 million at June 30, 2017 , and December 31, 2016 , 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 $601,000 and $850,000 at June 30, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $42.6 million at June 30, 2017 .
Net Gains (Losses) on Derivatives and Hedging Activities [Table Text Block]	Net (losses) gains on derivatives and hedging activities recorded in Other Income (Loss) for the three and six months ended June 30, 2017 and 2016 , were as follows (dollars in thousands): For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 Derivatives designated as hedging instruments Interest-rate swaps $ (752 ) $ (2,218 ) $ (1,411 ) $ (5,251 ) Forward-start interest-rate swaps 97 (190 ) 231 (536 ) Total net losses related to derivatives designated as hedging instruments (655 ) (2,408 ) (1,180 ) (5,787 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps (375 ) (1,245 ) (222 ) (4,717 ) Mortgage-delivery commitments 507 690 864 1,306 Total net gains (losses) related to derivatives not designated as hedging instruments 132 (555 ) 642 (3,411 ) Other (1) 105 — 156 — Net losses on derivatives and hedging activities $ (418 ) $ (2,963 ) $ (382 ) $ (9,198 ) ______________ (1) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount.
Gains (Losses) By Type of Hedged Item [Table Text Block]	The following tables present, by type of hedged item, the gains (losses) on derivatives and the related hedged items in fair-value hedge relationships and the impact of those derivatives on our net interest income for the three and six months ended June 30, 2017 and 2016 (dollars in thousands): For the Three Months Ended June 30, 2017 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (11,327 ) $ 10,554 $ (773 ) $ (8,283 ) Investments (6,863 ) 7,264 401 (8,099 ) COs – bonds 17,719 (18,099 ) (380 ) 2,082 Total $ (471 ) $ (281 ) $ (752 ) $ (14,300 ) For the Three Months Ended June 30, 2016 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (25,621 ) $ 24,655 $ (966 ) $ (26,128 ) Investments (26,830 ) 27,186 356 (8,883 ) COs – bonds 564 (2,172 ) (1,608 ) 7,158 Total $ (51,887 ) $ 49,669 $ (2,218 ) $ (27,853 ) For the Six Months Ended June 30, 2017 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 9,768 $ (9,899 ) $ (131 ) $ (21,688 ) Investments 3,405 (2,544 ) 861 (16,440 ) COs – bonds 17,795 (19,936 ) (2,141 ) 6,723 Total $ 30,968 $ (32,379 ) $ (1,411 ) $ (31,405 ) For the Six Months Ended June 30, 2016 Gain/(Loss) on Derivative Gain/(Loss) on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ (94,077 ) $ 92,888 $ (1,189 ) $ (56,252 ) Investments (76,285 ) 77,025 740 (17,894 ) COs – bonds 10,831 (15,633 ) (4,802 ) 15,230 Total $ (159,531 ) $ 154,280 $ (5,251 ) $ (58,916 ) ______________ (1)
Effect of Cash Flow Hedge-Related Derivative Instruments [Table Text Block]	The following table presents the losses recognized in accumulated other comprehensive loss, the losses reclassified from accumulated other comprehensive loss into income, and the effect of our hedging activities on our net losses on derivatives and hedging activities in the statement of income for our forward-start interest-rate swaps associated with hedged CO bonds in cash-flow hedge relationships (dollars in thousands). Derivatives and Hedged Items in Cash Flow Hedging Relationships 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) Interest-rate swaps - CO bonds For the Three Months Ended June 30, 2017 $ (4,943 ) Interest expense $ (3,392 ) $ 97 For the Three Months Ended June 30, 2016 (9,731 ) Interest expense (6,889 ) (190 ) For the Six Months Ended June 30, 2017 (5,081 ) Interest expense (7,707 ) 231 For the Six Months Ended June 30, 2016 (26,770 ) Interest expense (14,097 ) (536 )
Post-haircut Value of Incremental Collateral Based on Incremental Credit Rating Downgrades [Table Text Block]	The following table sets forth the post-haircut value of incremental collateral that certain uncleared derivatives counterparties could have required us to deliver in case of an incremental credit rating downgrades at June 30, 2017 . Post Haircut Value of Incremental Collateral to be Delivered as of June 30, 2017 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 9,858 AA- A+, A or A- 6,250 A- below A- 22,670 _______________________ (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.
Fair value of derivative assets instruments with and without the legal right of offset [Table Text Block]	The following table presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of June 30, 2017 , and December 31, 2016 and the fair value of derivatives that are not subject to such netting (dollars in thousands). Such netting includes any related cash collateral received from or pledged to counterparties and variation margin for daily settled contracts. June 30, 2017 December 31, 2016 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Derivatives meeting netting requirements Gross recognized amount Uncleared derivatives $ 9,168 $ (359,879 ) $ 12,594 $ (405,310 ) Cleared derivatives 33,595 (59,410 ) 42,414 (54,806 ) Total gross recognized amount 42,763 (419,289 ) 55,008 (460,116 ) Gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives (8,377 ) 30,847 (12,028 ) 47,605 Cleared derivatives 22,138 59,410 18,548 54,806 Total gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts 13,761 90,257 6,520 102,411 Net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives 791 (329,032 ) 566 (357,705 ) Cleared derivatives 55,733 — 60,962 — Total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts 56,524 (329,032 ) 61,528 (357,705 ) Derivatives not meeting netting requirements Mortgage delivery commitments 99 (197 ) 70 (171 ) Total derivative assets and total derivative liabilities Uncleared derivatives 791 (329,032 ) 566 (357,705 ) Cleared derivatives 55,733 — 60,962 — Mortgage delivery commitments 99 (197 ) 70 (171 ) Total derivative assets and total derivative liabilities presented in the statement of condition 56,623 (329,229 ) 61,598 (357,876 ) Non-cash collateral received or pledged not offset (1) Can be sold or repledged Uncleared derivatives — 11,933 — 30,306 Cannot be sold or repledged Uncleared derivatives — 297,802 — 290,444 Total non-cash collateral received or pledged, not offset — 309,735 — 320,750 Net amount Uncleared derivatives 791 (19,297 ) 566 (36,955 ) Cleared derivatives 55,733 — 60,962 — Mortgage delivery commitments 99 (197 ) 70 (171 ) Total net amount $ 56,623 $ (19,494 ) $ 61,598 $ (37,126 ) _______________________ (1) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At June 30, 2017 , and December 31, 2016 , we had additional net credit exposure of $118,000 and $2.0 million
Fair Value of derivative liabilities instruments with and without the legal right of offset [Table Text Block]	The following table presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of June 30, 2017 , and December 31, 2016 and the fair value of derivatives that are not subject to such netting (dollars in thousands). Such netting includes any related cash collateral received from or pledged to counterparties and variation margin for daily settled contracts. June 30, 2017 December 31, 2016 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Derivatives meeting netting requirements Gross recognized amount Uncleared derivatives $ 9,168 $ (359,879 ) $ 12,594 $ (405,310 ) Cleared derivatives 33,595 (59,410 ) 42,414 (54,806 ) Total gross recognized amount 42,763 (419,289 ) 55,008 (460,116 ) Gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives (8,377 ) 30,847 (12,028 ) 47,605 Cleared derivatives 22,138 59,410 18,548 54,806 Total gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts 13,761 90,257 6,520 102,411 Net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives 791 (329,032 ) 566 (357,705 ) Cleared derivatives 55,733 — 60,962 — Total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts 56,524 (329,032 ) 61,528 (357,705 ) Derivatives not meeting netting requirements Mortgage delivery commitments 99 (197 ) 70 (171 ) Total derivative assets and total derivative liabilities Uncleared derivatives 791 (329,032 ) 566 (357,705 ) Cleared derivatives 55,733 — 60,962 — Mortgage delivery commitments 99 (197 ) 70 (171 ) Total derivative assets and total derivative liabilities presented in the statement of condition 56,623 (329,229 ) 61,598 (357,876 ) Non-cash collateral received or pledged not offset (1) Can be sold or repledged Uncleared derivatives — 11,933 — 30,306 Cannot be sold or repledged Uncleared derivatives — 297,802 — 290,444 Total non-cash collateral received or pledged, not offset — 309,735 — 320,750 Net amount Uncleared derivatives 791 (19,297 ) 566 (36,955 ) Cleared derivatives 55,733 — 60,962 — Mortgage delivery commitments 99 (197 ) 70 (171 ) Total net amount $ 56,623 $ (19,494 ) $ 61,598 $ (37,126 ) _______________________ (1) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At June 30, 2017 , and December 31, 2016 , we had additional net credit exposure of $118,000 and $2.0 million

Deposits (Tables)

Deposits (Tables)	6 Months Ended
	Jun. 30, 2017
Deposits [Abstract]
Interest-bearing and Non-interest-bearing Deposits [Table Text Block]	The following table details interest- and noninterest-bearing deposits (dollars in thousands): June 30, 2017 December 31, 2016 Interest-bearing Demand and overnight $ 436,800 $ 440,731 Other 4,510 4,166 Noninterest-bearing Other 27,863 37,266 Total deposits $ 469,173 $ 482,163

Consolidated Obligations (Table

Consolidated Obligations (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
CO Bonds by Year of Contractual Maturity [Table Text Block]	The following table sets forth the outstanding CO bonds for which we were primarily liable at June 30, 2017 , and December 31, 2016 , by year of contractual maturity (dollars in thousands): June 30, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 12,230,385 1.33 % $ 8,734,955 1.43 % Due after one year through two years 6,320,065 1.36 7,752,420 1.19 Due after two years through three years 3,080,645 1.86 3,297,120 1.63 Due after three years through four years 1,817,190 1.79 1,637,335 1.87 Due after four years through five years 1,965,545 1.77 2,574,375 1.65 Thereafter 3,060,590 2.70 3,135,745 2.70 Total par value 28,474,420 1.60 % 27,131,950 1.58 % Premiums 101,843 118,145 Discounts (14,020 ) (14,906 ) Hedging adjustments (43,819 ) (63,755 ) $ 28,518,424 $ 27,171,434 _______________________ (1)
CO Bonds by Call Feature [Table Text Block]	Our CO bonds outstanding at June 30, 2017 , and December 31, 2016 , included (dollars in thousands): June 30, 2017 December 31, 2016 Par value of CO bonds Noncallable and nonputable $ 24,456,420 $ 22,388,950 Callable 4,018,000 4,743,000 Total par value $ 28,474,420 $ 27,131,950
CO Bonds by Year of Contractual Maturity or Next Call Date [Table Text Block]	The following is a summary of the CO bonds for which we were primarily liable at June 30, 2017 , and December 31, 2016 , by year of contractual maturity or next call date for callable CO bonds (dollars in thousands): Year of Contractual Maturity or Next Call Date June 30, 2017 December 31, 2016 Due in one year or less $ 15,325,385 $ 12,858,955 Due after one year through two years 6,170,065 7,013,420 Due after two years through three years 2,952,645 2,904,120 Due after three years through four years 1,254,190 1,289,335 Due after four years through five years 1,003,545 1,242,375 Thereafter 1,768,590 1,823,745 Total par value $ 28,474,420 $ 27,131,950
CO Bonds by Interest-rate-payment Type [Table Text Block]	The following table sets forth the CO bonds for which we were primarily liable by interest-rate-payment type at June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Par value of CO bonds Fixed-rate $ 20,357,420 $ 20,289,950 Simple variable-rate 6,665,000 5,300,000 Step-up 1,452,000 1,542,000 Total par value $ 28,474,420 $ 27,131,950
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 (dollars in thousands): Book Value Par Value Weighted Average Rate (1) June 30, 2017 $ 27,865,529 $ 27,892,943 0.95 % December 31, 2016 $ 30,053,964 $ 30,070,103 0.47 % _______________________ (1)

Affordable Housing Program (Tab

Affordable Housing Program (Tables)	6 Months Ended
	Jun. 30, 2017
Affordable Housing Program [Abstract]
Roll-forward of the AHP Liability[Table Text Block]	The following table presents a roll-forward of the AHP liability for the six months ended June 30, 2017 , and year ended December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Balance at beginning of period $ 81,627 $ 82,081 AHP expense for the period 8,610 19,397 AHP direct grant disbursements (10,491 ) (18,575 ) AHP subsidy for AHP advance disbursements (1,416 ) (1,378 ) Return of previously disbursed grants and subsidies 14 102 Balance at end of period $ 78,344 $ 81,627

Capital (Tables)

Capital (Tables)	6 Months Ended
	Jun. 30, 2017
Capital [Abstract]
Compliance with Regulatory Capital Requirements [Table Text Block]	The following tables demonstrate our compliance with our regulatory capital requirements at June 30, 2017 , and December 31, 2016 (dollars in thousands): Risk-Based Capital Requirements June 30, December 31, Permanent capital Class B capital stock $ 2,408,647 $ 2,411,306 Mandatorily redeemable capital stock 37,380 32,687 Retained earnings 1,245,325 1,216,986 Total permanent capital $ 3,691,352 $ 3,660,979 Risk-based capital requirement Credit-risk capital $ 344,501 $ 355,182 Market-risk capital 152,177 118,765 Operations-risk capital 149,003 142,184 Total risk-based capital requirement $ 645,681 $ 616,131 Permanent capital in excess of risk-based capital requirement $ 3,045,671 $ 3,044,848 June 30, 2017 December 31, 2016 Required Actual Required Actual Capital Ratio Risk-based capital $ 645,681 $ 3,691,352 $ 616,131 $ 3,660,979 Total regulatory capital $ 2,430,170 $ 3,691,352 $ 2,461,823 $ 3,660,979 Total capital-to-asset ratio 4.0 % 6.1 % 4.0 % 5.9 % Leverage Ratio Leverage capital $ 3,037,712 $ 5,537,028 $ 3,077,279 $ 5,491,469 Leverage capital-to-assets ratio 5.0 % 9.1 % 5.0 % 8.9 %

Accumulated Other Comprehensi41

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2017
AOCI Attributable to Parent [Abstract]
Schedule of Accumulated Other Comprehensive Loss [Table Text Block]	Accumulated Other Comprehensive Loss The following table presents a summary of changes in accumulated other comprehensive loss for the three and six months ended June 30, 2017 and 2016 (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, March 31, 2016 $ (85,888 ) $ (219,739 ) $ (81,065 ) $ (3,738 ) $ (390,430 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 27,941 — (9,731 ) — 18,210 Noncredit other-than-temporary impairment losses — (420 ) — — (420 ) Accretion of noncredit loss — 9,211 — — 9,211 Net actuarial loss — — — (2,918 ) (2,918 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 779 — — 779 Amortization - hedging activities (2) — — 6,893 — 6,893 Amortization - pension and postretirement benefits (3) — — — 333 333 Other comprehensive income (loss) 27,941 9,570 (2,838 ) (2,585 ) 32,088 Balance, June 30, 2016 $ (57,947 ) $ (210,169 ) $ (83,903 ) $ (6,323 ) $ (358,342 ) Balance, March 31, 2017 $ (109,903 ) $ (183,718 ) $ (44,006 ) $ (5,945 ) $ (343,572 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 15,594 — (4,943 ) — 10,651 Accretion of noncredit loss — 8,119 — — 8,119 Net actuarial gain — — — 224 224 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 531 — — 531 Amortization - hedging activities (4) — — 3,395 — 3,395 Amortization - pension and postretirement benefits (3) — — — 191 191 Other comprehensive income (loss) 15,594 8,650 (1,548 ) 415 23,111 Balance, June 30, 2017 $ (94,309 ) $ (175,068 ) $ (45,554 ) $ (5,530 ) $ (320,461 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to (from) accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $6.9 million recorded in CO bond interest expense and $4,000 recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Amortization of hedging activities includes $3.4 million recorded in CO bond interest expense and $4,000 recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. 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, 2015 $ (137,718 ) $ (229,785 ) $ (71,237 ) $ (3,857 ) $ (442,597 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 79,771 — (26,770 ) — 53,001 Noncredit other-than-temporary impairment losses — (656 ) — — (656 ) Accretion of noncredit loss — 18,352 — — 18,352 Net actuarial loss — — — (2,917 ) (2,917 ) Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 1,920 — — 1,920 Amortization - hedging activities (2) — — 14,104 — 14,104 Amortization - pension and postretirement benefits (3) — — — 451 451 Other comprehensive income (loss) 79,771 19,616 (12,666 ) (2,466 ) 84,255 Balance, June 30, 2016 $ (57,947 ) $ (210,169 ) $ (83,903 ) $ (6,323 ) $ (358,342 ) Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 42,500 — (5,081 ) — 37,419 Accretion of noncredit loss — 16,415 — — 16,415 Net actuarial gain — — — 224 224 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 896 — — 896 Amortization - hedging activities (4) — — 7,714 — 7,714 Amortization - pension and postretirement benefits (3) — — — 385 385 Other comprehensive income 42,500 17,311 2,633 609 63,053 Balance, June 30, 2017 $ (94,309 ) $ (175,068 ) $ (45,554 ) $ (5,530 ) $ (320,461 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to (from) accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $14.1 million recorded in CO bond interest expense and $7,000 recorded in net gains (losses) on derivatives and hedging activities in the statement of operations. (3) Recorded in other operating expenses in the statement of operations. (4) Amortization of hedging activities includes $7.7 million recorded in CO bond interest expense and $7,000

Fair Values (Tables)

Fair Values (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments [Table Text Block]	The carrying values, fair values, and fair-value hierarchy of our financial instruments at June 30, 2017 , and December 31, 2016 , were as follows (dollars in thousands). These fair values do not represent an estimate of our overall market value as a going concern, which would take into account, among other things, our future business opportunities and the net profitability of our assets and liabilities. June 30, 2017 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral Financial instruments Assets: Cash and due from banks $ 176,852 $ 176,852 $ 176,852 $ — $ — $ — Interest-bearing deposits 279,046 279,046 279,046 — — — Securities purchased under agreements to resell 4,349,000 4,348,852 — 4,348,852 — — Federal funds sold 4,460,000 4,459,941 — 4,459,941 — — Trading securities (1) 514,313 514,313 — 514,313 — — Available-for-sale securities (1) 6,641,796 6,641,796 — 6,626,382 15,414 — Held-to-maturity securities 1,898,097 2,160,053 — 1,011,431 1,148,622 — Advances 38,427,616 38,572,842 — 38,572,842 — — Mortgage loans, net 3,804,581 3,848,195 — 3,824,845 23,350 — Accrued interest receivable 85,997 85,997 — 85,997 — — Derivative assets (1) 56,623 56,623 — 42,862 — 13,761 Other assets (1) 21,703 21,703 10,336 11,367 — — Liabilities: Deposits (469,173 ) (469,169 ) — (469,169 ) — — COs: Bonds (28,518,424 ) (28,645,061 ) — (28,645,061 ) — — Discount notes (27,865,529 ) (27,864,927 ) — (27,864,927 ) — — Mandatorily redeemable capital stock (37,380 ) (37,380 ) (37,380 ) — — — Accrued interest payable (84,093 ) (84,093 ) — (84,093 ) — — Derivative liabilities (1) (329,229 ) (329,229 ) — (419,486 ) — 90,257 Other: Commitments to extend credit for advances — (4,377 ) — (4,377 ) — — Standby letters of credit (763 ) (763 ) — (763 ) — — _______________________ (1) Carried at fair value on a recurring basis. December 31, 2016 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral Financial instruments Assets: Cash and due from banks $ 520,031 $ 520,031 $ 520,031 $ — $ — $ — Interest-bearing deposits 278 278 278 — — — Securities purchased under agreements to resell 5,999,000 5,998,799 — 5,998,799 — — Federal funds sold 2,700,000 2,699,949 — 2,699,949 — — Trading securities (1) 612,622 612,622 — 612,622 — — Available-for-sale securities (1) 6,588,664 6,588,664 — 6,580,518 8,146 — Held-to-maturity securities 2,130,767 2,372,290 — 1,176,269 1,196,021 — Advances 39,099,339 39,273,044 — 39,273,044 — — Mortgage loans, net 3,693,894 3,736,548 — 3,708,123 28,425 — Accrued interest receivable 84,653 84,653 — 84,653 — — Derivative assets (1) 61,598 61,598 — 55,078 — 6,520 Other assets (1) 17,779 17,779 8,394 9,385 — — Liabilities: Deposits (482,163 ) (482,158 ) — (482,158 ) — — COs: Bonds (27,171,434 ) (27,298,499 ) — (27,298,499 ) — — Discount notes (30,053,964 ) (30,054,085 ) — (30,054,085 ) — — Mandatorily redeemable capital stock (32,687 ) (32,687 ) (32,687 ) — — — Accrued interest payable (80,822 ) (80,822 ) — (80,822 ) — — Derivative liabilities (1) (357,876 ) (357,876 ) — (460,287 ) — 102,411 Other: Commitments to extend credit for advances — (4,412 ) — (4,412 ) — — Standby letters of credit (1,064 ) (1,064 ) — (1,064 ) — — _______________________ (1) Carried at fair value on a recurring basis.
Fair Value Measured on Recurring Basis [Table Text Block]	The following tables present our assets and liabilities that are measured at fair value on the statement of condition, which are recorded on a recurring basis at June 30, 2017 , and December 31, 2016 , by fair-value hierarchy level (dollars in thousands): June 30, 2017 Level 1 Level 2 Level 3 Netting Adjustment (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 309,332 $ — $ — $ 309,332 U.S. government-guaranteed – single-family MBS — 7,634 — — 7,634 GSEs – single-family MBS — 534 — — 534 GSEs – multifamily MBS — 196,813 — — 196,813 Total trading securities — 514,313 — — 514,313 Available-for-sale securities: State or local HFA securities — — 15,414 — 15,414 Supranational institutions — 422,178 — — 422,178 U.S. government-owned corporations — 285,772 — — 285,772 GSEs — 120,353 — — 120,353 U.S. government guaranteed – single-family MBS — 110,447 — — 110,447 U.S. government guaranteed – multifamily MBS — 491,237 — — 491,237 GSEs – single-family MBS — 4,148,697 — — 4,148,697 GSEs – multifamily MBS — 1,047,698 — — 1,047,698 Total available-for-sale securities — 6,626,382 15,414 — 6,641,796 Derivative assets: Interest-rate-exchange agreements — 42,763 — 13,761 56,524 Mortgage delivery commitments — 99 — — 99 Total derivative assets — 42,862 — 13,761 56,623 Other assets 10,336 11,367 — — 21,703 Total assets at fair value $ 10,336 $ 7,194,924 $ 15,414 $ 13,761 $ 7,234,435 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (419,289 ) $ — $ 90,257 $ (329,032 ) Mortgage delivery commitments — (197 ) — — (197 ) Total liabilities at fair value $ — $ (419,486 ) $ — $ 90,257 $ (329,229 ) _______________________ (1) These amounts represent the application of the netting requirements which 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, 2016 Level 1 Level 2 Level 3 Netting Adjustment (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 399,521 $ — $ — $ 399,521 U.S. government-guaranteed – single-family MBS — 8,494 — — 8,494 GSEs – single-family MBS — 768 — — 768 GSEs – multifamily MBS — 203,839 — — 203,839 Total trading securities — 612,622 — — 612,622 Available-for-sale securities: State or local HFA securities — — 8,146 — 8,146 Supranational institutions — 422,620 — — 422,620 U.S. government-owned corporations — 271,957 — — 271,957 GSEs — 117,468 — — 117,468 U.S. government guaranteed – single-family MBS — 124,727 — — 124,727 U.S. government guaranteed – multifamily MBS — 563,361 — — 563,361 GSEs – single-family MBS — 4,403,855 — — 4,403,855 GSEs – multifamily MBS — 676,530 — — 676,530 Total available-for-sale securities — 6,580,518 8,146 — 6,588,664 Derivative assets: Interest-rate-exchange agreements — 55,008 — 6,520 61,528 Mortgage delivery commitments — 70 — — 70 Total derivative assets — 55,078 — 6,520 61,598 Other assets 8,394 9,385 — — 17,779 Total assets at fair value $ 8,394 $ 7,257,603 $ 8,146 $ 6,520 $ 7,280,663 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (460,116 ) $ — $ 102,411 $ (357,705 ) Mortgage delivery commitments — (171 ) — — (171 ) Total liabilities at fair value $ — $ (460,287 ) $ — $ 102,411 $ (357,876 ) _______________________ (1)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following table presents a reconciliation of available-for-sale securities that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the three and six months ended June 30, 2017 . There were no Level 3 available-for-sale securities during the six months ended June 30, 2016 (dollars in thousands). For the Three Months Ended For the Six Months Ended June 30, 2017 June 30, 2017 Balance at beginning of period $ 8,184 $ 8,146 Purchases 7,600 7,600 Unrealized losses included in other comprehensive income (370 ) (332 ) Balance at end of period $ 15,414 $ 15,414
Fair Value on a Nonrecurring Basis [Table Text Block]	The following tables present financial assets by level within the fair-value hierarchy which were recorded at fair value on a nonrecurring basis. The fair values presented are as of the date the fair value adjustment was recorded (dollars in thousands). June 30, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 2,077 $ 2,077 Mortgage loans held for portfolio — — 4,745 4,745 REO — — 654 654 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 7,476 $ 7,476 December 31, 2016 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 8,498 $ 8,498 Mortgage loans held for portfolio — — 5,618 5,618 REO — — 786 786 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 14,902 $ 14,902

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	The following table sets forth our off-balance-sheet commitments as of June 30, 2017 , and December 31, 2016 (dollars in thousands): June 30, 2017 December 31, 2016 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 4,042,006 $ 205,432 $ 4,247,438 $ 4,050,447 $ 179,632 $ 4,230,079 Commitments for unused lines of credit - advances (2) 1,274,172 — 1,274,172 1,255,140 — 1,255,140 Commitments to make additional advances 151,874 54,241 206,115 44,865 65,972 110,837 Commitments to invest in mortgage loans 71,314 — 71,314 22,524 — 22,524 Unsettled CO bonds, at par 107,745 — 107,745 — — — __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At June 30, 2017 , and December 31, 2016 , these amounts totaled $ 7.3 million and $2.7 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $285,000 at December 31, 2016 . (2) Commitments for unused line-of-credit advances are generally for periods of up to 12 months . Since many of these commitments are not expected to be drawn upon, the total commitment amount does not necessarily indicate future liquidity requirements.

Transactions with Shareholders

Transactions with Shareholders (Tables)	6 Months Ended
	Jun. 30, 2017
Transactions with Shareholders [Abstract]
Schedule of Transactions with Shareholders [Table Text Block]	The following tables present transactions with shareholders whose holdings of capital stock exceed 10 percent or more of total capital stock outstanding at June 30, 2017 , and December 31, 2016 (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 June 30, 2017 Citizens Bank, N.A. $ 245,034 10.0 % $ 5,108,880 13.3 % $ 1,661 4.4 % As of December 31, 2016 Citizens Bank, N.A. $ 357,508 14.6 % $ 7,260,446 18.6 % $ 2,625 7.3 %
Schedule of Transactions with Shareholders, Interest Income [Table Text Block]	We recognized interest income on outstanding advances and fees on letters of credit from Citizens Bank, N.A. during the three and six months ended June 30, 2017 and 2016 , as follows (dollars in thousands): For the Three Months Ended June 30, For the Six Months Ended June 30, Citizens Bank, N.A. 2017 2016 2017 2016 Interest income on advances $ 18,541 $ 8,082 $ 32,652 $ 16,286 Fees on letters of credit 701 779 1,446 1,619
Schedule of Transactions with Shareholders, Transactions with Directors' Financial Institutions [Table Text Block]	The following table 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 (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 June 30, 2017 $ 78,430 3.2 % $ 1,416,338 3.7 % $ 1,541 4.1 % As of December 31, 2016 91,374 3.7 1,554,753 4.0 1,631 4.5

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 514,313	$ 612,622
U.S. Treasury obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	309,332	399,521
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	7,634	8,494
MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	204,981	213,101
GSEs - single-family [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	534	768
GSEs - multifamily [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 196,813	$ 203,839

Trading Securities - Net Unreal

Trading Securities - Net Unrealized (Losses) Gains (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Trading Securities [Abstract]
Net unrealized losses or gains on trading securities	$ (852)	$ 84	$ (2,266)	$ 1,957

Available-for-Sale Securities M

Available-for-Sale Securities Major Security Types (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 6,736,105	$ 6,725,473
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		10,648	3,068
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(104,957)	(139,877)
Available-for-sale securities Fair Value		6,641,796	6,588,664
States or local housing-finance-agency obligations (HFA securities) [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	16,950	9,350
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(1,536)	(1,204)
Available-for-sale securities Fair Value		15,414	8,146
Supranational institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	448,953	452,021
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(26,775)	(29,401)
Available-for-sale securities Fair Value		422,178	422,620
U.S. government-owned corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	318,140	317,588
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(32,368)	(45,631)
Available-for-sale securities Fair Value		285,772	271,957
GSEs [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	130,770	130,798
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(10,417)	(13,330)
Available-for-sale securities Fair Value		120,353	117,468
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	914,813	909,757
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(71,096)	(89,566)
Available-for-sale securities Fair Value		843,717	820,191
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	112,759	127,032
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		55	16
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(2,367)	(2,321)
Available-for-sale securities Fair Value		110,447	124,727
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	493,695	565,593
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	45
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(2,458)	(2,277)
Available-for-sale securities Fair Value		491,237	563,361
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	5,821,292	5,815,716
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		10,648	3,068
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(33,861)	(50,311)
Available-for-sale securities Fair Value	[2]	5,798,079	5,768,473
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	4,169,847	4,447,803
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		6,711	1,765
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(27,861)	(45,713)
Available-for-sale securities Fair Value		4,148,697	4,403,855
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	1,044,991	675,288
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		3,882	1,242
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(1,175)	0
Available-for-sale securities Fair Value		$ 1,047,698	$ 676,530
[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	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 3,540,535	$ 3,882,972
Less than 12 Months, Unrealized Losses	(25,731)	(41,650)
12 Months or More, Fair Value	1,409,480	1,419,476
12 Months or More, Unrealized Losses	(79,226)	(98,227)
Total Fair Value	4,950,015	5,302,448
Total Unrealized Losses	(104,957)	(139,877)
HFA securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	15,414	8,146
Less than 12 Months, Unrealized Losses	(1,536)	(1,204)
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Losses	0	0
Total Fair Value	15,414	8,146
Total Unrealized Losses	(1,536)	(1,204)
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	422,178	422,620
12 Months or More, Unrealized Losses	(26,775)	(29,401)
Total Fair Value	422,178	422,620
Total Unrealized Losses	(26,775)	(29,401)
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	285,772	271,957
12 Months or More, Unrealized Losses	(32,368)	(45,631)
Total Fair Value	285,772	271,957
Total Unrealized Losses	(32,368)	(45,631)
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	120,353	117,468
12 Months or More, Unrealized Losses	(10,417)	(13,330)
Total Fair Value	120,353	117,468
Total Unrealized Losses	(10,417)	(13,330)
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	15,414	8,146
Less than 12 Months, Unrealized Losses	(1,536)	(1,204)
12 Months or More, Fair Value	828,303	812,045
12 Months or More, Unrealized Losses	(69,560)	(88,362)
Total Fair Value	843,717	820,191
Total Unrealized Losses	(71,096)	(89,566)
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	31,606
Less than 12 Months, Unrealized Losses	0	(4)
12 Months or More, Fair Value	81,466	90,854
12 Months or More, Unrealized Losses	(2,367)	(2,317)
Total Fair Value	81,466	122,460
Total Unrealized Losses	(2,367)	(2,321)
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	353,041	326,126
Less than 12 Months, Unrealized Losses	(1,479)	(1,261)
12 Months or More, Fair Value	138,196	165,246
12 Months or More, Unrealized Losses	(979)	(1,016)
Total Fair Value	491,237	491,372
Total Unrealized Losses	(2,458)	(2,277)
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	3,525,121	3,874,826
Less than 12 Months, Unrealized Losses	(24,195)	(40,446)
12 Months or More, Fair Value	581,177	607,431
12 Months or More, Unrealized Losses	(9,666)	(9,865)
Total Fair Value	4,106,298	4,482,257
Total Unrealized Losses	(33,861)	(50,311)
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	2,777,084	3,517,094
Less than 12 Months, Unrealized Losses	(21,541)	(39,181)
12 Months or More, Fair Value	361,515	351,331
12 Months or More, Unrealized Losses	(6,320)	(6,532)
Total Fair Value	3,138,599	3,868,425
Total Unrealized Losses	(27,861)	$ (45,713)
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	394,996
Less than 12 Months, Unrealized Losses	(1,175)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	394,996
Total Unrealized Losses	$ (1,175)

Available-for-Sale Securities R

Available-for-Sale Securities Redemption Terms (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 6,736,105	$ 6,725,473
Fair Value		6,641,796	6,588,664
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		16,950	9,350
Due after one year through five years, fair value		15,414	8,146
Due after five years through 10 years, amortized cost		170,161	171,589
Due after five years through 10 years, fair value		159,254	161,746
Due after 10 years, amortized cost		727,702	728,818
Due after 10 years, fair value		669,049	650,299
Amortized Cost	[1]	914,813	909,757
Fair Value		843,717	820,191
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	5,821,292	5,815,716
Fair Value	[2]	$ 5,798,079	$ 5,768,473
[1]	Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.
[2]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities Maj

Held-to-Maturity Securities Major Security Types (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 2,073,164	$ 2,323,145
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(175,067)	(192,378)
Carrying Value	[1],[2]	1,898,097	2,130,767
Gross Unrecognized Holding Gains		284,292	270,306
Gross Unrecognized Holding Losses		(22,336)	(28,783)
Held-to-maturity securities Fair Value		2,160,053	2,372,290
U.S. agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		1,602	2,159
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		1,602	2,159
Gross Unrecognized Holding Gains		29	56
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		1,631	2,215
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		159,689	162,568
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		159,689	162,568
Gross Unrecognized Holding Gains		10	11
Gross Unrecognized Holding Losses		(15,856)	(19,291)
Held-to-maturity securities Fair Value		143,843	143,288
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		161,291	164,727
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value	[1]	161,291	164,727
Gross Unrecognized Holding Gains		39	67
Gross Unrecognized Holding Losses		(15,856)	(19,291)
Held-to-maturity securities Fair Value		145,474	145,503
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		11,427	12,719
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		11,427	12,719
Gross Unrecognized Holding Gains		243	246
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		11,670	12,965
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		800	1,532
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		800	1,532
Gross Unrecognized Holding Gains		0	0
Gross Unrecognized Holding Losses		(1)	0
Held-to-maturity securities Fair Value		799	1,532
Asset-backed securities backed by home equity loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		12,568	13,515
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(530)	(574)
Carrying Value		12,038	12,941
Gross Unrecognized Holding Gains		581	602
Gross Unrecognized Holding Losses		(485)	(600)
Held-to-maturity securities Fair Value		12,134	12,943
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	1,911,873	2,158,418
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(175,067)	(192,378)
Carrying Value	[1],[3]	1,736,806	1,966,040
Gross Unrecognized Holding Gains		284,253	270,239
Gross Unrecognized Holding Losses		(6,480)	(9,492)
Held-to-maturity securities Fair Value	[3]	2,014,579	2,226,787
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		678,107	812,836
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		678,107	812,836
Gross Unrecognized Holding Gains		14,115	16,881
Gross Unrecognized Holding Losses		(292)	(519)
Held-to-maturity securities Fair Value		691,930	829,198
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		295,130	318,667
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		295,130	318,667
Gross Unrecognized Holding Gains		10,271	11,692
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		305,401	330,359
Private-label - residential MBS [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		913,841	999,149
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(174,537)	(191,804)
Carrying Value		739,304	807,345
Gross Unrecognized Holding Gains		259,043	240,818
Gross Unrecognized Holding Losses		(5,702)	(8,373)
Held-to-maturity securities Fair Value		$ 992,645	$ 1,039,790
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 2,160,053 and $2,372,290 at June 30, 2017 , and December 31, 2016
[3]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Held-to-Maturity Securities Fai

Held-to-Maturity Securities Fair Value and Unrealized Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	$ 16,727	$ 100,206
Less than 12 Months, Unrealized Losses	(192)	(521)
12 Months or More, Fair Value	454,921	563,669
12 Months or More, Unrealized Losses	(32,172)	(48,918)
Total Fair Value	471,648	663,875
Total Unrealized Losses	(32,364)	(49,439)
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	141,514	140,959
12 Months or More, Unrealized Losses	(15,856)	(19,291)
Total Fair Value	141,514	140,959
Total Unrealized Losses	(15,856)	(19,291)
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	799
Less than 12 Months, Unrealized Losses	(1)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	799
Total Unrealized Losses	(1)
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	11,143	11,898
12 Months or More, Unrealized Losses	(601)	(720)
Total Fair Value	11,143	11,898
Total Unrealized Losses	(601)	(720)
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	16,727	100,206
Less than 12 Months, Unrealized Losses	(192)	(521)
12 Months or More, Fair Value	313,407	422,710
12 Months or More, Unrealized Losses	(16,316)	(29,627)
Total Fair Value	330,134	522,916
Total Unrealized Losses	(16,508)	(30,148)
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	15,928	83,291
Less than 12 Months, Unrealized Losses	(191)	(393)
12 Months or More, Fair Value	17,590	13,405
12 Months or More, Unrealized Losses	(101)	(126)
Total Fair Value	33,518	96,696
Total Unrealized Losses	(292)	(519)
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	16,915
Less than 12 Months, Unrealized Losses	0	(128)
12 Months or More, Fair Value	284,674	397,407
12 Months or More, Unrealized Losses	(15,614)	(28,781)
Total Fair Value	284,674	414,322
Total Unrealized Losses	$ (15,614)	$ (28,909)

Held-to-Maturity Securities Red

Held-to-Maturity Securities Redemption Terms (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 2,073,164	$ 2,323,145
Carrying Value	[1],[2]	1,898,097	2,130,767
Fair Value		2,160,053	2,372,290
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Due in one year or less, Amortized Cost		109	0
Due in one year or less, Carrying Value	[1]	109	0
Due in one year or less, Fair Value		111	0
Due after one year through five years, Amortized Cost		15,972	16,637
Due after one year through five years, Carrying Value	[1]	15,972	16,637
Due after one year through five years, Fair Value		15,974	16,663
Due after five years through 10 years, Amortized Cost		0	0
Due after five years through 10 years, Carrying Value	[1]	0	0
Due after five years through 10 years, Fair Value		0	0
Due after 10 years, Amortized Cost		145,210	148,090
Due after 10 years, Carrying Value	[1]	145,210	148,090
Due after 10 years, Fair Value		129,389	128,840
Amortized Cost		161,291	164,727
Carrying Value	[1]	161,291	164,727
Fair Value		145,474	145,503
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	1,911,873	2,158,418
Carrying Value	[1],[3]	1,736,806	1,966,040
Fair Value	[3]	$ 2,014,579	$ 2,226,787
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 2,160,053 and $2,372,290 at June 30, 2017 , and December 31, 2016
[3]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Other-Than-Temporary Impairme53

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	6 Months Ended
	Jun. 30, 2017USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 66,522
Project Prepayment Rates - Weighted Average Percent	8.40%
Projected Default Rates, Weighted Average Percent	26.80%
Projected Loss Severities, Weighted Average Percent	35.50%
Current Credit Enhancement, Weighted Average Percent	11.10%
[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 Impairme54

Other-Than-Temporary Impairment OTTI Credit Losses Recognized During Life of Security (Details) - Held-to-maturity Securities [Member] $ in Thousands	Jun. 30, 2017USD ($)	[1]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	$ 1,056,852
Amortized Cost	787,257
Carrying Value	612,190
Fair Value	871,699
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	34,924
Amortized Cost	30,001
Carrying Value	23,642
Fair Value	31,335
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	1,018,372
Amortized Cost	753,997
Carrying Value	585,819
Fair Value	837,054
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	3,556
Amortized Cost	3,259
Carrying Value	2,729
Fair Value	$ 3,310
[1]	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 Impairme55

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		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at beginning of period		$ 482,221	$ 525,809	$ 490,404	$ 533,888
Additional credit losses for which an other-than-temporary impairment charge was previously recognized	[1]	568	1,003	986	2,350
Securities matured during the period	[2]	(5,565)	0	(5,565)	0
Increase in cash flows expected to be collected which are recognized over the remaining life of the security	[3]	(8,518)	(9,890)	(17,119)	(19,316)
Balance at end of period		$ 468,706	$ 516,922	$ 468,706	$ 516,922
[1]	For the three months ended June 30, 2017 and 2016 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to April 1, 2017 and 2016 , respectively. For the six months ended June 30, 2017 and 2016 , 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, 2017 and 2016
[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.
[3]	Represents amounts accreted as interest income during the current period.

Advances - Year of Contractual

Advances - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Maturity, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts		$ 3,046	$ 3,780
Due in one year or less		20,369,559	18,783,802
Due after one year through two years		8,740,980	10,966,780
Due after two years through three years		3,005,963	2,508,459
Due after three years through four years		2,034,081	2,177,432
Due after four years through five years		1,931,339	2,041,269
Thereafter		2,375,221	2,633,333
Total par value		$ 38,460,189	$ 39,114,855
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Rolling Year [Abstract]
Overdrawn demand-deposit accounts, Weighted average rate		1.45%	0.92%
Due in one year or less, Weighted average rate		1.35%	1.05%
Due after one year through two years, Weighted average rate		1.50%	1.15%
Due after two years through three years, Weighted average rate		1.78%	1.67%
Due after three years through four years, Weighted average rate		1.75%	1.64%
Due after four years through five years, Weighted average rate		1.97%	1.80%
Thereafter, Weighted average rate		1.81%	1.70%
Total Weighted average rate		1.50%	1.23%
Premiums		$ 19,735	$ 22,633
Discounts		(30,900)	(25,847)
Fair value of bifurcated derivatives	[1]	640	(153)
Hedging adjustments		(22,048)	(12,149)
Total Advances		$ 38,427,616	$ 39,099,339
[1]	At June 30, 2017 , and December 31, 2016

Advances Advances - Year of Con

Advances Advances - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts		$ 3,046	$ 3,780
Due in one year or less	[1]	25,883,734	26,447,977
Due after one year through two years	[1]	3,627,980	3,693,780
Due after two years through three years	[1]	3,005,963	2,508,459
Due after three years through four years	[1]	1,848,881	2,002,232
Due after four years through five years	[1]	1,769,339	1,891,269
Thereafter	[1]	2,321,246	2,567,358
Total par value		$ 38,460,189	$ 39,114,855
[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	Jun. 30, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	$ 3,046	$ 3,780
Due in one year or less	22,092,559	20,788,552
Due after one year through two years	8,946,230	10,946,530
Due after two years through three years	2,922,963	2,455,709
Due after three years through four years	1,847,081	1,974,932
Due after four years through five years	1,631,339	1,736,769
Thereafter	1,016,971	1,208,583
Total par value	$ 38,460,189	$ 39,114,855

Advances - Interest-Rate-Paymen

Advances - Interest-Rate-Payment Terms (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Fixed Rate [Abstract]
Fixed-rate	$ 32,303,868	$ 30,526,192
Federal Home Loan Bank, Advances, Floating Rate [Abstract]
Variable-rate	6,156,321	8,588,663
Total par value	$ 38,460,189	$ 39,114,855

Advances - Narratives (Details)

Advances - Narratives (Details) $ in Thousands	Jun. 30, 2017USD ($)Borrowers	Dec. 31, 2016USD ($)Borrowers
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank, Advances, Par Value	$ 38,460,189	$ 39,114,855
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount	12,200,000	$ 16,200,000
Minimum amount of advances outstanding per borrower	$ 1,000,000
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	31.70%	41.50%
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%
Federal Home Loan Bank, Advances, Callable Option [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank, Advances, Par Value	$ 5,700,000	$ 7,900,000
Federal Home Loan Bank, Advances, Putable Option [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank, Advances, Par Value	$ 2,600,000	$ 3,400,000

Mortgage Loans Held for Portf61

Mortgage Loans Held for Portfolio (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,735,848	$ 3,626,962
Premiums	68,395	67,523
Discounts	(1,613)	(1,696)
Deferred derivative gains, net	2,451	1,755
Total mortgage loans held for portfolio	3,805,081	3,694,544
Less: allowance for credit losses	(500)	(650)
Total mortgage loans, net of allowance for credit losses	$ 3,804,581	3,693,894
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	$ 3,357,891	3,235,835
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	$ 377,957	391,127
Single Family [Member] | Fixed-rate 15-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	500,527	528,486
Single Family [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,235,321	$ 3,098,476

Allowance for credit losses - C

Allowance for credit losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2017	Dec. 31, 2016
Mortgage Loans Past Due [Line Items]
Total past due		$ 63,030	$ 73,175
Total current loans		3,760,964	3,640,109
Total mortgage loans		3,823,994	3,713,284
In process of foreclosure, included above	[1]	$ 7,328	$ 8,997
Serious delinquency rate	[2]	0.48%	0.63%
Past due 90 days or more still accruing interest		$ 4,985	$ 5,807
Loans on nonaccrual status	[3]	$ 13,006	16,940
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		$ 19,951	24,531
Total current loans		368,309	377,438
Total mortgage loans		388,260	401,969
In process of foreclosure, included above	[1]	$ 1,297	$ 1,502
Serious delinquency rate	[2]	1.28%	1.44%
Past due 90 days or more still accruing interest		$ 4,985	$ 5,807
Loans on nonaccrual status	[3]	0	0
Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		43,079	48,644
Total current loans		3,392,655	3,262,671
Total mortgage loans		3,435,734	3,311,315
In process of foreclosure, included above	[1]	$ 6,031	$ 7,495
Serious delinquency rate	[2]	0.39%	0.53%
Past due 90 days or more still accruing interest		$ 0	$ 0
Loans on nonaccrual status	[3]	13,006	16,940
Past due 30-59 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		35,275	41,635
Past due 30-59 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		11,324	14,878
Past due 30-59 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		23,951	26,757
Past due 60-89 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		10,043	9,354
Past due 60-89 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		3,642	3,846
Past due 60-89 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		6,401	5,508
Past due 90 days or more delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		17,712	22,186
Past due 90 days or more delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		4,985	5,807
Past due 90 days or more delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		$ 12,727	$ 16,379
[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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired mortgage loans with no related allowance - Recorded Investment	$ 18,709		$ 18,709		$ 22,945
Individually evaluated impaired mortgage loans with no related allowance - Par Value	18,672		18,672		$ 22,905
Individually evaluated impaired mortgage loans with no related allowance - Average Recorded Investment	19,367	$ 24,770	20,324	$ 25,217
Individually evaluated impaired mortgage loans with no related allowance - Interest Income recognized	$ 107	$ 102	$ 223	$ 182

Allowance for credit losses - A

Allowance for credit losses - Allowance Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				$ 650
Reduction of provision for credit losses		$ (125)	$ (111)	(176)	$ (100)
Balance, end of period		500		500
Conventional mortgage loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period		625	1,025	650	1,025
Recoveries (charge-offs)		0	(14)	26	(25)
Reduction of provision for credit losses		(125)	(111)	(176)	(100)
Balance, end of period		500	900	500	900
Ending balance, individually evaluated for impairment		0	0	0	0
Ending balance, collectively evaluated for impairment		500	900	500	900
Recorded Investment Individually evaluated for impairment	[1]	18,709	24,583	18,709	24,583
Recorded Investment Collectively evaluated for impairment	[1]	$ 3,417,025	$ 3,208,989	$ 3,417,025	$ 3,208,989
[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 Activ65

Derivatives and Hedging Activities Derivatives in Statement of Condition (Details) - USD ($)		Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		$ 17,862,854,000	$ 19,965,133,000
Derivative Assets, before netting and collateral adjustments		42,862,000	55,078,000
Derivative Liabilities, before netting and collateral adjustments		(419,486,000)	(460,287,000)
Derivative Asset, cash collateral, and variation margin for daily settled contracts including related accrued interest	[1],[2]	13,761,000	6,520,000
Derivative Liability, cash collateral, and variation margin for daily settled contracts including related accrued interest	[1],[2]	90,257,000	102,411,000
Derivative Assets		56,623,000	61,598,000
Derivative Liabilities		(329,229,000)	(357,876,000)
Cash collateral and related accrued interest posted		62,000,000	109,800,000
Cash collateral and related accrued interest received		601,000	850,000
Variation margin for daily settled contracts		42,600,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		16,740,640,000	18,743,609,000
Derivative Assets, before netting and collateral adjustments		41,631,000	52,715,000
Derivative Liabilities, before netting and collateral adjustments		(410,700,000)	(449,276,000)
Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		16,212,840,000	18,215,809,000
Derivative Assets, before netting and collateral adjustments		41,631,000	52,715,000
Derivative Liabilities, before netting and collateral adjustments		(369,601,000)	(413,026,000)
Designated as Hedging Instrument [Member] | Forward-start interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		527,800,000	527,800,000
Derivative Assets, before netting and collateral adjustments		0	0
Derivative Liabilities, before netting and collateral adjustments		(41,099,000)	(36,250,000)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,122,214,000	1,221,524,000
Derivative Assets, before netting and collateral adjustments		1,231,000	2,363,000
Derivative Liabilities, before netting and collateral adjustments		(8,786,000)	(11,011,000)
Not Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,050,900,000	1,199,000,000
Derivative Assets, before netting and collateral adjustments		1,132,000	2,293,000
Derivative Liabilities, before netting and collateral adjustments		(8,589,000)	(10,840,000)
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets		99,000	70,000
Derivative Liabilities		(197,000)	(171,000)
Mortgages [Member] | Not Designated as Hedging Instrument [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	[3]	71,314,000	22,524,000
Derivative Assets, before netting and collateral adjustments	[3]	99,000	70,000
Derivative Liabilities, before netting and collateral adjustments	[3]	$ (197,000)	$ (171,000)
[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 $62.0 million and $109.8 million at June 30, 2017 , and December 31, 2016 , 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 $601,000 and $850,000 at June 30, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $42.6 million at June 30, 2017 .
[2]	Carried at fair value on a recurring basis.
[3]	Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income.

Derivatives and Hedging Activ66

Derivatives and Hedging Activities Derivatives in Statement of Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		$ (752)	$ (2,218)	$ (1,411)	$ (5,251)
Total net losses related to derivatives designated as hedging instruments		(655)	(2,408)	(1,180)	(5,787)
Total net gains (losses) related to derivatives not designated as hedging instruments		132	(555)	642	(3,411)
Other	[1]	105	0	156	0
Net losses on derivatives and hedging activities		(418)	(2,963)	(382)	(9,198)
Interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		(752)	(2,218)	(1,411)	(5,251)
Total net gains (losses) related to derivatives not designated as hedging instruments		(375)	(1,245)	(222)	(4,717)
Forward-start interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge ineffectiveness		97	(190)	231	(536)
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses) related to derivatives not designated as hedging instruments		$ 507	$ 690	$ 864	$ 1,306
[1]	Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount.

Derivatives and Hedging Activ67

Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Interest (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		$ (471)	$ (51,887)	$ 30,968	$ (159,531)
Gain/(Loss) on Hedged Item		(281)	49,669	(32,379)	154,280
Net Fair-Value Hedge Ineffectiveness		(752)	(2,218)	(1,411)	(5,251)
Effect of Derivatives on Net Interest Income	[1]	(14,300)	(27,853)	(31,405)	(58,916)
Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		(11,327)	(25,621)	9,768	(94,077)
Gain/(Loss) on Hedged Item		10,554	24,655	(9,899)	92,888
Net Fair-Value Hedge Ineffectiveness		(773)	(966)	(131)	(1,189)
Effect of Derivatives on Net Interest Income	[1]	(8,283)	(26,128)	(21,688)	(56,252)
Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		(6,863)	(26,830)	3,405	(76,285)
Gain/(Loss) on Hedged Item		7,264	27,186	(2,544)	77,025
Net Fair-Value Hedge Ineffectiveness		401	356	861	740
Effect of Derivatives on Net Interest Income	[1]	(8,099)	(8,883)	(16,440)	(17,894)
COs - bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		17,719	564	17,795	10,831
Gain/(Loss) on Hedged Item		(18,099)	(2,172)	(19,936)	(15,633)
Net Fair-Value Hedge Ineffectiveness		(380)	(1,608)	(2,141)	(4,802)
Effect of Derivatives on Net Interest Income	[1]	$ 2,082	$ 7,158	$ 6,723	$ 15,230
[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 Activ68

Derivatives and Hedging Activities Cash Flow Hedge Activity (Details) - COs - bonds [Member] - Interest-rate swaps [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Losses Recognized in Other Comprehensive Loss on Derivatives (Effective Portion)	$ (4,943)	$ (9,731)	$ (5,081)	$ (26,770)
Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion)	(3,392)	(6,889)	(7,707)	(14,097)
Gains (Losses) Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion)	$ 97	$ (190)	$ 231	$ (536)

Derivatives and Hedging Activ69

Derivatives and Hedging Activities Narratives (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Derivative [Line Items]
Maximum length of time which we are hedging our exposure to the variability in future cash flows for forecasted transactions	7 years
Deferred net losses on derivative accumulated in other comprehensive loss expected to be reclassified to earnings during the next 12 months	$ 4,900
Aggregate fair value of all uncleared derivative instruments with credit-risk-related contingent features that were in a net liability position	351,400
Post-haircut value of collateral already posted	326,500
Rating Downgrade from AAPlus to AA or AAMinus [Member]
Derivative [Line Items]
Incremental collateral	9,858	[1]
Rating Downgrade From AAMinus to APlus, A or AMinus [Member]
Derivative [Line Items]
Incremental collateral	6,250	[1]
Rating Downgrade From AMinus to below AMinus [Member]
Derivative [Line Items]
Incremental collateral	$ 22,670	[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 Activ70

Derivatives and Hedging Activities Fair Value of Derivative Instruments With or Without Legal Rights of Offset (Details) - USD ($)		Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Asset, total gross recognized amount		$ 42,763,000	$ 55,008,000
Derivative Liability, total gross recognized amount		(419,289,000)	(460,116,000)
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	13,761,000	6,520,000
Derivative Liability, Netting Adjustments and Cash Collateral	[1],[2]	90,257,000	102,411,000
Derivative Asset, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		56,524,000	61,528,000
Derivative Liability, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		(329,032,000)	(357,705,000)
Derivative assets		56,623,000	61,598,000
Derivative liabilities		(329,229,000)	(357,876,000)
Derivative Assets, Total non-cash collateral received or pledged, not offset		0	0
Derivative Liabilities, Total non-cash collateral received or pledged, not offset	[3]	309,735,000	320,750,000
Derivative Asset, Fair value, amount offset against collateral		56,623,000	61,598,000
Derivative Liability, Fair value, amount offset against collateral		(19,494,000)	(37,126,000)
Derivative Liabilities, additional net exposure, collateral pledged to counterparties in excess of net liabilities		118,000	2,000,000
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivative [Line Items]
Derivative Asset, Mortgage delivery commitments		99,000	70,000
Derivative Liabilities, Mortgage delivery commitments		(197,000)	(171,000)
Derivative assets		99,000	70,000
Derivative liabilities		(197,000)	(171,000)
Derivative Asset, Fair value, amount offset against collateral		99,000	70,000
Derivative Liability, Fair value, amount offset against collateral		(197,000)	(171,000)
Uncleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		9,168,000	12,594,000
Derivative Liability, total gross recognized amount		(359,879,000)	(405,310,000)
Derivative Assets, Netting Adjustments and Cash Collateral		(8,377,000)	(12,028,000)
Derivative Liability, Netting Adjustments and Cash Collateral		30,847,000	47,605,000
Derivative Asset, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		791,000	566,000
Derivative Liability, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		(329,032,000)	(357,705,000)
Derivative assets		791,000	566,000
Derivative liabilities		(329,032,000)	(357,705,000)
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	0
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged	[3]	11,933,000	30,306,000
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	0
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged	[3]	297,802,000	290,444,000
Derivative Asset, Fair value, amount offset against collateral		791,000	566,000
Derivative Liability, Fair value, amount offset against collateral		(19,297,000)	(36,955,000)
Cleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		33,595,000	42,414,000
Derivative Liability, total gross recognized amount		(59,410,000)	(54,806,000)
Derivative Assets, Netting Adjustments and Cash Collateral		22,138,000	18,548,000
Derivative Liability, Netting Adjustments and Cash Collateral		59,410,000	54,806,000
Derivative Asset, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		55,733,000	60,962,000
Derivative Liability, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		0	0
Derivative assets		55,733,000	60,962,000
Derivative liabilities		0	0
Derivative Asset, Fair value, amount offset against collateral		55,733,000	60,962,000
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 $62.0 million and $109.8 million at June 30, 2017 , and December 31, 2016 , 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 $601,000 and $850,000 at June 30, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $42.6 million at June 30, 2017 .
[2]	Carried at fair value on a recurring basis.
[3]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At June 30, 2017 , and December 31, 2016 , we had additional net credit exposure of $118,000 and $2.0 million

Deposits Narratives (Details)

Deposits Narratives (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Deposits [Abstract]
Interest-bearing deposit demand and overnight	$ 436,800	$ 440,731
Interest-bearing deposit other	4,510	4,166
Non-interest bearing deposits other	27,863	37,266
Total deposits	$ 469,173	$ 482,163

Consolidated Obligations CO Bon

Consolidated Obligations CO Bonds - Year of Contractual Maturiry (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Schedule of Short-term and Long-term Debt [Line Items]
Due in one year or less		$ 12,230,385	$ 8,734,955
Due in one year or less, weighted average rate	[1]	1.33%	1.43%
Due after one year through two years		$ 6,320,065	$ 7,752,420
Due after one year through two years, weighted average rate	[1]	1.36%	1.19%
Due after two years through three years		$ 3,080,645	$ 3,297,120
Due after two years through three years, weighted average rate	[1]	1.86%	1.63%
Due after three years through four years		$ 1,817,190	$ 1,637,335
Due after three years through four years, weighted average rate	[1]	1.79%	1.87%
Due after four years through five years		$ 1,965,545	$ 2,574,375
Due after four years through five years, weighted average rate	[1]	1.77%	1.65%
Thereafter		$ 3,060,590	$ 3,135,745
Thereafter, weighted average rate	[1]	2.70%	2.70%
Total par value		$ 28,474,420	$ 27,131,950
Total par value, weighted average rate	[1]	1.60%	1.58%
Hedging adjustments		$ (43,819)	$ (63,755)
Total		28,518,424	27,171,434
COs - bonds [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Premiums		101,843	118,145
Discounts		$ (14,020)	$ (14,906)
[1]	The CO bonds' weighted-average rate excludes concession fees.

Consolidated Obligations CO B73

Consolidated Obligations CO Bonds - Outstanding By Call Features (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 28,474,420	$ 27,131,950
Noncallable and nonputable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	24,456,420	22,388,950
Callable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 4,018,000	$ 4,743,000

Consolidated Obligations CO B74

Consolidated Obligations CO Bonds - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Due in one year or less	$ 15,325,385	$ 12,858,955
Due after one year through two years	6,170,065	7,013,420
Due after two years through three years	2,952,645	2,904,120
Due after three years through four years	1,254,190	1,289,335
Due after four years through five years	1,003,545	1,242,375
Thereafter	1,768,590	1,823,745
Total par value	$ 28,474,420	$ 27,131,950

Consolidated Obligations CO B75

Consolidated Obligations CO Bonds - Interest-Rate-Payment Type (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Fixed-rate	$ 20,357,420	$ 20,289,950
Simple variable-rate	6,665,000	5,300,000
Step-up	1,452,000	1,542,000
Total par value	$ 28,474,420	$ 27,131,950

Consolidated Obligations CO - D

Consolidated Obligations CO - Discount Notes (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Federal Home Loan Bank, Consolidated Obligations, Discount Notes		$ 27,865,529	$ 30,053,964
Par value		$ 27,892,943	$ 30,070,103
Weighted Average Rate	[1]	0.95%	0.47%
[1]	The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program Roll

Affordable Housing Program Roll-forward AHP liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Affordable Housing Program [Roll Forward]
Balance at beginning of period			$ 81,627	$ 82,081	$ 82,081
AHP expense for the period	$ 4,418	$ 5,312	8,610	8,632	19,397
AHP direct grant disbursements			(10,491)	$ (7,025)	(18,575)
AHP subsidy for AHP advance disbursements			(1,416)		(1,378)
Return of previously disbursed grants and subsidies			14		102
Balance at end of period	$ 78,344		$ 78,344		$ 81,627

Capital Requirements (Details)

Capital Requirements (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
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	$ 2,408,647	$ 2,411,306
Mandatorily redeemable capital stock	37,380	32,687
Retained earnings	1,245,325	1,216,986
Total permanent capital	3,691,352	3,660,979
Credit-risk capital	344,501	355,182
Market-risk capital	152,177	118,765
Operations-risk capital	149,003	142,184
Total risk-based capital requirement	645,681	616,131
Permanent capital in excess of risk-based capital requirement	3,045,671	3,044,848
Regulatory capital, Required	2,430,170	2,461,823
Leverage capital, Required	3,037,712	3,077,279
Risk-based capital, Actual	3,691,352	3,660,979
Regulatory capital, Actual	$ 3,691,352	$ 3,660,979
Capital-to-asset ratio, Actual	6.10%	5.90%
Leverage capital, Actual	$ 5,537,028	$ 5,491,469
Leverage capital-to-assets ratio, Actual	9.10%	8.90%

Accumulated Other Comprehensi79

Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended				6 Months Ended
		Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		$ 104,168,000		$ 89,780,000		$ 202,343,000		$ 180,640,000
Amortization of hedging activities recorded in net gains (losses) on derivatives and hedging activities		(418,000)		(2,963,000)		(382,000)		(9,198,000)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance						(383,514,000)
Amortization - hedging activities		3,395,000		6,893,000		7,714,000		14,104,000
Amortization - pension and postretirement benefits		(415,000)		2,585,000		(609,000)		2,466,000
Other comprehensive income (loss)		23,111,000		32,088,000		63,053,000		84,255,000
Ending balance		(320,461,000)				(320,461,000)
Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(44,006,000)		(81,065,000)		(48,187,000)		(71,237,000)
Net unrealized gains (losses)		(4,943,000)		(9,731,000)		(5,081,000)		(26,770,000)
Amortization - hedging activities		3,395,000	[1]	6,893,000	[2]	7,714,000	[3]	14,104,000	[4]
Other comprehensive income (loss)		(1,548,000)		(2,838,000)		2,633,000		(12,666,000)
Ending balance		(45,554,000)		(83,903,000)		(45,554,000)		(83,903,000)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(5,945,000)		(3,738,000)		(6,139,000)		(3,857,000)
Net actuarial loss		224,000		(2,918,000)		224,000		(2,917,000)
Amortization - pension and postretirement benefits	[5]	191,000		333,000		385,000		451,000
Other comprehensive income (loss)		415,000		(2,585,000)		609,000		(2,466,000)
Ending balance		(5,530,000)		(6,323,000)		(5,530,000)		(6,323,000)
Total Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(343,572,000)		(390,430,000)		(383,514,000)		(442,597,000)
Net unrealized gains (losses)		10,651,000		18,210,000		37,419,000		53,001,000
Noncredit other-than-temporary impairment losses				(420,000)				(656,000)
Accretion of noncredit loss		8,119,000		9,211,000		16,415,000		18,352,000
Net actuarial loss		224,000		(2,918,000)		224,000		(2,917,000)
Noncredit other-than-temporary impairment losses reclassified to credit loss	[6]	531,000		779,000		896,000		1,920,000
Amortization - hedging activities		3,395,000	[1]	6,893,000	[2]	7,714,000	[3]	14,104,000	[4]
Amortization - pension and postretirement benefits	[5]	191,000		333,000		385,000		451,000
Other comprehensive income (loss)		23,111,000		32,088,000		63,053,000		84,255,000
Ending balance		(320,461,000)		(358,342,000)		(320,461,000)		(358,342,000)
Available-for-sale Securities [Member] | Net Unrealized Losses on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(109,903,000)		(85,888,000)		(136,809,000)		(137,718,000)
Net unrealized gains (losses)		15,594,000		27,941,000		42,500,000		79,771,000
Other comprehensive income (loss)		15,594,000		27,941,000		42,500,000		79,771,000
Ending balance		(94,309,000)		(57,947,000)		(94,309,000)		(57,947,000)
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 balance		(183,718,000)		(219,739,000)		(192,379,000)		(229,785,000)
Noncredit other-than-temporary impairment losses				(420,000)				(656,000)
Accretion of noncredit loss		8,119,000		9,211,000		16,415,000		18,352,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[6]	531,000		779,000		896,000		1,920,000
Other comprehensive income (loss)		8,650,000		9,570,000		17,311,000		19,616,000
Ending balance		(175,068,000)		(210,169,000)		(175,068,000)		(210,169,000)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		3,400,000		6,900,000		7,700,000		14,100,000
Amortization of hedging activities recorded in net gains (losses) on derivatives and hedging activities		$ 4,000		$ 4,000		$ 7,000		$ 7,000
[1]	Amortization of hedging activities includes $3.4 million recorded in CO bond interest expense and $4,000
[2]	Amortization of hedging activities includes $6.9 million recorded in CO bond interest expense and $4,000
[3]	Amortization of hedging activities includes $7.7 million recorded in CO bond interest expense and $7,000
[4]	Amortization of hedging activities includes $14.1 million recorded in CO bond interest expense and $7,000
[5]	Recorded in other operating expenses in the statement of operations.
[6]	Recorded in net amount of impairment losses reclassified to (from) 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		Jun. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 176,852	$ 520,031
Trading securities		514,313	612,622
Available-for-sale securities Fair Value		6,641,796	6,588,664
Held-to-maturity securities	[1],[2]	1,898,097	2,130,767
Held-to-maturity securities Fair Value		2,160,053	2,372,290
Accrued interest receivable		85,997	84,653
Derivative assets		56,623	61,598
Derivative Assets, Netting Adjustments and Cash Collateral	[3],[4]	13,761	6,520
Mandatorily redeemable capital stock		(37,380)	(32,687)
Accrued interest payable		(84,093)	(80,822)
Derivative liabilities		(329,229)	(357,876)
Derivative Liability, Netting Adjustments and Cash Collateral	[3],[4]	90,257	102,411
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		176,852	520,031
Interest-bearing deposits		279,046	278
Securities purchased under agreements to resell		0	0
Federal funds sold		0	0
Trading securities	[4]	0	0
Available-for-sale securities Fair Value	[4]	0	0
Held-to-maturity securities Fair Value		0	0
Advances		0	0
Mortgage loans, net		0	0
Accrued interest receivable		0	0
Derivative assets	[4]	0	0
Other assets	[4]	10,336	8,394
Deposits		0	0
Mandatorily redeemable capital stock		(37,380)	(32,687)
Accrued interest payable		0	0
Derivative liabilities	[4]	0	0
Level 1 [Member] | Commitments to extend credit for advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 1 [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 1 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0	0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		0	0
Interest-bearing deposits		0	0
Securities purchased under agreements to resell		4,348,852	5,998,799
Federal funds sold		4,459,941	2,699,949
Trading securities	[4]	514,313	612,622
Available-for-sale securities Fair Value	[4]	6,626,382	6,580,518
Held-to-maturity securities Fair Value		1,011,431	1,176,269
Advances		38,572,842	39,273,044
Mortgage loans, net		3,824,845	3,708,123
Accrued interest receivable		85,997	84,653
Derivative assets	[4]	42,862	55,078
Other assets	[4]	11,367	9,385
Deposits		(469,169)	(482,158)
Mandatorily redeemable capital stock		0	0
Accrued interest payable		(84,093)	(80,822)
Derivative liabilities	[4]	(419,486)	(460,287)
Level 2 [Member] | Commitments to extend credit for advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(4,377)	(4,412)
Level 2 [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(763)	(1,064)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(27,864,927)	(30,054,085)
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]	15,414	8,146
Held-to-maturity securities Fair Value		1,148,622	1,196,021
Advances		0	0
Mortgage loans, net		23,350	28,425
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 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 3 [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 3 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0	0
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		176,852	520,031
Interest-bearing deposits		279,046	278
Securities purchased under agreements to resell		4,349,000	5,999,000
Federal funds sold		4,460,000	2,700,000
Trading securities	[4]	514,313	612,622
Available-for-sale securities Fair Value	[4]	6,641,796	6,588,664
Held-to-maturity securities		1,898,097	2,130,767
Advances		38,427,616	39,099,339
Mortgage loans, net		3,804,581	3,693,894
Accrued interest receivable		85,997	84,653
Derivative assets	[4]	56,623	61,598
Other assets	[4]	21,703	17,779
Deposits		(469,173)	(482,163)
Mandatorily redeemable capital stock		(37,380)	(32,687)
Accrued interest payable		(84,093)	(80,822)
Derivative liabilities	[4]	(329,229)	(357,876)
Carrying Value [Member] | Commitments to extend credit for advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Carrying Value [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(763)	(1,064)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(27,865,529)	(30,053,964)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		176,852	520,031
Interest-bearing deposits		279,046	278
Securities purchased under agreements to resell		4,348,852	5,998,799
Federal funds sold		4,459,941	2,699,949
Trading securities	[4]	514,313	612,622
Available-for-sale securities Fair Value	[4]	6,641,796	6,588,664
Held-to-maturity securities Fair Value		2,160,053	2,372,290
Advances		38,572,842	39,273,044
Mortgage loans, net		3,848,195	3,736,548
Accrued interest receivable		85,997	84,653
Derivative assets	[4]	56,623	61,598
Other assets	[4]	21,703	17,779
Deposits		(469,169)	(482,158)
Mandatorily redeemable capital stock		(37,380)	(32,687)
Accrued interest payable		(84,093)	(80,822)
Derivative liabilities	[4]	(329,229)	(357,876)
Total Fair Value [Member] | Commitments to extend credit for advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(4,377)	(4,412)
Total Fair Value [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(763)	(1,064)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(27,864,927)	(30,054,085)
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		(28,645,061)	(27,298,499)
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		(28,518,424)	(27,171,434)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (28,645,061)	$ (27,298,499)
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 2,160,053 and $2,372,290 at June 30, 2017 , and December 31, 2016
[3]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $62.0 million and $109.8 million at June 30, 2017 , and December 31, 2016 , 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 $601,000 and $850,000 at June 30, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $42.6 million at June 30, 2017 .
[4]	Carried at fair value on a recurring basis.

Fair Values Fair Value Measured

Fair Values Fair Value Measured on Recurring Basis (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		$ 514,313	$ 612,622
Available-for-sale securities Fair Value		6,641,796	6,588,664
Derivative assets		56,623	61,598
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	13,761	6,520
Derivative liabilities		(329,229)	(357,876)
Derivative Liability, Netting Adjustments and Cash Collateral	[1],[2]	90,257	102,411
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	0	0
Available-for-sale securities Fair Value	[2]	0	0
Derivative assets	[2]	0	0
Other assets	[2]	10,336	8,394
Derivative liabilities	[2]	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	514,313	612,622
Available-for-sale securities Fair Value	[2]	6,626,382	6,580,518
Derivative assets	[2]	42,862	55,078
Other assets	[2]	11,367	9,385
Derivative liabilities	[2]	(419,486)	(460,287)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[2]	0	0
Available-for-sale securities Fair Value	[2]	15,414	8,146
Derivative assets	[2]	0	0
Other assets	[2]	0	0
Derivative liabilities	[2]	0	0
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[3]	13,761	6,520
Derivative Liability, Netting Adjustments and Cash Collateral	[3]	90,257	102,411
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	[3]	13,761	6,520
Derivative Liability, Netting Adjustments and Cash Collateral	[3]	90,257	102,411
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		10,336	8,394
Total assets at fair value		10,336	8,394
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		514,313	612,622
Available-for-sale securities Fair Value		6,626,382	6,580,518
Derivative assets		42,862	55,078
Other assets		11,367	9,385
Total assets at fair value		7,194,924	7,257,603
Total liabilities at fair value		(419,486)	(460,287)
Recurring [Member] | Level 2 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		42,763	55,008
Derivative liabilities		(419,289)	(460,116)
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		15,414	8,146
Derivative assets		0	0
Other assets		0	0
Total assets at fair value		15,414	8,146
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	[2]	514,313	612,622
Available-for-sale securities Fair Value	[2]	6,641,796	6,588,664
Derivative assets	[2]	56,623	61,598
Other assets	[2]	21,703	17,779
Derivative liabilities	[2]	(329,229)	(357,876)
Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		514,313	612,622
Available-for-sale securities Fair Value		6,641,796	6,588,664
Derivative assets		56,623	61,598
Other assets		21,703	17,779
Total assets at fair value		7,234,435	7,280,663
Total liabilities at fair value		(329,229)	(357,876)
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		56,524	61,528
Derivative liabilities		(329,032)	(357,705)
U.S. Treasury obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		309,332	399,521
U.S. Treasury obligations [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0	0
U.S. Treasury obligations [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		309,332	399,521
U.S. Treasury obligations [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0	0
U.S. Treasury obligations [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		309,332	399,521
U.S. government-guaranteed - single-family MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		7,634	8,494
Available-for-sale securities Fair Value		110,447	124,727
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		7,634	8,494
Available-for-sale securities Fair Value		110,447	124,727
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		7,634	8,494
Available-for-sale securities Fair Value		110,447	124,727
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		491,237	563,361
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		491,237	563,361
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		491,237	563,361
HFA securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		15,414	8,146
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		15,414	8,146
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		15,414	8,146
Supranational institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		422,178	422,620
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		422,178	422,620
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		422,178	422,620
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		285,772	271,957
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		285,772	271,957
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		285,772	271,957
GSEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		120,353	117,468
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		120,353	117,468
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		120,353	117,468
Single Family [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		534	768
Available-for-sale securities Fair Value		4,148,697	4,403,855
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		534	768
Available-for-sale securities Fair Value		4,148,697	4,403,855
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		534	768
Available-for-sale securities Fair Value		4,148,697	4,403,855
Multifamily [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		196,813	203,839
Available-for-sale securities Fair Value		1,047,698	676,530
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		196,813	203,839
Available-for-sale securities Fair Value		1,047,698	676,530
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		196,813	203,839
Available-for-sale securities Fair Value		1,047,698	676,530
Mortgages [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		99	70
Derivative liabilities		(197)	(171)
Mortgages [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
Mortgages [Member] | Recurring [Member] | Level 2 [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		99	70
Derivative liabilities		(197)	(171)
Mortgages [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
Mortgages [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		99	70
Derivative liabilities		$ (197)	$ (171)
[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 $62.0 million and $109.8 million at June 30, 2017 , and December 31, 2016 , 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 $601,000 and $850,000 at June 30, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $42.6 million at June 30, 2017 .
[2]	Carried at fair value on a recurring basis.
[3]	These amounts represent the application of the netting requirements which 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.

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	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 8,184	$ 8,146
Purchases	7,600	7,600
Unrealized losses included in other comprehensive income	(370)	(332)
Balance at end of period	$ 15,414	$ 15,414

Fair Values Fair Value Measur83

Fair Values Fair Value Measured on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	$ 2,160,053	$ 2,372,290
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	1,011,431	1,176,269
Mortgage loans held for portfolio	3,824,845	3,708,123
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	1,148,622	1,196,021
Mortgage loans held for portfolio	23,350	28,425
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	0	0
REO	0	0
Total assets recorded at fair value on a nonrecurring basis	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	0	0
REO	0	0
Total assets recorded at fair value on a nonrecurring basis	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	4,745	5,618
REO	654	786
Total assets recorded at fair value on a nonrecurring basis	7,476	14,902
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	2,160,053	2,372,290
Mortgage loans held for portfolio	3,848,195	3,736,548
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	4,745	5,618
REO	654	786
Total assets recorded at fair value on a nonrecurring basis	7,476	14,902
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	992,645	1,039,790
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	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	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	2,077	8,498
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	$ 2,077	$ 8,498

Commitments and Contingencies84

Commitments and Contingencies (Details) - USD ($)		6 Months Ended
		Jun. 30, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Value of the guarantees related to standby letters of credit		$ 38,564,000	$ 40,235,000
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		$ 955,200,000,000	932,100,000,000
Standby Letters of Credit Issuance Commitments [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 7,300,000	2,700,000
Off-balance-sheet Commitments Expiring After One Year			285,000
Maximum [Member]
Loss Contingencies [Line Items]
Term of standby letters of credit		20 years
Standby letters of credit outstanding [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[1]	$ 4,042,006,000	4,050,447,000
Off-balance-sheet Commitments Expiring After One Year	[1]	205,432,000	179,632,000
Total Off-balance Sheet Commitments	[1]	4,247,438,000	4,230,079,000
Value of the guarantees related to standby letters of credit		763,000	1,100,000
Commitments of unused lines of credit - advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[2]	1,274,172,000	1,255,140,000
Off-balance-sheet Commitments Expiring After One Year	[2]	0	0
Total Off-balance Sheet Commitments	[2]	$ 1,274,172,000	1,255,140,000
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		$ 151,874,000	44,865,000
Off-balance-sheet Commitments Expiring After One Year		54,241,000	65,972,000
Total Off-balance Sheet Commitments		206,115,000	110,837,000
Commitments to Invest in mortgage loans [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		71,314,000	22,524,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		71,314,000	22,524,000
Unsettled CO bonds, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		107,745,000	0
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		$ 107,745,000	$ 0
[1]	The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At June 30, 2017 , and December 31, 2016 , these amounts totaled $ 7.3 million and $2.7 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $285,000 at December 31, 2016
[2]	Commitments for unused line-of-credit advances are generally for periods of up to 12 months

Transactions with Shareholder85

Transactions with Shareholders (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 2,408,647		$ 2,408,647		$ 2,411,306
Par Value of Advances	38,460,189		38,460,189		39,114,855
Total Accrued Interest Receivable	85,997		85,997		84,653
Interest income on advances	127,736	$ 81,011	234,319	$ 159,230
Fees on letters of credit	2,122	1,934	4,134	3,902
Citizens Bank, N.A. [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 245,034		$ 245,034		$ 357,508
Percent of Total Capital Stock Outstanding	10.00%		10.00%		14.60%
Par Value of Advances	$ 5,108,880		$ 5,108,880		$ 7,260,446
Percentage of Total Par Value of Advances	13.30%		13.30%		18.60%
Total Accrued Interest Receivable	$ 1,661		$ 1,661		$ 2,625
Percent of Total Accrued Interest Receivable on Advances	4.40%		4.40%		7.30%
Interest income on advances	$ 18,541	8,082	$ 32,652	16,286
Fees on letters of credit	701	$ 779	1,446	$ 1,619
Directors' Financial Institutions [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 78,430		$ 78,430		$ 91,374
Percent of Total Capital Stock Outstanding	3.20%		3.20%		3.70%
Par Value of Advances	$ 1,416,338		$ 1,416,338		$ 1,554,753
Percentage of Total Par Value of Advances	3.70%		3.70%		4.00%
Total Accrued Interest Receivable	$ 1,541		$ 1,541		$ 1,631
Percent of Total Accrued Interest Receivable on Advances	4.10%		4.10%		4.50%
Minimum [Member]
Transactions with Shareholders [Line Items]
Definition of shareholder concentration, minimum percent	10.00%		10.00%

Subsequent Events Subsequent 86

Subsequent Events Subsequent Events (Details) - Common Class B [Member] - Subsequent Event [Member] - USD ($) $ in Millions	Aug. 02, 2017	Jul. 21, 2017
Subsequent Event [Line Items]
Annualized rate of cash dividends		4.22%
Dividend, including dividends on mandatorily redeemable capital stock	$ 26