Federal Home Loan Bank of Boston 10-Q 11 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 30, 2017
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Mar. 31, 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	Q1
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		25,379,782

Statements of Condition (unaudi

Statements of Condition (unaudited) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
ASSETS
Cash and due from banks		$ 12,817	$ 520,031
Interest-bearing deposits		246,317	278
Securities purchased under agreements to resell		2,999,000	5,999,000
Federal funds sold		5,150,000	2,700,000
Investment securities:
Trading securities		516,150	612,622
Available-for-sale securities - includes $4,657 and $7,968 pledged as collateral at March 31, 2017, and December 31, 2016, respectively that may be repledged		6,299,801	6,588,664
Held-to-maturity securities - includes $17,127 and $23,618 pledged as collateral at March 31, 2017, and December 31, 2016, respectively that may be repledged	[1],[2]	2,004,511	2,130,767
Total investment securities		8,820,462	9,332,053
Advances		35,479,424	39,099,339
Mortgage loans held for portfolio, net of allowance for credit losses of $625 and $650 at March 31, 2017, and December 31, 2016, respectively		3,675,598	3,693,894
Accrued interest receivable		78,816	84,653
Premises, software, and equipment, net		5,500	5,211
Derivative assets, net		52,693	61,598
Other assets		48,175	49,529
Total Assets		56,568,802	61,545,586
Deposits
Interest-bearing		468,755	444,897
Non-interest-bearing		21,513	37,266
Total deposits		490,268	482,163
Consolidated obligations (COs):
Bonds		27,978,423	27,171,434
Discount notes		24,179,050	30,053,964
Total consolidated obligations		52,157,473	57,225,398
Mandatorily redeemable capital stock		32,677	32,687
Accrued interest payable		100,964	80,822
Affordable Housing Program (AHP) payable		80,170	81,627
Derivative liabilities, net		325,083	357,876
Other liabilities		36,306	40,235
Total liabilities		53,222,941	58,300,808
Commitments and contingencies (Note 18)
Capital
Capital stock – Class B – putable ($100 par value), 24,587 shares and 24,113 shares issued and outstanding at March 31, 2017, and December 31, 2016, respectively		2,458,667	2,411,306
Retained earnings:
Unrestricted		994,011	987,711
Restricted		236,755	229,275
Total retained earnings		1,230,766	1,216,986
Accumulated other comprehensive loss		(343,572)	(383,514)
Total capital		3,345,861	3,244,778
Total Liabilities and Capital		$ 56,568,802	$ 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 $2,249,437 and $2,372,290 at March 31, 2017, and December 31, 2016, respectively.

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Available-for-sale securities pledged as collateral that may be repledged	$ 4,657	$ 7,968
Held-to-maturity securities pledged as collateral that may be repledged (a)	17,127	23,618
Allowance for credit losses	625	650
Fair value of held-to-maturity securities	$ 2,249,437	$ 2,372,290
Common Class B [Member]
Common Stock, Class B, putable shares issued	24,587	24,113
Common Stock, Class B, putable par value per share	$ 100	$ 100
Common Stock, Class B, putable shares outstanding	24,587	24,113

Statements of Operations (unaud

Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
INTEREST INCOME
Advances	$ 106,583	$ 78,219
Prepayment fees on advances, net	164	2,069
Securities purchased under agreements to resell	4,418	3,193
Federal funds sold	10,284	5,616
Investment securities:
Trading securities	2,553	2,236
Available-for-sale securities	24,664	25,145
Held-to-maturity securities	20,354	22,170
Prepayment fees on investments	65	325
Total investment securities	47,636	49,876
Mortgage loans held for portfolio	29,947	31,076
Other	59	107
Total interest income	199,091	170,156
Consolidated obligations:
Bonds	98,175	90,860
Discount notes	37,579	22,697
Total consolidated obligations	135,754	113,557
Deposits	502	115
Mandatorily redeemable capital stock	329	379
Other borrowings	2	1
Total interest expense	136,587	114,052
NET INTEREST INCOME	62,504	56,104
(Reduction of) provision for credit losses	(51)	11
NET INTEREST INCOME AFTER (REDUCTION OF) PROVISION FOR CREDIT LOSSES	62,555	56,093
OTHER INCOME (LOSS)
Total other-than-temporary impairment losses on investment securities	(53)	(442)
Net amount of impairment losses reclassified from accumulated other comprehensive loss	(365)	(905)
Net other-than-temporary impairment losses on investment securities, credit portion	(418)	(1,347)
Loss on early extinguishment of debt	0	(558)
Service fees	2,012	1,968
Net unrealized (losses) gains on trading securities	(1,414)	1,873
Net gains (losses) on derivatives and hedging activities	36	(6,235)
Other	(207)	(38)
Total other income	9	(4,337)
OTHER EXPENSE
Compensation and benefits	10,838	10,327
Other operating expenses	5,884	5,252
Federal Housing Finance Agency (the FHFA)	1,002	1,003
Office of Finance	842	816
Other	2,408	1,536
Total other expense	20,974	18,934
INCOME BEFORE ASSESSMENTS	41,590	32,822
AHP	4,192	3,320
NET INCOME	$ 37,398	$ 29,502

Statements of Comprehensive Inc

Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 37,398	$ 29,502
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent [Abstract]
Net unrealized gains on available-for-sale securities	26,906	51,830
Net noncredit portion of other-than-temporary impairment losses on held-to-maturity securities
Net amount of impairment losses reclassified to non-interest income	365	905
Accretion of noncredit portion	8,296	9,141
Total net noncredit portion of other-than-temporary impairment losses on held-to-maturity securities	8,661	10,046
Net unrealized gains (losses) relating to hedging activities
Unrealized losses	(138)	(17,039)
Reclassification adjustment for previously deferred hedging gains and losses included in net income	4,319	7,211
Total net unrealized gains (losses) relating to hedging activities	4,181	(9,828)
Pension and postretirement benefits	194	119
Total other comprehensive income	39,942	52,167
Comprehensive income	$ 77,340	$ 81,669

Statements of Capital (unaudite

Statements of Capital (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	$ 3,244,778	$ 3,022,913
Comprehensive income	77,340	81,669
Proceeds from sale of capital stock	181,947	69,730
Repurchase of capital stock	(134,586)	(105,313)
Shares reclassified to mandatorily redeemable capital stock		(40)
Cash dividends on capital stock	(23,618)	(19,529)
Period end	3,345,861	3,049,430
Retained Earnings, Unrestricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	987,711	934,214
Comprehensive income	29,918	23,602
Cash dividends on capital stock	(23,618)	(19,529)
Period end	994,011	938,287
Retained Earnings, Restricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	229,275	194,634
Comprehensive income	7,480	5,900
Period end	236,755	200,534
Retained Earnings, Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,216,986	1,128,848
Comprehensive income	37,398	29,502
Cash dividends on capital stock	(23,618)	(19,529)
Period end	1,230,766	1,138,821
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	(383,514)	(442,597)
Comprehensive income	39,942	52,167
Period end	$ (343,572)	$ (390,430)
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	1,820	697
Proceeds from sale of capital stock	$ 181,947	$ 69,730
Repurchase of capital stock, shares	(1,346)	(1,053)
Repurchase of capital stock	$ (134,586)	$ (105,313)
Shares reclassified to mandatorily redeemable capital stock, shares		(1)
Shares reclassified to mandatorily redeemable capital stock		$ (40)
Period end, shares	24,587	23,010
Period end	$ 2,458,667	$ 2,301,039

Statements of Cash Flows (unaud

Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
OPERATING ACTIVITIES
Net income	$ 37,398	$ 29,502
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	(4,855)	(8,153)
(Reduction of) provision for credit losses	(51)	11
Change in net fair-value adjustments on derivatives and hedging activities	(3,811)	6,317
Net other-than-temporary impairment losses on investment securities, credit portion	418	1,347
Loss on early extinguishment of debt	0	558
Other adjustments	1,597	656
Net change in:
Market value of trading securities	1,414	(1,873)
Accrued interest receivable	5,837	4,798
Other assets	(2,404)	(1,190)
Accrued interest payable	20,142	11,890
Other liabilities	(5,724)	(3,217)
Total adjustments	12,563	11,144
Net cash provided by operating activities	49,961	40,646
INVESTING ACTIVITIES
Interest-bearing deposits	(225,734)	(87,084)
Securities purchased under agreements to resell	3,000,000	(324,000)
Federal funds sold	(2,450,000)	(1,370,000)
Premises, software, and equipment	(786)	(385)
Trading securities:
Proceeds from long-term	403,333	4,231
Purchases of long-term	(308,671)	0
Available-for-sale securities:
Proceeds from long-term	298,387	216,181
Purchases of long-term	0	(850,766)
Held-to-maturity securities:
Proceeds from long-term	146,485	134,411
Advances to members:
Proceeds	124,105,993	88,178,413
Disbursements	(120,511,148)	(86,556,909)
Mortgage loans held for portfolio:
Proceeds	122,979	106,852
Purchases	(108,181)	(102,896)
Proceeds from sale of foreclosed assets	1,384	1,595
Net cash provided by (used in) investing activities	4,474,041	(650,357)
FINANCING ACTIVITIES
Net change in deposits	8,105	79,270
Net payments on derivatives with a financing element	(2,353)	(3,386)
Net proceeds from issuance of consolidated obligations:
Discount notes	38,926,960	36,534,002
Bonds	2,094,792	5,722,758
Payments for maturing and retiring consolidated obligations:
Discount notes	(44,804,024)	(38,657,232)
Bonds	(1,278,430)	(3,191,164)
Proceeds from issuance of capital stock	181,947	69,730
Payments for redemption of mandatorily redeemable capital stock	(10)	(6,785)
Payments for repurchase of capital stock	(134,586)	(105,313)
Cash dividends paid	(23,617)	(19,529)
Net cash (used in) provided by financing activities	(5,031,216)	422,351
Net decrease in cash and due from banks	(507,214)	(187,360)
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	12,817	66,858	520,031
Supplemental disclosures:
Interest paid	128,146	112,927
AHP payments	5,385	1,990	$ 18,575
Noncash transfers of mortgage loans held for portfolio to other assets	$ 940	$ 721

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation [Text Block]	Basis of Presentation The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete annual financial statements. In the opinion of management, all adjustments considered necessary have been included. All such adjustments consist of normal recurring accruals. The presentation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. The results of operations for interim periods are not necessarily indicative of the results to be expected for the year ending December 31, 2017. The unaudited financial statements should be read in conjunction with the Federal Home Loan Bank of Boston's audited financial statements and related notes in our Annual Report on Form 10-K for the year ended December 31, 2016, filed with the Securities and Exchange Commission (the SEC) on March 24, 2017 (the 2016 Annual Report). Unless otherwise indicated or the context requires otherwise, all references in this discussion to “the Bank,” "we," "us," "our," or similar references mean the Federal Home Loan Bank of Boston.

Summary of Significant Accounti

Summary of Significant Accounting Policies Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies As of March 31, 2017 , we have not made any significant changes to the 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. We utilize two derivatives clearing organizations (DCOs), for all cleared derivative transactions, LCH.Clearnet LLC and CME Clearing. 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 transfers. We continue to characterize our variation margin related at LCH.Clearnet LLC contracts as cash collateral. At both DCOs, initial margin is considered cash collateral.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	3 Months Ended
	Mar. 31, 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. We are in the process of evaluating this guidance and its effect on our financial condition, results of operations, and 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. We are in the process of evaluating this guidance and its effect on our financial condition, results of operations, and cash flows. 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, and cash flows.

Trading Securities

Trading Securities	3 Months Ended
	Mar. 31, 2017
Trading Securities [Abstract]
Trading Securities (and Certain Trading Assets) Disclosure [Text Block]	Trading Securities Major Security Types . Our trading securities as of March 31, 2017 , and December 31, 2016 , were (dollars in thousands): March 31, 2017 December 31, 2016 U.S. Treasury obligations $ 308,698 $ 399,521 Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 8,050 8,494 GSEs – single-family 644 768 GSEs – multifamily 198,758 203,839 207,452 213,101 Total $ 516,150 $ 612,622 Net unrealized losses or gains on trading securities for the three months ended March 31, 2017 , and 2016 , amounted to net losses of $1.4 million and net gains of $1.9 million for securities held on March 31, 2017 , and 2016 , respectively. We do not participate in speculative trading practices and typically hold these investments over a longer time horizon.

Available-for-Sale Securities

Available-for-Sale Securities	3 Months Ended
	Mar. 31, 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 March 31, 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) $ 9,350 $ — $ (1,166 ) $ 8,184 Supranational institutions 447,485 — (25,146 ) 422,339 U.S. government-owned corporations 313,779 — (37,163 ) 276,616 GSEs 129,336 — (10,992 ) 118,344 899,950 — (74,467 ) 825,483 MBS U.S. government guaranteed – single-family 119,919 62 (2,303 ) 117,678 U.S. government guaranteed – multifamily 512,927 — (2,795 ) 510,132 GSEs – single-family 4,208,100 3,950 (36,542 ) 4,175,508 GSEs – multifamily 668,808 2,192 — 671,000 5,509,754 6,204 (41,640 ) 5,474,318 Total $ 6,409,704 $ 6,204 $ (116,107 ) $ 6,299,801 _______________________ (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 March 31, 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 $ 8,184 $ (1,166 ) $ — $ — $ 8,184 $ (1,166 ) Supranational institutions — — 422,339 (25,146 ) 422,339 (25,146 ) U.S. government-owned corporations — — 276,616 (37,163 ) 276,616 (37,163 ) GSEs — — 118,344 (10,992 ) 118,344 (10,992 ) 8,184 (1,166 ) 817,299 (73,301 ) 825,483 (74,467 ) MBS U.S. government guaranteed – single-family — — 86,435 (2,303 ) 86,435 (2,303 ) U.S. government guaranteed – multifamily 364,121 (1,760 ) 146,011 (1,035 ) 510,132 (2,795 ) GSEs – single-family 3,017,265 (30,967 ) 327,482 (5,575 ) 3,344,747 (36,542 ) 3,381,386 (32,727 ) 559,928 (8,913 ) 3,941,314 (41,640 ) Total temporarily impaired $ 3,389,570 $ (33,893 ) $ 1,377,227 $ (82,214 ) $ 4,766,797 $ (116,107 ) 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 March 31, 2017 , and December 31, 2016 , were (dollars in thousands): March 31, 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 9,350 8,184 9,350 8,146 Due after five years through 10 years 169,829 160,476 171,589 161,746 Due after 10 years 720,771 656,823 728,818 650,299 899,950 825,483 909,757 820,191 MBS (1) 5,509,754 5,474,318 5,815,716 5,768,473 Total $ 6,409,704 $ 6,299,801 $ 6,725,473 $ 6,588,664 _______________________ (1) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities

Held-to-Maturity Securities	3 Months Ended
	Mar. 31, 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 March 31, 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 $ 1,922 $ — $ 1,922 $ 41 $ — $ 1,963 HFA securities 161,289 — 161,289 11 (17,212 ) 144,088 163,211 — 163,211 52 (17,212 ) 146,051 MBS U.S. government guaranteed – single-family 12,073 — 12,073 243 — 12,316 U.S. government guaranteed – multifamily 1,489 — 1,489 — (3 ) 1,486 GSEs – single-family 744,548 — 744,548 15,430 (455 ) 759,523 GSEs – multifamily 296,207 — 296,207 10,735 — 306,942 Private-label – residential 957,620 (183,165 ) 774,455 243,699 (7,609 ) 1,010,545 Asset-backed securities (ABS) backed by home equity loans 13,080 (552 ) 12,528 554 (508 ) 12,574 2,025,017 (183,717 ) 1,841,300 270,661 (8,575 ) 2,103,386 Total $ 2,188,228 $ (183,717 ) $ 2,004,511 $ 270,713 $ (25,787 ) $ 2,249,437 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 March 31, 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 $ — $ — $ 141,759 $ (17,212 ) $ 141,759 $ (17,212 ) MBS U.S. government guaranteed - multifamily 1,486 (3 ) — — 1,486 (3 ) GSEs – single-family 21,376 (331 ) 23,144 (124 ) 44,520 (455 ) Private-label – residential 14,825 (115 ) 326,790 (23,148 ) 341,615 (23,263 ) ABS backed by home equity loans — — 11,584 (656 ) 11,584 (656 ) 37,687 (449 ) 361,518 (23,928 ) 399,205 (24,377 ) Total $ 37,687 $ (449 ) $ 503,277 $ (41,140 ) $ 540,964 $ (41,589 ) 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 March 31, 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. March 31, 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 $ — $ — $ — $ — $ — $ — Due after one year through five years 16,401 16,401 16,446 16,637 16,637 16,663 Due after five years through 10 years — — — — — — Due after 10 years 146,810 146,810 129,605 148,090 148,090 128,840 163,211 163,211 146,051 164,727 164,727 145,503 MBS (2) 2,025,017 1,841,300 2,103,386 2,158,418 1,966,040 2,226,787 Total $ 2,188,228 $ 2,004,511 $ 2,249,437 $ 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) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Other-Than-Temporary Impairment

Other-Than-Temporary Impairment	3 Months Ended
	Mar. 31, 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 March 31, 2017 . At March 31, 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 March 31, 2017 . Private-Label Residential MBS and ABS Backed by Home Equity Loans. For those securities for which a credit loss was recognized during the three months ended March 31, 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) $ 46,262 7.7 % 31.7 % 37.6 % 4.4 % _______________________ (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 March 31, 2017 (dollars in thousands). Securities are classified in the table below based on their classifications at the time of issuance. March 31, 2017 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 37,589 $ 32,394 $ 25,666 $ 33,369 Private-label residential MBS – Alt-A 1,062,245 786,567 610,130 846,087 ABS backed by home equity loans – Subprime 3,670 3,359 2,808 3,362 Total other-than-temporarily impaired securities $ 1,103,504 $ 822,320 $ 638,604 $ 882,818 _______________________ (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 March 31, 2017 2016 Balance at beginning of period $ 490,404 $ 533,888 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 418 1,347 Reductions: Increase in cash flows expected to be collected which are recognized over the remaining life of the security (2) (8,601 ) (9,426 ) Balance at end of period $ 482,221 $ 525,809 _______________________ (1) For the three months March 31, 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 amounts accreted as interest income during the current period.

Advances

Advances	3 Months Ended
	Mar. 31, 2017
Advances [Abstract]
Federal Home Loan Bank, Advances [Text Block]	Advances General Terms. At both March 31, 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). March 31, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 7,935 1.21 % $ 3,780 0.92 % Due in one year or less 17,444,622 1.22 18,783,802 1.05 Due after one year through two years 8,673,994 1.31 10,966,780 1.15 Due after two years through three years 2,821,139 1.72 2,508,459 1.67 Due after three years through four years 2,011,518 1.74 2,177,432 1.64 Due after four years through five years 1,889,679 1.86 2,041,269 1.80 Thereafter 2,671,123 1.63 2,633,333 1.70 Total par value 35,520,010 1.38 % 39,114,855 1.23 % Premiums 21,143 22,633 Discounts (28,551 ) (25,847 ) Fair value of bifurcated derivatives (1) (576 ) (153 ) Hedging adjustments (32,602 ) (12,149 ) Total $ 35,479,424 $ 39,099,339 _________________________ (1) At March 31, 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 March 31, 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 $ 5.9 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 March 31, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 7,935 $ 3,780 Due in one year or less 23,108,797 26,447,977 Due after one year through two years 3,410,994 3,693,780 Due after two years through three years 2,821,139 2,508,459 Due after three years through four years 1,826,318 2,002,232 Due after four years through five years 1,739,679 1,891,269 Thereafter 2,605,148 2,567,358 Total par value $ 35,520,010 $ 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 March 31, 2017 , and December 31, 2016 , we had putable advances outstanding totaling $ 3.3 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 March 31, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 7,935 $ 3,780 Due in one year or less 19,278,622 20,788,552 Due after one year through two years 8,991,244 10,946,530 Due after two years through three years 2,723,139 2,455,709 Due after three years through four years 1,842,518 1,974,932 Due after four years through five years 1,594,179 1,736,769 Thereafter 1,082,373 1,208,583 Total par value $ 35,520,010 $ 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 March 31, 2017 December 31, 2016 Fixed-rate $ 28,953,692 $ 30,526,192 Variable-rate 6,566,318 8,588,663 Total par value $ 35,520,010 $ 39,114,855 Credit-Risk Exposure and Security Terms . At March 31, 2017 , and December 31, 2016 , we had $12.4 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 six borrowers at both March 31, 2017 , and December 31, 2016 , representing 35.0 percent and 41.5 percent , respectively, of total par value of outstanding advances. For information related to our credit risk on advances and allowance for credit losses, see Note 10 — Allowance for Credit Losses.

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	3 Months Ended
	Mar. 31, 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): March 31, 2017 December 31, 2016 Real estate Fixed-rate 15-year single-family mortgages $ 509,001 $ 528,486 Fixed-rate 20- and 30-year single-family mortgages 3,100,731 3,098,476 Premiums 66,437 67,523 Discounts (1,681 ) (1,696 ) Deferred derivative gains, net 1,735 1,755 Total mortgage loans held for portfolio 3,676,223 3,694,544 Less: allowance for credit losses (625 ) (650 ) Total mortgage loans, net of allowance for credit losses $ 3,675,598 $ 3,693,894 The following table details the par value of mortgage loans held for portfolio (dollars in thousands): March 31, 2017 December 31, 2016 Conventional mortgage loans $ 3,228,586 $ 3,235,835 Government mortgage loans 381,146 391,127 Total par value $ 3,609,732 $ 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. "Mortgage Partnership Finance," and "MPF" are registered trademarks of the Federal Home Loan Bank of Chicago.

Allowance for Credit Losses

Allowance for Credit Losses	3 Months Ended
	Mar. 31, 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 March 31, 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 three months ended March 31, 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 March 31, 2017 , and December 31, 2016 . At March 31, 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 March 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 27,972 $ 14,051 $ 42,023 Past due 60-89 days delinquent 7,066 3,647 10,713 Past due 90 days or more delinquent 14,464 5,093 19,557 Total past due 49,502 22,791 72,293 Total current loans 3,253,714 368,795 3,622,509 Total mortgage loans $ 3,303,216 $ 391,586 $ 3,694,802 Other delinquency statistics In process of foreclosure, included above (1) $ 7,193 $ 1,003 $ 8,196 Serious delinquency rate (2) 0.46 % 1.30 % 0.55 % Past due 90 days or more still accruing interest $ — $ 5,093 $ 5,093 Loans on nonaccrual status (3) $ 14,753 $ — $ 14,753 _______________________ (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 March 31, 2017 , and December 31, 2016 , and the average recorded investment and interest income recognized on these loans during the three months ended March 31, 2017 and 2016 (dollars in thousands). As of March 31, 2017 As of December 31, 2016 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 21,352 $ 21,311 $ 22,945 $ 22,905 For the Three Months Ended March 31, 2017 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 21,699 $ 116 $ 25,841 $ 80 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 March 31, 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 months ended March 31, 2017 and 2016 , as well as the recorded investment in mortgage loans by impairment methodology at March 31, 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 March 31, 2017 2016 Allowance for credit losses Balance, beginning of period $ 650 $ 1,025 Recoveries (charge-offs) 26 (11 ) (Reduction of) provision for credit losses (51 ) 11 Balance, end of period $ 625 $ 1,025 Ending balance, individually evaluated for impairment $ — $ — Ending balance, collectively evaluated for impairment $ 625 $ 1,025 Recorded investment, end of period (1) Individually evaluated for impairment $ 21,352 $ 25,316 Collectively evaluated for impairment $ 3,281,864 $ 3,151,522 _________________________ (1) These amounts exclude government mortgage loans because we make no allowance for credit losses based on our investments in government mortgage loans, as discussed above under — Government Mortgage Loans Held for Portfolio.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 2017 December 31, 2016 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 17,424,429 $ 58,357 $ (375,167 ) $ 18,215,809 $ 52,715 $ (413,026 ) Forward-start interest-rate swaps 527,800 — (36,253 ) 527,800 — (36,250 ) Total derivatives designated as hedging instruments 17,952,229 58,357 (411,420 ) 18,743,609 52,715 (449,276 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,099,500 1,995 (9,011 ) 1,199,000 2,293 (10,840 ) Mortgage-delivery commitments (1) 37,827 202 (9 ) 22,524 70 (171 ) Total derivatives not designated as hedging instruments 1,137,327 2,197 (9,020 ) 1,221,524 2,363 (11,011 ) Total notional amount of derivatives $ 19,089,556 $ 19,965,133 Total derivatives before netting and collateral adjustments 60,554 (420,440 ) 55,078 (460,287 ) Netting adjustments, cash collateral, and variation margin for daily settled contracts including related accrued interest (2) (7,861 ) 95,357 6,520 102,411 Derivative assets and derivative liabilities $ 52,693 $ (325,083 ) $ 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 $57.7 million and $109.8 million at March 31, 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 $851,000 and $850,000 at March 31, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $30.6 million at March 31, 2017 . Net (losses) gains on derivatives and hedging activities recorded in Other Income (Loss) for the three months ended March 31, 2017 and 2016 , were as follows (dollars in thousands): For the Three Months Ended March 31, 2017 2016 Derivatives designated as hedging instruments Interest-rate swaps $ (659 ) $ (3,033 ) Forward-start interest-rate swaps 134 (346 ) Total net losses related to derivatives designated as hedging instruments (525 ) (3,379 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps 153 (3,472 ) Mortgage-delivery commitments 357 616 Total net gains (losses) related to derivatives not designated as hedging instruments 510 (2,856 ) Other (1) 51 — Net gains (losses) on derivatives and hedging activities $ 36 $ (6,235 ) ______________ (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 months ended March 31, 2017 and 2016 (dollars in thousands): For the Three Months Ended March 31, 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 $ 21,095 $ (20,453 ) $ 642 $ (13,405 ) Investments 10,268 (9,808 ) 460 (8,341 ) COs – bonds 76 (1,837 ) (1,761 ) 4,641 Total $ 31,439 $ (32,098 ) $ (659 ) $ (17,105 ) For the Three Months Ended March 31, 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 $ (68,456 ) $ 68,233 $ (223 ) $ (30,124 ) Investments (49,455 ) 49,839 384 (9,011 ) COs – bonds 10,267 (13,461 ) (3,194 ) 8,072 Total $ (107,644 ) $ 104,611 $ (3,033 ) $ (31,063 ) ______________ (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 March 31, 2017 $ (138 ) Interest expense $ (4,315 ) $ 134 For the Three Months Ended March 31, 2016 (17,039 ) Interest expense (7,208 ) (346 ) For the three months ended March 31, 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 March 31, 2017 , the maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions is eight years . As of March 31, 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 $7.2 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 March 31, 2017 , was $355.3 million for which we had delivered collateral with a post-haircut value of $324.7 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 based on incremental credit rating downgrades at March 31, 2017 . Post Haircut Value of Incremental Collateral to be Delivered as of March 31, 2017 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 11,638 AA- A+, A or A- 12,399 A- below A- 16,808 _______________________ (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, LCH.Clearnet LLC and CME Clearing. 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.Clearnet LLC 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. Based on this analysis, we are presenting a net derivative receivable or payable for all of our transactions through a particular clearing member with a particular 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 March 31, 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 March 31, 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. March 31, 2017 December 31, 2016 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Derivatives meeting netting requirements Gross recognized amount Uncleared derivatives $ 13,350 $ (367,754 ) $ 12,594 $ (405,310 ) Cleared derivatives 47,002 (52,677 ) 42,414 (54,806 ) Total gross recognized amount 60,352 (420,431 ) 55,008 (460,116 ) Gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives (12,518 ) 42,680 (12,028 ) 47,605 Cleared derivatives 4,657 52,677 18,548 54,806 Total gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts (7,861 ) 95,357 6,520 102,411 Net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives 832 (325,074 ) 566 (357,705 ) Cleared derivatives 51,659 — 60,962 — Total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts 52,491 (325,074 ) 61,528 (357,705 ) Derivatives not meeting netting requirements Mortgage delivery commitments 202 (9 ) 70 (171 ) Total derivative assets and total derivative liabilities Uncleared derivatives 832 (325,074 ) 566 (357,705 ) Cleared derivatives 51,659 — 60,962 — Mortgage delivery commitments 202 (9 ) 70 (171 ) Total derivative assets and total derivative liabilities presented in the statement of condition 52,693 (325,083 ) 61,598 (357,876 ) Non-cash collateral received or pledged not offset (1) Can be sold or repledged Uncleared derivatives — 21,063 — 30,306 Cannot be sold or repledged Uncleared derivatives — 278,113 — 290,444 Total non-cash collateral received or pledged, not offset — 299,176 — 320,750 Net amount Uncleared derivatives 832 (25,898 ) 566 (36,955 ) Cleared derivatives 51,659 — 60,962 — Mortgage delivery commitments 202 (9 ) 70 (171 ) Total net amount $ 52,693 $ (25,907 ) $ 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 March 31, 2017 , and December 31, 2016 , we had additional net credit exposure of $1.1 million and $2.0 million , respectively, due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.

Deposits

Deposits	3 Months Ended
	Mar. 31, 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. Members that service mortgage loans may deposit funds collected in connection with mortgage loans pending disbursement of such funds to the owners of the mortgage loans. We classify these items as "other" in the following table. The following table details interest- and noninterest-bearing deposits (dollars in thousands): March 31, 2017 December 31, 2016 Interest-bearing Demand and overnight $ 465,931 $ 440,731 Other 2,824 4,166 Noninterest-bearing Other 21,513 37,266 Total deposits $ 490,268 $ 482,163

Consolidated Obligations

Consolidated Obligations	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 , by year of contractual maturity (dollars in thousands): March 31, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 11,252,735 1.37 % $ 8,734,955 1.43 % Due after one year through two years 6,436,440 1.31 7,752,420 1.19 Due after two years through three years 3,197,930 1.71 3,297,120 1.63 Due after three years through four years 1,361,695 1.89 1,637,335 1.87 Due after four years through five years 2,551,775 1.68 2,574,375 1.65 Thereafter 3,147,595 2.73 3,135,745 2.70 Total par value 27,948,170 1.60 % 27,131,950 1.58 % Premiums 106,776 118,145 Discounts (14,606 ) (14,906 ) Hedging adjustments (61,917 ) (63,755 ) $ 27,978,423 $ 27,171,434 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Our CO bonds outstanding at March 31, 2017 , and December 31, 2016 , included (dollars in thousands): March 31, 2017 December 31, 2016 Par value of CO bonds Noncallable and nonputable $ 23,290,170 $ 22,388,950 Callable 4,658,000 4,743,000 Total par value $ 27,948,170 $ 27,131,950 The following is a summary of the CO bonds for which we were primarily liable at March 31, 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 March 31, 2017 December 31, 2016 Due in one year or less $ 15,067,735 $ 12,858,955 Due after one year through two years 5,916,440 7,013,420 Due after two years through three years 2,979,930 2,904,120 Due after three years through four years 1,013,695 1,289,335 Due after four years through five years 1,284,775 1,242,375 Thereafter 1,685,595 1,823,745 Total par value $ 27,948,170 $ 27,131,950 The following table sets forth the CO bonds for which we were primarily liable by interest-rate-payment type at March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 2017 December 31, 2016 Par value of CO bonds Fixed-rate $ 20,386,170 $ 20,289,950 Simple variable-rate 6,005,000 5,300,000 Step-up 1,557,000 1,542,000 Total par value $ 27,948,170 $ 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) March 31, 2017 $ 24,179,050 $ 24,193,530 0.65 % December 31, 2016 $ 30,053,964 $ 30,070,103 0.47 % _______________________ (1) The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program

Affordable Housing Program	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2017 , and year ended December 31, 2016 (dollars in thousands): March 31, 2017 December 31, 2016 Balance at beginning of period $ 81,627 $ 82,081 AHP expense for the period 4,192 19,397 AHP direct grant disbursements (5,385 ) (18,575 ) AHP subsidy for AHP advance disbursements (267 ) (1,378 ) Return of previously disbursed grants and subsidies 3 102 Balance at end of period $ 80,170 $ 81,627

Capital

Capital	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): Risk-Based Capital Requirements March 31, December 31, Permanent capital Class B capital stock $ 2,458,667 $ 2,411,306 Mandatorily redeemable capital stock 32,677 32,687 Retained earnings 1,230,766 1,216,986 Total permanent capital $ 3,722,110 $ 3,660,979 Risk-based capital requirement Credit-risk capital $ 352,679 $ 355,182 Market-risk capital 168,602 118,765 Operations-risk capital 156,385 142,184 Total risk-based capital requirement $ 677,666 $ 616,131 Permanent capital in excess of risk-based capital requirement $ 3,044,444 $ 3,044,848 March 31, 2017 December 31, 2016 Required Actual Required Actual Capital Ratio Risk-based capital $ 677,666 $ 3,722,110 $ 616,131 $ 3,660,979 Total regulatory capital $ 2,262,752 $ 3,722,110 $ 2,461,823 $ 3,660,979 Total capital-to-asset ratio 4.0 % 6.6 % 4.0 % 5.9 % Leverage Ratio Leverage capital $ 2,828,440 $ 5,583,165 $ 3,077,279 $ 5,491,469 Leverage capital-to-assets ratio 5.0 % 9.9 % 5.0 % 8.9 %

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 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 months ended March 31, 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, December 31, 2015 $ (137,718 ) $ (229,785 ) $ (71,237 ) $ (3,857 ) $ (442,597 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 51,830 — (17,039 ) — 34,791 Noncredit other-than-temporary impairment losses — (8 ) — — (8 ) Accretion of noncredit loss — 9,141 — — 9,141 Net actuarial gain — — — 1 1 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 913 — — 913 Amortization - hedging activities (2) — — 7,211 — 7,211 Amortization - pension and postretirement benefits (3) — — — 118 118 Other comprehensive income (loss) 51,830 10,046 (9,828 ) 119 52,167 Balance, March 31, 2016 $ (85,888 ) $ (219,739 ) $ (81,065 ) $ (3,738 ) $ (390,430 ) Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 26,906 — (138 ) — 26,768 Accretion of noncredit loss — 8,296 — — 8,296 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 365 — — 365 Amortization - hedging activities (4) — — 4,319 — 4,319 Amortization - pension and postretirement benefits (3) — — — 194 194 Other comprehensive income 26,906 8,661 4,181 194 39,942 Balance, March 31, 2017 $ (109,903 ) $ (183,718 ) $ (44,006 ) $ (5,945 ) $ (343,572 ) _______________________ (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 $7.2 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 $4.3 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.

Fair Values

Fair Values	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2017 . The carrying values, fair values, and fair-value hierarchy of our financial instruments at March 31, 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. March 31, 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 $ 12,817 $ 12,817 $ 12,817 $ — $ — $ — Interest-bearing deposits 246,317 246,317 246,317 — — — Securities purchased under agreements to resell 2,999,000 2,998,891 — 2,998,891 — — Federal funds sold 5,150,000 5,149,928 — 5,149,928 — — Trading securities (1) 516,150 516,150 — 516,150 — — Available-for-sale securities (1) 6,299,801 6,299,801 — 6,291,617 8,184 — Held-to-maturity securities 2,004,511 2,249,437 — 1,082,230 1,167,207 — Advances 35,479,424 35,643,128 — 35,643,128 — — Mortgage loans, net 3,675,598 3,708,652 — 3,682,550 26,102 — Accrued interest receivable 78,816 78,816 — 78,816 — — Derivative assets (1) 52,693 52,693 — 60,554 — (7,861 ) Other assets (1) 21,046 21,046 11,652 9,394 — — Liabilities: Deposits (490,268 ) (490,263 ) — (490,263 ) — — COs: Bonds (27,978,423 ) (28,100,611 ) — (28,100,611 ) — — Discount notes (24,179,050 ) (24,177,609 ) — (24,177,609 ) — — Mandatorily redeemable capital stock (32,677 ) (32,677 ) (32,677 ) — — — Accrued interest payable (100,964 ) (100,964 ) — (100,964 ) — — Derivative liabilities (1) (325,083 ) (325,083 ) — (420,440 ) — 95,357 Other: Commitments to extend credit for advances — (4,811 ) — (4,811 ) — — Standby letters of credit (1,040 ) (1,040 ) — (1,040 ) — — _______________________ (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 March 31, 2017 , and December 31, 2016 , by fair-value hierarchy level (dollars in thousands): March 31, 2017 Level 1 Level 2 Level 3 Netting Adjustment (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 308,698 $ — $ — $ 308,698 U.S. government-guaranteed – single-family MBS — 8,050 — — 8,050 GSEs – single-family MBS — 644 — — 644 GSEs – multifamily MBS — 198,758 — — 198,758 Total trading securities — 516,150 — — 516,150 Available-for-sale securities: State or local HFA securities — — 8,184 — 8,184 Supranational institutions — 422,339 — — 422,339 U.S. government-owned corporations — 276,616 — — 276,616 GSEs — 118,344 — — 118,344 U.S. government guaranteed – single-family MBS — 117,678 — — 117,678 U.S. government guaranteed – multifamily MBS — 510,132 — — 510,132 GSEs – single-family MBS — 4,175,508 — — 4,175,508 GSEs – multifamily MBS — 671,000 — — 671,000 Total available-for-sale securities — 6,291,617 8,184 — 6,299,801 Derivative assets: Interest-rate-exchange agreements — 60,352 — (7,861 ) 52,491 Mortgage delivery commitments — 202 — — 202 Total derivative assets — 60,554 — (7,861 ) 52,693 Other assets 11,652 9,394 — — 21,046 Total assets at fair value $ 11,652 $ 6,877,715 $ 8,184 $ (7,861 ) $ 6,889,690 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (420,431 ) $ — $ 95,357 $ (325,074 ) Mortgage delivery commitments — (9 ) — — (9 ) Total liabilities at fair value $ — $ (420,440 ) $ — $ 95,357 $ (325,083 ) _______________________ (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 months ended March 31, 2017 . There were no Level 3 available-for-sale securities during the three months ended March 31, 2016 (dollars in thousands). March 31, 2017 Balance at beginning of period $ 8,146 Purchases — Unrealized gains included in other comprehensive income 38 Balance at end of period $ 8,184 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). March 31, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 5,264 $ 5,264 Mortgage loans held for portfolio — — 5,145 5,145 REO — — 544 544 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 10,953 $ 10,953 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	3 Months Ended
	Mar. 31, 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 March 31, 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 and 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 March 31, 2017 , and December 31, 2016 . The par amounts of other FHLBanks' outstanding COs for which we are jointly and severally liable totaled $ 907.1 billion and $932.1 billion at March 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 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) $ 4,472,318 $ 174,997 $ 4,647,315 $ 4,050,447 $ 179,632 $ 4,230,079 Commitments for unused lines of credit - advances (2) 1,261,985 — 1,261,985 1,255,140 — 1,255,140 Commitments to make additional advances 33,928 73,193 107,121 44,865 65,972 110,837 Commitments to invest in mortgage loans 37,827 — 37,827 22,524 — 22,524 Unsettled CO bonds, at par 70,750 — 70,750 — — — __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At March 31, 2017 , and December 31, 2016 , these amounts totaled $ 44.1 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 $1.0 million and $1.1 million at March 31, 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 . We are subject to various legal proceedings arising in the normal course of business from time to time. We would record an accrual for a loss contingency when it is probable that a loss has been incurred and the amount can be reasonably estimated. Management does not anticipate that the ultimate liability, if any, arising out of these matters will have a material effect on our financial condition, results of operations, or cash flows.

Transactions with Shareholders

Transactions with Shareholders	3 Months Ended
	Mar. 31, 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 March 31, 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 March 31, 2017 Citizens Bank, N.A. $ 352,223 14.1 % $ 5,260,581 14.8 % $ 2,345 6.2 % 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 months ended March 31, 2017 and 2016 , as follows (dollars in thousands): For the Three Months Ended March 31, Citizens Bank, N.A. 2017 2016 Interest income on advances $ 14,111 $ 8,204 Fees on letters of credit 745 840 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 March 31, 2017 $ 82,433 3.3 % $ 1,319,925 3.7 % $ 1,564 4.2 % 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	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On April 3, 2017 , we conducted a partial repurchase of excess capital stock under the Excess Stock Management Program in the amount of $180.2 million . On April 18, 2017 , the board of directors declared a cash dividend at an annualized rate of 4.08 percent based on capital stock balances outstanding during the first quarter of 2017. The dividend, including dividends on mandatorily redeemable capital stock, amounted to $25.2 million and was paid on May 2, 2017 .

Summary of Significant Accoun28

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 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, LCH.Clearnet LLC and CME Clearing. 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 transfers. We continue to characterize our variation margin related at LCH.Clearnet LLC 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-netting agreements.
Fair Value of Financial Instruments, Policy	We measure certain held-to-maturity investment securities, mortgage loans held for portfolio, and real-estate-owned property (REO) at fair value on a nonrecurring basis, that is, they are not measured at fair value on an ongoing basis but are subject to fair-value adjustments only in certain circumstances (for example, upon recognizing an other-than-temporary impairment on a held-to-maturity security).
Joint and Several Liability, Policy	We evaluate the financial condition of the other FHLBanks primarily based on known regulatory actions, publicly available financial information, and individual long-term credit-rating action as of each period-end presented.

Trading Securities (Tables)

Trading Securities (Tables)	3 Months Ended
	Mar. 31, 2017
Trading Securities [Abstract]
Trading Securities by Major Security Type [Table Text Block]	Our trading securities as of March 31, 2017 , and December 31, 2016 , were (dollars in thousands): March 31, 2017 December 31, 2016 U.S. Treasury obligations $ 308,698 $ 399,521 Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 8,050 8,494 GSEs – single-family 644 768 GSEs – multifamily 198,758 203,839 207,452 213,101 Total $ 516,150 $ 612,622

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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) $ 9,350 $ — $ (1,166 ) $ 8,184 Supranational institutions 447,485 — (25,146 ) 422,339 U.S. government-owned corporations 313,779 — (37,163 ) 276,616 GSEs 129,336 — (10,992 ) 118,344 899,950 — (74,467 ) 825,483 MBS U.S. government guaranteed – single-family 119,919 62 (2,303 ) 117,678 U.S. government guaranteed – multifamily 512,927 — (2,795 ) 510,132 GSEs – single-family 4,208,100 3,950 (36,542 ) 4,175,508 GSEs – multifamily 668,808 2,192 — 671,000 5,509,754 6,204 (41,640 ) 5,474,318 Total $ 6,409,704 $ 6,204 $ (116,107 ) $ 6,299,801 _______________________ (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 March 31, 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 $ 8,184 $ (1,166 ) $ — $ — $ 8,184 $ (1,166 ) Supranational institutions — — 422,339 (25,146 ) 422,339 (25,146 ) U.S. government-owned corporations — — 276,616 (37,163 ) 276,616 (37,163 ) GSEs — — 118,344 (10,992 ) 118,344 (10,992 ) 8,184 (1,166 ) 817,299 (73,301 ) 825,483 (74,467 ) MBS U.S. government guaranteed – single-family — — 86,435 (2,303 ) 86,435 (2,303 ) U.S. government guaranteed – multifamily 364,121 (1,760 ) 146,011 (1,035 ) 510,132 (2,795 ) GSEs – single-family 3,017,265 (30,967 ) 327,482 (5,575 ) 3,344,747 (36,542 ) 3,381,386 (32,727 ) 559,928 (8,913 ) 3,941,314 (41,640 ) Total temporarily impaired $ 3,389,570 $ (33,893 ) $ 1,377,227 $ (82,214 ) $ 4,766,797 $ (116,107 ) 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 March 31, 2017 , and December 31, 2016 , were (dollars in thousands): March 31, 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 9,350 8,184 9,350 8,146 Due after five years through 10 years 169,829 160,476 171,589 161,746 Due after 10 years 720,771 656,823 728,818 650,299 899,950 825,483 909,757 820,191 MBS (1) 5,509,754 5,474,318 5,815,716 5,768,473 Total $ 6,409,704 $ 6,299,801 $ 6,725,473 $ 6,588,664 _______________________ (1) MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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 $ 1,922 $ — $ 1,922 $ 41 $ — $ 1,963 HFA securities 161,289 — 161,289 11 (17,212 ) 144,088 163,211 — 163,211 52 (17,212 ) 146,051 MBS U.S. government guaranteed – single-family 12,073 — 12,073 243 — 12,316 U.S. government guaranteed – multifamily 1,489 — 1,489 — (3 ) 1,486 GSEs – single-family 744,548 — 744,548 15,430 (455 ) 759,523 GSEs – multifamily 296,207 — 296,207 10,735 — 306,942 Private-label – residential 957,620 (183,165 ) 774,455 243,699 (7,609 ) 1,010,545 Asset-backed securities (ABS) backed by home equity loans 13,080 (552 ) 12,528 554 (508 ) 12,574 2,025,017 (183,717 ) 1,841,300 270,661 (8,575 ) 2,103,386 Total $ 2,188,228 $ (183,717 ) $ 2,004,511 $ 270,713 $ (25,787 ) $ 2,249,437 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 March 31, 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 $ — $ — $ 141,759 $ (17,212 ) $ 141,759 $ (17,212 ) MBS U.S. government guaranteed - multifamily 1,486 (3 ) — — 1,486 (3 ) GSEs – single-family 21,376 (331 ) 23,144 (124 ) 44,520 (455 ) Private-label – residential 14,825 (115 ) 326,790 (23,148 ) 341,615 (23,263 ) ABS backed by home equity loans — — 11,584 (656 ) 11,584 (656 ) 37,687 (449 ) 361,518 (23,928 ) 399,205 (24,377 ) Total $ 37,687 $ (449 ) $ 503,277 $ (41,140 ) $ 540,964 $ (41,589 ) 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 March 31, 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. March 31, 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 $ — $ — $ — $ — $ — $ — Due after one year through five years 16,401 16,401 16,446 16,637 16,637 16,663 Due after five years through 10 years — — — — — — Due after 10 years 146,810 146,810 129,605 148,090 148,090 128,840 163,211 163,211 146,051 164,727 164,727 145,503 MBS (2) 2,025,017 1,841,300 2,103,386 2,158,418 1,966,040 2,226,787 Total $ 2,188,228 $ 2,004,511 $ 2,249,437 $ 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) 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 Impairme32

Other-Than-Temporary Impairment (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 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) $ 46,262 7.7 % 31.7 % 37.6 % 4.4 % _______________________ (1) Securities are classified based upon the current performance characteristics of the underlying loan pool and therefore the manner in which the loan pool backing the security has been modeled (as prime, Alt-A, or subprime), rather than their classification of the security at the time of issuance.
Total Securities Other-than-Temporarily Impaired during the Life of the Security [Table Text Block]	The following table sets forth our securities for which other-than-temporary impairment credit losses were recognized during the life of the security through March 31, 2017 (dollars in thousands). Securities are classified in the table below based on their classifications at the time of issuance. March 31, 2017 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 37,589 $ 32,394 $ 25,666 $ 33,369 Private-label residential MBS – Alt-A 1,062,245 786,567 610,130 846,087 ABS backed by home equity loans – Subprime 3,670 3,359 2,808 3,362 Total other-than-temporarily impaired securities $ 1,103,504 $ 822,320 $ 638,604 $ 882,818 _______________________ (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.
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 March 31, 2017 2016 Balance at beginning of period $ 490,404 $ 533,888 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 418 1,347 Reductions: Increase in cash flows expected to be collected which are recognized over the remaining life of the security (2) (8,601 ) (9,426 ) Balance at end of period $ 482,221 $ 525,809 _______________________ (1) For the three months March 31, 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 amounts accreted as interest income during the current period.

Advances (Tables)

Advances (Tables)	3 Months Ended
	Mar. 31, 2017
Advances [Abstract]
Advances [Table Text Block]	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 March 31, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 7,935 $ 3,780 Due in one year or less 23,108,797 26,447,977 Due after one year through two years 3,410,994 3,693,780 Due after two years through three years 2,821,139 2,508,459 Due after three years through four years 1,826,318 2,002,232 Due after four years through five years 1,739,679 1,891,269 Thereafter 2,605,148 2,567,358 Total par value $ 35,520,010 $ 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 The following table details interest-rate-payment types for our outstanding advances (dollars in thousands): Par value of advances March 31, 2017 December 31, 2016 Fixed-rate $ 28,953,692 $ 30,526,192 Variable-rate 6,566,318 8,588,663 Total par value $ 35,520,010 $ 39,114,855 At both March 31, 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). March 31, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 7,935 1.21 % $ 3,780 0.92 % Due in one year or less 17,444,622 1.22 18,783,802 1.05 Due after one year through two years 8,673,994 1.31 10,966,780 1.15 Due after two years through three years 2,821,139 1.72 2,508,459 1.67 Due after three years through four years 2,011,518 1.74 2,177,432 1.64 Due after four years through five years 1,889,679 1.86 2,041,269 1.80 Thereafter 2,671,123 1.63 2,633,333 1.70 Total par value 35,520,010 1.38 % 39,114,855 1.23 % Premiums 21,143 22,633 Discounts (28,551 ) (25,847 ) Fair value of bifurcated derivatives (1) (576 ) (153 ) Hedging adjustments (32,602 ) (12,149 ) Total $ 35,479,424 $ 39,099,339 _________________________ (1) At March 31, 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. 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 March 31, 2017 December 31, 2016 Overdrawn demand-deposit accounts $ 7,935 $ 3,780 Due in one year or less 19,278,622 20,788,552 Due after one year through two years 8,991,244 10,946,530 Due after two years through three years 2,723,139 2,455,709 Due after three years through four years 1,842,518 1,974,932 Due after four years through five years 1,594,179 1,736,769 Thereafter 1,082,373 1,208,583 Total par value $ 35,520,010 $ 39,114,855

Mortgage Loans Held for Portf34

Mortgage Loans Held for Portfolio (Tables)	3 Months Ended
	Mar. 31, 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): March 31, 2017 December 31, 2016 Real estate Fixed-rate 15-year single-family mortgages $ 509,001 $ 528,486 Fixed-rate 20- and 30-year single-family mortgages 3,100,731 3,098,476 Premiums 66,437 67,523 Discounts (1,681 ) (1,696 ) Deferred derivative gains, net 1,735 1,755 Total mortgage loans held for portfolio 3,676,223 3,694,544 Less: allowance for credit losses (625 ) (650 ) Total mortgage loans, net of allowance for credit losses $ 3,675,598 $ 3,693,894 The following table details the par value of mortgage loans held for portfolio (dollars in thousands): March 31, 2017 December 31, 2016 Conventional mortgage loans $ 3,228,586 $ 3,235,835 Government mortgage loans 381,146 391,127 Total par value $ 3,609,732 $ 3,626,962

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 27,972 $ 14,051 $ 42,023 Past due 60-89 days delinquent 7,066 3,647 10,713 Past due 90 days or more delinquent 14,464 5,093 19,557 Total past due 49,502 22,791 72,293 Total current loans 3,253,714 368,795 3,622,509 Total mortgage loans $ 3,303,216 $ 391,586 $ 3,694,802 Other delinquency statistics In process of foreclosure, included above (1) $ 7,193 $ 1,003 $ 8,196 Serious delinquency rate (2) 0.46 % 1.30 % 0.55 % Past due 90 days or more still accruing interest $ — $ 5,093 $ 5,093 Loans on nonaccrual status (3) $ 14,753 $ — $ 14,753 _______________________ (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 March 31, 2017 , and December 31, 2016 , and the average recorded investment and interest income recognized on these loans during the three months ended March 31, 2017 and 2016 (dollars in thousands). As of March 31, 2017 As of December 31, 2016 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 21,352 $ 21,311 $ 22,945 $ 22,905
Individually Evaluated Impaired Loans, Average Recorded Investment and Interest Income Recognized [Table Text Block]	For the Three Months Ended March 31, 2017 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 21,699 $ 116 $ 25,841 $ 80
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 months ended March 31, 2017 and 2016 , as well as the recorded investment in mortgage loans by impairment methodology at March 31, 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 March 31, 2017 2016 Allowance for credit losses Balance, beginning of period $ 650 $ 1,025 Recoveries (charge-offs) 26 (11 ) (Reduction of) provision for credit losses (51 ) 11 Balance, end of period $ 625 $ 1,025 Ending balance, individually evaluated for impairment $ — $ — Ending balance, collectively evaluated for impairment $ 625 $ 1,025 Recorded investment, end of period (1) Individually evaluated for impairment $ 21,352 $ 25,316 Collectively evaluated for impairment $ 3,281,864 $ 3,151,522 _________________________ (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 Activ36

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 2017 December 31, 2016 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 17,424,429 $ 58,357 $ (375,167 ) $ 18,215,809 $ 52,715 $ (413,026 ) Forward-start interest-rate swaps 527,800 — (36,253 ) 527,800 — (36,250 ) Total derivatives designated as hedging instruments 17,952,229 58,357 (411,420 ) 18,743,609 52,715 (449,276 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,099,500 1,995 (9,011 ) 1,199,000 2,293 (10,840 ) Mortgage-delivery commitments (1) 37,827 202 (9 ) 22,524 70 (171 ) Total derivatives not designated as hedging instruments 1,137,327 2,197 (9,020 ) 1,221,524 2,363 (11,011 ) Total notional amount of derivatives $ 19,089,556 $ 19,965,133 Total derivatives before netting and collateral adjustments 60,554 (420,440 ) 55,078 (460,287 ) Netting adjustments, cash collateral, and variation margin for daily settled contracts including related accrued interest (2) (7,861 ) 95,357 6,520 102,411 Derivative assets and derivative liabilities $ 52,693 $ (325,083 ) $ 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 $57.7 million and $109.8 million at March 31, 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 $851,000 and $850,000 at March 31, 2017 , and December 31, 2016 , respectively. Variation margin for daily settled contracts was $30.6 million at March 31, 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 months ended March 31, 2017 and 2016 , were as follows (dollars in thousands): For the Three Months Ended March 31, 2017 2016 Derivatives designated as hedging instruments Interest-rate swaps $ (659 ) $ (3,033 ) Forward-start interest-rate swaps 134 (346 ) Total net losses related to derivatives designated as hedging instruments (525 ) (3,379 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps 153 (3,472 ) Mortgage-delivery commitments 357 616 Total net gains (losses) related to derivatives not designated as hedging instruments 510 (2,856 ) Other (1) 51 — Net gains (losses) on derivatives and hedging activities $ 36 $ (6,235 ) ______________ (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 months ended March 31, 2017 and 2016 (dollars in thousands): For the Three Months Ended March 31, 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 $ 21,095 $ (20,453 ) $ 642 $ (13,405 ) Investments 10,268 (9,808 ) 460 (8,341 ) COs – bonds 76 (1,837 ) (1,761 ) 4,641 Total $ 31,439 $ (32,098 ) $ (659 ) $ (17,105 ) For the Three Months Ended March 31, 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 $ (68,456 ) $ 68,233 $ (223 ) $ (30,124 ) Investments (49,455 ) 49,839 384 (9,011 ) COs – bonds 10,267 (13,461 ) (3,194 ) 8,072 Total $ (107,644 ) $ 104,611 $ (3,033 ) $ (31,063 ) ______________ (1) The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item.
Effect of Cash Flow Hedge-Related Derivative Instruments [Table Text Block]	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 March 31, 2017 $ (138 ) Interest expense $ (4,315 ) $ 134 For the Three Months Ended March 31, 2016 (17,039 ) Interest expense (7,208 ) (346 )
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 based on incremental credit rating downgrades at March 31, 2017 . Post Haircut Value of Incremental Collateral to be Delivered as of March 31, 2017 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 11,638 AA- A+, A or A- 12,399 A- below A- 16,808 _______________________ (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 March 31, 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. March 31, 2017 December 31, 2016 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Derivatives meeting netting requirements Gross recognized amount Uncleared derivatives $ 13,350 $ (367,754 ) $ 12,594 $ (405,310 ) Cleared derivatives 47,002 (52,677 ) 42,414 (54,806 ) Total gross recognized amount 60,352 (420,431 ) 55,008 (460,116 ) Gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives (12,518 ) 42,680 (12,028 ) 47,605 Cleared derivatives 4,657 52,677 18,548 54,806 Total gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts (7,861 ) 95,357 6,520 102,411 Net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives 832 (325,074 ) 566 (357,705 ) Cleared derivatives 51,659 — 60,962 — Total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts 52,491 (325,074 ) 61,528 (357,705 ) Derivatives not meeting netting requirements Mortgage delivery commitments 202 (9 ) 70 (171 ) Total derivative assets and total derivative liabilities Uncleared derivatives 832 (325,074 ) 566 (357,705 ) Cleared derivatives 51,659 — 60,962 — Mortgage delivery commitments 202 (9 ) 70 (171 ) Total derivative assets and total derivative liabilities presented in the statement of condition 52,693 (325,083 ) 61,598 (357,876 ) Non-cash collateral received or pledged not offset (1) Can be sold or repledged Uncleared derivatives — 21,063 — 30,306 Cannot be sold or repledged Uncleared derivatives — 278,113 — 290,444 Total non-cash collateral received or pledged, not offset — 299,176 — 320,750 Net amount Uncleared derivatives 832 (25,898 ) 566 (36,955 ) Cleared derivatives 51,659 — 60,962 — Mortgage delivery commitments 202 (9 ) 70 (171 ) Total net amount $ 52,693 $ (25,907 ) $ 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 March 31, 2017 , and December 31, 2016 , we had additional net credit exposure of $1.1 million and $2.0 million , respectively, due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.
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 March 31, 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. March 31, 2017 December 31, 2016 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Derivatives meeting netting requirements Gross recognized amount Uncleared derivatives $ 13,350 $ (367,754 ) $ 12,594 $ (405,310 ) Cleared derivatives 47,002 (52,677 ) 42,414 (54,806 ) Total gross recognized amount 60,352 (420,431 ) 55,008 (460,116 ) Gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives (12,518 ) 42,680 (12,028 ) 47,605 Cleared derivatives 4,657 52,677 18,548 54,806 Total gross amounts of netting adjustments, cash collateral, and variation margin for daily settled contracts (7,861 ) 95,357 6,520 102,411 Net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts Uncleared derivatives 832 (325,074 ) 566 (357,705 ) Cleared derivatives 51,659 — 60,962 — Total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts 52,491 (325,074 ) 61,528 (357,705 ) Derivatives not meeting netting requirements Mortgage delivery commitments 202 (9 ) 70 (171 ) Total derivative assets and total derivative liabilities Uncleared derivatives 832 (325,074 ) 566 (357,705 ) Cleared derivatives 51,659 — 60,962 — Mortgage delivery commitments 202 (9 ) 70 (171 ) Total derivative assets and total derivative liabilities presented in the statement of condition 52,693 (325,083 ) 61,598 (357,876 ) Non-cash collateral received or pledged not offset (1) Can be sold or repledged Uncleared derivatives — 21,063 — 30,306 Cannot be sold or repledged Uncleared derivatives — 278,113 — 290,444 Total non-cash collateral received or pledged, not offset — 299,176 — 320,750 Net amount Uncleared derivatives 832 (25,898 ) 566 (36,955 ) Cleared derivatives 51,659 — 60,962 — Mortgage delivery commitments 202 (9 ) 70 (171 ) Total net amount $ 52,693 $ (25,907 ) $ 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 March 31, 2017 , and December 31, 2016 , we had additional net credit exposure of $1.1 million and $2.0 million , respectively, due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.

Deposits (Tables)

Deposits (Tables)	3 Months Ended
	Mar. 31, 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): March 31, 2017 December 31, 2016 Interest-bearing Demand and overnight $ 465,931 $ 440,731 Other 2,824 4,166 Noninterest-bearing Other 21,513 37,266 Total deposits $ 490,268 $ 482,163

Consolidated Obligations (Table

Consolidated Obligations (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 , by year of contractual maturity (dollars in thousands): March 31, 2017 December 31, 2016 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 11,252,735 1.37 % $ 8,734,955 1.43 % Due after one year through two years 6,436,440 1.31 7,752,420 1.19 Due after two years through three years 3,197,930 1.71 3,297,120 1.63 Due after three years through four years 1,361,695 1.89 1,637,335 1.87 Due after four years through five years 2,551,775 1.68 2,574,375 1.65 Thereafter 3,147,595 2.73 3,135,745 2.70 Total par value 27,948,170 1.60 % 27,131,950 1.58 % Premiums 106,776 118,145 Discounts (14,606 ) (14,906 ) Hedging adjustments (61,917 ) (63,755 ) $ 27,978,423 $ 27,171,434 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees.
CO Bonds by Call Feature [Table Text Block]	Our CO bonds outstanding at March 31, 2017 , and December 31, 2016 , included (dollars in thousands): March 31, 2017 December 31, 2016 Par value of CO bonds Noncallable and nonputable $ 23,290,170 $ 22,388,950 Callable 4,658,000 4,743,000 Total par value $ 27,948,170 $ 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 March 31, 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 March 31, 2017 December 31, 2016 Due in one year or less $ 15,067,735 $ 12,858,955 Due after one year through two years 5,916,440 7,013,420 Due after two years through three years 2,979,930 2,904,120 Due after three years through four years 1,013,695 1,289,335 Due after four years through five years 1,284,775 1,242,375 Thereafter 1,685,595 1,823,745 Total par value $ 27,948,170 $ 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 2017 December 31, 2016 Par value of CO bonds Fixed-rate $ 20,386,170 $ 20,289,950 Simple variable-rate 6,005,000 5,300,000 Step-up 1,557,000 1,542,000 Total par value $ 27,948,170 $ 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) March 31, 2017 $ 24,179,050 $ 24,193,530 0.65 % December 31, 2016 $ 30,053,964 $ 30,070,103 0.47 % _______________________ (1) The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program (Tab

Affordable Housing Program (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2017 , and year ended December 31, 2016 (dollars in thousands): March 31, 2017 December 31, 2016 Balance at beginning of period $ 81,627 $ 82,081 AHP expense for the period 4,192 19,397 AHP direct grant disbursements (5,385 ) (18,575 ) AHP subsidy for AHP advance disbursements (267 ) (1,378 ) Return of previously disbursed grants and subsidies 3 102 Balance at end of period $ 80,170 $ 81,627

Capital (Tables)

Capital (Tables)	3 Months Ended
	Mar. 31, 2017
Capital [Abstract]
Compliance with Regulatory Capital Requirements [Table Text Block]	The following tables demonstrate our compliance with our regulatory capital requirements at March 31, 2017 , and December 31, 2016 (dollars in thousands): Risk-Based Capital Requirements March 31, December 31, Permanent capital Class B capital stock $ 2,458,667 $ 2,411,306 Mandatorily redeemable capital stock 32,677 32,687 Retained earnings 1,230,766 1,216,986 Total permanent capital $ 3,722,110 $ 3,660,979 Risk-based capital requirement Credit-risk capital $ 352,679 $ 355,182 Market-risk capital 168,602 118,765 Operations-risk capital 156,385 142,184 Total risk-based capital requirement $ 677,666 $ 616,131 Permanent capital in excess of risk-based capital requirement $ 3,044,444 $ 3,044,848 March 31, 2017 December 31, 2016 Required Actual Required Actual Capital Ratio Risk-based capital $ 677,666 $ 3,722,110 $ 616,131 $ 3,660,979 Total regulatory capital $ 2,262,752 $ 3,722,110 $ 2,461,823 $ 3,660,979 Total capital-to-asset ratio 4.0 % 6.6 % 4.0 % 5.9 % Leverage Ratio Leverage capital $ 2,828,440 $ 5,583,165 $ 3,077,279 $ 5,491,469 Leverage capital-to-assets ratio 5.0 % 9.9 % 5.0 % 8.9 %

Accumulated Other Comprehensi41

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 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 months ended March 31, 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, December 31, 2015 $ (137,718 ) $ (229,785 ) $ (71,237 ) $ (3,857 ) $ (442,597 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 51,830 — (17,039 ) — 34,791 Noncredit other-than-temporary impairment losses — (8 ) — — (8 ) Accretion of noncredit loss — 9,141 — — 9,141 Net actuarial gain — — — 1 1 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 913 — — 913 Amortization - hedging activities (2) — — 7,211 — 7,211 Amortization - pension and postretirement benefits (3) — — — 118 118 Other comprehensive income (loss) 51,830 10,046 (9,828 ) 119 52,167 Balance, March 31, 2016 $ (85,888 ) $ (219,739 ) $ (81,065 ) $ (3,738 ) $ (390,430 ) Balance, December 31, 2016 $ (136,809 ) $ (192,379 ) $ (48,187 ) $ (6,139 ) $ (383,514 ) Other comprehensive income (loss) before reclassifications: Net unrealized gains (losses) 26,906 — (138 ) — 26,768 Accretion of noncredit loss — 8,296 — — 8,296 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 365 — — 365 Amortization - hedging activities (4) — — 4,319 — 4,319 Amortization - pension and postretirement benefits (3) — — — 194 194 Other comprehensive income 26,906 8,661 4,181 194 39,942 Balance, March 31, 2017 $ (109,903 ) $ (183,718 ) $ (44,006 ) $ (5,945 ) $ (343,572 ) _______________________ (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 $7.2 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 $4.3 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.

Fair Values (Tables)

Fair Values (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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. March 31, 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 $ 12,817 $ 12,817 $ 12,817 $ — $ — $ — Interest-bearing deposits 246,317 246,317 246,317 — — — Securities purchased under agreements to resell 2,999,000 2,998,891 — 2,998,891 — — Federal funds sold 5,150,000 5,149,928 — 5,149,928 — — Trading securities (1) 516,150 516,150 — 516,150 — — Available-for-sale securities (1) 6,299,801 6,299,801 — 6,291,617 8,184 — Held-to-maturity securities 2,004,511 2,249,437 — 1,082,230 1,167,207 — Advances 35,479,424 35,643,128 — 35,643,128 — — Mortgage loans, net 3,675,598 3,708,652 — 3,682,550 26,102 — Accrued interest receivable 78,816 78,816 — 78,816 — — Derivative assets (1) 52,693 52,693 — 60,554 — (7,861 ) Other assets (1) 21,046 21,046 11,652 9,394 — — Liabilities: Deposits (490,268 ) (490,263 ) — (490,263 ) — — COs: Bonds (27,978,423 ) (28,100,611 ) — (28,100,611 ) — — Discount notes (24,179,050 ) (24,177,609 ) — (24,177,609 ) — — Mandatorily redeemable capital stock (32,677 ) (32,677 ) (32,677 ) — — — Accrued interest payable (100,964 ) (100,964 ) — (100,964 ) — — Derivative liabilities (1) (325,083 ) (325,083 ) — (420,440 ) — 95,357 Other: Commitments to extend credit for advances — (4,811 ) — (4,811 ) — — Standby letters of credit (1,040 ) (1,040 ) — (1,040 ) — — _______________________ (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 March 31, 2017 , and December 31, 2016 , by fair-value hierarchy level (dollars in thousands): March 31, 2017 Level 1 Level 2 Level 3 Netting Adjustment (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 308,698 $ — $ — $ 308,698 U.S. government-guaranteed – single-family MBS — 8,050 — — 8,050 GSEs – single-family MBS — 644 — — 644 GSEs – multifamily MBS — 198,758 — — 198,758 Total trading securities — 516,150 — — 516,150 Available-for-sale securities: State or local HFA securities — — 8,184 — 8,184 Supranational institutions — 422,339 — — 422,339 U.S. government-owned corporations — 276,616 — — 276,616 GSEs — 118,344 — — 118,344 U.S. government guaranteed – single-family MBS — 117,678 — — 117,678 U.S. government guaranteed – multifamily MBS — 510,132 — — 510,132 GSEs – single-family MBS — 4,175,508 — — 4,175,508 GSEs – multifamily MBS — 671,000 — — 671,000 Total available-for-sale securities — 6,291,617 8,184 — 6,299,801 Derivative assets: Interest-rate-exchange agreements — 60,352 — (7,861 ) 52,491 Mortgage delivery commitments — 202 — — 202 Total derivative assets — 60,554 — (7,861 ) 52,693 Other assets 11,652 9,394 — — 21,046 Total assets at fair value $ 11,652 $ 6,877,715 $ 8,184 $ (7,861 ) $ 6,889,690 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (420,431 ) $ — $ 95,357 $ (325,074 ) Mortgage delivery commitments — (9 ) — — (9 ) Total liabilities at fair value $ — $ (420,440 ) $ — $ 95,357 $ (325,083 ) _______________________ (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.
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 months ended March 31, 2017 . There were no Level 3 available-for-sale securities during the three months ended March 31, 2016 (dollars in thousands). March 31, 2017 Balance at beginning of period $ 8,146 Purchases — Unrealized gains included in other comprehensive income 38 Balance at end of period $ 8,184
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). March 31, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 5,264 $ 5,264 Mortgage loans held for portfolio — — 5,145 5,145 REO — — 544 544 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 10,953 $ 10,953 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)	3 Months Ended
	Mar. 31, 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 March 31, 2017 , and December 31, 2016 (dollars in thousands): March 31, 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) $ 4,472,318 $ 174,997 $ 4,647,315 $ 4,050,447 $ 179,632 $ 4,230,079 Commitments for unused lines of credit - advances (2) 1,261,985 — 1,261,985 1,255,140 — 1,255,140 Commitments to make additional advances 33,928 73,193 107,121 44,865 65,972 110,837 Commitments to invest in mortgage loans 37,827 — 37,827 22,524 — 22,524 Unsettled CO bonds, at par 70,750 — 70,750 — — — __________________________ (1) The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At March 31, 2017 , and December 31, 2016 , these amounts totaled $ 44.1 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)	3 Months Ended
	Mar. 31, 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 March 31, 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 March 31, 2017 Citizens Bank, N.A. $ 352,223 14.1 % $ 5,260,581 14.8 % $ 2,345 6.2 % 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 months ended March 31, 2017 and 2016 , as follows (dollars in thousands): For the Three Months Ended March 31, Citizens Bank, N.A. 2017 2016 Interest income on advances $ 14,111 $ 8,204 Fees on letters of credit 745 840
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 March 31, 2017 $ 82,433 3.3 % $ 1,319,925 3.7 % $ 1,564 4.2 % 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	Mar. 31, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 516,150	$ 612,622
U.S. Treasury obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	308,698	399,521
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	8,050	8,494
MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	207,452	213,101
GSEs - single-family [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	644	768
GSEs - multifamily [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 198,758	$ 203,839

Trading Securities - Net Unreal

Trading Securities - Net Unrealized (Losses) Gains (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Trading Securities [Abstract]
Net unrealized (losses) gains on trading securities	$ (1,414)	$ 1,873

Available-for-Sale Securities M

Available-for-Sale Securities Major Security Types (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 6,409,704	$ 6,725,473
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		6,204	3,068
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(116,107)	(139,877)
Available-for-sale securities Fair Value		6,299,801	6,588,664
States or local housing-finance-agency obligations (HFA securities) [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	9,350	9,350
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(1,166)	(1,204)
Available-for-sale securities Fair Value		8,184	8,146
Supranational institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	447,485	452,021
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(25,146)	(29,401)
Available-for-sale securities Fair Value		422,339	422,620
U.S. government-owned corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	313,779	317,588
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(37,163)	(45,631)
Available-for-sale securities Fair Value		276,616	271,957
GSEs [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	129,336	130,798
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(10,992)	(13,330)
Available-for-sale securities Fair Value		118,344	117,468
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	899,950	909,757
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(74,467)	(89,566)
Available-for-sale securities Fair Value		825,483	820,191
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	119,919	127,032
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		62	16
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(2,303)	(2,321)
Available-for-sale securities Fair Value		117,678	124,727
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	512,927	565,593
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	45
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(2,795)	(2,277)
Available-for-sale securities Fair Value		510,132	563,361
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	5,509,754	5,815,716
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		6,204	3,068
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(41,640)	(50,311)
Available-for-sale securities Fair Value	[2]	5,474,318	5,768,473
Single Family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	4,208,100	4,447,803
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		3,950	1,765
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(36,542)	(45,713)
Available-for-sale securities Fair Value		4,175,508	4,403,855
Multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	668,808	675,288
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		2,192	1,242
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Available-for-sale securities Fair Value		$ 671,000	$ 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	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 3,389,570	$ 3,882,972
Less than 12 Months, Unrealized Losses	(33,893)	(41,650)
12 Months or More, Fair Value	1,377,227	1,419,476
12 Months or More, Unrealized Losses	(82,214)	(98,227)
Total Fair Value	4,766,797	5,302,448
Total Unrealized Losses	(116,107)	(139,877)
HFA securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	8,184	8,146
Less than 12 Months, Unrealized Losses	(1,166)	(1,204)
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Losses	0	0
Total Fair Value	8,184	8,146
Total Unrealized Losses	(1,166)	(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	422,339	422,620
12 Months or More, Unrealized Losses	(25,146)	(29,401)
Total Fair Value	422,339	422,620
Total Unrealized Losses	(25,146)	(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	276,616	271,957
12 Months or More, Unrealized Losses	(37,163)	(45,631)
Total Fair Value	276,616	271,957
Total Unrealized Losses	(37,163)	(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	118,344	117,468
12 Months or More, Unrealized Losses	(10,992)	(13,330)
Total Fair Value	118,344	117,468
Total Unrealized Losses	(10,992)	(13,330)
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	8,184	8,146
Less than 12 Months, Unrealized Losses	(1,166)	(1,204)
12 Months or More, Fair Value	817,299	812,045
12 Months or More, Unrealized Losses	(73,301)	(88,362)
Total Fair Value	825,483	820,191
Total Unrealized Losses	(74,467)	(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	86,435	90,854
12 Months or More, Unrealized Losses	(2,303)	(2,317)
Total Fair Value	86,435	122,460
Total Unrealized Losses	(2,303)	(2,321)
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	364,121	326,126
Less than 12 Months, Unrealized Losses	(1,760)	(1,261)
12 Months or More, Fair Value	146,011	165,246
12 Months or More, Unrealized Losses	(1,035)	(1,016)
Total Fair Value	510,132	491,372
Total Unrealized Losses	(2,795)	(2,277)
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	3,381,386	3,874,826
Less than 12 Months, Unrealized Losses	(32,727)	(40,446)
12 Months or More, Fair Value	559,928	607,431
12 Months or More, Unrealized Losses	(8,913)	(9,865)
Total Fair Value	3,941,314	4,482,257
Total Unrealized Losses	(41,640)	(50,311)
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	3,017,265	3,517,094
Less than 12 Months, Unrealized Losses	(30,967)	(39,181)
12 Months or More, Fair Value	327,482	351,331
12 Months or More, Unrealized Losses	(5,575)	(6,532)
Total Fair Value	3,344,747	3,868,425
Total Unrealized Losses	$ (36,542)	$ (45,713)

Available-for-Sale Securities R

Available-for-Sale Securities Redemption Terms (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 6,409,704	$ 6,725,473
Fair Value		6,299,801	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		9,350	9,350
Due after one year through five years, fair value		8,184	8,146
Due after five years through 10 years, amortized cost		169,829	171,589
Due after five years through 10 years, fair value		160,476	161,746
Due after 10 years, amortized cost		720,771	728,818
Due after 10 years, fair value		656,823	650,299
Amortized Cost	[1]	899,950	909,757
Fair Value		825,483	820,191
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	5,509,754	5,815,716
Fair Value	[2]	$ 5,474,318	$ 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		Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 2,188,228	$ 2,323,145
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(183,717)	(192,378)
Carrying Value	[1],[2]	2,004,511	2,130,767
Gross Unrecognized Holding Gains		270,713	270,306
Gross Unrecognized Holding Losses		(25,787)	(28,783)
Held-to-maturity securities Fair Value		2,249,437	2,372,290
U.S. agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		1,922	2,159
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		1,922	2,159
Gross Unrecognized Holding Gains		41	56
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		1,963	2,215
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		161,289	162,568
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		161,289	162,568
Gross Unrecognized Holding Gains		11	11
Gross Unrecognized Holding Losses		(17,212)	(19,291)
Held-to-maturity securities Fair Value		144,088	143,288
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		163,211	164,727
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value	[1]	163,211	164,727
Gross Unrecognized Holding Gains		52	67
Gross Unrecognized Holding Losses		(17,212)	(19,291)
Held-to-maturity securities Fair Value		146,051	145,503
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		12,073	12,719
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		12,073	12,719
Gross Unrecognized Holding Gains		243	246
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		12,316	12,965
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		1,489	1,532
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		1,489	1,532
Gross Unrecognized Holding Gains		0	0
Gross Unrecognized Holding Losses		(3)	0
Held-to-maturity securities Fair Value		1,486	1,532
Asset-backed securities backed by home equity loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		13,080	13,515
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(552)	(574)
Carrying Value		12,528	12,941
Gross Unrecognized Holding Gains		554	602
Gross Unrecognized Holding Losses		(508)	(600)
Held-to-maturity securities Fair Value		12,574	12,943
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	2,025,017	2,158,418
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(183,717)	(192,378)
Carrying Value	[1],[3]	1,841,300	1,966,040
Gross Unrecognized Holding Gains		270,661	270,239
Gross Unrecognized Holding Losses		(8,575)	(9,492)
Held-to-maturity securities Fair Value	[3]	2,103,386	2,226,787
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		744,548	812,836
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		744,548	812,836
Gross Unrecognized Holding Gains		15,430	16,881
Gross Unrecognized Holding Losses		(455)	(519)
Held-to-maturity securities Fair Value		759,523	829,198
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		296,207	318,667
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		296,207	318,667
Gross Unrecognized Holding Gains		10,735	11,692
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		306,942	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		957,620	999,149
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(183,165)	(191,804)
Carrying Value		774,455	807,345
Gross Unrecognized Holding Gains		243,699	240,818
Gross Unrecognized Holding Losses		(7,609)	(8,373)
Held-to-maturity securities Fair Value		$ 1,010,545	$ 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 $2,249,437 and $2,372,290 at March 31, 2017, and December 31, 2016, respectively.
[3]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Held-to-Maturity Securities Fai

Held-to-Maturity Securities Fair Value and Unrealized Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	$ 37,687	$ 100,206
Less than 12 Months, Unrealized Losses	(449)	(521)
12 Months or More, Fair Value	503,277	563,669
12 Months or More, Unrealized Losses	(41,140)	(48,918)
Total Fair Value	540,964	663,875
Total Unrealized Losses	(41,589)	(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	141,759	140,959
12 Months or More, Unrealized Losses	(17,212)	(19,291)
Total Fair Value	141,759	140,959
Total Unrealized Losses	(17,212)	(19,291)
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	1,486
Less than 12 Months, Unrealized Losses	(3)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	1,486
Total Unrealized Losses	(3)
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	11,584	11,898
12 Months or More, Unrealized Losses	(656)	(720)
Total Fair Value	11,584	11,898
Total Unrealized Losses	(656)	(720)
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	37,687	100,206
Less than 12 Months, Unrealized Losses	(449)	(521)
12 Months or More, Fair Value	361,518	422,710
12 Months or More, Unrealized Losses	(23,928)	(29,627)
Total Fair Value	399,205	522,916
Total Unrealized Losses	(24,377)	(30,148)
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	21,376	83,291
Less than 12 Months, Unrealized Losses	(331)	(393)
12 Months or More, Fair Value	23,144	13,405
12 Months or More, Unrealized Losses	(124)	(126)
Total Fair Value	44,520	96,696
Total Unrealized Losses	(455)	(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	14,825	16,915
Less than 12 Months, Unrealized Losses	(115)	(128)
12 Months or More, Fair Value	326,790	397,407
12 Months or More, Unrealized Losses	(23,148)	(28,781)
Total Fair Value	341,615	414,322
Total Unrealized Losses	$ (23,263)	$ (28,909)

Held-to-Maturity Securities Red

Held-to-Maturity Securities Redemption Terms (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 2,188,228	$ 2,323,145
Carrying Value	[1],[2]	2,004,511	2,130,767
Fair Value		2,249,437	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		0	0
Due in one year or less, Carrying Value	[1]	0	0
Due in one year or less, Fair Value		0	0
Due after one year through five years, Amortized Cost		16,401	16,637
Due after one year through five years, Carrying Value	[1]	16,401	16,637
Due after one year through five years, Fair Value		16,446	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		146,810	148,090
Due after 10 years, Carrying Value	[1]	146,810	148,090
Due after 10 years, Fair Value		129,605	128,840
Amortized Cost		163,211	164,727
Carrying Value	[1]	163,211	164,727
Fair Value		146,051	145,503
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	2,025,017	2,158,418
Carrying Value	[1],[3]	1,841,300	1,966,040
Fair Value	[3]	$ 2,103,386	$ 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 $2,249,437 and $2,372,290 at March 31, 2017, and December 31, 2016, respectively.
[3]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay their obligations with or without call or prepayment fees.

Other-Than-Temporary 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	3 Months Ended
	Mar. 31, 2017USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 46,262
Project Prepayment Rates - Weighted Average Percent	7.70%
Projected Default Rates, Weighted Average Percent	31.70%
Projected Loss Severities, Weighted Average Percent	37.60%
Current Credit Enhancement, Weighted Average Percent	4.40%
[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	Mar. 31, 2017USD ($)	[1]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	$ 1,103,504
Amortized Cost	822,320
Carrying Value	638,604
Fair Value	882,818
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	37,589
Amortized Cost	32,394
Carrying Value	25,666
Fair Value	33,369
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	1,062,245
Amortized Cost	786,567
Carrying Value	610,130
Fair Value	846,087
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	3,670
Amortized Cost	3,359
Carrying Value	2,808
Fair Value	$ 3,362
[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
		Mar. 31, 2017	Mar. 31, 2016
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at beginning of period		$ 490,404	$ 533,888
Additional credit losses for which an other-than-temporary impairment charge was previously recognized	[1]	418	1,347
Increase in cash flows expected to be collected which are recognized over the remaining life of the security	[2]	(8,601)	(9,426)
Balance at end of period		$ 482,221	$ 525,809
[1]	For the three months March 31, 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 amounts accreted as interest income during the current period.

Advances - Year of Contractual

Advances - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Maturity, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts		$ 7,935	$ 3,780
Due in one year or less		17,444,622	18,783,802
Due after one year through two years		8,673,994	10,966,780
Due after two years through three years		2,821,139	2,508,459
Due after three years through four years		2,011,518	2,177,432
Due after four years through five years		1,889,679	2,041,269
Thereafter		2,671,123	2,633,333
Total par value		$ 35,520,010	$ 39,114,855
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Rolling Year [Abstract]
Overdrawn demand-deposit accounts, Weighted average rate		1.21%	0.92%
Due in one year or less, Weighted average rate		1.22%	1.05%
Due after one year through two years, Weighted average rate		1.31%	1.15%
Due after two years through three years, Weighted average rate		1.72%	1.67%
Due after three years through four years, Weighted average rate		1.74%	1.64%
Due after four years through five years, Weighted average rate		1.86%	1.80%
Thereafter, Weighted average rate		1.63%	1.70%
Total Weighted average rate		1.38%	1.23%
Premiums		$ 21,143	$ 22,633
Discounts		(28,551)	(25,847)
Fair value of bifurcated derivatives	[1]	(576)	(153)
Hedging adjustments		(32,602)	(12,149)
Total Advances		$ 35,479,424	$ 39,099,339
[1]	At March 31, 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.

Advances Advances - Year of Con

Advances Advances - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands		Mar. 31, 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		$ 7,935	$ 3,780
Due in one year or less	[1]	23,108,797	26,447,977
Due after one year through two years	[1]	3,410,994	3,693,780
Due after two years through three years	[1]	2,821,139	2,508,459
Due after three years through four years	[1]	1,826,318	2,002,232
Due after four years through five years	[1]	1,739,679	1,891,269
Thereafter	[1]	2,605,148	2,567,358
Total par value		$ 35,520,010	$ 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	Mar. 31, 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	$ 7,935	$ 3,780
Due in one year or less	19,278,622	20,788,552
Due after one year through two years	8,991,244	10,946,530
Due after two years through three years	2,723,139	2,455,709
Due after three years through four years	1,842,518	1,974,932
Due after four years through five years	1,594,179	1,736,769
Thereafter	1,082,373	1,208,583
Total par value	$ 35,520,010	$ 39,114,855

Advances - Interest-Rate-Paymen

Advances - Interest-Rate-Payment Terms (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Fixed Rate [Abstract]
Total fixed-rate	$ 28,953,692	$ 30,526,192
Federal Home Loan Bank, Advances, Floating Rate [Abstract]
Total variable-rate	6,566,318	8,588,663
Total par value	$ 35,520,010	$ 39,114,855

Advances - Narratives (Details)

Advances - Narratives (Details) $ in Thousands	Mar. 31, 2017USD ($)Borrowers	Dec. 31, 2016USD ($)Borrowers
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank, Advances, Par Value	$ 35,520,010	$ 39,114,855
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount	12,400,000	$ 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	6	6
Total outstanding advances greater than $1.0 billion per borrower as a percentage of advances outstanding	35.00%	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	$ 5,900,000	$ 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	$ 3,300,000	$ 3,400,000

Mortgage Loans Held for Portf61

Mortgage Loans Held for Portfolio (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,609,732	$ 3,626,962
Premiums	66,437	67,523
Discounts	(1,681)	(1,696)
Deferred derivative gains, net	1,735	1,755
Total mortgage loans held for portfolio	3,676,223	3,694,544
Less: allowance for credit losses	(625)	(650)
Total mortgage loans, net of allowance for credit losses	$ 3,675,598	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	$ 3,228,586	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	$ 381,146	391,127
Single Family [Member] | Fixed-rate 15-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	509,001	528,486
Single Family [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,100,731	$ 3,098,476

Allowance for credit losses - C

Allowance for credit losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Mortgage Loans Past Due [Line Items]
Total past due		$ 72,293	$ 73,175
Total current loans		3,622,509	3,640,109
Total mortgage loans		3,694,802	3,713,284
In process of foreclosure, included above	[1]	$ 8,196	$ 8,997
Serious delinquency rate	[2]	0.55%	0.63%
Past due 90 days or more still accruing interest		$ 5,093	$ 5,807
Loans on nonaccrual status	[3]	$ 14,753	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		$ 22,791	24,531
Total current loans		368,795	377,438
Total mortgage loans		391,586	401,969
In process of foreclosure, included above	[1]	$ 1,003	$ 1,502
Serious delinquency rate	[2]	1.30%	1.44%
Past due 90 days or more still accruing interest		$ 5,093	$ 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		49,502	48,644
Total current loans		3,253,714	3,262,671
Total mortgage loans		3,303,216	3,311,315
In process of foreclosure, included above	[1]	$ 7,193	$ 7,495
Serious delinquency rate	[2]	0.46%	0.53%
Past due 90 days or more still accruing interest		$ 0	$ 0
Loans on nonaccrual status	[3]	14,753	16,940
Past due 30-59 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		42,023	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		14,051	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		27,972	26,757
Past due 60-89 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		10,713	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		3,647	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		7,066	5,508
Past due 90 days or more delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		19,557	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		5,093	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		$ 14,464	$ 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 or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class.
[3]	Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan.

Allowance for credit losses - I

Allowance for credit losses - Individually Evaluated Impaired Loans (Details) - Conventional mortgage loans [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired mortgage loans with no related allowance - Recorded Investment	$ 21,352		$ 22,945
Individually evaluated impaired mortgage loans with no related allowance - Par Value	21,311		$ 22,905
Individually evaluated impaired mortgage loans with no related allowance - Average Recorded Investment	21,699	$ 25,841
Individually evaluated impaired mortgage loans with no related allowance - Interest Income recognized	$ 116	$ 80

Allowance for credit losses - A

Allowance for credit losses - Allowance Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period		$ 650
(Reduction of) provision for credit losses		(51)	$ 11
Balance, end of period		625
Conventional mortgage loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period		650	1,025
Recoveries (charge-offs)		26	(11)
(Reduction of) provision for credit losses		(51)	11
Balance, end of period		625	1,025
Ending balance, individually evaluated for impairment		0	0
Ending balance, collectively evaluated for impairment		625	1,025
Recorded Investment Individually evaluated for impairment	[1]	21,352	25,316
Recorded Investment Collectively evaluated for impairment	[1]	$ 3,281,864	$ 3,151,522
[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 ($)		Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		$ 19,089,556,000	$ 19,965,133,000
Derivative Assets, before netting and collateral adjustments		60,554,000	55,078,000
Derivative Liabilities, before netting and collateral adjustments		(420,440,000)	(460,287,000)
Derivative Asset, netting adjustments, cash collateral and variation margin for daily settled contracts including related accrued interest	[1],[2]	(7,861,000)	6,520,000
Derivative Liability, netting adjustments, cash collateral and variation margin for daily settled contracts including related accrued interest	[1],[2]	95,357,000	102,411,000
Derivative Assets		52,693,000	61,598,000
Derivative Liabilities		(325,083,000)	(357,876,000)
Cash collateral and related accrued interest posted		57,700,000	109,800,000
Cash collateral and related accrued interest received		851,000	850,000
Variation margin for daily settled contracts		30,600,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		17,952,229,000	18,743,609,000
Derivative Assets, before netting and collateral adjustments		58,357,000	52,715,000
Derivative Liabilities, before netting and collateral adjustments		(411,420,000)	(449,276,000)
Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		17,424,429,000	18,215,809,000
Derivative Assets, before netting and collateral adjustments		58,357,000	52,715,000
Derivative Liabilities, before netting and collateral adjustments		(375,167,000)	(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		(36,253,000)	(36,250,000)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,137,327,000	1,221,524,000
Derivative Assets, before netting and collateral adjustments		2,197,000	2,363,000
Derivative Liabilities, before netting and collateral adjustments		(9,020,000)	(11,011,000)
Not Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,099,500,000	1,199,000,000
Derivative Assets, before netting and collateral adjustments		1,995,000	2,293,000
Derivative Liabilities, before netting and collateral adjustments		(9,011,000)	(10,840,000)
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets		202,000	70,000
Derivative Liabilities		(9,000)	(171,000)
Mortgages [Member] | Not Designated as Hedging Instrument [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	[3]	37,827,000	22,524,000
Derivative Assets, before netting and collateral adjustments	[3]	202,000	70,000
Derivative Liabilities, before netting and collateral adjustments	[3]	$ (9,000)	$ (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 $57.7 million and $109.8 million at March 31, 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 $851,000 and $850,000 at March 31, 2017, and December 31, 2016, respectively. Variation margin for daily settled contracts was $30.6 million at March 31, 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
		Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		$ (659)	$ (3,033)
Total net losses related to derivatives designated as hedging instruments		(525)	(3,379)
Total net gains (losses) related to derivatives not designated as hedging instruments		510	(2,856)
Other	[1]	51	0
Net gains (losses) on derivatives and hedging activities		36	(6,235)
Interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		(659)	(3,033)
Total net gains (losses) related to derivatives not designated as hedging instruments		153	(3,472)
Forward-start interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge ineffectiveness		134	(346)
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses) related to derivatives not designated as hedging instruments		$ 357	$ 616
[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
		Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		$ 31,439	$ (107,644)
Gain/(Loss) on Hedged Item		(32,098)	104,611
Net Fair-Value Hedge Ineffectiveness		(659)	(3,033)
Effect of Derivatives on Net Interest Income	[1]	(17,105)	(31,063)
Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		21,095	(68,456)
Gain/(Loss) on Hedged Item		(20,453)	68,233
Net Fair-Value Hedge Ineffectiveness		642	(223)
Effect of Derivatives on Net Interest Income	[1]	(13,405)	(30,124)
Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		10,268	(49,455)
Gain/(Loss) on Hedged Item		(9,808)	49,839
Net Fair-Value Hedge Ineffectiveness		460	384
Effect of Derivatives on Net Interest Income	[1]	(8,341)	(9,011)
COs - bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		76	10,267
Gain/(Loss) on Hedged Item		(1,837)	(13,461)
Net Fair-Value Hedge Ineffectiveness		(1,761)	(3,194)
Effect of Derivatives on Net Interest Income	[1]	$ 4,641	$ 8,072
[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
	Mar. 31, 2017	Mar. 31, 2016
Derivative [Line Items]
Losses Recognized in Other Comprehensive Loss on Derivatives (Effective Portion)	$ (138)	$ (17,039)
Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion)	(4,315)	(7,208)
Gains (Losses) Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion)	$ 134	$ (346)

Derivatives and Hedging Activ69

Derivatives and Hedging Activities Narratives (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Derivative [Line Items]
Maximum length of time which we are hedging our exposure to the variability in future cash flows for forecasted transactions	8 years
Deferred net losses on derivative accumulated in other comprehensive loss expected to be reclassified to earnings during the next 12 months	$ 7,200
Aggregate fair value of all uncleared derivative instruments with credit-risk-related contingent features that were in a net liability position	355,300
Post-haircut value of collateral already posted	324,700
Rating Downgrade from AAPlus to AA or AAMinus [Member]
Derivative [Line Items]
Incremental collateral	11,638	[1]
Rating Downgrade From AAMinus to APlus, A or AMinus [Member]
Derivative [Line Items]
Incremental collateral	12,399	[1]
Rating Downgrade From AMinus to below AMinus [Member]
Derivative [Line Items]
Incremental collateral	$ 16,808	[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 ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Asset, total gross recognized amount		$ 60,352	$ 55,008
Derivative Liability, total gross recognized amount		(420,431)	(460,116)
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	(7,861)	6,520
Derivative Liability, Netting Adjustments and Cash Collateral	[1],[2]	95,357	102,411
Derivative Asset, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		52,491	61,528
Derivative Liability, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		(325,074)	(357,705)
Derivative assets		52,693	61,598
Derivative liabilities		(325,083)	(357,876)
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]	299,176	320,750
Derivative Asset, Fair value, amount offset against collateral		52,693	61,598
Derivative Liability, Fair value, amount offset against collateral		(25,907)	(37,126)
Derivative Liabilities, additional net exposure, collateral pledged to counterparties in excess of net liabilities		1,100	2,000
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivative [Line Items]
Derivative Asset, Mortgage delivery commitments		202	70
Derivative Liabilities, Mortgage delivery commitments		(9)	(171)
Derivative assets		202	70
Derivative liabilities		(9)	(171)
Derivative Asset, Fair value, amount offset against collateral		202	70
Derivative Liability, Fair value, amount offset against collateral		(9)	(171)
Uncleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		13,350	12,594
Derivative Liability, total gross recognized amount		(367,754)	(405,310)
Derivative Assets, Netting Adjustments and Cash Collateral		(12,518)	(12,028)
Derivative Liability, Netting Adjustments and Cash Collateral		42,680	47,605
Derivative Asset, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		832	566
Derivative Liability, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		(325,074)	(357,705)
Derivative assets		832	566
Derivative liabilities		(325,074)	(357,705)
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]	21,063	30,306
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]	278,113	290,444
Derivative Asset, Fair value, amount offset against collateral		832	566
Derivative Liability, Fair value, amount offset against collateral		(25,898)	(36,955)
Cleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		47,002	42,414
Derivative Liability, total gross recognized amount		(52,677)	(54,806)
Derivative Assets, Netting Adjustments and Cash Collateral		4,657	18,548
Derivative Liability, Netting Adjustments and Cash Collateral		52,677	54,806
Derivative Asset, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		51,659	60,962
Derivative Liability, total net amounts after netting adjustments, cash collateral, and variation margin for daily settled contracts		0	0
Derivative assets		51,659	60,962
Derivative liabilities		0	0
Derivative Asset, Fair value, amount offset against collateral		51,659	60,962
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 $57.7 million and $109.8 million at March 31, 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 $851,000 and $850,000 at March 31, 2017, and December 31, 2016, respectively. Variation margin for daily settled contracts was $30.6 million at March 31, 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 March 31, 2017, and December 31, 2016, we had additional net credit exposure of $1.1 million and $2.0 million, respectively, due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position.

Deposits Narratives (Details)

Deposits Narratives (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Interest-bearing deposit demand and overnight	$ 465,931	$ 440,731
Interest-bearing deposit other	2,824	4,166
Non-interest bearing deposits other	21,513	37,266
Total deposits	$ 490,268	$ 482,163

Consolidated Obligations CO Bon

Consolidated Obligations CO Bonds - Year of Contractual Maturiry (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Schedule of Short-term and Long-term Debt [Line Items]
Due in one year or less		$ 11,252,735	$ 8,734,955
Due in one year or less, weighted average rate	[1]	1.37%	1.43%
Due after one year through two years		$ 6,436,440	$ 7,752,420
Due after one year through two years, weighted average rate	[1]	1.31%	1.19%
Due after two years through three years		$ 3,197,930	$ 3,297,120
Due after two years through three years, weighted average rate	[1]	1.71%	1.63%
Due after three years through four years		$ 1,361,695	$ 1,637,335
Due after three years through four years, weighted average rate	[1]	1.89%	1.87%
Due after four years through five years		$ 2,551,775	$ 2,574,375
Due after four years through five years, weighted average rate	[1]	1.68%	1.65%
Thereafter		$ 3,147,595	$ 3,135,745
Thereafter, weighted average rate	[1]	2.73%	2.70%
Total par value		$ 27,948,170	$ 27,131,950
Total par value, weighted average rate	[1]	1.60%	1.58%
Hedging adjustments		$ (61,917)	$ (63,755)
Total		27,978,423	27,171,434
COs - bonds [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Premiums		106,776	118,145
Discounts		$ (14,606)	$ (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	Mar. 31, 2017	Dec. 31, 2016
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 27,948,170	$ 27,131,950
Noncallable and nonputable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	23,290,170	22,388,950
Callable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 4,658,000	$ 4,743,000

Consolidated Obligations CO B74

Consolidated Obligations CO Bonds - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Due in one year or less	$ 15,067,735	$ 12,858,955
Due after one year through two years	5,916,440	7,013,420
Due after two years through three years	2,979,930	2,904,120
Due after three years through four years	1,013,695	1,289,335
Due after four years through five years	1,284,775	1,242,375
Thereafter	1,685,595	1,823,745
Total par value	$ 27,948,170	$ 27,131,950

Consolidated Obligations CO B75

Consolidated Obligations CO Bonds - Interest-Rate-Payment Type (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Fixed-rate	$ 20,386,170	$ 20,289,950
Simple variable-rate	6,005,000	5,300,000
Step-up	1,557,000	1,542,000
Total par value	$ 27,948,170	$ 27,131,950

Consolidated Obligations CO - D

Consolidated Obligations CO - Discount Notes (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Federal Home Loan Bank, Consolidated Obligations, Discount Notes		$ 24,179,050	$ 30,053,964
Par value		$ 24,193,530	$ 30,070,103
Weighted Average Rate	[1]	0.65%	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		12 Months Ended
	Mar. 31, 2017	Mar. 31, 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	4,192	3,320	19,397
AHP direct grant disbursements	(5,385)	$ (1,990)	(18,575)
AHP subsidy for AHP advance disbursements	(267)		(1,378)
Return of previously disbursed grants and subsidies	3		102
Balance at end of period	$ 80,170		$ 81,627

Capital Requirements (Details)

Capital Requirements (Details) - USD ($) $ in Thousands	Mar. 31, 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	$ 2,458,667	$ 2,411,306
Mandatorily redeemable capital stock	32,677	32,687
Retained earnings	1,230,766	1,216,986
Total permanent capital	3,722,110	3,660,979
Credit-risk capital	352,679	355,182
Market-risk capital	168,602	118,765
Operations-risk capital	156,385	142,184
Total risk-based capital requirement	677,666	616,131
Permanent capital in excess of risk-based capital requirement	3,044,444	3,044,848
Regulatory capital, Required	2,262,752	2,461,823
Leverage capital, Required	2,828,440	3,077,279
Risk-based capital, Actual	3,722,110	3,660,979
Regulatory capital, Actual	$ 3,722,110	$ 3,660,979
Capital-to-asset ratio, Actual	6.60%	5.90%
Leverage capital, Actual	$ 5,583,165	$ 5,491,469
Leverage capital-to-assets ratio, Actual	9.90%	8.90%

Accumulated Other Comprehensi79

Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended
		Mar. 31, 2017		Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		$ 98,175,000		$ 90,860,000
Amortization of hedging activities recorded in losses on derivatives and hedging activities		36,000		(6,235,000)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(383,514,000)
Accretion of noncredit loss		8,296,000		9,141,000
Amortization - hedging activities		4,319,000		7,211,000
Amortization - pension and postretirement benefits		(194,000)		(119,000)
Other comprehensive income (loss)		39,942,000		52,167,000
Ending balance		(343,572,000)
Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(48,187,000)		(71,237,000)
Net unrealized gains (losses)		(138,000)		(17,039,000)
Amortization - hedging activities		4,319,000	[1]	7,211,000	[2]
Other comprehensive income (loss)		4,181,000		(9,828,000)
Ending balance		(44,006,000)		(81,065,000)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(6,139,000)		(3,857,000)
Net actuarial gain				1,000
Amortization - pension and postretirement benefits	[3]	194,000		118,000
Other comprehensive income (loss)		194,000		119,000
Ending balance		(5,945,000)		(3,738,000)
Total Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(383,514,000)		(442,597,000)
Net unrealized gains (losses)		26,768,000		34,791,000
Noncredit other-than-temporary impairment losses				(8,000)
Accretion of noncredit loss		8,296,000		9,141,000
Net actuarial gain				1,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[4]	365,000		913,000
Amortization - hedging activities		4,319,000	[1]	7,211,000	[2]
Amortization - pension and postretirement benefits	[3]	194,000		118,000
Other comprehensive income (loss)		39,942,000		52,167,000
Ending balance		(343,572,000)		(390,430,000)
Available-for-sale Securities [Member] | Net Unrealized Losses on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(136,809,000)		(137,718,000)
Net unrealized gains (losses)		26,906,000		51,830,000
Other comprehensive income (loss)		26,906,000		51,830,000
Ending balance		(109,903,000)		(85,888,000)
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		(192,379,000)		(229,785,000)
Noncredit other-than-temporary impairment losses				(8,000)
Accretion of noncredit loss		8,296,000		9,141,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[4]	365,000		913,000
Other comprehensive income (loss)		8,661,000		10,046,000
Ending balance		(183,718,000)		(219,739,000)
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		4,300,000		7,200,000
Amortization of hedging activities recorded in losses on derivatives and hedging activities		$ 4,000		$ 4,000
[1]	Amortization of hedging activities includes $4.3 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.
[2]	Amortization of hedging activities includes $7.2 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]	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		Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 12,817	$ 520,031
Trading securities		516,150	612,622
Available-for-sale securities Fair Value		6,299,801	6,588,664
Held-to-maturity securities	[1],[2]	2,004,511	2,130,767
Held-to-maturity securities Fair Value		2,249,437	2,372,290
Accrued interest receivable		78,816	84,653
Derivative assets		52,693	61,598
Derivative Assets, Netting Adjustments and Cash Collateral	[3],[4]	(7,861)	6,520
Mandatorily redeemable capital stock		(32,677)	(32,687)
Accrued interest payable		(100,964)	(80,822)
Derivative liabilities		(325,083)	(357,876)
Derivative Liability, Netting Adjustments and Cash Collateral	[3],[4]	95,357	102,411
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		12,817	520,031
Interest-bearing deposits		246,317	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]	11,652	8,394
Deposits		0	0
Mandatorily redeemable capital stock		(32,677)	(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		2,998,891	5,998,799
Federal funds sold		5,149,928	2,699,949
Trading securities	[4]	516,150	612,622
Available-for-sale securities Fair Value	[4]	6,291,617	6,580,518
Held-to-maturity securities Fair Value		1,082,230	1,176,269
Advances		35,643,128	39,273,044
Mortgage loans, net		3,682,550	3,708,123
Accrued interest receivable		78,816	84,653
Derivative assets	[4]	60,554	55,078
Other assets	[4]	9,394	9,385
Deposits		(490,263)	(482,158)
Mandatorily redeemable capital stock		0	0
Accrued interest payable		(100,964)	(80,822)
Derivative liabilities	[4]	(420,440)	(460,287)
Level 2 [Member] | Commitments to extend credit for advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(4,811)	(4,412)
Level 2 [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,040)	(1,064)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(24,177,609)	(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]	8,184	8,146
Held-to-maturity securities Fair Value		1,167,207	1,196,021
Advances		0	0
Mortgage loans, net		26,102	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		12,817	520,031
Interest-bearing deposits		246,317	278
Securities purchased under agreements to resell		2,999,000	5,999,000
Federal funds sold		5,150,000	2,700,000
Trading securities	[4]	516,150	612,622
Available-for-sale securities Fair Value	[4]	6,299,801	6,588,664
Held-to-maturity securities		2,004,511	2,130,767
Advances		35,479,424	39,099,339
Mortgage loans, net		3,675,598	3,693,894
Accrued interest receivable		78,816	84,653
Derivative assets	[4]	52,693	61,598
Other assets	[4]	21,046	17,779
Deposits		(490,268)	(482,163)
Mandatorily redeemable capital stock		(32,677)	(32,687)
Accrued interest payable		(100,964)	(80,822)
Derivative liabilities	[4]	(325,083)	(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		(1,040)	(1,064)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(24,179,050)	(30,053,964)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		12,817	520,031
Interest-bearing deposits		246,317	278
Securities purchased under agreements to resell		2,998,891	5,998,799
Federal funds sold		5,149,928	2,699,949
Trading securities	[4]	516,150	612,622
Available-for-sale securities Fair Value	[4]	6,299,801	6,588,664
Held-to-maturity securities Fair Value		2,249,437	2,372,290
Advances		35,643,128	39,273,044
Mortgage loans, net		3,708,652	3,736,548
Accrued interest receivable		78,816	84,653
Derivative assets	[4]	52,693	61,598
Other assets	[4]	21,046	17,779
Deposits		(490,263)	(482,158)
Mandatorily redeemable capital stock		(32,677)	(32,687)
Accrued interest payable		(100,964)	(80,822)
Derivative liabilities	[4]	(325,083)	(357,876)
Total Fair Value [Member] | Commitments to extend credit for advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(4,811)	(4,412)
Total Fair Value [Member] | Standby letters of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,040)	(1,064)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(24,177,609)	(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		(28,100,611)	(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		(27,978,423)	(27,171,434)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (28,100,611)	$ (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 $2,249,437 and $2,372,290 at March 31, 2017, and December 31, 2016, respectively.
[3]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $57.7 million and $109.8 million at March 31, 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 $851,000 and $850,000 at March 31, 2017, and December 31, 2016, respectively. Variation margin for daily settled contracts was $30.6 million at March 31, 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		Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		$ 516,150	$ 612,622
Available-for-sale securities Fair Value		6,299,801	6,588,664
Derivative assets		52,693	61,598
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	(7,861)	6,520
Derivative liabilities		(325,083)	(357,876)
Derivative Liability, Netting Adjustments and Cash Collateral	[1],[2]	95,357	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]	11,652	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]	516,150	612,622
Available-for-sale securities Fair Value	[2]	6,291,617	6,580,518
Derivative assets	[2]	60,554	55,078
Other assets	[2]	9,394	9,385
Derivative liabilities	[2]	(420,440)	(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]	8,184	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]	(7,861)	6,520
Derivative Liability, Netting Adjustments and Cash Collateral	[3]	95,357	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]	(7,861)	6,520
Derivative Liability, Netting Adjustments and Cash Collateral	[3]	95,357	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		11,652	8,394
Total assets at fair value		11,652	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		516,150	612,622
Available-for-sale securities Fair Value		6,291,617	6,580,518
Derivative assets		60,554	55,078
Other assets		9,394	9,385
Total assets at fair value		6,877,715	7,257,603
Total liabilities at fair value		(420,440)	(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		60,352	55,008
Derivative liabilities		(420,431)	(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		8,184	8,146
Derivative assets		0	0
Other assets		0	0
Total assets at fair value		8,184	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]	516,150	612,622
Available-for-sale securities Fair Value	[2]	6,299,801	6,588,664
Derivative assets	[2]	52,693	61,598
Other assets	[2]	21,046	17,779
Derivative liabilities	[2]	(325,083)	(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		516,150	612,622
Available-for-sale securities Fair Value		6,299,801	6,588,664
Derivative assets		52,693	61,598
Other assets		21,046	17,779
Total assets at fair value		6,889,690	7,280,663
Total liabilities at fair value		(325,083)	(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		52,491	61,528
Derivative liabilities		(325,074)	(357,705)
U.S. Treasury obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		308,698	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		308,698	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		308,698	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		8,050	8,494
Available-for-sale securities Fair Value		117,678	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		8,050	8,494
Available-for-sale securities Fair Value		117,678	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		8,050	8,494
Available-for-sale securities Fair Value		117,678	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		510,132	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		510,132	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		510,132	563,361
HFA securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		8,184	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		8,184	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		8,184	8,146
Supranational institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		422,339	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		422,339	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		422,339	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		276,616	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		276,616	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		276,616	271,957
GSEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		118,344	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		118,344	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		118,344	117,468
Single Family [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		644	768
Available-for-sale securities Fair Value		4,175,508	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		644	768
Available-for-sale securities Fair Value		4,175,508	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		644	768
Available-for-sale securities Fair Value		4,175,508	4,403,855
Multifamily [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		198,758	203,839
Available-for-sale securities Fair Value		671,000	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		198,758	203,839
Available-for-sale securities Fair Value		671,000	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		198,758	203,839
Available-for-sale securities Fair Value		671,000	676,530
Mortgages [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		202	70
Derivative liabilities		(9)	(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		202	70
Derivative liabilities		(9)	(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		202	70
Derivative liabilities		$ (9)	$ (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 $57.7 million and $109.8 million at March 31, 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 $851,000 and $850,000 at March 31, 2017, and December 31, 2016, respectively. Variation margin for daily settled contracts was $30.6 million at March 31, 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] $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 8,146
Purchases	0
Unrealized gains included in other comprehensive income	38
Balance at end of period	$ 8,184

Fair Values Fair Value Measur83

Fair Values Fair Value Measured on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	$ 2,249,437	$ 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	1,082,230	1,176,269
Mortgage loans held for portfolio	3,682,550	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	1,167,207	1,196,021
Mortgage loans held for portfolio	26,102	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	5,145	5,618
REO	544	786
Total assets recorded at fair value on a nonrecurring basis	10,953	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	2,249,437	2,372,290
Mortgage loans held for portfolio	3,708,652	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	5,145	5,618
REO	544	786
Total assets recorded at fair value on a nonrecurring basis	10,953	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	1,010,545	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	5,264	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	$ 5,264	$ 8,498

Commitments and Contingencies84

Commitments and Contingencies (Details) - USD ($)		3 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Final expiration date of standby letters of credit		2,026
Value of the guarantees related to standby letters of credit		$ 36,306,000	$ 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		$ 907,100,000,000	932,100,000,000
Standby Letters of Credit Issuance Commitments [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 44,100,000	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]	$ 4,472,318,000	4,050,447,000
Off-balance-sheet Commitments Expiring After One Year	[1]	174,997,000	179,632,000
Total Off-balance Sheet Commitments	[1]	4,647,315,000	4,230,079,000
Value of the guarantees related to standby letters of credit		1,000,000	1,100,000
Commitments of unused lines of credit - advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[2]	1,261,985,000	1,255,140,000
Off-balance-sheet Commitments Expiring After One Year	[2]	0	0
Total Off-balance Sheet Commitments	[2]	$ 1,261,985,000	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		$ 33,928,000	44,865,000
Off-balance-sheet Commitments Expiring After One Year		73,193,000	65,972,000
Total Off-balance Sheet Commitments		107,121,000	110,837,000
Commitments to Invest in mortgage loans [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		37,827,000	22,524,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		37,827,000	22,524,000
Unsettled CO bonds, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		70,750,000	0
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		$ 70,750,000	$ 0
[1]	The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At March 31, 2017, and December 31, 2016, these amounts totaled $44.1 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 Shareholder85

Transactions with Shareholders (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 2,458,667		$ 2,411,306
Par Value of Advances	35,520,010		39,114,855
Total Accrued Interest Receivable	78,816		84,653
Interest income on advances	106,583	$ 78,219
Fees on letters of credit	2,012	1,968
Citizens Bank, N.A. [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 352,223		$ 357,508
Percent of Total Capital Stock Outstanding	14.10%		14.60%
Par Value of Advances	$ 5,260,581		$ 7,260,446
Percentage of Total Par Value of Advances	14.80%		18.60%
Total Accrued Interest Receivable	$ 2,345		$ 2,625
Percent of Total Accrued Interest Receivable on Advances	6.20%		7.30%
Interest income on advances	$ 14,111	8,204
Fees on letters of credit	745	$ 840
Directors' Financial Institutions [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding	$ 82,433		$ 91,374
Percent of Total Capital Stock Outstanding	3.30%		3.70%
Par Value of Advances	$ 1,319,925		$ 1,554,753
Percentage of Total Par Value of Advances	3.70%		4.00%
Total Accrued Interest Receivable	$ 1,564		$ 1,631
Percent of Total Accrued Interest Receivable on Advances	4.20%		4.50%
Minimum [Member]
Transactions with Shareholders [Line Items]
Definition of shareholder concentration, minimum percent	10.00%

Subsequent Events Subsequent 86

Subsequent Events Subsequent Events (Details) - USD ($) $ in Thousands	May 02, 2017	Apr. 03, 2017	Mar. 31, 2017	Mar. 31, 2016	Apr. 18, 2017
Subsequent Event [Line Items]
Excess capital stock repurchased			$ 134,586	$ 105,313
Common Class B [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Excess capital stock repurchased		$ 180,200
Annualized rate of cash dividends					4.08%
Dividend, including dividends on mandatorily redeemable capital stock	$ 25,200