Federal Home Loan Bank of Boston 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Entity Registrant Name	FEDERAL HOME LOAN BANK OF BOSTON
Entity Central Index Key	1,331,463
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	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		24,417,272

Statements of Condition (unaudi

Statements of Condition (unaudited) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks		$ 26,681	$ 261,673
Interest-bearing deposits		51,160	246
Securities purchased under agreements to resell		2,999,000	5,349,000
Federal funds sold		6,225,000	3,450,000
Investment securities:
Trading securities		942,874	191,510
Available-for-sale securities - includes $3,348 and $1,414 pledged as collateral at March 31, 2018 and December 31, 2017, respectively that may be repledged		6,966,772	7,324,736
Held-to-maturity securities - includes $8,231 and $6,444 pledged as collateral at March 31, 2018 and December 31, 2017, respectively that may be repledged	[1],[2]	1,545,726	1,626,122
Total investment securities		9,455,372	9,142,368
Advances		37,987,775	37,565,967
Mortgage loans held for portfolio, net of allowance for credit losses of $500 at March 31, 2018. and December 31, 2017		4,026,998	4,004,737
Loans to other FHLBanks		0	400,000
Accrued interest receivable		93,749	94,100
Premises, software, and equipment, net		6,077	6,388
Derivative assets, net		30,079	34,786
Other assets		56,220	52,681
Total Assets		60,958,111	60,361,946
Deposits
Interest-bearing		502,676	450,922
Non-interest-bearing		25,156	26,147
Total deposits		527,832	477,069
Consolidated obligations (COs):
Bonds		27,125,212	28,344,623
Discount notes		29,467,314	27,720,906
Total consolidated obligations		56,592,526	56,065,529
Mandatorily redeemable capital stock		36,113	35,923
Accrued interest payable		101,593	90,626
Affordable Housing Program (AHP) payable		80,445	81,600
Derivative liabilities, net		260,565	300,450
Other liabilities		40,469	45,619
Total liabilities		57,639,543	57,096,816
Commitments and contingencies (Note 17)
Capital
Capital stock – Class B – putable ($100 par value), 23,239 shares and 22,837 shares issued and outstanding at March 31, 2018, and December 31, 2017, respectively		2,323,891	2,283,721
Retained earnings:
Unrestricted		1,057,195	1,041,033
Restricted		278,327	267,316
Total retained earnings		1,335,522	1,308,349
Accumulated other comprehensive loss		(340,845)	(326,940)
Total capital		3,318,568	3,265,130
Total Liabilities and Capital		$ 60,958,111	$ 60,361,946
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,823,482 and $1,903,227 at March 31, 2018 , and December 31, 2017

Statements of Condition (Parent

Statements of Condition (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Available-for-sale securities pledged as collateral that may be repledged	$ 3,348	$ 1,414
Held-to-maturity securities pledged as collateral that may be repledged (a)	8,231	6,444
Allowance for credit losses	500	500
Fair value of held-to-maturity securities	$ 1,823,482	$ 1,903,227
Common Class B [Member]
Common Stock, Class B, putable shares issued	23,239	22,837
Common Stock, Class B, putable par value per share	$ 100	$ 100
Common Stock, Class B, putable shares outstanding	23,239	22,837

Statements of Operations (unaud

Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
INTEREST INCOME
Advances	$ 177,450	$ 106,583
Prepayment fees on advances, net	156	164
Securities purchased under agreements to resell	10,363	4,418
Federal funds sold	22,761	10,284
Investment securities:
Trading securities	2,483	2,553
Available-for-sale securities	40,778	24,664
Held-to-maturity securities	18,561	20,354
Prepayment fees on investments	22	65
Total investment securities	61,844	47,636
Mortgage loans held for portfolio	33,025	29,947
Other	334	59
Total interest income	305,933	199,091
Consolidated obligations:
Bonds	119,201	98,175
Discount notes	104,980	37,579
Total consolidated obligations	224,181	135,754
Deposits	1,347	502
Mandatorily redeemable capital stock	486	329
Other borrowings	8	2
Total interest expense	226,022	136,587
NET INTEREST INCOME	79,911	62,504
Provision for (reduction of) credit losses	9	(51)
NET INTEREST INCOME AFTER PROVISION FOR (REDUCTION OF) CREDIT LOSSES	79,902	62,555
OTHER INCOME (LOSS)
Total other-than-temporary impairment losses on investment securities	(7)	(53)
Net amount of impairment losses reclassified from accumulated other comprehensive loss	(72)	(365)
Net other-than-temporary impairment losses on investment securities, credit portion	(79)	(418)
Service fees	2,356	2,012
Net unrealized losses on trading securities	(1,964)	(1,414)
Net gains on derivatives and hedging activities	1,140	36
Other	341	(207)
Total other income	1,794	9
OTHER EXPENSE
Compensation and benefits	10,743	10,466
Other operating expenses	5,882	5,884
Federal Housing Finance Agency (the FHFA)	930	1,002
Office of Finance	830	842
Other	2,083	2,780
Total other expense	20,468	20,974
INCOME BEFORE ASSESSMENTS	61,228	41,590
AHP	6,171	4,192
NET INCOME	$ 55,057	$ 37,398

Statements of Comprehensive Inc

Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 55,057	$ 37,398
Other comprehensive income:
Net unrealized (losses) gains on available-for-sale securities	(31,622)	26,906
Net noncredit portion of other-than-temporary impairment losses on held-to-maturity securities	7,428	8,661
Net unrealized gains relating to hedging activities	10,104	4,181
Pension and postretirement benefits	185	194
Total other comprehensive (loss) income	(13,905)	39,942
Comprehensive income	$ 41,152	$ 77,340

Statements of Capital (unaudite

Statements of Capital (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	$ 3,265,130	$ 3,244,778
Comprehensive income	41,152	77,340
Proceeds from sale of capital stock	408,332	181,947
Repurchase of capital stock	(367,871)	(134,586)
Shares reclassified to mandatorily redeemable capital stock	(291)
Cash dividends on capital stock	(27,884)	(23,618)
Period end	3,318,568	3,345,861
Retained Earnings, Unrestricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,041,033	987,711
Comprehensive income	44,046	29,918
Cash dividends on capital stock	(27,884)	(23,618)
Period end	1,057,195	994,011
Retained Earnings, Restricted
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	267,316	229,275
Comprehensive income	11,011	7,480
Period end	278,327	236,755
Retained Earnings, Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,308,349	1,216,986
Comprehensive income	55,057	37,398
Cash dividends on capital stock	(27,884)	(23,618)
Period end	1,335,522	1,230,766
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	(326,940)	(383,514)
Comprehensive income	(13,905)	39,942
Period end	$ (340,845)	$ (343,572)
Common Class B [Member] | Capital Stock Class B - Putable
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period, shares	22,837	24,113
Beginning of period	$ 2,283,721	$ 2,411,306
Proceeds from sale of capital stock, shares	4,083	1,820
Proceeds from sale of capital stock	$ 408,332	$ 181,947
Repurchase of capital stock, shares	(3,678)	(1,346)
Repurchase of capital stock	$ (367,871)	$ (134,586)
Shares reclassified to mandatorily redeemable capital stock, shares	(3)
Shares reclassified to mandatorily redeemable capital stock	$ (291)
Period end, shares	23,239	24,587
Period end	$ 2,323,891	$ 2,458,667

Statements of Cash Flows (unaud

Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
OPERATING ACTIVITIES
Net Income	$ 55,057	$ 37,398
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,036	(4,855)
Provision for (reduction of) credit losses	9	(51)
Change in net fair-value adjustments on derivatives and hedging activities	54,303	(3,811)
Net other-than-temporary impairment losses on investment securities, credit portion	79	418
Other adjustments	735	1,597
Net change in:
Market value of trading securities	1,964	1,414
Accrued interest receivable	351	5,837
Other assets	(2,159)	(2,404)
Accrued interest payable	10,967	20,142
Other liabilities	(4,600)	(5,724)
Total adjustments	63,685	12,563
Net cash provided by operating activities	118,742	49,961
INVESTING ACTIVITIES
Interest-bearing deposits	(93,777)	(225,734)
Securities purchased under agreements to resell	2,350,000	3,000,000
Federal funds sold	(2,775,000)	(2,450,000)
Premises, software, and equipment	(139)	(786)
Loans to other FHLBanks	400,000	0
Trading securities:
Proceeds	3,337	403,333
Purchases	(749,072)	(308,671)
Available-for-sale securities:
Proceeds from long-term	294,897	298,387
Held-to-maturity securities:
Proceeds from long-term	85,694	146,485
Advances to members:
Repaid	178,092,765	124,105,993
Originated	(178,561,964)	(120,511,148)
Mortgage loans held for portfolio:
Proceeds	98,311	122,979
Purchases	(124,220)	(108,181)
Proceeds from sale of foreclosed assets	796	1,384
Net cash (used in) provided by investing activities	(978,372)	4,474,041
FINANCING ACTIVITIES
Net change in deposits	51,014	8,105
Net payments on derivatives with a financing element	0	(2,353)
Net proceeds from issuance of consolidated obligations:
Discount notes	46,679,715	38,926,960
Bonds	2,320,993	2,094,792
Payments for maturing and retiring consolidated obligations:
Discount notes	(44,948,350)	(44,804,024)
Bonds	(3,491,210)	(1,278,430)
Proceeds from issuance of capital stock	408,332	181,947
Payments for repurchase of capital stock	(367,871)	(134,586)
Payments for redemption of mandatorily redeemable capital stock	(101)	(10)
Cash dividends paid	(27,884)	(23,617)
Net cash provided by (used in) financing activities	624,638	(5,031,216)
Net decrease in cash and due from banks	(234,992)	(507,214)
Cash and due from banks at beginning of the period	261,673	520,031	$ 520,031
Cash and due from banks at end of the period	26,681	12,817	261,673
Supplemental disclosures:
Interest paid	207,991	128,146
AHP payments	5,163	5,385	$ 18,628
Noncash receipt of trading securities	7,130	0
Noncash transfers of mortgage loans held for portfolio to other assets	$ 471	$ 940

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation [Text Block]	Basis of Presentation

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	3 Months Ended
	Mar. 31, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Recently Issued and Adopted Accounting Guidance Effective January 1, 2018 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. On March 10, 2017, the Financial Accounting Standards Board (FASB) issued amended guidance to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The amendments require that employers disaggregate the service cost component from the other components of net benefit cost. The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This guidance resulted in the reclassification of $372,000 of non-service cost components of net benefit cost from compensation and benefits expense to other non-interest expense in the statements of operations for the three months ended March 31, 2017. Recognition and Measurement of Financial Assets and Financial Liabilities. On January 5, 2016, the FASB issued amended guidance on certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. This guidance requires, among other things, that we: • Present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when we elect to measure the liability at fair value in accordance with the fair value option for financial instruments. • Present separately financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the statement of condition or the accompanying notes to the financial statements. • Discontinue the disclosure of the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the statement of condition. This guidance did not have any effect on our financial condition, results of operations, or cash flows. In accordance with the updated guidance, we have made insignificant revisions to Note 16 — Fair Values to specify the measurement category for each form of financial asset (that is, securities or loans and receivables). Becoming effective January 1, 2019 Targeted Improvements to Accounting for Hedging Activities, On August 28, 2017, the FASB issued amended guidance to improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. This guidance requires that, for fair value hedges, the entire change in the fair value of the hedging instrument included in the assessment of hedge effectiveness be presented in the same income statement line that is used to present the earnings effect of the hedged item. For cash flow hedges, the entire change in the fair value of the hedging instrument included in the assessment of hedge effectiveness must be recorded in other comprehensive income. In addition, the amendments include certain targeted improvements to the assessment of hedge effectiveness and permit, among other things, the following: • Measurement of the change in fair value of the hedged item on the basis of the benchmark rate component of the contractual coupon cash flows determined at hedge inception; • Measurement of the hedged item in a partial-term fair value hedge of interest-rate risk by assuming the hedged item has a term that reflects only the designated cash flows being hedged; • Consideration of only how changes in the benchmark interest rate affect a decision to settle a prepayable instrument before its scheduled maturity in calculating the change in the fair value of the hedged item attributable to interest-rate risk; • For a cash flow hedge of interest-rate risk of a variable-rate financial instrument, an entity could designate as the hedged risk the variability in cash flows attributable to the contractually specified interest-rate; • For a closed portfolio of prepayable financial assets or one or more beneficial interests secured by a portfolio of prepayable financial instruments, an entity can designate an amount that is not expected to be affected by prepayments, defaults, and other events affecting the timing and amount of cash flows (the “last-of-layer” method) into a hedging relationship; • An entity can perform subsequent assessments of hedge effectiveness qualitatively in instances where initial quantitative testing is required; and • For financial instruments eligible to be designated as a hedged item under the last-of-layer method, a one-time reclassification of prepayable financial instruments from held-to-maturity to available-for-sale at the date of adoption is permitted. This guidance becomes effective for us for interim and annual periods beginning on January 1, 2019, and while early adoption is permitted, we do not intend to adopt this guidance early. For all cash flow hedges existing on the date of adoption, this guidance will be applied through a cumulative-effect adjustment to accumulated other comprehensive income with a corresponding adjustment to retained earnings as of the beginning of the year of adoption. The amended presentation and disclosure guidance is required only prospectively. We are in the process of evaluating this guidance, and its anticipated effect on our financial condition, results of operations, and cash flows has not yet been determined. Premium Amortization on Purchased Callable Debt Securities. On March 30, 2017, the FASB issued amended guidance to shorten the amortization period for certain purchased callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. This guidance affects all entities that hold investments in callable debt securities that have an amortized cost basis in excess of the amount that is repayable by the issuer at the earliest call date (that is, at a premium). This guidance is effective for us for interim and annual periods beginning on January 1, 2019, and while early adoption is permitted, we do not intend to adopt this guidance early. This guidance will be applied using a modified retrospective method through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. We currently do not have a significant amount of assets that are in scope to be evaluated under the updated guidance. As such, adoption of this guidance is not expected to have a material effect on our financial condition, results of operations, or cash flows. Leases. On February 25, 2016, the FASB issued guidance that requires recognition of lease assets and lease liabilities on the statement of condition and disclosure of key information about leasing arrangements. In particular, this guidance requires a lessee of operating or finance leases to recognize on the statement of condition a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. However, for leases with a term of 12 months or less a lessee is permitted to make an accounting policy election not to recognize lease assets and lease liabilities. Under previous GAAP, a lessee was not required to recognize lease assets and lease liabilities arising from operating leases on the statement of condition. The guidance becomes effective for us for the interim and annual periods beginning on January 1, 2019, and while early application is permitted, we do not intend to adopt the new guidance early. We are in the process of evaluating this guidance and its anticipated effect on our financial condition, results of operations, and cash flows. Becoming effective January 1, 2020 Financial Instruments - Credit Losses. On June 16, 2016, the FASB issued amended guidance for the accounting of credit losses on financial instruments. The amendments require entities to measure expected credit losses based on relevant information about past events (including historical experience), current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. The new guidance requires a financial asset, or a group of financial assets, measured at amortized cost to be presented at the net amount expected to be collected over the contractual term of the financial asset(s). The guidance also requires, among other things, that we: • Reflect in the statement of operations the measurement of credit losses for newly recognized financial assets, as well as the expected increases or decreases of expected credit losses that have taken place during the period. • Determine the allowance for credit losses for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination that are measured at amortized cost in a similar manner to other financial assets measured at amortized cost. The initial allowance for credit losses is required to be added to the purchase price. • Record credit losses relating to available-for-sale debt securities through an allowance for credit losses. The amendments limit the allowance for credit losses to the amount by which fair value is below amortized cost. • Further disaggregate the current disclosure of credit quality indicators in relation to the amortized cost of financing receivables by the year of origination.

Trading Securities

Trading Securities	3 Months Ended
	Mar. 31, 2018
Trading Securities [Abstract]
Trading Securities (and Certain Trading Assets) Disclosure [Text Block]	Trading Securities Table 3.1 - Trading Securities by Major Security Type (dollars in thousands) March 31, 2018 December 31, 2017 U.S. Treasury obligations $ 749,578 $ — Corporate bonds 7,170 — 756,748 — Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 6,429 6,807 Government-sponsored enterprise (GSE)s – single-family 275 346 GSEs – multifamily 179,422 184,357 186,126 191,510 Total $ 942,874 $ 191,510 Net unrealized losses on trading securities for the three months ended March 31, 2018 and 2017 , amounted to $2.0 million and $1.4 million , respectively.

Available-for-Sale Securities

Available-for-Sale Securities	3 Months Ended
	Mar. 31, 2018
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Disclosure [Text Block]	Available-for-Sale Securities Table 4.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) March 31, 2018 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value State or local housing-finance-agency obligations (HFA securities) $ 42,700 $ — $ (5,205 ) $ 37,495 Supranational institutions 423,968 — (17,238 ) 406,730 U.S. government-owned corporations 299,687 — (14,660 ) 285,027 GSEs 123,318 — (5,567 ) 117,751 889,673 — (42,670 ) 847,003 MBS U.S. government guaranteed – single-family 95,666 75 (3,513 ) 92,228 U.S. government guaranteed – multifamily 420,987 — (6,834 ) 414,153 GSEs – single-family 4,391,152 974 (103,886 ) 4,288,240 GSEs – multifamily 1,323,247 2,120 (219 ) 1,325,148 6,231,052 3,169 (114,452 ) 6,119,769 Total $ 7,120,725 $ 3,169 $ (157,122 ) $ 6,966,772 _______________________ (1) Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments. December 31, 2017 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 42,700 $ — $ (5,017 ) $ 37,683 Supranational institutions 438,667 — (20,382 ) 418,285 U.S. government-owned corporations 313,985 — (21,908 ) 292,077 GSEs 128,744 — (7,401 ) 121,343 924,096 — (54,708 ) 869,388 MBS U.S. government guaranteed – single-family 98,720 55 (2,998 ) 95,777 U.S. government guaranteed – multifamily 447,975 — (4,602 ) 443,373 GSEs – single-family 4,625,333 1,194 (63,535 ) 4,562,992 GSEs – multifamily 1,350,943 2,263 — 1,353,206 6,522,971 3,512 (71,135 ) 6,455,348 Total $ 7,447,067 $ 3,512 $ (125,843 ) $ 7,324,736 _______________________ (1) Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments. Table 4.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position (dollars in thousands) March 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 29,193 $ (4,157 ) $ 8,302 $ (1,048 ) $ 37,495 $ (5,205 ) Supranational institutions — — 406,730 (17,238 ) 406,730 (17,238 ) U.S. government-owned corporations — — 285,027 (14,660 ) 285,027 (14,660 ) GSEs — — 117,751 (5,567 ) 117,751 (5,567 ) 29,193 (4,157 ) 817,810 (38,513 ) 847,003 (42,670 ) MBS U.S. government guaranteed – single-family — — 68,864 (3,513 ) 68,864 (3,513 ) U.S. government guaranteed – multifamily — — 414,153 (6,834 ) 414,153 (6,834 ) GSEs – single-family 1,794,394 (29,597 ) 2,376,944 (74,289 ) 4,171,338 (103,886 ) GSEs – multifamily 226,781 (219 ) — — 226,781 (219 ) 2,021,175 (29,816 ) 2,859,961 (84,636 ) 4,881,136 (114,452 ) Total temporarily impaired $ 2,050,368 $ (33,973 ) $ 3,677,771 $ (123,149 ) $ 5,728,139 $ (157,122 ) December 31, 2017 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 29,345 $ (4,005 ) $ 8,338 $ (1,012 ) $ 37,683 $ (5,017 ) Supranational institutions — — 418,285 (20,382 ) 418,285 (20,382 ) U.S. government-owned corporations — — 292,077 (21,908 ) 292,077 (21,908 ) GSEs — — 121,343 (7,401 ) 121,343 (7,401 ) 29,345 (4,005 ) 840,043 (50,703 ) 869,388 (54,708 ) MBS U.S. government guaranteed – single-family — — 70,877 (2,998 ) 70,877 (2,998 ) U.S. government guaranteed – multifamily 64,219 (571 ) 379,154 (4,031 ) 443,373 (4,602 ) GSEs – single-family 1,853,323 (12,661 ) 2,540,006 (50,874 ) 4,393,329 (63,535 ) 1,917,542 (13,232 ) 2,990,037 (57,903 ) 4,907,579 (71,135 ) Total temporarily impaired $ 1,946,887 $ (17,237 ) $ 3,830,080 $ (108,606 ) $ 5,776,967 $ (125,843 ) Table 4.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ — $ — $ — $ — Due after one year through five years 42,700 37,495 42,700 37,683 Due after five years through 10 years 423,968 406,730 438,667 418,285 Due after 10 years 423,005 402,778 442,729 413,420 889,673 847,003 924,096 869,388 MBS (1) 6,231,052 6,119,769 6,522,971 6,455,348 Total $ 7,120,725 $ 6,966,772 $ 7,447,067 $ 7,324,736 _______________________ (1)

Held-to-Maturity Securities

Held-to-Maturity Securities	3 Months Ended
	Mar. 31, 2018
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity Securities Disclosure [Text Block]	Held-to-Maturity Securities Table 5.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) March 31, 2018 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value U.S. agency obligations $ 854 $ — $ 854 $ 5 $ — $ 859 HFA securities 145,185 — 145,185 22 (6,616 ) 138,591 146,039 — 146,039 27 (6,616 ) 139,450 MBS U.S. government guaranteed – single-family 9,527 — 9,527 173 — 9,700 GSEs – single-family 528,730 — 528,730 9,130 (1,126 ) 536,734 GSEs – multifamily 213,723 — 213,723 3,728 — 217,451 Private-label – residential 790,847 (150,767 ) 640,080 275,649 (2,939 ) 912,790 Asset-backed securities (ABS) backed by home equity loans 7,649 (22 ) 7,627 26 (296 ) 7,357 1,550,476 (150,789 ) 1,399,687 288,706 (4,361 ) 1,684,032 Total $ 1,696,515 $ (150,789 ) $ 1,545,726 $ 288,733 $ (10,977 ) $ 1,823,482 December 31, 2017 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value U.S. agency obligations $ 1,042 $ — $ 1,042 $ 10 $ — $ 1,052 HFA securities 146,410 — 146,410 26 (14,372 ) 132,064 147,452 — 147,452 36 (14,372 ) 133,116 MBS U.S. government guaranteed – single-family 10,097 — 10,097 190 — 10,287 U.S. government guaranteed – multifamily 280 — 280 — — 280 GSEs – single-family 568,948 — 568,948 10,410 (310 ) 579,048 GSEs – multifamily 214,641 — 214,641 6,451 — 221,092 Private-label – residential 835,070 (158,194 ) 676,876 278,217 (3,195 ) 951,898 ABS backed by home equity loans 7,851 (23 ) 7,828 27 (349 ) 7,506 1,636,887 (158,217 ) 1,478,670 295,295 (3,854 ) 1,770,111 Total $ 1,784,339 $ (158,217 ) $ 1,626,122 $ 295,331 $ (18,226 ) $ 1,903,227 Table 5.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position (dollars in thousands) March 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 127,734 $ (6,616 ) $ 127,734 $ (6,616 ) MBS GSEs – single-family 118,383 (793 ) 27,254 (333 ) 145,637 (1,126 ) Private-label – residential — — 148,538 (4,917 ) 148,538 (4,917 ) ABS backed by home equity loans — — 7,223 (296 ) 7,223 (296 ) 118,383 (793 ) 183,015 (5,546 ) 301,398 (6,339 ) Total $ 118,383 $ (793 ) $ 310,749 $ (12,162 ) $ 429,132 $ (12,955 ) December 31, 2017 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 121,203 $ (14,372 ) $ 121,203 $ (14,372 ) MBS GSEs – single-family 44,759 (52 ) 28,771 (258 ) 73,530 (310 ) Private-label – residential — — 158,963 (5,558 ) 158,963 (5,558 ) ABS backed by home equity loans — — 7,371 (350 ) 7,371 (350 ) 44,759 (52 ) 195,105 (6,166 ) 239,864 (6,218 ) Total $ 44,759 $ (52 ) $ 316,308 $ (20,538 ) $ 361,067 $ (20,590 ) Table 5.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 551 $ 551 $ 554 $ 264 $ 264 $ 267 Due after one year through five years 11,138 11,138 11,162 11,613 11,613 11,645 Due after five years through 10 years 18,245 18,245 18,127 18,245 18,245 18,226 Due after 10 years 116,105 116,105 109,607 117,330 117,330 102,978 146,039 146,039 139,450 147,452 147,452 133,116 MBS (2) 1,550,476 1,399,687 1,684,032 1,636,887 1,478,670 1,770,111 Total $ 1,696,515 $ 1,545,726 $ 1,823,482 $ 1,784,339 $ 1,626,122 $ 1,903,227 _______________________ (1) Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss. (2)

Other-Than-Temporary Impairment

Other-Than-Temporary Impairment	3 Months Ended
	Mar. 31, 2018
Other than Temporary Impairment Losses, Investments [Abstract]
Other-than-Temporary Impairment [Text Block]	Other-Than-Temporary Impairment We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter. Available-for-Sale Securities We determined that none of our available-for-sale securities were other-than-temporarily impaired at March 31, 2018 . At March 31, 2018 , we held certain available-for-sale securities in an unrealized loss position. These unrealized losses reflect the impact of normal yield and spread fluctuations attendant with security markets. We consider these unrealized losses temporary because we expect to recover the entire amortized cost basis on these available-for-sale securities in an unrealized loss position and neither intend to sell these securities nor is it more likely than not that we will be required to sell these securities before the anticipated recovery of each security's remaining amortized cost basis. Additionally, there have been no shortfalls of principal or interest on any available-for-sale security. Held-to-Maturity Securities HFA Securities and Agency MBS. We have reviewed our investments in HFA securities and agency MBS and have determined that all unrealized losses are temporary. We do not intend to sell the investments nor is it more likely than not that we will be required to sell the investments before recovery of the amortized cost basis, we do not consider these investments to be other-than-temporarily impaired at March 31, 2018 . 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, 2018 , Table 6.1 presents a summary of the average projected values over the remaining lives of the securities for the significant inputs used to measure the amount of the credit loss recognized in earnings, as well as related current credit enhancement. Credit enhancement is defined as the percentage of subordinated tranches, over-collateralization, and other credit enhancement, if any, in a security structure that will generally absorb losses before we will experience a credit loss on the security. The calculated averages represent the dollar-weighted average of Alt-A other-than-temporarily impaired private-label residential MBS. Table 6.1 - Significant Inputs and Current Credit Enhancement for Securities with a Current Period Credit Loss (dollars in thousands) Weighted Average of Significant Inputs Weighted Average Current Credit Enhancement Private-label MBS by Classification Par Value Projected Prepayment Rates Projected Default Rates Projected Loss Severities Alt-A - Private-label residential MBS (1) $ 10,345 12.3 % 20.8 % 31.9 % 5.3 % _______________________ (1) Securities are classified based upon the current performance characteristics of the underlying loan pool and therefore the manner in which the loan pool backing the security has been modeled (as prime, Alt-A, or subprime), rather than their classification of the security at the time of issuance. Table 6.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) March 31, 2018 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 28,890 $ 24,692 $ 19,333 $ 27,065 Private-label residential MBS – Alt-A 907,387 658,402 512,993 780,710 ABS backed by home equity loans – Subprime 171 159 137 164 Total other-than-temporarily impaired securities $ 936,448 $ 683,253 $ 532,463 $ 807,939 _______________________ (1) Securities are classified based on their classifications at the time of issuance. We have instituted litigation related to certain of the private-label MBS in which we invested. Our complaint asserts, among others, claims for untrue or misleading statements in the sale of securities. It is possible that classifications of private-label MBS as provided herein when based on classification at the time of issuance as disclosed by those securities' issuance documents, as well as other statements about the securities, are inaccurate. Table 6.3 presents a roll forward of the amounts related to credit losses recognized in earnings. The roll forward is the amount of credit losses on investment securities for which we recognized a portion of other-than-temporary impairment charges into accumulated other comprehensive loss. Table 6.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Balance at beginning of period $ 452,523 $ 490,404 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 79 418 Reductions: Portion of increase in cash flows expected to be collected over the remaining life of the security that are recognized in the current period as interest income (7,316 ) (8,601 ) Balance at end of period $ 445,286 $ 482,221 _______________________ (1) For the three months ended March 31, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to January 1, 2018 and 2017

Advances

Advances	3 Months Ended
	Mar. 31, 2018
Advances [Abstract]
Federal Home Loan Bank, Advances [Text Block]	Advances General Terms. At both March 31, 2018 , and December 31, 2017 , we had advances outstanding with interest rates ranging from zero percent to 7.72 percent . Table 7.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 7,674 2.16 % $ 5,698 1.70 % Due in one year or less 19,913,161 1.86 21,501,397 1.56 Due after one year through two years 9,464,785 1.92 7,462,785 1.65 Due after two years through three years 2,615,780 1.98 2,709,951 1.85 Due after three years through four years 1,987,993 2.16 2,084,105 2.03 Due after four years through five years 2,427,407 1.74 2,071,989 1.56 Thereafter 1,699,565 2.30 1,811,241 2.23 Total par value 38,116,365 1.91 % 37,647,166 1.66 % Premiums 16,735 17,931 Discounts (34,553 ) (32,757 ) Fair value of bifurcated derivatives (1) (2,215 ) (1,591 ) Hedging adjustments (108,557 ) (64,782 ) Total $ 37,987,775 $ 37,565,967 _________________________ (1) At March 31, 2018 , and December 31, 2017 , we had certain advances with embedded features that met the requirements to be separated from the host contract and designated as stand-alone derivatives. Table 7.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (1) (dollars in thousands) March 31, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,674 $ 5,698 Due in one year or less 26,252,136 25,842,572 Due after one year through two years 3,964,785 3,722,785 Due after two years through three years 2,605,780 2,709,951 Due after three years through four years 1,837,993 1,924,105 Due after four years through five years 1,802,407 1,684,789 Thereafter 1,645,590 1,757,266 Total par value $ 38,116,365 $ 37,647,166 _______________________ (1) Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees. Table 7.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value March 31, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,674 $ 5,698 Due in one year or less 21,405,861 22,828,547 Due after one year through two years 9,892,785 7,921,035 Due after two years through three years 2,624,780 2,686,951 Due after three years through four years 1,843,093 1,984,705 Due after four years through five years 1,393,607 1,216,989 Thereafter 948,565 1,003,241 Total par value $ 38,116,365 $ 37,647,166 Table 7.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances March 31, 2018 December 31, 2017 Fixed-rate $ 30,623,916 $ 31,658,293 Variable-rate 7,492,449 5,988,873 Total par value $ 38,116,365 $ 37,647,166 Credit-Risk Exposure and Security Terms . Our potential credit risk from advances is principally concentrated in commercial banks, insurance companies, savings institutions, and credit unions. At March 31, 2018 , and December 31, 2017 , we had $11.2 billion and $12.1 billion , respectively, of advances issued to members with at least $1.0 billion of advances outstanding. These advances were made to five borrowers and six borrowers, respectively, at March 31, 2018 , and December 31, 2017 , representing 29.4 percent and 32.3 percent , respectively, of total par value of outstanding advances. For information related to our credit risk on advances and allowance for credit losses, see Note 9 — Allowance for Credit Losses

Mortgage Loans Held for Portfol

Mortgage Loans Held for Portfolio	3 Months Ended
	Mar. 31, 2018
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portofolio [Text Block]	Mortgage Loans Held for Portfolio We invest in mortgage loans through the 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. Table 8.1 - Mortgage Loans Held for Portfolio (dollars in thousands) March 31, 2018 December 31, 2017 Real estate Fixed-rate 15-year single-family mortgages $ 448,260 $ 466,952 Fixed-rate 20- and 30-year single-family mortgages 3,509,845 3,466,752 Premiums 68,785 70,074 Discounts (1,599 ) (1,541 ) Deferred derivative gains, net 2,207 3,000 Total mortgage loans held for portfolio 4,027,498 4,005,237 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,026,998 $ 4,004,737 Table 8.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) March 31, 2018 December 31, 2017 Conventional mortgage loans $ 3,600,878 $ 3,568,473 Government mortgage loans 357,227 365,231 Total par value $ 3,958,105 $ 3,933,704 See Note 9 — Allowance for Credit Losses for information related to our credit risk from our investments in mortgage loans and allowance for credit losses based on these investments.

Allowance for Credit Losses

Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Allowance for Credit Losses [Text Block]	Allowance for Credit Losses An allowance for credit losses is a valuation allowance separately established for each identified portfolio segment, if necessary, to provide for probable losses inherent in our portfolio as of the statement of condition date. To the extent necessary, an allowance for credit losses for off-balance-sheet credit exposure is recorded as a liability. For additional information see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2017 Annual Report. Secured Member Credit Products We manage our credit exposure to secured member credit products through an integrated approach that generally includes establishing a credit limit for each borrower. This approach includes an ongoing review of each borrower's financial condition, and collateral and lending policies that are intended to limit risk of loss while balancing borrowers' needs for a reliable source of funding. At March 31, 2018 , and December 31, 2017 , none of our secured member credit products outstanding were past due, on nonaccrual status, or considered impaired. In addition, there were no troubled debt restructurings related to credit products during the three months ended March 31, 2018 , and 2017 . Based upon the collateral held as security, our credit extension and collateral policies, management's credit analysis, and the repayment history on secured member credit products, we have not recorded any allowance for credit losses on our secured member credit products at March 31, 2018 , and December 31, 2017 . At March 31, 2018 , and December 31, 2017 , no liability to reflect an allowance for credit losses for off-balance-sheet credit exposures was recorded. See Note 17 — Commitments and Contingencies for additional information on our off-balance-sheet credit exposure. Government Mortgage Loans Held for Portfolio Due to government guarantees or insurance on our government loans, there is no allowance for credit losses for the government mortgage loan portfolio as of March 31, 2018 , and December 31, 2017 . Additionally, these mortgage loans are not placed on nonaccrual status due to the government guarantee or insurance on these loans and the contractual obligation of the loan servicers to repurchase their related loans when certain criteria are met. For additional information see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2017 Annual Report. Conventional Mortgage Loans Held for Portfolio For information on our conventional mortgage loans held for portfolio see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2017 Annual Report. Credit Quality Indicators. Key credit quality indicators for mortgage loans include the migration of past due loans, nonaccrual loans, loans in process of foreclosure, and impaired loans. Table 9.1 sets forth certain key credit quality indicators for our investments in mortgage loans at March 31, 2018 , and December 31, 2017 (dollars in thousands): Table 9.1 - Recorded Investment in Delinquent Mortgage Loans (dollars in thousands) March 31, 2018 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 26,962 $ 13,427 $ 40,389 Past due 60-89 days delinquent 6,543 4,295 10,838 Past due 90 days or more delinquent 12,635 5,199 17,834 Total past due 46,140 22,921 69,061 Total current loans 3,635,455 343,853 3,979,308 Total mortgage loans $ 3,681,595 $ 366,774 $ 4,048,369 Other delinquency statistics In process of foreclosure, included above (1) $ 5,360 $ 1,529 $ 6,889 Serious delinquency rate (2) 0.36 % 1.42 % 0.46 % Past due 90 days or more still accruing interest $ — $ 5,199 $ 5,199 Loans on nonaccrual status (3) $ 13,245 $ — $ 13,245 _______________________ (1) Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported. (2) Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class. (3) Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan. December 31, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 28,622 $ 13,862 $ 42,484 Past due 60-89 days delinquent 6,617 4,142 10,759 Past due 90 days or more delinquent 13,310 4,831 18,141 Total past due 48,549 22,835 71,384 Total current loans 3,601,952 352,249 3,954,201 Total mortgage loans $ 3,650,501 $ 375,084 $ 4,025,585 Other delinquency statistics In process of foreclosure, included above (1) $ 6,389 $ 1,306 $ 7,695 Serious delinquency rate (2) 0.38 % 1.29 % 0.46 % Past due 90 days or more still accruing interest $ — $ 4,831 $ 4,831 Loans on nonaccrual status (3) $ 13,598 $ — $ 13,598 _______________________ (1) Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported. (2) Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class. (3) Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan. Individually Evaluated Impaired Loans. Table 9.2 - Individually Impaired Conventional Mortgage Loans (dollars in thousands) March 31, 2018 December 31, 2017 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 16,540 $ 16,505 $ 17,668 $ 17,630 Table 9.3 - Average Recorded Investment of Individually Impaired Mortgage Loans and Related Interest Income (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 16,731 $ 112 $ 21,699 $ 116 Credit Enhancements. For information on our credit enhancements held for portfolio see Item 8 — Financial Statements and Supplementary Data — Note 10 — Allowance for Credit Losses in the 2017 Annual Report. Roll-Forward of Allowance for Credit Losses on Mortgage Loans. Table 9.4 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the three months ended March 31, 2018 and 2017 , as well as the recorded investment in mortgage loans by impairment methodology at March 31, 2018 and 2017 . The recorded investment in a loan is the par amount of the loan, adjusted for accrued interest, unamortized premiums or discounts, deferred derivative gains and losses, and direct write-downs. The recorded investment is net of any valuation allowance. Table 9.4 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Allowance for credit losses Balance, beginning of period $ 500 $ 650 Charge-offs, net of recoveries (9 ) 26 Provision for (reduction of) credit losses 9 (51 ) Balance, end of period $ 500 $ 625 Ending balance, individually evaluated for impairment $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 625 Recorded investment, end of period (1) Individually evaluated for impairment $ 16,540 $ 21,352 Collectively evaluated for impairment $ 3,665,055 $ 3,281,864 _________________________ (1)

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities [Text Block]	Derivatives and Hedging Activities Table 10.1 - Fair Value of Derivative Instruments (dollars in thousands) March 31, 2018 December 31, 2017 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 13,961,344 $ 16,113 $ (316,074 ) $ 14,118,994 $ 52,557 $ (332,830 ) Forward-start interest-rate swaps 388,200 — (469 ) 481,200 — (9,807 ) Total derivatives designated as hedging instruments 14,349,544 16,113 (316,543 ) 14,600,194 52,557 (342,637 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,292,700 4,517 (2,941 ) 1,166,900 3,512 (4,688 ) Mortgage-delivery commitments (1) 32,756 283 (6 ) 42,918 169 (27 ) Total derivatives not designated as hedging instruments 1,325,456 4,800 (2,947 ) 1,209,818 3,681 (4,715 ) Total notional amount of derivatives $ 15,675,000 $ 15,810,012 Total derivatives before netting and collateral adjustments 20,913 (319,490 ) 56,238 (347,352 ) Netting adjustments and cash collateral, including related accrued interest (2) 9,166 58,925 (21,452 ) 46,902 Derivative assets and derivative liabilities $ 30,079 $ (260,565 ) $ 34,786 $ (300,450 ) _______________________ (1) Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income. (2) Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $68.7 million and $25.8 million at March 31, 2018 , and December 31, 2017 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $601,000 and $350,000 at March 31, 2018 , and December 31, 2017 . Table 10.2 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Derivatives designated as hedging instruments Interest-rate swaps $ 1,108 $ (659 ) Forward-start interest-rate swaps 76 134 Total net gains (losses) related to derivatives designated as hedging instruments 1,184 (525 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps 624 153 Mortgage-delivery commitments (518 ) 357 Total net gains related to derivatives not designated as hedging instruments 106 510 Other (1) (150 ) 51 Net gains on derivatives and hedging activities $ 1,140 $ 36 ______________ (1) Consists of price alignment amount on derivatives for which variation margin is characterized as a daily settlement amount. Table 10.3 - Effect of Fair Value Hedge Relationships (dollars in thousands) For the Three Months Ended March 31, 2018 Gain/(Loss) on Derivative (Loss)/Gain on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 43,797 $ (43,775 ) $ 22 $ 5,695 Investments 34,846 (34,423 ) 423 (7,311 ) COs – bonds (41,771 ) 42,434 663 (3,017 ) Total $ 36,872 $ (35,764 ) $ 1,108 $ (4,633 ) For the Three Months Ended March 31, 2017 Gain/(Loss) on Derivative (Loss)/Gain on 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 ) ______________ (1) The net interest on derivatives in fair-value hedge relationships is presented in the statement of operations as interest income or interest expense of the respective hedged item. Table 10.4 - Effect of Cash Flow Hedge Relationships (dollars in thousands) Derivatives and Hedged Items in Cash Flow Hedging Relationships Gains (Losses) Recognized in Other Comprehensive Loss on Derivatives (Effective Portion) Location of Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Gains Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion) Forward-start Interest-rate swaps - CO bonds For the Three Months Ended March 31, 2018 $ 9,166 Interest expense $ (934 ) $ 76 For the Three Months Ended March 31, 2017 (138 ) Interest expense (4,315 ) 134 For the three months ended March 31, 2018 and 2017 , there were no reclassifications from accumulated other comprehensive loss into earnings as a result of the discontinuance of cash-flow hedges because the original forecasted transactions were not expected to occur by the end of the originally specified time period or within a two-month period thereafter. As of March 31, 2018 , the maximum length of time over which we are hedging our exposure to the variability in future cash flows for forecasted transactions is seven years . As of March 31, 2018 , the amount of deferred net losses on derivatives accumulated in other comprehensive loss related to cash flow hedges expected to be reclassified to earnings during the next 12 months is $3.1 million . Managing Credit Risk on Derivatives. We enter into derivatives that we clear (cleared derivatives) with a DCO, our counterparty for such derivatives. We also enter into derivatives that are not cleared (uncleared derivatives) under master-netting agreements. Certain of our uncleared derivatives master-netting agreements contain provisions that require us to post additional collateral with our uncleared derivatives counterparties if our credit ratings are lowered. Under the terms that govern such agreements, if our credit rating is lowered by Moody's or S&P to a certain level, we are required to deliver additional collateral on uncleared derivatives in a net liability position, unless the collateral delivery threshold is set to zero. In the event of a split between such credit ratings, the lower rating governs. The aggregate fair value of all uncleared derivatives with these provisions that were in a net-liability position (before cash collateral and related accrued interest) at March 31, 2018 , was $299.3 million for which we had delivered collateral with a post-haircut value of $276.4 million in accordance with the terms of the master-netting agreements. Securities collateral is subject to valuation haircuts in accordance with the terms of the master-netting arrangements. Table 10.5 sets forth the post-haircut value of incremental collateral that certain uncleared derivatives counterparties could have required us to deliver based on incremental credit rating downgrades at March 31, 2018 . Table 10.5 - Post Haircut Value of Incremental Collateral to be Delivered as of March 31, 2018 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 3,080 AA- A+, A or A- 14,994 A- below A- 18,797 _______________________ (1) Ratings are expressed in this table according to S&P's conventions but include the equivalent of such rating by Moody's. If there is a split rating, the lower rating is used. Cleared Derivatives. For cleared derivatives, the DCO is our counterparty. The DCO notifies the clearing member of the required initial and variation margin and our agent (clearing member) in turn notifies us. We utilize two DCOs, for all cleared derivative transactions, CME Inc. and LCH Ltd. Based upon certain amendments, effective January 3, 2017, made by CME Inc. to its rulebook, we began to characterize variation margin payments related to CME Inc. contracts as daily settlement payments, rather than collateral. However, throughout 2017, we continued to characterize our variation margin related to LCH Ltd. contracts as cash collateral. We began to characterize variation margin payments related to LCH Ltd. contracts as daily settlement payments, rather than cash collateral, based upon a change effective January 16, 2018, to LCH Ltd.’s rulebook. A t both DCOs, initial margin has been, and continues to be, considered cash collateral. We post initial margin and exchange variation margin through a clearing member who acts as our agent to the DCO and who guarantees our performance to the DCO, subject to the terms of relevant agreements. These arrangements expose us to credit risk in the event that one of our clearing members or one of the DCOs fails to meet its obligations. The use of cleared derivatives is intended to mitigate credit risk exposure because the DCO, which is fully secured at all times through margin received from its clearing members, is substituted for the credit risk exposure of individual counterparties in uncleared derivatives, and collateral is posted at least once daily for changes in the fair value of cleared derivatives through a clearing member. For cleared derivatives, the DCO determines initial margin requirements. We clear our trades via clearing members of the DCOs. These clearing members who act as our agent to the DCOs are CFTC-registered futures commission merchants. Our clearing members may require us to post margin in excess of DCO requirements based on our credit or other considerations, including but not limited to, credit rating downgrades. We were not required to post any such excess margin by our clearing members based on credit considerations at March 31, 2018 . Offsetting of Certain Derivatives. We present derivatives, any related cash collateral, including initial and certain variation margin, received or pledged, and associated accrued interest, on a net basis by counterparty. We have analyzed the rights, rules, and regulations governing our cleared derivatives and determined that those rights, rules, and regulations should result in a net claim through each of our clearing members with the related DCO upon an event of default including a bankruptcy, insolvency or similar proceeding involving the DCO or one of our clearing members, or both. For this purpose, net claim generally means a single net amount reflecting the aggregation of all amounts indirectly owed by us to the relevant DCO and indirectly payable to us from the relevant DCO. Table 10.6 presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of March 31, 2018 , and December 31, 2017 , and the fair value of derivatives that are not subject to such netting. Such netting includes any related cash collateral received from or pledged to counterparties. Table 10.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) March 31, 2018 Derivative Instruments Meeting Netting Requirements Non-cash Collateral Received or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 20,069 $ (18,671 ) $ 283 $ 1,681 $ — $ — $ 1,681 Cleared 561 27,837 28,398 — — 28,398 Total $ 30,079 $ 30,079 Derivative Liabilities Uncleared $ (317,892 ) $ 57,333 $ (6 ) $ (260,565 ) $ 10,687 $ 237,658 $ (12,220 ) Cleared (1,592 ) 1,592 — — — — Total $ (260,565 ) $ (12,220 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At March 31, 2018 , we had additional net credit exposure of $178,000 due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2017 Derivative Instruments Meeting Netting Requirements Non-cash Collateral Received or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 15,587 $ (13,481 ) $ 169 $ 2,275 $ — $ — $ 2,275 Cleared 40,482 (7,971 ) 32,511 — — 32,511 Total $ 34,786 $ 34,786 Derivative Liabilities Uncleared $ (335,289 ) $ 34,866 $ (27 ) $ (300,450 ) $ 7,627 $ 280,486 $ (12,337 ) Cleared (12,036 ) 12,036 — — — — Total $ (300,450 ) $ (12,337 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2017 , we had additional net credit exposure of $502,000

Deposits

Deposits	3 Months Ended
	Mar. 31, 2018
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, which we classify as "other" in the following table. Table 11.1 - Deposits (dollars in thousands) March 31, 2018 December 31, 2017 Interest-bearing Demand and overnight $ 500,634 $ 447,700 Short-term 2,042 3,222 Noninterest-bearing Other 25,156 26,147 Total deposits $ 527,832 $ 477,069

Consolidated Obligations

Consolidated Obligations	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Consolidated Obligations [Text Block]	Consolidated Obligations CO Bonds for which we have received issuance proceeds and are primarily liable. Table 12.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 10,747,200 1.55 % $ 12,186,510 1.35 % Due after one year through two years 5,596,915 1.82 5,288,470 1.63 Due after two years through three years 3,065,675 1.89 3,128,240 1.81 Due after three years through four years 2,681,605 1.77 2,759,460 1.74 Due after four years through five years 1,723,330 2.04 1,572,775 2.00 Thereafter 3,337,165 2.82 3,389,695 2.76 Total par value 27,151,890 1.85 % 28,325,150 1.70 % Premiums 87,594 90,836 Discounts (16,160 ) (15,685 ) Hedging adjustments (98,112 ) (55,678 ) $ 27,125,212 $ 28,344,623 _______________________ (1) The CO bonds' weighted-average rate excludes concession fees. Table 12.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds March 31, 2018 December 31, 2017 Noncallable and nonputable $ 22,644,890 $ 23,931,150 Callable 4,507,000 4,394,000 Total par value $ 27,151,890 $ 28,325,150 Table 12.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date March 31, 2018 December 31, 2017 Due in one year or less $ 14,137,200 $ 15,309,510 Due after one year through two years 5,813,915 5,580,470 Due after two years through three years 2,857,675 3,020,240 Due after three years through four years 1,539,605 1,542,460 Due after four years through five years 1,148,330 1,107,775 Thereafter 1,655,165 1,764,695 Total par value $ 27,151,890 $ 28,325,150 Table 12.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds March 31, 2018 December 31, 2017 Fixed-rate $ 21,582,890 $ 21,416,150 Simple variable-rate 4,027,000 5,432,000 Step-up 1,542,000 1,477,000 Total par value $ 27,151,890 $ 28,325,150 CO Discount Notes. Outstanding CO discount notes for which we were primarily liable, all of which are due within one year, were as follows (dollars in thousands): Table 12.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) March 31, 2018 $ 29,467,314 $ 29,508,841 1.61 % December 31, 2017 $ 27,720,906 $ 27,752,860 1.25 % _______________________ (1)

Affordable Housing Program

Affordable Housing Program	3 Months Ended
	Mar. 31, 2018
Affordable Housing Program [Abstract]
Affordable Housing Program [Text Block]	Affordable Housing Program Table 13.1 - AHP Liability (dollars in thousands) March 31, 2018 December 31, 2017 Balance at beginning of period $ 81,600 $ 81,627 AHP expense for the period 6,171 21,307 AHP direct grant disbursements (5,163 ) (18,628 ) AHP subsidy for AHP advance disbursements (2,172 ) (2,782 ) Return of previously disbursed grants and subsidies 9 76 Balance at end of period $ 80,445 $ 81,600

Capital

Capital	3 Months Ended
	Mar. 31, 2018
Capital [Abstract]
Capital [Text Block]	Capital We are subject to capital requirements under our capital plan, the Federal Home Loan Bank Act of 1932, as amended (the FHLBank Act), and FHFA regulations: 1. Risk-based capital. We are required to maintain at all times permanent capital, defined as Class B stock, including Class B stock classified as mandatorily redeemable capital stock, and retained earnings, in an amount at least equal to the sum of our credit-risk capital requirement, market-risk capital requirement, and operations-risk capital requirement, calculated in accordance with FHFA rules and regulations, referred to herein as the risk-based capital requirement. Only permanent capital satisfies the risk-based capital requirement. 2. Total regulatory capital. We are required to maintain at all times a total capital-to-assets ratio of at least four percent . Total regulatory capital is the sum of permanent capital, the amount paid-in for Class A stock, the amount of any general loss allowance if consistent with GAAP and not established for specific assets, and other amounts from sources determined by the FHFA as available to absorb losses. We have never issued Class A stock. 3. Leverage capital. We are required to maintain at all times a leverage capital-to-assets ratio of at least five percent . Leverage capital is defined as the sum of permanent capital weighted 1.5 times and all other capital without a weighting factor. The FHFA may require us to maintain a greater amount of permanent capital than is required as defined by the risk-based capital requirements. Table 14.1 demonstrates our compliance with our regulatory capital requirements at March 31, 2018 , and December 31, 2017 . Table 14.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements March 31, 2018 December 31, 2017 Permanent capital Class B capital stock $ 2,323,891 $ 2,283,721 Mandatorily redeemable capital stock 36,113 35,923 Retained earnings 1,335,522 1,308,349 Total permanent capital $ 3,695,526 $ 3,627,993 Risk-based capital requirement Credit-risk capital $ 338,828 $ 328,557 Market-risk capital 211,211 170,102 Operations-risk capital 165,012 149,598 Total risk-based capital requirement $ 715,051 $ 648,257 Permanent capital in excess of risk-based capital requirement $ 2,980,475 $ 2,979,736 March 31, 2018 December 31, 2017 Required Actual Required Actual Capital Ratio Risk-based capital $ 715,051 $ 3,695,526 $ 648,257 $ 3,627,993 Total regulatory capital $ 2,438,324 $ 3,695,526 $ 2,414,478 $ 3,627,993 Total capital-to-asset ratio 4.0 % 6.1 % 4.0 % 6.0 % Leverage Ratio Leverage capital $ 3,047,906 $ 5,543,289 $ 3,018,097 $ 5,441,990 Leverage capital-to-assets ratio 5.0 % 9.1 % 5.0 % 9.0 %

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2018
AOCI Attributable to Parent [Abstract]
Accumulated Other Comprehensive Loss [Text Block]	Accumulated Other Comprehensive Loss Table 15.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Accumulated Other Comprehensive Loss Balance, 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 (2) — — 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 ) Balance, December 31, 2017 $ (122,331 ) $ (158,218 ) $ (40,436 ) $ (5,955 ) $ (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (31,622 ) — 9,166 — (22,456 ) Accretion of noncredit loss — 7,356 — — 7,356 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 72 — — 72 Amortization - hedging activities (4) — — 938 — 938 Amortization - pension and postretirement benefits (3) — — — 185 185 Other comprehensive (loss) income (31,622 ) 7,428 10,104 185 (13,905 ) Balance, March 31, 2018 $ (153,953 ) $ (150,790 ) $ (30,332 ) $ (5,770 ) $ (340,845 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $4.3 million recorded in CO bond interest expense and $4,000 recorded in net losses on derivatives and hedging activities in the statement of operations. (3) Recorded in other non-interest expenses in the statement of operations. (4) Amortization of hedging activities includes $934,000 recorded in CO bond interest expense and $4,000

Fair Values

Fair Values	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value [Text Block]	Fair Values A fair-value hierarchy is used to prioritize the inputs of valuation techniques used to measure fair value. A description of the application of the fair-value hierarchy, valuation techniques, and significant inputs is disclosed in Item 8 — Financial Statements and Supplementary Data — Note 18 — Fair Values in the 2017 Annual Report. There have been no material changes in the fair-value hierarchy classification of financial assets and liabilities, valuation techniques, or significant inputs during the three months ended March 31, 2018 . We record trading securities, available-for-sale securities, derivative assets, derivative liabilities, and certain other assets at fair value on a recurring basis, and under certain circumstances, certain private-label MBS, certain mortgage loans, and certain other assets on a non-recurring basis. We record all other financial assets and liabilities at amortized cost. Refer to the tables below related to financial assets and liabilities held at fair value on either a recurring or non-recurring basis for further details. Table 16.1 - Fair Value Summary (dollars in thousands) March 31, 2018 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 26,681 $ 26,681 $ 26,681 $ — $ — $ — Interest-bearing deposits 51,160 51,160 51,160 — — — Securities purchased under agreements to resell 2,999,000 2,998,981 — 2,998,981 — — Federal funds sold 6,225,000 6,224,991 — 6,224,991 — — Trading securities (1) 942,874 942,874 — 942,874 — — Available-for-sale securities (1) 6,966,772 6,966,772 — 6,929,277 37,495 — Held-to-maturity securities 1,545,726 1,823,482 — 764,744 1,058,738 — Advances 37,987,775 37,962,720 — 37,962,720 — — Mortgage loans, net 4,026,998 3,966,900 — 3,945,318 21,582 — Accrued interest receivable 93,749 93,749 — 93,749 — — Derivative assets (1) 30,079 30,079 — 20,913 — 9,166 Other assets (1) 25,122 25,122 12,031 13,091 — — Liabilities: Deposits (527,832 ) (527,791 ) — (527,791 ) — — COs: Bonds (27,125,212 ) (27,005,475 ) — (27,005,475 ) — — Discount notes (29,467,314 ) (29,465,498 ) — (29,465,498 ) — — Mandatorily redeemable capital stock (36,113 ) (36,113 ) (36,113 ) — — — Accrued interest payable (101,593 ) (101,593 ) — (101,593 ) — — Derivative liabilities (1) (260,565 ) (260,565 ) — (319,490 ) — 58,925 Other: Commitments to extend credit for advances — (3,829 ) — (3,829 ) — — Standby letters of credit (1,148 ) (1,148 ) — (1,148 ) — — _______________________ (1) Carried at fair value on a recurring basis. (2) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. December 31, 2017 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 261,673 $ 261,673 $ 261,673 $ — $ — $ — Interest-bearing deposits 246 246 246 — — — Securities purchased under agreements to resell 5,349,000 5,348,898 — 5,348,898 — — Federal funds sold 3,450,000 3,449,981 — 3,449,981 — — Trading securities (1) 191,510 191,510 — 191,510 — — Available-for-sale securities (1) 7,324,736 7,324,736 — 7,287,053 37,683 — Held-to-maturity securities 1,626,122 1,903,227 — 811,759 1,091,468 — Advances 37,565,967 37,591,048 — 37,591,048 — — Mortgage loans, net 4,004,737 4,035,928 — 4,013,704 22,224 — Loans to other FHLBanks (3) 400,000 399,997 — 399,997 — — Accrued interest receivable 94,100 94,100 — 94,100 — — Derivative assets (1) 34,786 34,786 — 56,238 — (21,452 ) Other assets (1) 22,351 22,351 9,726 12,625 — — Liabilities: Deposits (477,069 ) (477,060 ) — (477,060 ) — — COs: Bonds (28,344,623 ) (28,353,945 ) — (28,353,945 ) — — Discount notes (27,720,906 ) (27,719,598 ) — (27,719,598 ) — — Mandatorily redeemable capital stock (35,923 ) (35,923 ) (35,923 ) — — — Accrued interest payable (90,626 ) (90,626 ) — (90,626 ) — — Derivative liabilities (1) (300,450 ) (300,450 ) — (347,352 ) — 46,902 Other: Commitments to extend credit for advances — (3,817 ) — (3,817 ) — — Standby letters of credit (1,100 ) (1,100 ) — (1,100 ) — — _______________________ (1) Carried at fair value on a recurring basis. (2) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. (3) The Fair Value Summary table for December 31, 2017, has been revised to correct the omission of Loans to Other FHLBanks. This revision had no impact on the Statements of Condition, Statements of Operations, or Statements of Cash Flows. Fair Value Measured on a Recurring Basis. Table 16.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (dollars in thousands) March 31, 2018 Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 749,578 $ — $ — $ 749,578 Corporate bonds — 7,170 — — 7,170 U.S. government-guaranteed – single-family MBS — 6,429 — — 6,429 GSEs – single-family MBS — 275 — — 275 GSEs – multifamily MBS — 179,422 — — 179,422 Total trading securities — 942,874 — — 942,874 Available-for-sale securities: State or local HFA securities — — 37,495 — 37,495 Supranational institutions — 406,730 — — 406,730 U.S. government-owned corporations — 285,027 — — 285,027 GSEs — 117,751 — — 117,751 U.S. government guaranteed – single-family MBS — 92,228 — — 92,228 U.S. government guaranteed – multifamily MBS — 414,153 — — 414,153 GSEs – single-family MBS — 4,288,240 — — 4,288,240 GSEs – multifamily — 1,325,148 — — 1,325,148 Total available-for-sale securities — 6,929,277 37,495 — 6,966,772 Derivative assets: Interest-rate-exchange agreements — 20,630 — 9,166 29,796 Mortgage delivery commitments — 283 — — 283 Total derivative assets — 20,913 — 9,166 30,079 Other assets 12,031 13,091 — — 25,122 Total assets at fair value $ 12,031 $ 7,906,155 $ 37,495 $ 9,166 $ 7,964,847 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (319,484 ) $ — $ 58,925 $ (260,559 ) Mortgage delivery commitments — (6 ) — — (6 ) Total liabilities at fair value $ — $ (319,490 ) $ — $ 58,925 $ (260,565 ) _______________________ (1) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. December 31, 2017 Level 1 Level 2 Level 3 Netting (1) Total Assets: Trading securities: U.S. government-guaranteed – single-family MBS $ — $ 6,807 $ — $ — $ 6,807 GSEs – single-family MBS — 346 — — 346 GSEs – multifamily MBS — 184,357 — — 184,357 Total trading securities — 191,510 — — 191,510 Available-for-sale securities: State or local HFA securities — — 37,683 — 37,683 Supranational institutions — 418,285 — — 418,285 U.S. government-owned corporations — 292,077 — — 292,077 GSEs — 121,343 — — 121,343 U.S. government guaranteed – single-family MBS — 95,777 — — 95,777 U.S. government guaranteed – multifamily MBS — 443,373 — — 443,373 GSEs – single-family MBS — 4,562,992 — — 4,562,992 GSEs – multifamily MBS — 1,353,206 — — 1,353,206 Total available-for-sale securities — 7,287,053 37,683 — 7,324,736 Derivative assets: Interest-rate-exchange agreements — 56,069 — (21,452 ) 34,617 Mortgage delivery commitments — 169 — — 169 Total derivative assets — 56,238 — (21,452 ) 34,786 Other assets 9,726 12,625 — — 22,351 Total assets at fair value $ 9,726 $ 7,547,426 $ 37,683 $ (21,452 ) $ 7,573,383 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (347,325 ) $ — $ 46,902 $ (300,423 ) Mortgage delivery commitments — (27 ) — — (27 ) Total liabilities at fair value $ — $ (347,352 ) $ — $ 46,902 $ (300,450 ) _______________________ (1) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. Table 16.3 presents a reconciliation of available-for-sale securities that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the three months ended March 31, 2018 and 2017 . Table 16.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Balance at beginning of period $ 37,683 $ 8,146 Unrealized (losses) gains included in other comprehensive income (188 ) 38 Balance at end of period $ 37,495 $ 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). Table 16.4 - Fair Value of Assets Measured at Fair Value on a Nonrecurring Basis (1) (dollars in thousands) March 31, 2018 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,890 $ 1,890 Mortgage loans held for portfolio — — 354 354 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 2,244 $ 2,244 December 31, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,970 $ 1,970 Mortgage loans held for portfolio — — 4,608 4,608 REO — — 784 784 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 7,362 $ 7,362 _______________________ (1) The fair values presented are as of the date the fair value adjustment was recorded during the three months ended March 31, 2018 , and year ended December 31, 2017

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies Joint and Several Liability. COs are backed by the financial resources of the FHLBanks. The FHFA has authority to require any FHLBank to repay all or a portion of the principal and interest on COs for which another FHLBank is the primary obligor. No FHLBank has ever been asked or required to repay the principal or interest on any CO on behalf of another FHLBank. We evaluate the financial condition of the other FHLBanks primarily based on known regulatory actions, publicly available financial information, and individual long-term credit-rating action as of each period-end presented. Based on this evaluation, as of March 31, 2018 , and through the filing of this report, we believe there is only a remote likelihood that we will be required to repay the principal or interest on any CO on behalf of another FHLBank. We have considered applicable FASB guidance and determined it is not necessary to recognize a liability for the fair value of our joint and several liability for all of the COs. The joint and several obligation is mandated by the FHLBank Act, as implemented by FHFA regulations, and is not the result of an arms-length transaction among the FHLBanks. The FHLBanks have no control over the amount of the guaranty or the determination of how each FHLBank would perform under the joint and several obligation. Because the FHLBanks are subject to the authority of the FHFA as it relates to decisions involving the allocation of the joint and several liability for the FHLBanks' COs, the FHLBanks' joint and several obligation is excluded from the initial recognition and measurement provisions. Accordingly, we have not recognized a liability for our joint and several obligation related to other FHLBanks' COs at March 31, 2018 , and December 31, 2017 . The par amounts of other FHLBanks' outstanding COs for which we are jointly and severally liable totaled $ 962.6 billion and $978.2 billion at March 31, 2018 , and December 31, 2017 , respectively. See Note 12 — Consolidated Obligations for additional information. Off-Balance-Sheet Commitments Table 17.1 - Off-Balance Sheet Commitments (dollars in thousands) March 31, 2018 December 31, 2017 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 6,147,846 $ 277,842 $ 6,425,688 $ 5,034,725 $ 223,167 $ 5,257,892 Commitments for unused lines of credit - advances (2) 1,207,681 — 1,207,681 1,216,592 — 1,216,592 Commitments to make additional advances 40,228 52,427 92,655 18,851 63,488 82,339 Commitments to invest in mortgage loans 32,756 — 32,756 42,918 — 42,918 Unsettled CO bonds, at par 25,000 — 25,000 52,550 — 52,550 Unsettled CO discount notes, at par 1,762,000 — 1,762,000 — — — __________________________ (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, 2018 , and December 31, 2017 , these amounts totaled $ 2.4 million and $1.4 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $543,000 at December 31, 2017 . (2) Commitments for unused line-of-credit advances are generally for periods of up to 12 months . Since many of these commitments are not expected to be drawn upon, the total commitment amount does not necessarily indicate future liquidity requirements. Standby Letters of Credit. We issue standby letters of credit on behalf of our members to support certain obligations of the members to third-party beneficiaries. These standby letters of credit are subject to the same collateralization and borrowing limits that are applicable to advances. Standby letters of credit may be offered to assist members in facilitating residential housing finance, community lending, and asset-liability management, and to provide liquidity. In particular, members often use standby letters of credit as security for deposits from federal, state, and municipal government agencies. Standby letters of credit are executed for members for a fee. If we are required to make payment for a beneficiary's draw, our strategy is to take prompt action to recover the funds paid to the third-party beneficiary, including converting the payment amount into a collateralized advance to the primary obligor, withdrawing the payment amount from the primary obligor's demand deposit account with us, or selling collateral pledged by the primary obligor in a commercially reasonable manner to offset the payment amount. Historically, however, standby letters of credit usually expire without being drawn upon. The original terms of these standby letters of credit have original expiration periods of up to 20 years , currently expiring no later than 2027 . Currently, we offer new standby letters of credit with expiration periods of up to 10 years . Our unearned fees for the value of the guarantees related to standby letters of credit are recorded in other liabilities and totaled $1.1 million at March 31, 2018 , and December 31, 2017 . Commitments to Invest in Mortgage Loans. Commitments to invest in mortgage loans are generally for periods not to exceed 45 business days. Such commitments are recorded as derivatives at their fair values on the statement of condition. Pledged Collateral. We have pledged securities, as collateral, related to derivatives. See Note 10 — Derivatives and Hedging Activities for additional information about our pledged collateral and other credit-risk-related contingent features. Legal Proceedings

Transactions with Shareholders

Transactions with Shareholders	3 Months Ended
	Mar. 31, 2018
Transactions with Shareholders [Abstract]
Transactions with Shareholders [Text Block]	Transactions with Shareholders Shareholder Concentrations. We consider shareholder concentrations as members or nonmembers whose capital stock holdings (including mandatorily redeemable capital stock) are in excess of 10 percent of total capital stock outstanding at any time during the year. Table 18.1 - Shareholder Concentrations, Balance Sheet (dollars in thousands) Capital Stock Outstanding Percent of Total Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of March 31, 2018 Citizens Bank, N.A. $ 253,348 10.7 % $ 5,508,833 14.5 % $ 4,406 9.1 % As of December 31, 2017 Citizens Bank, N.A. $ 227,287 9.8 % $ 4,858,592 12.9 % $ 2,558 6.0 % We held sufficient collateral to support the advances to the above institution such that we do not expect to incur any credit losses on these advances. We recognized interest income on outstanding advances and fees on letters of credit from Citizens Bank, N.A. during the three months ended March 31, 2018 , and 2017 , as follows (dollars in thousands): Table 18.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Three Months Ended March 31, Citizens Bank, N.A. 2018 2017 Interest income on advances $ 26,892 $ 14,111 Fees on letters of credit 1,097 745 Transactions with Directors' Institutions. We provide, in the ordinary course of business, products and services to members whose officers or directors serve on our board of directors. In accordance with FHFA regulations, transactions with directors' institutions are conducted on the same terms as those with any other member. Table 18.3 presents the outstanding balances of capital stock, advances, and accrued interest receivable with members whose officers or directors serve on our board of directors, and those balances as a percentage of our total balance as reported on our statement of condition: Table 18.3 - Transactions with Directors' Institutions (dollars in thousands) Capital Stock Outstanding Percent of Total Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of March 31, 2018 $ 112,214 4.8 % $ 2,062,824 5.4 % $ 2,646 5.5 % As of December 31, 2017 114,498 4.9 2,133,374 5.7 2,466 5.8

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On April 20, 2018 , the board of directors declared a cash dividend at an annualized rate of 5.46 percent based on capital stock balances outstanding during the first quarter of 2018. The dividend, including dividends on mandatorily redeemable capital stock, amounted to $32.4 million and was paid on May 2, 2018

Basis of Presentation Summary o

Basis of Presentation Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Investment, Policy	We evaluate our individual available-for-sale and held-to-maturity securities for other-than-temporary impairment each quarter.
Derivatives, Policy	We 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.We utilize two DCOs, for all cleared derivative transactions, CME Inc. and LCH Ltd. Based upon certain amendments, effective January 3, 2017, made by CME Inc. to its rulebook, we began to characterize variation margin payments related to CME Inc. contracts as daily settlement payments, rather than collateral. However, throughout 2017, we continued to characterize our variation margin related to LCH Ltd. contracts as cash collateral. We began to characterize variation margin payments related to LCH Ltd. contracts as daily settlement payments, rather than cash collateral, based upon a change effective January 16, 2018, to LCH Ltd.’s rulebook. At both DCOs, initial margin has been, and continues to be, considered cash collateral.
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, 2018
Trading Securities [Abstract]
Trading Securities by Major Security Type [Table Text Block]	Table 3.1 - Trading Securities by Major Security Type (dollars in thousands) March 31, 2018 December 31, 2017 U.S. Treasury obligations $ 749,578 $ — Corporate bonds 7,170 — 756,748 — Mortgage backed securities (MBS) U.S. government-guaranteed – single-family 6,429 6,807 Government-sponsored enterprise (GSE)s – single-family 275 346 GSEs – multifamily 179,422 184,357 186,126 191,510 Total $ 942,874 $ 191,510

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale (AFS) Securities by Major Security Type [Table Text Block]	Table 4.1 - Available-for-Sale Securities by Major Security Type (dollars in thousands) March 31, 2018 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value State or local housing-finance-agency obligations (HFA securities) $ 42,700 $ — $ (5,205 ) $ 37,495 Supranational institutions 423,968 — (17,238 ) 406,730 U.S. government-owned corporations 299,687 — (14,660 ) 285,027 GSEs 123,318 — (5,567 ) 117,751 889,673 — (42,670 ) 847,003 MBS U.S. government guaranteed – single-family 95,666 75 (3,513 ) 92,228 U.S. government guaranteed – multifamily 420,987 — (6,834 ) 414,153 GSEs – single-family 4,391,152 974 (103,886 ) 4,288,240 GSEs – multifamily 1,323,247 2,120 (219 ) 1,325,148 6,231,052 3,169 (114,452 ) 6,119,769 Total $ 7,120,725 $ 3,169 $ (157,122 ) $ 6,966,772 _______________________ (1) Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments. December 31, 2017 Amounts Recorded in Accumulated Other Comprehensive Loss Amortized Cost (1) Unrealized Gains Unrealized Losses Fair Value HFA securities $ 42,700 $ — $ (5,017 ) $ 37,683 Supranational institutions 438,667 — (20,382 ) 418,285 U.S. government-owned corporations 313,985 — (21,908 ) 292,077 GSEs 128,744 — (7,401 ) 121,343 924,096 — (54,708 ) 869,388 MBS U.S. government guaranteed – single-family 98,720 55 (2,998 ) 95,777 U.S. government guaranteed – multifamily 447,975 — (4,602 ) 443,373 GSEs – single-family 4,625,333 1,194 (63,535 ) 4,562,992 GSEs – multifamily 1,350,943 2,263 — 1,353,206 6,522,971 3,512 (71,135 ) 6,455,348 Total $ 7,447,067 $ 3,512 $ (125,843 ) $ 7,324,736 _______________________ (1) Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.
Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
AFS Securities in a Continuous Unrealized Loss Position [Table Text Block]	Table 4.2 - Available-for-Sale Securities in a Continuous Unrealized Loss Position (dollars in thousands) March 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 29,193 $ (4,157 ) $ 8,302 $ (1,048 ) $ 37,495 $ (5,205 ) Supranational institutions — — 406,730 (17,238 ) 406,730 (17,238 ) U.S. government-owned corporations — — 285,027 (14,660 ) 285,027 (14,660 ) GSEs — — 117,751 (5,567 ) 117,751 (5,567 ) 29,193 (4,157 ) 817,810 (38,513 ) 847,003 (42,670 ) MBS U.S. government guaranteed – single-family — — 68,864 (3,513 ) 68,864 (3,513 ) U.S. government guaranteed – multifamily — — 414,153 (6,834 ) 414,153 (6,834 ) GSEs – single-family 1,794,394 (29,597 ) 2,376,944 (74,289 ) 4,171,338 (103,886 ) GSEs – multifamily 226,781 (219 ) — — 226,781 (219 ) 2,021,175 (29,816 ) 2,859,961 (84,636 ) 4,881,136 (114,452 ) Total temporarily impaired $ 2,050,368 $ (33,973 ) $ 3,677,771 $ (123,149 ) $ 5,728,139 $ (157,122 ) December 31, 2017 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ 29,345 $ (4,005 ) $ 8,338 $ (1,012 ) $ 37,683 $ (5,017 ) Supranational institutions — — 418,285 (20,382 ) 418,285 (20,382 ) U.S. government-owned corporations — — 292,077 (21,908 ) 292,077 (21,908 ) GSEs — — 121,343 (7,401 ) 121,343 (7,401 ) 29,345 (4,005 ) 840,043 (50,703 ) 869,388 (54,708 ) MBS U.S. government guaranteed – single-family — — 70,877 (2,998 ) 70,877 (2,998 ) U.S. government guaranteed – multifamily 64,219 (571 ) 379,154 (4,031 ) 443,373 (4,602 ) GSEs – single-family 1,853,323 (12,661 ) 2,540,006 (50,874 ) 4,393,329 (63,535 ) 1,917,542 (13,232 ) 2,990,037 (57,903 ) 4,907,579 (71,135 ) Total temporarily impaired $ 1,946,887 $ (17,237 ) $ 3,830,080 $ (108,606 ) $ 5,776,967 $ (125,843 )
Investments Classified by Contractual Maturity Date [Table Text Block]	Table 4.3 - Available-for-Sale Securities by Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Year of Maturity Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ — $ — $ — $ — Due after one year through five years 42,700 37,495 42,700 37,683 Due after five years through 10 years 423,968 406,730 438,667 418,285 Due after 10 years 423,005 402,778 442,729 413,420 889,673 847,003 924,096 869,388 MBS (1) 6,231,052 6,119,769 6,522,971 6,455,348 Total $ 7,120,725 $ 6,966,772 $ 7,447,067 $ 7,324,736 _______________________ (1)

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities by Major Security Type [Table Text Block]	Table 5.1 - Held-to-Maturity Securities by Major Security Type (dollars in thousands) March 31, 2018 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value U.S. agency obligations $ 854 $ — $ 854 $ 5 $ — $ 859 HFA securities 145,185 — 145,185 22 (6,616 ) 138,591 146,039 — 146,039 27 (6,616 ) 139,450 MBS U.S. government guaranteed – single-family 9,527 — 9,527 173 — 9,700 GSEs – single-family 528,730 — 528,730 9,130 (1,126 ) 536,734 GSEs – multifamily 213,723 — 213,723 3,728 — 217,451 Private-label – residential 790,847 (150,767 ) 640,080 275,649 (2,939 ) 912,790 Asset-backed securities (ABS) backed by home equity loans 7,649 (22 ) 7,627 26 (296 ) 7,357 1,550,476 (150,789 ) 1,399,687 288,706 (4,361 ) 1,684,032 Total $ 1,696,515 $ (150,789 ) $ 1,545,726 $ 288,733 $ (10,977 ) $ 1,823,482 December 31, 2017 Amortized Cost Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss Carrying Value Gross Unrecognized Holding Gains Gross Unrecognized Holding Losses Fair Value U.S. agency obligations $ 1,042 $ — $ 1,042 $ 10 $ — $ 1,052 HFA securities 146,410 — 146,410 26 (14,372 ) 132,064 147,452 — 147,452 36 (14,372 ) 133,116 MBS U.S. government guaranteed – single-family 10,097 — 10,097 190 — 10,287 U.S. government guaranteed – multifamily 280 — 280 — — 280 GSEs – single-family 568,948 — 568,948 10,410 (310 ) 579,048 GSEs – multifamily 214,641 — 214,641 6,451 — 221,092 Private-label – residential 835,070 (158,194 ) 676,876 278,217 (3,195 ) 951,898 ABS backed by home equity loans 7,851 (23 ) 7,828 27 (349 ) 7,506 1,636,887 (158,217 ) 1,478,670 295,295 (3,854 ) 1,770,111 Total $ 1,784,339 $ (158,217 ) $ 1,626,122 $ 295,331 $ (18,226 ) $ 1,903,227
Held-to-maturity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities in a Continuous Unrealized Loss Position [Table Text Block]	Table 5.2 - Held-to-Maturity Securities in a Continuous Unrealized Loss Position (dollars in thousands) March 31, 2018 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 127,734 $ (6,616 ) $ 127,734 $ (6,616 ) MBS GSEs – single-family 118,383 (793 ) 27,254 (333 ) 145,637 (1,126 ) Private-label – residential — — 148,538 (4,917 ) 148,538 (4,917 ) ABS backed by home equity loans — — 7,223 (296 ) 7,223 (296 ) 118,383 (793 ) 183,015 (5,546 ) 301,398 (6,339 ) Total $ 118,383 $ (793 ) $ 310,749 $ (12,162 ) $ 429,132 $ (12,955 ) December 31, 2017 Continuous Unrealized Loss Less than 12 Months Continuous Unrealized Loss 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses HFA securities $ — $ — $ 121,203 $ (14,372 ) $ 121,203 $ (14,372 ) MBS GSEs – single-family 44,759 (52 ) 28,771 (258 ) 73,530 (310 ) Private-label – residential — — 158,963 (5,558 ) 158,963 (5,558 ) ABS backed by home equity loans — — 7,371 (350 ) 7,371 (350 ) 44,759 (52 ) 195,105 (6,166 ) 239,864 (6,218 ) Total $ 44,759 $ (52 ) $ 316,308 $ (20,538 ) $ 361,067 $ (20,590 )
HTM Securities by Contractual Maturity [Table Text Block]	Table 5.3 - Held-to-Maturity Securities by Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Year of Maturity Amortized Cost Carrying Value (1) Fair Value Amortized Cost Carrying Value (1) Fair Value Due in one year or less $ 551 $ 551 $ 554 $ 264 $ 264 $ 267 Due after one year through five years 11,138 11,138 11,162 11,613 11,613 11,645 Due after five years through 10 years 18,245 18,245 18,127 18,245 18,245 18,226 Due after 10 years 116,105 116,105 109,607 117,330 117,330 102,978 146,039 146,039 139,450 147,452 147,452 133,116 MBS (2) 1,550,476 1,399,687 1,684,032 1,636,887 1,478,670 1,770,111 Total $ 1,696,515 $ 1,545,726 $ 1,823,482 $ 1,784,339 $ 1,626,122 $ 1,903,227 _______________________ (1) Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss. (2)

Other-Than-Temporary Impairme31

Other-Than-Temporary Impairment (Tables)	3 Months Ended
	Mar. 31, 2018
Other than Temporary Impairment Losses, Investments [Abstract]
Significant Inputs for OTTI [Table Text Block]	For those securities for which a credit loss was recognized during the three months ended March 31, 2018 , Table 6.1 presents a summary of the average projected values over the remaining lives of the securities for the significant inputs used to measure the amount of the credit loss recognized in earnings, as well as related current credit enhancement. Credit enhancement is defined as the percentage of subordinated tranches, over-collateralization, and other credit enhancement, if any, in a security structure that will generally absorb losses before we will experience a credit loss on the security. The calculated averages represent the dollar-weighted average of Alt-A other-than-temporarily impaired private-label residential MBS. Table 6.1 - Significant Inputs and Current Credit Enhancement for Securities with a Current Period Credit Loss (dollars in thousands) Weighted Average of Significant Inputs Weighted Average Current Credit Enhancement Private-label MBS by Classification Par Value Projected Prepayment Rates Projected Default Rates Projected Loss Severities Alt-A - Private-label residential MBS (1) $ 10,345 12.3 % 20.8 % 31.9 % 5.3 % _______________________ (1)
Total Securities Other-than-Temporarily Impaired during the Life of the Security [Table Text Block]	Table 6.2 - Total MBS Other-than-Temporarily Impaired During the Life of the Security (dollars in thousands) March 31, 2018 Other-Than-Temporarily Impaired Investment (1) Par Value Amortized Cost Carrying Value Fair Value Private-label residential MBS – Prime $ 28,890 $ 24,692 $ 19,333 $ 27,065 Private-label residential MBS – Alt-A 907,387 658,402 512,993 780,710 ABS backed by home equity loans – Subprime 171 159 137 164 Total other-than-temporarily impaired securities $ 936,448 $ 683,253 $ 532,463 $ 807,939 _______________________ (1)
Rollforward of the Amounts Related to Credit Losses Recognized into Earnings [Table Text Block]	Table 6.3 presents a roll forward of the amounts related to credit losses recognized in earnings. The roll forward is the amount of credit losses on investment securities for which we recognized a portion of other-than-temporary impairment charges into accumulated other comprehensive loss. Table 6.3 - Roll Forward of the Amounts Related to Credit Loss Recognized into Earnings (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Balance at beginning of period $ 452,523 $ 490,404 Additions: Additional credit losses for which an other-than-temporary impairment charge was previously recognized (1) 79 418 Reductions: Portion of increase in cash flows expected to be collected over the remaining life of the security that are recognized in the current period as interest income (7,316 ) (8,601 ) Balance at end of period $ 445,286 $ 482,221 _______________________ (1) For the three months ended March 31, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to January 1, 2018 and 2017

Advances (Tables)

Advances (Tables)	3 Months Ended
	Mar. 31, 2018
Advances [Abstract]
Advances [Table Text Block]	Table 7.1 - Advances Outstanding by Year of Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Amount Weighted Average Rate Amount Weighted Average Rate Overdrawn demand-deposit accounts $ 7,674 2.16 % $ 5,698 1.70 % Due in one year or less 19,913,161 1.86 21,501,397 1.56 Due after one year through two years 9,464,785 1.92 7,462,785 1.65 Due after two years through three years 2,615,780 1.98 2,709,951 1.85 Due after three years through four years 1,987,993 2.16 2,084,105 2.03 Due after four years through five years 2,427,407 1.74 2,071,989 1.56 Thereafter 1,699,565 2.30 1,811,241 2.23 Total par value 38,116,365 1.91 % 37,647,166 1.66 % Premiums 16,735 17,931 Discounts (34,553 ) (32,757 ) Fair value of bifurcated derivatives (1) (2,215 ) (1,591 ) Hedging adjustments (108,557 ) (64,782 ) Total $ 37,987,775 $ 37,565,967 _________________________ (1) At March 31, 2018 , and December 31, 2017 Table 7.4 - Advances by Current Interest Rate Terms (dollars in thousands) Par value of advances March 31, 2018 December 31, 2017 Fixed-rate $ 30,623,916 $ 31,658,293 Variable-rate 7,492,449 5,988,873 Total par value $ 38,116,365 $ 37,647,166 Table 7.2 - Advances Outstanding by Year of Contractual Maturity or Next Call Date (1) (dollars in thousands) March 31, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,674 $ 5,698 Due in one year or less 26,252,136 25,842,572 Due after one year through two years 3,964,785 3,722,785 Due after two years through three years 2,605,780 2,709,951 Due after three years through four years 1,837,993 1,924,105 Due after four years through five years 1,802,407 1,684,789 Thereafter 1,645,590 1,757,266 Total par value $ 38,116,365 $ 37,647,166 _______________________ (1) Table 7.3 - Advances Outstanding by Year of Contractual Maturity or Next Put Date (dollars in thousands) Year of Contractual Maturity or Next Put Date, Par Value March 31, 2018 December 31, 2017 Overdrawn demand-deposit accounts $ 7,674 $ 5,698 Due in one year or less 21,405,861 22,828,547 Due after one year through two years 9,892,785 7,921,035 Due after two years through three years 2,624,780 2,686,951 Due after three years through four years 1,843,093 1,984,705 Due after four years through five years 1,393,607 1,216,989 Thereafter 948,565 1,003,241 Total par value $ 38,116,365 $ 37,647,166

Mortgage Loans Held for Portf33

Mortgage Loans Held for Portfolio (Tables)	3 Months Ended
	Mar. 31, 2018
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans Held for Portfolio [Table Text Block]	Table 8.1 - Mortgage Loans Held for Portfolio (dollars in thousands) March 31, 2018 December 31, 2017 Real estate Fixed-rate 15-year single-family mortgages $ 448,260 $ 466,952 Fixed-rate 20- and 30-year single-family mortgages 3,509,845 3,466,752 Premiums 68,785 70,074 Discounts (1,599 ) (1,541 ) Deferred derivative gains, net 2,207 3,000 Total mortgage loans held for portfolio 4,027,498 4,005,237 Less: allowance for credit losses (500 ) (500 ) Total mortgage loans, net of allowance for credit losses $ 4,026,998 $ 4,004,737 Table 8.2 - Mortgage Loans Held for Portfolio by Collateral/Guarantee Type (dollars in thousands) March 31, 2018 December 31, 2017 Conventional mortgage loans $ 3,600,878 $ 3,568,473 Government mortgage loans 357,227 365,231 Total par value $ 3,958,105 $ 3,933,704

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Recorded Investment in Delinquent Mortgage Loans [Table Text Block]	Table 9.1 sets forth certain key credit quality indicators for our investments in mortgage loans at March 31, 2018 , and December 31, 2017 (dollars in thousands): Table 9.1 - Recorded Investment in Delinquent Mortgage Loans (dollars in thousands) March 31, 2018 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 26,962 $ 13,427 $ 40,389 Past due 60-89 days delinquent 6,543 4,295 10,838 Past due 90 days or more delinquent 12,635 5,199 17,834 Total past due 46,140 22,921 69,061 Total current loans 3,635,455 343,853 3,979,308 Total mortgage loans $ 3,681,595 $ 366,774 $ 4,048,369 Other delinquency statistics In process of foreclosure, included above (1) $ 5,360 $ 1,529 $ 6,889 Serious delinquency rate (2) 0.36 % 1.42 % 0.46 % Past due 90 days or more still accruing interest $ — $ 5,199 $ 5,199 Loans on nonaccrual status (3) $ 13,245 $ — $ 13,245 _______________________ (1) Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported. (2) Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class. (3) Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan. December 31, 2017 Recorded Investment in Conventional Mortgage Loans Recorded Investment in Government Mortgage Loans Total Past due 30-59 days delinquent $ 28,622 $ 13,862 $ 42,484 Past due 60-89 days delinquent 6,617 4,142 10,759 Past due 90 days or more delinquent 13,310 4,831 18,141 Total past due 48,549 22,835 71,384 Total current loans 3,601,952 352,249 3,954,201 Total mortgage loans $ 3,650,501 $ 375,084 $ 4,025,585 Other delinquency statistics In process of foreclosure, included above (1) $ 6,389 $ 1,306 $ 7,695 Serious delinquency rate (2) 0.38 % 1.29 % 0.46 % Past due 90 days or more still accruing interest $ — $ 4,831 $ 4,831 Loans on nonaccrual status (3) $ 13,598 $ — $ 13,598 _______________________ (1) Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported. (2) Loans that are 90 days or more past due or in the process of foreclosure expressed as a percentage of the recorded investment in the total loan portfolio class. (3) Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan.
Individually Evaluated Impaired Loans, Average Recorded Investment and Interest Income Recognized [Table Text Block]	Table 9.3 - Average Recorded Investment of Individually Impaired Mortgage Loans and Related Interest Income (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Individually evaluated impaired mortgage loans with no related allowance $ 16,731 $ 112 $ 21,699 $ 116 Table 9.2 - Individually Impaired Conventional Mortgage Loans (dollars in thousands) March 31, 2018 December 31, 2017 Recorded Investment Par Value Recorded Investment Par Value Individually evaluated impaired mortgage loans with no related allowance $ 16,540 $ 16,505 $ 17,668 $ 17,630
Rollforward of Allowance for Credit Losses on Mortgage Loans [Table Text Block]	Table 9.4 presents a roll forward of the allowance for credit losses on conventional mortgage loans for the three months ended March 31, 2018 and 2017 , as well as the recorded investment in mortgage loans by impairment methodology at March 31, 2018 and 2017 . The recorded investment in a loan is the par amount of the loan, adjusted for accrued interest, unamortized premiums or discounts, deferred derivative gains and losses, and direct write-downs. The recorded investment is net of any valuation allowance. Table 9.4 - Allowance for Credit Losses on Conventional Mortgage Loans (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Allowance for credit losses Balance, beginning of period $ 500 $ 650 Charge-offs, net of recoveries (9 ) 26 Provision for (reduction of) credit losses 9 (51 ) Balance, end of period $ 500 $ 625 Ending balance, individually evaluated for impairment $ — $ — Ending balance, collectively evaluated for impairment $ 500 $ 625 Recorded investment, end of period (1) Individually evaluated for impairment $ 16,540 $ 21,352 Collectively evaluated for impairment $ 3,665,055 $ 3,281,864 _________________________ (1)

Derivatives and Hedging Activ35

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments [Table Text Block]	Table 10.1 - Fair Value of Derivative Instruments (dollars in thousands) March 31, 2018 December 31, 2017 Notional Amount of Derivatives Derivative Assets Derivative Liabilities Notional Derivative Derivative Derivatives designated as hedging instruments Interest-rate swaps $ 13,961,344 $ 16,113 $ (316,074 ) $ 14,118,994 $ 52,557 $ (332,830 ) Forward-start interest-rate swaps 388,200 — (469 ) 481,200 — (9,807 ) Total derivatives designated as hedging instruments 14,349,544 16,113 (316,543 ) 14,600,194 52,557 (342,637 ) Derivatives not designated as hedging instruments Economic hedges: Interest-rate swaps 1,292,700 4,517 (2,941 ) 1,166,900 3,512 (4,688 ) Mortgage-delivery commitments (1) 32,756 283 (6 ) 42,918 169 (27 ) Total derivatives not designated as hedging instruments 1,325,456 4,800 (2,947 ) 1,209,818 3,681 (4,715 ) Total notional amount of derivatives $ 15,675,000 $ 15,810,012 Total derivatives before netting and collateral adjustments 20,913 (319,490 ) 56,238 (347,352 ) Netting adjustments and cash collateral, including related accrued interest (2) 9,166 58,925 (21,452 ) 46,902 Derivative assets and derivative liabilities $ 30,079 $ (260,565 ) $ 34,786 $ (300,450 ) _______________________ (1) Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income. (2) Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $68.7 million and $25.8 million at March 31, 2018 , and December 31, 2017 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $601,000 and $350,000 at March 31, 2018 , and December 31, 2017 .
Net Gains (Losses) on Derivatives and Hedging Activities [Table Text Block]	Table 10.2 - Net Gains and Losses on Derivatives and Hedging Activities (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Derivatives designated as hedging instruments Interest-rate swaps $ 1,108 $ (659 ) Forward-start interest-rate swaps 76 134 Total net gains (losses) related to derivatives designated as hedging instruments 1,184 (525 ) Derivatives not designated as hedging instruments: Economic hedges: Interest-rate swaps 624 153 Mortgage-delivery commitments (518 ) 357 Total net gains related to derivatives not designated as hedging instruments 106 510 Other (1) (150 ) 51 Net gains on derivatives and hedging activities $ 1,140 $ 36 ______________
Gains (Losses) By Type of Hedged Item [Table Text Block]	Table 10.3 - Effect of Fair Value Hedge Relationships (dollars in thousands) For the Three Months Ended March 31, 2018 Gain/(Loss) on Derivative (Loss)/Gain on Hedged Item Net Fair-Value Hedge Ineffectiveness Effect of Derivatives on Net Interest Income (1) Hedged Item: Advances $ 43,797 $ (43,775 ) $ 22 $ 5,695 Investments 34,846 (34,423 ) 423 (7,311 ) COs – bonds (41,771 ) 42,434 663 (3,017 ) Total $ 36,872 $ (35,764 ) $ 1,108 $ (4,633 ) For the Three Months Ended March 31, 2017 Gain/(Loss) on Derivative (Loss)/Gain on 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 ) ______________ (1)
Effect of Cash Flow Hedge-Related Derivative Instruments [Table Text Block]	Table 10.4 - Effect of Cash Flow Hedge Relationships (dollars in thousands) Derivatives and Hedged Items in Cash Flow Hedging Relationships Gains (Losses) Recognized in Other Comprehensive Loss on Derivatives (Effective Portion) Location of Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Gains Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion) Forward-start Interest-rate swaps - CO bonds For the Three Months Ended March 31, 2018 $ 9,166 Interest expense $ (934 ) $ 76 For the Three Months Ended March 31, 2017 (138 ) Interest expense (4,315 ) 134
Post-haircut Value of Incremental Collateral Based on Incremental Credit Rating Downgrades [Table Text Block]	Table 10.5 sets forth the post-haircut value of incremental collateral that certain uncleared derivatives counterparties could have required us to deliver based on incremental credit rating downgrades at March 31, 2018 . Table 10.5 - Post Haircut Value of Incremental Collateral to be Delivered as of March 31, 2018 (dollars in thousands) Ratings Downgrade (1) From To Incremental Collateral AA+ AA or AA- $ 3,080 AA- A+, A or A- 14,994 A- below A- 18,797 _______________________ (1) Ratings are expressed in this table according to S&P's conventions but include the equivalent of such rating by Moody's. If there is a split rating, the lower rating is used.
Offsetting Assets [Table Text Block]	Table 10.6 presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of March 31, 2018 , and December 31, 2017 , and the fair value of derivatives that are not subject to such netting. Such netting includes any related cash collateral received from or pledged to counterparties. Table 10.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) March 31, 2018 Derivative Instruments Meeting Netting Requirements Non-cash Collateral Received or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 20,069 $ (18,671 ) $ 283 $ 1,681 $ — $ — $ 1,681 Cleared 561 27,837 28,398 — — 28,398 Total $ 30,079 $ 30,079 Derivative Liabilities Uncleared $ (317,892 ) $ 57,333 $ (6 ) $ (260,565 ) $ 10,687 $ 237,658 $ (12,220 ) Cleared (1,592 ) 1,592 — — — — Total $ (260,565 ) $ (12,220 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At March 31, 2018 , we had additional net credit exposure of $178,000 due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2017 Derivative Instruments Meeting Netting Requirements Non-cash Collateral Received or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 15,587 $ (13,481 ) $ 169 $ 2,275 $ — $ — $ 2,275 Cleared 40,482 (7,971 ) 32,511 — — 32,511 Total $ 34,786 $ 34,786 Derivative Liabilities Uncleared $ (335,289 ) $ 34,866 $ (27 ) $ (300,450 ) $ 7,627 $ 280,486 $ (12,337 ) Cleared (12,036 ) 12,036 — — — — Total $ (300,450 ) $ (12,337 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2017 , we had additional net credit exposure of $502,000
Offsetting Liabilities [Table Text Block]	Table 10.6 presents separately the fair value of derivatives that are subject to netting due to a legal right of offset based on the terms of our master netting arrangements or similar agreements as of March 31, 2018 , and December 31, 2017 , and the fair value of derivatives that are not subject to such netting. Such netting includes any related cash collateral received from or pledged to counterparties. Table 10.6 - Netting of Derivative Assets and Derivative Liabilities (dollars in thousands) March 31, 2018 Derivative Instruments Meeting Netting Requirements Non-cash Collateral Received or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 20,069 $ (18,671 ) $ 283 $ 1,681 $ — $ — $ 1,681 Cleared 561 27,837 28,398 — — 28,398 Total $ 30,079 $ 30,079 Derivative Liabilities Uncleared $ (317,892 ) $ 57,333 $ (6 ) $ (260,565 ) $ 10,687 $ 237,658 $ (12,220 ) Cleared (1,592 ) 1,592 — — — — Total $ (260,565 ) $ (12,220 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At March 31, 2018 , we had additional net credit exposure of $178,000 due to instances where our collateral pledged to a counterparty exceeded our net derivative liability position. December 31, 2017 Derivative Instruments Meeting Netting Requirements Non-cash Collateral Received or Pledged Not Offset (2) Gross Recognized Amount Gross Amounts of Netting Adjustments (1) Mortgage Delivery Commitments Total Derivative Assets and Total Derivative Liabilities Can Be Sold or Repledged Cannot Be Sold or Repledged Net Amount Derivative Assets Uncleared $ 15,587 $ (13,481 ) $ 169 $ 2,275 $ — $ — $ 2,275 Cleared 40,482 (7,971 ) 32,511 — — 32,511 Total $ 34,786 $ 34,786 Derivative Liabilities Uncleared $ (335,289 ) $ 34,866 $ (27 ) $ (300,450 ) $ 7,627 $ 280,486 $ (12,337 ) Cleared (12,036 ) 12,036 — — — — Total $ (300,450 ) $ (12,337 ) _______________________ (1) Includes gross amounts of netting adjustments and cash collateral. (2) Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2017 , we had additional net credit exposure of $502,000

Deposits (Tables)

Deposits (Tables)	3 Months Ended
	Mar. 31, 2018
Deposits [Abstract]
Interest-bearing and Non-interest-bearing Deposits [Table Text Block]	Table 11.1 - Deposits (dollars in thousands) March 31, 2018 December 31, 2017 Interest-bearing Demand and overnight $ 500,634 $ 447,700 Short-term 2,042 3,222 Noninterest-bearing Other 25,156 26,147 Total deposits $ 527,832 $ 477,069

Consolidated Obligations (Table

Consolidated Obligations (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
CO Bonds by Year of Contractual Maturity [Table Text Block]	Table 12.1 - CO Bonds Outstanding by Contractual Maturity (dollars in thousands) March 31, 2018 December 31, 2017 Year of Contractual Maturity Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Due in one year or less $ 10,747,200 1.55 % $ 12,186,510 1.35 % Due after one year through two years 5,596,915 1.82 5,288,470 1.63 Due after two years through three years 3,065,675 1.89 3,128,240 1.81 Due after three years through four years 2,681,605 1.77 2,759,460 1.74 Due after four years through five years 1,723,330 2.04 1,572,775 2.00 Thereafter 3,337,165 2.82 3,389,695 2.76 Total par value 27,151,890 1.85 % 28,325,150 1.70 % Premiums 87,594 90,836 Discounts (16,160 ) (15,685 ) Hedging adjustments (98,112 ) (55,678 ) $ 27,125,212 $ 28,344,623 _______________________ (1) Table 12.3 - CO Bonds Outstanding by Contractual Maturity or Next Call Date (dollars in thousands) Year of Contractual Maturity or Next Call Date March 31, 2018 December 31, 2017 Due in one year or less $ 14,137,200 $ 15,309,510 Due after one year through two years 5,813,915 5,580,470 Due after two years through three years 2,857,675 3,020,240 Due after three years through four years 1,539,605 1,542,460 Due after four years through five years 1,148,330 1,107,775 Thereafter 1,655,165 1,764,695 Total par value $ 27,151,890 $ 28,325,150
CO Bonds Long-term Debt Instruments [Table Text Block]	Table 12.2 - CO Bonds Outstanding by Call Feature (dollars in thousands) Par Value of CO bonds March 31, 2018 December 31, 2017 Noncallable and nonputable $ 22,644,890 $ 23,931,150 Callable 4,507,000 4,394,000 Total par value $ 27,151,890 $ 28,325,150 Table 12.4 - CO Bonds by Interest Rate-Payment Type (dollars in thousands) Par Value of CO bonds March 31, 2018 December 31, 2017 Fixed-rate $ 21,582,890 $ 21,416,150 Simple variable-rate 4,027,000 5,432,000 Step-up 1,542,000 1,477,000 Total par value $ 27,151,890 $ 28,325,150
CO Discount Notes [Table Text Block]	Outstanding CO discount notes for which we were primarily liable, all of which are due within one year, were as follows (dollars in thousands): Table 12.5 - CO Discount Notes Outstanding (dollars in thousands) Book Value Par Value Weighted Average Rate (1) March 31, 2018 $ 29,467,314 $ 29,508,841 1.61 % December 31, 2017 $ 27,720,906 $ 27,752,860 1.25 % _______________________ (1)

Affordable Housing Program (Tab

Affordable Housing Program (Tables)	3 Months Ended
	Mar. 31, 2018
Affordable Housing Program [Abstract]
Roll-forward of the AHP Liability[Table Text Block]	Table 13.1 - AHP Liability (dollars in thousands) March 31, 2018 December 31, 2017 Balance at beginning of period $ 81,600 $ 81,627 AHP expense for the period 6,171 21,307 AHP direct grant disbursements (5,163 ) (18,628 ) AHP subsidy for AHP advance disbursements (2,172 ) (2,782 ) Return of previously disbursed grants and subsidies 9 76 Balance at end of period $ 80,445 $ 81,600

Capital (Tables)

Capital (Tables)	3 Months Ended
	Mar. 31, 2018
Capital [Abstract]
Compliance with Regulatory Capital Requirements [Table Text Block]	Table 14.1 - Regulatory Capital Requirements (dollars in thousands) Risk-Based Capital Requirements March 31, 2018 December 31, 2017 Permanent capital Class B capital stock $ 2,323,891 $ 2,283,721 Mandatorily redeemable capital stock 36,113 35,923 Retained earnings 1,335,522 1,308,349 Total permanent capital $ 3,695,526 $ 3,627,993 Risk-based capital requirement Credit-risk capital $ 338,828 $ 328,557 Market-risk capital 211,211 170,102 Operations-risk capital 165,012 149,598 Total risk-based capital requirement $ 715,051 $ 648,257 Permanent capital in excess of risk-based capital requirement $ 2,980,475 $ 2,979,736 March 31, 2018 December 31, 2017 Required Actual Required Actual Capital Ratio Risk-based capital $ 715,051 $ 3,695,526 $ 648,257 $ 3,627,993 Total regulatory capital $ 2,438,324 $ 3,695,526 $ 2,414,478 $ 3,627,993 Total capital-to-asset ratio 4.0 % 6.1 % 4.0 % 6.0 % Leverage Ratio Leverage capital $ 3,047,906 $ 5,543,289 $ 3,018,097 $ 5,441,990 Leverage capital-to-assets ratio 5.0 % 9.1 % 5.0 % 9.0 %

Accumulated Other Comprehensi40

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2018
AOCI Attributable to Parent [Abstract]
Schedule of Accumulated Other Comprehensive Loss [Table Text Block]	Accumulated Other Comprehensive Loss Table 15.1 - Accumulated Other Comprehensive Loss (dollars in thousands) Net Unrealized Loss on Available-for-sale Securities Noncredit Portion of Other-than-temporary Impairment Losses on Held-to-maturity Securities Net Unrealized Loss Relating to Hedging Activities Pension and Postretirement Benefits Total Accumulated Other Comprehensive Loss Balance, 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 (2) — — 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 ) Balance, December 31, 2017 $ (122,331 ) $ (158,218 ) $ (40,436 ) $ (5,955 ) $ (326,940 ) Other comprehensive income (loss) before reclassifications: Net unrealized (losses) gains (31,622 ) — 9,166 — (22,456 ) Accretion of noncredit loss — 7,356 — — 7,356 Reclassifications from other comprehensive income to net income Noncredit other-than-temporary impairment losses reclassified to credit loss (1) — 72 — — 72 Amortization - hedging activities (4) — — 938 — 938 Amortization - pension and postretirement benefits (3) — — — 185 185 Other comprehensive (loss) income (31,622 ) 7,428 10,104 185 (13,905 ) Balance, March 31, 2018 $ (153,953 ) $ (150,790 ) $ (30,332 ) $ (5,770 ) $ (340,845 ) _______________________ (1) Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations. (2) Amortization of hedging activities includes $4.3 million recorded in CO bond interest expense and $4,000 recorded in net losses on derivatives and hedging activities in the statement of operations. (3) Recorded in other non-interest expenses in the statement of operations. (4) Amortization of hedging activities includes $934,000 recorded in CO bond interest expense and $4,000

Fair Values (Tables)

Fair Values (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments [Table Text Block]	Table 16.1 - Fair Value Summary (dollars in thousands) March 31, 2018 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 26,681 $ 26,681 $ 26,681 $ — $ — $ — Interest-bearing deposits 51,160 51,160 51,160 — — — Securities purchased under agreements to resell 2,999,000 2,998,981 — 2,998,981 — — Federal funds sold 6,225,000 6,224,991 — 6,224,991 — — Trading securities (1) 942,874 942,874 — 942,874 — — Available-for-sale securities (1) 6,966,772 6,966,772 — 6,929,277 37,495 — Held-to-maturity securities 1,545,726 1,823,482 — 764,744 1,058,738 — Advances 37,987,775 37,962,720 — 37,962,720 — — Mortgage loans, net 4,026,998 3,966,900 — 3,945,318 21,582 — Accrued interest receivable 93,749 93,749 — 93,749 — — Derivative assets (1) 30,079 30,079 — 20,913 — 9,166 Other assets (1) 25,122 25,122 12,031 13,091 — — Liabilities: Deposits (527,832 ) (527,791 ) — (527,791 ) — — COs: Bonds (27,125,212 ) (27,005,475 ) — (27,005,475 ) — — Discount notes (29,467,314 ) (29,465,498 ) — (29,465,498 ) — — Mandatorily redeemable capital stock (36,113 ) (36,113 ) (36,113 ) — — — Accrued interest payable (101,593 ) (101,593 ) — (101,593 ) — — Derivative liabilities (1) (260,565 ) (260,565 ) — (319,490 ) — 58,925 Other: Commitments to extend credit for advances — (3,829 ) — (3,829 ) — — Standby letters of credit (1,148 ) (1,148 ) — (1,148 ) — — _______________________ (1) Carried at fair value on a recurring basis. (2) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. December 31, 2017 Carrying Value Total Fair Value Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (2) Financial instruments Assets: Cash and due from banks $ 261,673 $ 261,673 $ 261,673 $ — $ — $ — Interest-bearing deposits 246 246 246 — — — Securities purchased under agreements to resell 5,349,000 5,348,898 — 5,348,898 — — Federal funds sold 3,450,000 3,449,981 — 3,449,981 — — Trading securities (1) 191,510 191,510 — 191,510 — — Available-for-sale securities (1) 7,324,736 7,324,736 — 7,287,053 37,683 — Held-to-maturity securities 1,626,122 1,903,227 — 811,759 1,091,468 — Advances 37,565,967 37,591,048 — 37,591,048 — — Mortgage loans, net 4,004,737 4,035,928 — 4,013,704 22,224 — Loans to other FHLBanks (3) 400,000 399,997 — 399,997 — — Accrued interest receivable 94,100 94,100 — 94,100 — — Derivative assets (1) 34,786 34,786 — 56,238 — (21,452 ) Other assets (1) 22,351 22,351 9,726 12,625 — — Liabilities: Deposits (477,069 ) (477,060 ) — (477,060 ) — — COs: Bonds (28,344,623 ) (28,353,945 ) — (28,353,945 ) — — Discount notes (27,720,906 ) (27,719,598 ) — (27,719,598 ) — — Mandatorily redeemable capital stock (35,923 ) (35,923 ) (35,923 ) — — — Accrued interest payable (90,626 ) (90,626 ) — (90,626 ) — — Derivative liabilities (1) (300,450 ) (300,450 ) — (347,352 ) — 46,902 Other: Commitments to extend credit for advances — (3,817 ) — (3,817 ) — — Standby letters of credit (1,100 ) (1,100 ) — (1,100 ) — — _______________________ (1) Carried at fair value on a recurring basis. (2) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. (3)
Fair Value Measured on Recurring Basis [Table Text Block]	Table 16.2 - Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (dollars in thousands) March 31, 2018 Level 1 Level 2 Level 3 Netting Adjustments and Cash Collateral (1) Total Assets: Trading securities: U.S. Treasury obligations $ — $ 749,578 $ — $ — $ 749,578 Corporate bonds — 7,170 — — 7,170 U.S. government-guaranteed – single-family MBS — 6,429 — — 6,429 GSEs – single-family MBS — 275 — — 275 GSEs – multifamily MBS — 179,422 — — 179,422 Total trading securities — 942,874 — — 942,874 Available-for-sale securities: State or local HFA securities — — 37,495 — 37,495 Supranational institutions — 406,730 — — 406,730 U.S. government-owned corporations — 285,027 — — 285,027 GSEs — 117,751 — — 117,751 U.S. government guaranteed – single-family MBS — 92,228 — — 92,228 U.S. government guaranteed – multifamily MBS — 414,153 — — 414,153 GSEs – single-family MBS — 4,288,240 — — 4,288,240 GSEs – multifamily — 1,325,148 — — 1,325,148 Total available-for-sale securities — 6,929,277 37,495 — 6,966,772 Derivative assets: Interest-rate-exchange agreements — 20,630 — 9,166 29,796 Mortgage delivery commitments — 283 — — 283 Total derivative assets — 20,913 — 9,166 30,079 Other assets 12,031 13,091 — — 25,122 Total assets at fair value $ 12,031 $ 7,906,155 $ 37,495 $ 9,166 $ 7,964,847 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (319,484 ) $ — $ 58,925 $ (260,559 ) Mortgage delivery commitments — (6 ) — — (6 ) Total liabilities at fair value $ — $ (319,490 ) $ — $ 58,925 $ (260,565 ) _______________________ (1) These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty. December 31, 2017 Level 1 Level 2 Level 3 Netting (1) Total Assets: Trading securities: U.S. government-guaranteed – single-family MBS $ — $ 6,807 $ — $ — $ 6,807 GSEs – single-family MBS — 346 — — 346 GSEs – multifamily MBS — 184,357 — — 184,357 Total trading securities — 191,510 — — 191,510 Available-for-sale securities: State or local HFA securities — — 37,683 — 37,683 Supranational institutions — 418,285 — — 418,285 U.S. government-owned corporations — 292,077 — — 292,077 GSEs — 121,343 — — 121,343 U.S. government guaranteed – single-family MBS — 95,777 — — 95,777 U.S. government guaranteed – multifamily MBS — 443,373 — — 443,373 GSEs – single-family MBS — 4,562,992 — — 4,562,992 GSEs – multifamily MBS — 1,353,206 — — 1,353,206 Total available-for-sale securities — 7,287,053 37,683 — 7,324,736 Derivative assets: Interest-rate-exchange agreements — 56,069 — (21,452 ) 34,617 Mortgage delivery commitments — 169 — — 169 Total derivative assets — 56,238 — (21,452 ) 34,786 Other assets 9,726 12,625 — — 22,351 Total assets at fair value $ 9,726 $ 7,547,426 $ 37,683 $ (21,452 ) $ 7,573,383 Liabilities: Derivative liabilities Interest-rate-exchange agreements $ — $ (347,325 ) $ — $ 46,902 $ (300,423 ) Mortgage delivery commitments — (27 ) — — (27 ) Total liabilities at fair value $ — $ (347,352 ) $ — $ 46,902 $ (300,450 ) _______________________ (1)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Table 16.3 presents a reconciliation of available-for-sale securities that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the three months ended March 31, 2018 and 2017 . Table 16.3 - Roll Forward of Level 3 Available-for-Sale Securities (dollars in thousands) For the Three Months Ended March 31, 2018 2017 Balance at beginning of period $ 37,683 $ 8,146 Unrealized (losses) gains included in other comprehensive income (188 ) 38 Balance at end of period $ 37,495 $ 8,184
Fair Value on a Nonrecurring Basis [Table Text Block]	Table 16.4 - Fair Value of Assets Measured at Fair Value on a Nonrecurring Basis (1) (dollars in thousands) March 31, 2018 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,890 $ 1,890 Mortgage loans held for portfolio — — 354 354 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 2,244 $ 2,244 December 31, 2017 Level 1 Level 2 Level 3 Total Held-to-maturity securities: Private-label residential MBS $ — $ — $ 1,970 $ 1,970 Mortgage loans held for portfolio — — 4,608 4,608 REO — — 784 784 Total assets recorded at fair value on a nonrecurring basis $ — $ — $ 7,362 $ 7,362 _______________________ (1) The fair values presented are as of the date the fair value adjustment was recorded during the three months ended March 31, 2018 , and year ended December 31, 2017

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Off-Balance Sheet Commitments [Table Text Block]	Table 17.1 - Off-Balance Sheet Commitments (dollars in thousands) March 31, 2018 December 31, 2017 Expire within one year Expire after one year Total Expire within one year Expire after one year Total Standby letters of credit outstanding (1) $ 6,147,846 $ 277,842 $ 6,425,688 $ 5,034,725 $ 223,167 $ 5,257,892 Commitments for unused lines of credit - advances (2) 1,207,681 — 1,207,681 1,216,592 — 1,216,592 Commitments to make additional advances 40,228 52,427 92,655 18,851 63,488 82,339 Commitments to invest in mortgage loans 32,756 — 32,756 42,918 — 42,918 Unsettled CO bonds, at par 25,000 — 25,000 52,550 — 52,550 Unsettled CO discount notes, at par 1,762,000 — 1,762,000 — — — __________________________ (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, 2018 , and December 31, 2017 , these amounts totaled $ 2.4 million and $1.4 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $543,000 at December 31, 2017 . (2) Commitments for unused line-of-credit advances are generally for periods of up to 12 months . Since many of these commitments are not expected to be drawn upon, the total commitment amount does not necessarily indicate future liquidity requirements.

Transactions with Shareholders

Transactions with Shareholders (Tables)	3 Months Ended
	Mar. 31, 2018
Transactions with Shareholders [Abstract]
Schedule of Transactions with Shareholders [Table Text Block]	Table 18.1 - Shareholder Concentrations, Balance Sheet (dollars in thousands) Capital Stock Outstanding Percent of Total Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of March 31, 2018 Citizens Bank, N.A. $ 253,348 10.7 % $ 5,508,833 14.5 % $ 4,406 9.1 % As of December 31, 2017 Citizens Bank, N.A. $ 227,287 9.8 % $ 4,858,592 12.9 % $ 2,558 6.0 %
Schedule of Transactions with Shareholders, Interest Income [Table Text Block]	Table 18.2 - Shareholder Concentrations, Income Statement (dollars in thousands) For the Three Months Ended March 31, Citizens Bank, N.A. 2018 2017 Interest income on advances $ 26,892 $ 14,111 Fees on letters of credit 1,097 745
Schedule of Transactions with Shareholders, Transactions with Directors' Financial Institutions [Table Text Block]	Table 18.3 - Transactions with Directors' Institutions (dollars in thousands) Capital Stock Outstanding Percent of Total Par Value of Advances Percent of Total Par Value of Advances Total Accrued Interest Receivable Percent of Total Accrued Interest Receivable on Advances As of March 31, 2018 $ 112,214 4.8 % $ 2,062,824 5.4 % $ 2,646 5.5 % As of December 31, 2017 114,498 4.9 2,133,374 5.7 2,466 5.8

Recently Issued and Adopted A44

Recently Issued and Adopted Accounting Guidance Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (Details)	3 Months Ended
	Mar. 31, 2018USD ($)
Accounting Standards Update 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost	$ 372,000

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 942,874	$ 191,510
U.S. Treasury obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	749,578	0
Corporate bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	7,170	0
Other Than Mortgage-backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	756,748	0
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	6,429	6,807
MBS [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	186,126	191,510
GSEs - single-family [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	275	346
GSEs - multifamily [Member] | Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 179,422	$ 184,357

Trading Securities - Net Unreal

Trading Securities - Net Unrealized (Losses) Gains (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Trading Securities [Abstract]
Net unrealized losses on trading securities	$ (1,964)	$ (1,414)

Available-for-Sale Securities M

Available-for-Sale Securities Major Security Types (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 7,120,725	$ 7,447,067
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		3,169	3,512
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(157,122)	(125,843)
Available-for-sale securities Fair Value		6,966,772	7,324,736
States or local housing-finance-agency obligations (HFA securities) [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	42,700	42,700
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(5,205)	(5,017)
Available-for-sale securities Fair Value		37,495	37,683
Supranational institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	423,968	438,667
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(17,238)	(20,382)
Available-for-sale securities Fair Value		406,730	418,285
U.S. government-owned corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	299,687	313,985
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(14,660)	(21,908)
Available-for-sale securities Fair Value		285,027	292,077
GSEs [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	123,318	128,744
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(5,567)	(7,401)
Available-for-sale securities Fair Value		117,751	121,343
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	889,673	924,096
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(42,670)	(54,708)
Available-for-sale securities Fair Value		847,003	869,388
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	95,666	98,720
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		75	55
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(3,513)	(2,998)
Available-for-sale securities Fair Value		92,228	95,777
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	420,987	447,975
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		0	0
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(6,834)	(4,602)
Available-for-sale securities Fair Value		414,153	443,373
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	6,231,052	6,522,971
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		3,169	3,512
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(114,452)	(71,135)
Available-for-sale securities Fair Value	[2]	6,119,769	6,455,348
Single Family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	4,391,152	4,625,333
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		974	1,194
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(103,886)	(63,535)
Available-for-sale securities Fair Value		4,288,240	4,562,992
Multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	1,323,247	1,350,943
Unrealized Gains Amounts Recorded in Accumulated Other Comprehensive Loss		2,120	2,263
Unrealized Losses Amounts Recorded in Accumulated Other Comprehensive Loss		(219)	0
Available-for-sale securities Fair Value		$ 1,325,148	$ 1,353,206
[1]	Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.
[2]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Available-for-Sale Securities S

Available-for-Sale Securities Securities with Unrealized Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 2,050,368	$ 1,946,887
Less than 12 Months, Unrealized Losses	(33,973)	(17,237)
12 Months or More, Fair Value	3,677,771	3,830,080
12 Months or More, Unrealized Losses	(123,149)	(108,606)
Total Fair Value	5,728,139	5,776,967
Total Unrealized Losses	(157,122)	(125,843)
HFA securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	29,193	29,345
Less than 12 Months, Unrealized Losses	(4,157)	(4,005)
12 Months or More, Fair Value	8,302	8,338
12 Months or More, Unrealized Losses	(1,048)	(1,012)
Total Fair Value	37,495	37,683
Total Unrealized Losses	(5,205)	(5,017)
Supranational institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	406,730	418,285
12 Months or More, Unrealized Losses	(17,238)	(20,382)
Total Fair Value	406,730	418,285
Total Unrealized Losses	(17,238)	(20,382)
U.S. government-owned corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	285,027	292,077
12 Months or More, Unrealized Losses	(14,660)	(21,908)
Total Fair Value	285,027	292,077
Total Unrealized Losses	(14,660)	(21,908)
GSEs [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	117,751	121,343
12 Months or More, Unrealized Losses	(5,567)	(7,401)
Total Fair Value	117,751	121,343
Total Unrealized Losses	(5,567)	(7,401)
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	29,193	29,345
Less than 12 Months, Unrealized Losses	(4,157)	(4,005)
12 Months or More, Fair Value	817,810	840,043
12 Months or More, Unrealized Losses	(38,513)	(50,703)
Total Fair Value	847,003	869,388
Total Unrealized Losses	(42,670)	(54,708)
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	68,864	70,877
12 Months or More, Unrealized Losses	(3,513)	(2,998)
Total Fair Value	68,864	70,877
Total Unrealized Losses	(3,513)	(2,998)
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	64,219
Less than 12 Months, Unrealized Losses	0	(571)
12 Months or More, Fair Value	414,153	379,154
12 Months or More, Unrealized Losses	(6,834)	(4,031)
Total Fair Value	414,153	443,373
Total Unrealized Losses	(6,834)	(4,602)
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	2,021,175	1,917,542
Less than 12 Months, Unrealized Losses	(29,816)	(13,232)
12 Months or More, Fair Value	2,859,961	2,990,037
12 Months or More, Unrealized Losses	(84,636)	(57,903)
Total Fair Value	4,881,136	4,907,579
Total Unrealized Losses	(114,452)	(71,135)
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,794,394	1,853,323
Less than 12 Months, Unrealized Losses	(29,597)	(12,661)
12 Months or More, Fair Value	2,376,944	2,540,006
12 Months or More, Unrealized Losses	(74,289)	(50,874)
Total Fair Value	4,171,338	4,393,329
Total Unrealized Losses	(103,886)	$ (63,535)
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	226,781
Less than 12 Months, Unrealized Losses	(219)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	226,781
Total Unrealized Losses	$ (219)

Available-for-Sale Securities R

Available-for-Sale Securities Redemption Terms (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	$ 7,120,725	$ 7,447,067
Fair Value		6,966,772	7,324,736
Other Than Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, amortized cost		0	0
Due in one year or less, fair value		0	0
Due after one year through five years, amortized cost		42,700	42,700
Due after one year through five years, fair value		37,495	37,683
Due after five years through 10 years, amortized cost		423,968	438,667
Due after five years through 10 years, fair value		406,730	418,285
Due after 10 years, amortized cost		423,005	442,729
Due after 10 years, fair value		402,778	413,420
Amortized Cost	[1]	889,673	924,096
Fair Value		847,003	869,388
MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1],[2]	6,231,052	6,522,971
Fair Value	[2]	$ 6,119,769	$ 6,455,348
[1]	Amortized cost of available-for-sale securities includes adjustments made to the cost basis of an investment for accretion, amortization, collection of cash, and fair-value hedge accounting adjustments.
[2]	MBS are not presented by contractual maturity because their expected maturities will likely differ from contractual maturities because borrowers of the underlying loans may have the right to call or prepay obligations with or without call or prepayment fees.

Held-to-Maturity Securities Maj

Held-to-Maturity Securities Major Security Types (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 1,696,515	$ 1,784,339
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(150,789)	(158,217)
Carrying Value	[1],[2]	1,545,726	1,626,122
Gross Unrecognized Holding Gains		288,733	295,331
Gross Unrecognized Holding Losses		(10,977)	(18,226)
Held-to-maturity securities Fair Value		1,823,482	1,903,227
U.S. agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		854	1,042
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		854	1,042
Gross Unrecognized Holding Gains		5	10
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		859	1,052
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		145,185	146,410
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		145,185	146,410
Gross Unrecognized Holding Gains		22	26
Gross Unrecognized Holding Losses		(6,616)	(14,372)
Held-to-maturity securities Fair Value		138,591	132,064
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		146,039	147,452
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value	[1]	146,039	147,452
Gross Unrecognized Holding Gains		27	36
Gross Unrecognized Holding Losses		(6,616)	(14,372)
Held-to-maturity securities Fair Value		139,450	133,116
U.S. government-guaranteed - single-family MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		9,527	10,097
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		9,527	10,097
Gross Unrecognized Holding Gains		173	190
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		9,700	10,287
U.S. government guaranteed - multifamily MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost			280
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss			0
Carrying Value			280
Gross Unrecognized Holding Gains			0
Gross Unrecognized Holding Losses			0
Held-to-maturity securities Fair Value			280
Asset Backed Securities Backed by Home Equity Loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		7,649	7,851
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(22)	(23)
Carrying Value		7,627	7,828
Gross Unrecognized Holding Gains		26	27
Gross Unrecognized Holding Losses		(296)	(349)
Held-to-maturity securities Fair Value		7,357	7,506
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	1,550,476	1,636,887
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(150,789)	(158,217)
Carrying Value	[1],[3]	1,399,687	1,478,670
Gross Unrecognized Holding Gains		288,706	295,295
Gross Unrecognized Holding Losses		(4,361)	(3,854)
Held-to-maturity securities Fair Value	[3]	1,684,032	1,770,111
GSEs - single-family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		528,730	568,948
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		528,730	568,948
Gross Unrecognized Holding Gains		9,130	10,410
Gross Unrecognized Holding Losses		(1,126)	(310)
Held-to-maturity securities Fair Value		536,734	579,048
GSEs - multifamily [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		213,723	214,641
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		0	0
Carrying Value		213,723	214,641
Gross Unrecognized Holding Gains		3,728	6,451
Gross Unrecognized Holding Losses		0	0
Held-to-maturity securities Fair Value		217,451	221,092
Private-label - residential MBS [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		790,847	835,070
Other-Than-Temporary Impairment Recognized in Accumulated Other Comprehensive Loss		(150,767)	(158,194)
Carrying Value		640,080	676,876
Gross Unrecognized Holding Gains		275,649	278,217
Gross Unrecognized Holding Losses		(2,939)	(3,195)
Held-to-maturity securities Fair Value		$ 912,790	$ 951,898
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,823,482 and $1,903,227 at March 31, 2018 , and December 31, 2017
[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, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	$ 118,383	$ 44,759
Less than 12 Months, Unrealized Losses	(793)	(52)
12 Months or More, Fair Value	310,749	316,308
12 Months or More, Unrealized Losses	(12,162)	(20,538)
Total Fair Value	429,132	361,067
Total Unrealized Losses	(12,955)	(20,590)
HFA securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	127,734	121,203
12 Months or More, Unrealized Losses	(6,616)	(14,372)
Total Fair Value	127,734	121,203
Total Unrealized Losses	(6,616)	(14,372)
Asset Backed Securities Backed by Home Equity Loans [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	7,223	7,371
12 Months or More, Unrealized Losses	(296)	(350)
Total Fair Value	7,223	7,371
Total Unrealized Losses	(296)	(350)
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	118,383	44,759
Less than 12 Months, Unrealized Losses	(793)	(52)
12 Months or More, Fair Value	183,015	195,105
12 Months or More, Unrealized Losses	(5,546)	(6,166)
Total Fair Value	301,398	239,864
Total Unrealized Losses	(6,339)	(6,218)
Single Family [Member] | GSEs – MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	118,383	44,759
Less than 12 Months, Unrealized Losses	(793)	(52)
12 Months or More, Fair Value	27,254	28,771
12 Months or More, Unrealized Losses	(333)	(258)
Total Fair Value	145,637	73,530
Total Unrealized Losses	(1,126)	(310)
Private-label - residential MBS [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	148,538	158,963
12 Months or More, Unrealized Losses	(4,917)	(5,558)
Total Fair Value	148,538	158,963
Total Unrealized Losses	$ (4,917)	$ (5,558)

Held-to-Maturity Securities Red

Held-to-Maturity Securities Redemption Terms (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		$ 1,696,515	$ 1,784,339
Carrying Value	[1],[2]	1,545,726	1,626,122
Fair Value		1,823,482	1,903,227
Other Than Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Due in one year or less, Amortized Cost		551	264
Due in one year or less, Carrying Value	[1]	551	264
Due in one year or less, Fair Value		554	267
Due after one year through five years, Amortized Cost		11,138	11,613
Due after one year through five years, Carrying Value	[1]	11,138	11,613
Due after one year through five years, Fair Value		11,162	11,645
Due after five years through 10 years, Amortized Cost		18,245	18,245
Due after five years through 10 years, Carrying Value	[1]	18,245	18,245
Due after five years through 10 years, Fair Value		18,127	18,226
Due after 10 years, Amortized Cost		116,105	117,330
Due after 10 years, Carrying Value	[1]	116,105	117,330
Due after 10 years, Fair Value		109,607	102,978
Amortized Cost		146,039	147,452
Carrying Value	[1]	146,039	147,452
Fair Value		139,450	133,116
MBS [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	[3]	1,550,476	1,636,887
Carrying Value	[1],[3]	1,399,687	1,478,670
Fair Value	[3]	$ 1,684,032	$ 1,770,111
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,823,482 and $1,903,227 at March 31, 2018 , and December 31, 2017
[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, 2018USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 10,345
Project Prepayment Rates - Weighted Average Percent	12.30%
Projected Default Rates, Weighted Average Percent	20.80%
Projected Loss Severities, Weighted Average Percent	31.90%
Current Credit Enhancement, Weighted Average Percent	5.30%
[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, 2018USD ($)	[1]
Other-than-temporary Impairment Credit Losses Recognized During the Life of the Security [Abstract]
Par Value	$ 936,448
Amortized Cost	683,253
Carrying Value	532,463
Fair Value	807,939
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	28,890
Amortized Cost	24,692
Carrying Value	19,333
Fair Value	27,065
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	907,387
Amortized Cost	658,402
Carrying Value	512,993
Fair Value	780,710
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	171
Amortized Cost	159
Carrying Value	137
Fair Value	$ 164
[1]	Securities are classified based on their classifications at the time of issuance. We have instituted litigation related to certain of the private-label MBS in which we invested. Our complaint asserts, among others, claims for untrue or misleading statements in the sale of securities. It is possible that classifications of private-label MBS as provided herein when based on classification at the time of issuance as disclosed by those securities' issuance documents, as well as other statements about the securities, are inaccurate.

Other-Than-Temporary 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, 2018	Mar. 31, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at beginning of period		$ 452,523	$ 490,404
Additional credit losses for which an other-than-temporary impairment charge was previously recognized	[1]	79	418
Portion of increase in cash flows expected to be collected over the remaining life of the security that are recognized in the current period as interest income		(7,316)	(8,601)
Balance at end of period		$ 445,286	$ 482,221
[1]	For the three months ended March 31, 2018 and 2017 , additional credit losses for which an other-than-temporary impairment charge was previously recognized relate to securities that were also previously impaired prior to January 1, 2018 and 2017

Advances - Year of Contractual

Advances - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Maturity, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	[1]	$ 7,674	$ 5,698
Due in one year or less		19,913,161	21,501,397
Due after one year through two years		9,464,785	7,462,785
Due after two years through three years		2,615,780	2,709,951
Due after three years through four years		1,987,993	2,084,105
Due after four years through five years		2,427,407	2,071,989
Thereafter		1,699,565	1,811,241
Total par value	[1]	$ 38,116,365	$ 37,647,166
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Rolling Year [Abstract]
Overdrawn demand-deposit accounts, Weighted average rate		2.16%	1.70%
Due in one year or less, Weighted average rate		1.86%	1.56%
Due after one year through two years, Weighted average rate		1.92%	1.65%
Due after two years through three years, Weighted average rate		1.98%	1.85%
Due after three years through four years, Weighted average rate		2.16%	2.03%
Due after four years through five years, Weighted average rate		1.74%	1.56%
Thereafter, Weighted average rate		2.30%	2.23%
Total Weighted average rate		1.91%	1.66%
Premiums		$ 16,735	$ 17,931
Discounts		(34,553)	(32,757)
Fair value of bifurcated derivatives	[2]	(2,215)	(1,591)
Hedging adjustments		(108,557)	(64,782)
Total Advances		$ 37,987,775	$ 37,565,967
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.
[2]	At March 31, 2018 , and December 31, 2017

Advances Advances - Year of Con

Advances Advances - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	[1]	$ 7,674	$ 5,698
Due in one year or less	[1]	26,252,136	25,842,572
Due after one year through two years	[1]	3,964,785	3,722,785
Due after two years through three years	[1]	2,605,780	2,709,951
Due after three years through four years	[1]	1,837,993	1,924,105
Due after four years through five years	[1]	1,802,407	1,684,789
Thereafter	[1]	1,645,590	1,757,266
Total par value	[1]	$ 38,116,365	$ 37,647,166
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Advances - Outstanding by the E

Advances - Outstanding by the Earlier of Contractual Maturity or Next Put Date (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, Rolling Year, Par Value [Abstract]
Overdrawn demand-deposit accounts	[1]	$ 7,674	$ 5,698
Due in one year or less		21,405,861	22,828,547
Due after one year through two years		9,892,785	7,921,035
Due after two years through three years		2,624,780	2,686,951
Due after three years through four years		1,843,093	1,984,705
Due after four years through five years		1,393,607	1,216,989
Thereafter		948,565	1,003,241
Total par value	[1]	$ 38,116,365	$ 37,647,166
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Advances - Interest-Rate-Paymen

Advances - Interest-Rate-Payment Terms (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, by Interest Rate Type [Abstract]
Fixed-rate		$ 30,623,916	$ 31,658,293
Variable-rate		7,492,449	5,988,873
Total par value	[1]	$ 38,116,365	$ 37,647,166
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Advances - Narratives (Details)

Advances - Narratives (Details) $ in Billions	Mar. 31, 2018USD ($)Borrowers	Dec. 31, 2017USD ($)Borrowers
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount	$ 11.2	$ 12.1
Minimum amount of advances outstanding per borrower	$ 1
Federal Home Loan Bank Advances [Member]
Credit Risk Exposure and Security Terms [Abstract]
Number of financial institutions with more than $1.0 billion advances borrowing | Borrowers	5	6
Total outstanding advances greater than $1.0 billion per borrower as a percentage of advances outstanding	29.40%	32.30%
Minimum [Member]
Federal Home Loan Bank, Advances [Line Items]
Interest rates of advances outstanding	0.00%	0.00%
Maximum [Member]
Federal Home Loan Bank, Advances [Line Items]
Interest rates of advances outstanding	7.72%	7.72%

Mortgage Loans Held for Portf61

Mortgage Loans Held for Portfolio (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,958,105	$ 3,933,704
Premiums	68,785	70,074
Discounts	(1,599)	(1,541)
Deferred derivative gains, net	2,207	3,000
Total mortgage loans held for portfolio	4,027,498	4,005,237
Allowance for credit losses	(500)	(500)
Total mortgage loans, net of allowance for credit losses	$ 4,026,998	4,004,737
Fixed-rate 15-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Original contractual terms	15 years
Conventional Mortgage Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,600,878	3,568,473
Minimum [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Original contractual terms	20 years
Maximum [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Original contractual terms	30 years
Government Mortgage Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 357,227	365,231
Single Family [Member] | Fixed-rate 15-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	448,260	466,952
Single Family [Member] | Fixed-rate 20- and 30-year single-family mortgages
Mortgage Loans on Real Estate [Line Items]
Par Value	$ 3,509,845	$ 3,466,752

Allowance for credit losses - C

Allowance for credit losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Mortgage Loans Past Due [Line Items]
Total past due		$ 69,061	$ 71,384
Total current loans		3,979,308	3,954,201
Total mortgage loans		4,048,369	4,025,585
In process of foreclosure, included above	[1]	$ 6,889	$ 7,695
Serious delinquency rate	[2]	0.46%	0.46%
Past due 90 days or more still accruing interest		$ 5,199	$ 4,831
Loans on nonaccrual status	[3]	$ 13,245	13,598
Number of days past due, loans at serious delinquent status		90 days
Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		$ 22,921	22,835
Total current loans		343,853	352,249
Total mortgage loans		366,774	375,084
In process of foreclosure, included above	[1]	$ 1,529	$ 1,306
Serious delinquency rate	[2]	1.42%	1.29%
Past due 90 days or more still accruing interest		$ 5,199	$ 4,831
Loans on nonaccrual status	[3]	0	0
Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		46,140	48,549
Total current loans		3,635,455	3,601,952
Total mortgage loans		3,681,595	3,650,501
In process of foreclosure, included above	[1]	$ 5,360	$ 6,389
Serious delinquency rate	[2]	0.36%	0.38%
Past due 90 days or more still accruing interest		$ 0	$ 0
Loans on nonaccrual status	[3]	13,245	13,598
Past due 30-59 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		40,389	42,484
Past due 30-59 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		13,427	13,862
Past due 30-59 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		26,962	28,622
Past due 60-89 days delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		10,838	10,759
Past due 60-89 days delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		4,295	4,142
Past due 60-89 days delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		6,543	6,617
Past due 90 days or more delinquent [Member]
Mortgage Loans Past Due [Line Items]
Total past due		17,834	18,141
Past due 90 days or more delinquent [Member] | Recorded Investment in Government Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		5,199	4,831
Past due 90 days or more delinquent [Member] | Recorded Investment in Conventional Mortgage Loans [Member]
Mortgage Loans Past Due [Line Items]
Total past due		$ 12,635	$ 13,310
[1]	Includes loans where the decision of foreclosure or similar alternative such as pursuit of deed-in-lieu of foreclosure has been reported.
[2]	Loans that are 90 days
[3]	Includes conventional mortgage loans with contractual principal or interest payments 90 days or more past due and not accruing interest as well as loans modified within the previous six months under our temporary loan modification plan.

Allowance for credit losses - I

Allowance for credit losses - Individually Evaluated Impaired Loans (Details) - Conventional Mortgage Loans [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired mortgage loans with no related allowance - Recorded Investment	$ 16,540		$ 17,668
Individually evaluated impaired mortgage loans with no related allowance - Par Value	16,505		$ 17,630
Individually evaluated impaired mortgage loans with no related allowance - Average Recorded Investment	16,731	$ 21,699
Individually evaluated impaired mortgage loans with no related allowance - Interest Income recognized	$ 112	$ 116

Allowance for credit losses - A

Allowance for credit losses - Allowance Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period		$ 500
Provision for (reduction of) credit losses		9	$ (51)
Balance, end of period		500
Conventional Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period		500	650
Charge-offs, net of recoveries		(9)	26
Provision for (reduction of) credit losses		9	(51)
Balance, end of period		500	625
Ending balance, individually evaluated for impairment		0	0
Ending balance, collectively evaluated for impairment		500	625
Recorded Investment Individually evaluated for impairment	[1]	16,540	21,352
Recorded Investment Collectively evaluated for impairment	[1]	$ 3,665,055	$ 3,281,864
[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, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		$ 15,675,000,000	$ 15,810,012,000
Derivative Assets, before netting and collateral adjustments		20,913,000	56,238,000
Derivative Liabilities, before netting and collateral adjustments		(319,490,000)	(347,352,000)
Derivative Asset, netting adjustments and cash collateral including related accrued interest	[1],[2]	9,166,000	(21,452,000)
Derivative Liability, netting adjustments and cash collateral including related accrued interest	[1],[2]	58,925,000	46,902,000
Derivative assets		30,079,000	34,786,000
Derivative liabilities		(260,565,000)	(300,450,000)
Cash collateral and related accrued interest posted		68,700,000	25,800,000
Cash collateral and related accrued interest received		601,000	350,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		14,349,544,000	14,600,194,000
Derivative Assets, before netting and collateral adjustments		16,113,000	52,557,000
Derivative Liabilities, before netting and collateral adjustments		(316,543,000)	(342,637,000)
Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		13,961,344,000	14,118,994,000
Derivative Assets, before netting and collateral adjustments		16,113,000	52,557,000
Derivative Liabilities, before netting and collateral adjustments		(316,074,000)	(332,830,000)
Designated as Hedging Instrument [Member] | Forward-start interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		388,200,000	481,200,000
Derivative Assets, before netting and collateral adjustments		0	0
Derivative Liabilities, before netting and collateral adjustments		(469,000)	(9,807,000)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,325,456,000	1,209,818,000
Derivative Assets, before netting and collateral adjustments		4,800,000	3,681,000
Derivative Liabilities, before netting and collateral adjustments		(2,947,000)	(4,715,000)
Not Designated as Hedging Instrument [Member] | Interest-rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives		1,292,700,000	1,166,900,000
Derivative Assets, before netting and collateral adjustments		4,517,000	3,512,000
Derivative Liabilities, before netting and collateral adjustments		(2,941,000)	(4,688,000)
Mortgages [Member] | Not Designated as Hedging Instrument [Member] | Mortgage-delivery commitments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount of Derivatives	[3]	32,756,000	42,918,000
Derivative Assets, before netting and collateral adjustments	[3]	283,000	169,000
Derivative Liabilities, before netting and collateral adjustments	[3]	$ (6,000)	$ (27,000)
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $68.7 million and $25.8 million at March 31, 2018 , and December 31, 2017 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $601,000 and $350,000 at March 31, 2018 , and December 31, 2017 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Mortgage-delivery commitments are classified as derivatives with changes in fair value recorded in other income.

Derivatives and Hedging Activ66

Derivatives and Hedging Activities Derivatives in Statement of Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		$ 1,108	$ (659)
Total net gains (losses) related to derivatives designated as hedging instruments		1,184	(525)
Total net gains related to derivatives not designated as hedging instruments		106	510
Other	[1]	(150)	51
Net gains on derivatives and hedging activities		1,140	36
Interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives and hedged items in fair-value hedging relationships		1,108	(659)
Forward-start interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge ineffectiveness		76	134
Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		(518)	357
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest-rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains related to derivatives not designated as hedging instruments		$ 624	$ 153
[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, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		$ 36,872	$ 31,439
(Loss)/Gain on Hedged Item		(35,764)	(32,098)
Net Fair-Value Hedge Ineffectiveness		1,108	(659)
Effect of Derivatives on Net Interest Income	[1]	(4,633)	(17,105)
Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		43,797	21,095
(Loss)/Gain on Hedged Item		(43,775)	(20,453)
Net Fair-Value Hedge Ineffectiveness		22	642
Effect of Derivatives on Net Interest Income	[1]	5,695	(13,405)
Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		34,846	10,268
(Loss)/Gain on Hedged Item		(34,423)	(9,808)
Net Fair-Value Hedge Ineffectiveness		423	460
Effect of Derivatives on Net Interest Income	[1]	(7,311)	(8,341)
COs - bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivative		(41,771)	76
(Loss)/Gain on Hedged Item		42,434	(1,837)
Net Fair-Value Hedge Ineffectiveness		663	(1,761)
Effect of Derivatives on Net Interest Income	[1]	$ (3,017)	$ 4,641
[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, 2018	Mar. 31, 2017
Derivative [Line Items]
Gains (Losses) Recognized in Other Comprehensive Loss on Derivatives (Effective Portion)	$ 9,166	$ (138)
Losses Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion)	(934)	(4,315)
Gains Recognized in Net Losses on Derivatives and Hedging Activities (Ineffective Portion)	$ 76	$ 134

Derivatives and Hedging Activ69

Derivatives and Hedging Activities Narratives (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Derivative [Line Items]
Maximum length of time which we are hedging our exposure to the variability in future cash flows for forecasted transactions	7 years
Deferred net losses on derivative accumulated in other comprehensive loss expected to be reclassified to earnings during the next 12 months	$ 3,100
Aggregate fair value of all uncleared derivative instruments with credit-risk-related contingent features that were in a net liability position	299,300
Post-haircut value of collateral already posted	276,400
Rating Downgrade from AAPlus to AA or AAMinus [Member]
Derivative [Line Items]
Incremental collateral	3,080	[1]
Rating Downgrade From AAMinus to APlus, A or AMinus [Member]
Derivative [Line Items]
Incremental collateral	14,994	[1]
Rating Downgrade From AMinus to below AMinus [Member]
Derivative [Line Items]
Incremental collateral	$ 18,797	[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 ($)		Mar. 31, 2018		Dec. 31, 2017
Derivative [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	$ 9,166,000		$ (21,452,000)
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2]	58,925,000		46,902,000
Derivative assets		30,079,000		34,786,000
Derivative liabilities		(260,565,000)		(300,450,000)
Derivative Asset, Fair value, amount offset against collateral		30,079,000		34,786,000
Derivative Liability, Fair value, amount offset against collateral		(12,220,000)		(12,337,000)
Derivative Liabilities, additional net exposure, collateral pledged to counterparties in excess of net liabilities		178,000		502,000
Uncleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		20,069,000		15,587,000
Derivative Liability, total gross recognized amount		(317,892,000)		(335,289,000)
Derivative Assets, Netting Adjustments and Cash Collateral		(18,671,000)	[3]	(13,481,000)	[4]
Derivative liability, Netting Adjustments and Cash Collateral		57,333,000	[3]	34,866,000	[4]
Derivative assets		1,681,000		2,275,000
Derivative liabilities		(260,565,000)		(300,450,000)
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		10,687,000	[5]	7,627,000	[6]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		237,658,000	[5]	280,486,000	[6]
Derivative Asset, Fair value, amount offset against collateral		1,681,000		2,275,000
Derivative Liability, Fair value, amount offset against collateral		(12,220,000)		(12,337,000)
Uncleared derivatives [Member] | Mortgages [Member] | Mortgage-delivery commitments [Member]
Derivative [Line Items]
Derivative Asset, Mortgage delivery commitments		283,000		169,000
Derivative Liabilities, Mortgage delivery commitments		(6,000)		(27,000)
Cleared derivatives [Member]
Derivative [Line Items]
Derivative Asset, total gross recognized amount		561,000		40,482,000
Derivative Liability, total gross recognized amount		(1,592,000)		(12,036,000)
Derivative Assets, Netting Adjustments and Cash Collateral		27,837,000	[3]	(7,971,000)	[4]
Derivative liability, Netting Adjustments and Cash Collateral		1,592,000	[3]	12,036,000	[4]
Derivative assets		28,398,000		32,511,000
Derivative liabilities		0		0
Derivative Assets, fair value of securities pledged as collateral than can be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that can be sold or repledged		0	[5]	0	[6]
Derivative Assets, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Liabilities, fair value of securities pledged as collateral that cannot be sold or repledged		0	[5]	0	[6]
Derivative Asset, Fair value, amount offset against collateral		28,398,000		32,511,000
Derivative Liability, Fair value, amount offset against collateral		$ 0		$ 0
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $68.7 million and $25.8 million at March 31, 2018 , and December 31, 2017 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $601,000 and $350,000 at March 31, 2018 , and December 31, 2017 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Includes gross amounts of netting adjustments and cash collateral.
[4]	Includes gross amounts of netting adjustments and cash collateral.
[5]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At March 31, 2018 , we had additional net credit exposure of $178,000
[6]	Includes non-cash collateral at fair value. Any overcollateralization with a counterparty is not included in the determination of the net amount. At December 31, 2017 , we had additional net credit exposure of $502,000

Deposits Narratives (Details)

Deposits Narratives (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deposits [Abstract]
Interest-bearing deposit demand and overnight	$ 500,634	$ 447,700
Interest-bearing deposit other	2,042	3,222
Non-interest bearing deposits other	25,156	26,147
Total deposits	$ 527,832	$ 477,069

Consolidated Obligations CO Bon

Consolidated Obligations CO Bonds - Year of Contractual Maturity (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule of Short-term and Long-term Debt [Line Items]
Due in one year or less		$ 10,747,200	$ 12,186,510
Due in one year or less, weighted average rate	[1]	1.55%	1.35%
Due after one year through two years		$ 5,596,915	$ 5,288,470
Due after one year through two years, weighted average rate	[1]	1.82%	1.63%
Due after two years through three years		$ 3,065,675	$ 3,128,240
Due after two years through three years, weighted average rate	[1]	1.89%	1.81%
Due after three years through four years		$ 2,681,605	$ 2,759,460
Due after three years through four years, weighted average rate	[1]	1.77%	1.74%
Due after four years through five years		$ 1,723,330	$ 1,572,775
Due after four years through five years, weighted average rate	[1]	2.04%	2.00%
Thereafter		$ 3,337,165	$ 3,389,695
Thereafter, weighted average rate	[1]	2.82%	2.76%
Total par value		$ 27,151,890	$ 28,325,150
Total par value, weighted average rate	[1]	1.85%	1.70%
Hedging adjustments		$ (98,112)	$ (55,678)
Total		27,125,212	28,344,623
COs - bonds [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Premiums		87,594	90,836
Discounts		$ (16,160)	$ (15,685)
[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, 2018	Dec. 31, 2017
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 27,151,890	$ 28,325,150
Noncallable and nonputable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	22,644,890	23,931,150
Callable [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Total par value	$ 4,507,000	$ 4,394,000

Consolidated Obligations CO B74

Consolidated Obligations CO Bonds - Year of Contractual Maturity or Next Call Date (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Due in one year or less	$ 14,137,200	$ 15,309,510
Due after one year through two years	5,813,915	5,580,470
Due after two years through three years	2,857,675	3,020,240
Due after three years through four years	1,539,605	1,542,460
Due after four years through five years	1,148,330	1,107,775
Thereafter	1,655,165	1,764,695
Total par value	$ 27,151,890	$ 28,325,150

Consolidated Obligations CO B75

Consolidated Obligations CO Bonds - Interest-Rate-Payment Type (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Fixed-rate	$ 21,582,890	$ 21,416,150
Simple variable-rate	4,027,000	5,432,000
Step-up	1,542,000	1,477,000
Total par value	$ 27,151,890	$ 28,325,150

Consolidated Obligations CO - D

Consolidated Obligations CO - Discount Notes (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Federal Home Loan Bank, Consolidated Obligations, Discount Notes		$ 29,467,314	$ 27,720,906
Par value		$ 29,508,841	$ 27,752,860
Weighted Average Rate	[1]	1.61%	1.25%
[1]	The CO discount notes' weighted-average rate represents a yield to maturity excluding concession fees.

Affordable Housing Program Narr

Affordable Housing Program Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Affordable Housing Program [Roll Forward]
Balance at beginning of period	$ 81,600	$ 81,627	$ 81,627
AHP expense for the period	6,171	4,192	21,307
AHP direct grant disbursements	(5,163)	$ (5,385)	(18,628)
AHP subsidy for AHP advance disbursements	(2,172)		(2,782)
Return of previously disbursed grants and subsidies	9		76
Balance at end of period	$ 80,445		$ 81,600

Capital Requirements (Details)

Capital Requirements (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Capital [Abstract]
Capital-to-asset ratio, Required	4.00%	4.00%
Leverage capital-to-assets ratio, Required	5.00%	5.00%
Multiplier for Determining Permanent Capital in Leverage Capital Calculation	1.5
Class B capital stock	$ 2,323,891	$ 2,283,721
Mandatorily redeemable capital stock	36,113	35,923
Retained earnings	1,335,522	1,308,349
Total permanent capital	3,695,526	3,627,993
Credit-risk capital	338,828	328,557
Market-risk capital	211,211	170,102
Operations-risk capital	165,012	149,598
Total risk-based capital requirement	715,051	648,257
Permanent capital in excess of risk-based capital requirement	2,980,475	2,979,736
Regulatory capital, Required	2,438,324	2,414,478
Leverage capital, Required	3,047,906	3,018,097
Risk-based capital, Actual	3,695,526	3,627,993
Regulatory capital, Actual	$ 3,695,526	$ 3,627,993
Capital-to-asset ratio, Actual	6.10%	6.00%
Leverage capital, Actual	$ 5,543,289	$ 5,441,990
Leverage capital-to-assets ratio, Actual	9.10%	9.00%

Accumulated Other Comprehensi79

Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		$ 119,201,000		$ 98,175,000
Amortization of hedging activities recorded in (loss) gain on derivatives and hedging activities		1,140,000		36,000
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		3,265,130,000		3,244,778,000
Total other comprehensive (loss) income		(13,905,000)		39,942,000
Period end		3,318,568,000		3,345,861,000
Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(40,436,000)		(48,187,000)
Net unrealized gains (losses)		9,166,000		(138,000)
Amortization - hedging activities		938,000	[1]	4,319,000	[2]
Total other comprehensive (loss) income		10,104,000		4,181,000
Period end		(30,332,000)		(44,006,000)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(5,955,000)		(6,139,000)
Amortization - pension and postretirement benefits	[3]	185,000		194,000
Total other comprehensive (loss) income		185,000		194,000
Period end		(5,770,000)		(5,945,000)
Total Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(326,940,000)		(383,514,000)
Net unrealized gains (losses)		(22,456,000)		26,768,000
Accretion of noncredit loss		7,356,000		8,296,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[4]	72,000		365,000
Amortization - hedging activities		938,000	[1]	4,319,000	[2]
Amortization - pension and postretirement benefits	[3]	185,000		194,000
Total other comprehensive (loss) income		(13,905,000)		39,942,000
Period end		(340,845,000)		(343,572,000)
Available-for-sale Securities [Member] | Net Unrealized Loss on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(122,331,000)		(136,809,000)
Net unrealized gains (losses)		(31,622,000)		26,906,000
Total other comprehensive (loss) income		(31,622,000)		26,906,000
Period end		(153,953,000)		(109,903,000)
Held-to-maturity Securities [Member] | Noncredit Portion of Other-Than-Temporary Impairment Losses on Held-to-Maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of period		(158,218,000)		(192,379,000)
Accretion of noncredit loss		7,356,000		8,296,000
Noncredit other-than-temporary impairment losses reclassified to credit loss	[4]	72,000		365,000
Total other comprehensive (loss) income		7,428,000		8,661,000
Period end		(150,790,000)		(183,718,000)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Unrealized Loss Relating to Hedging Activities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of hedging activities recorded in interest expense CO bonds		934,000		4,300,000
Amortization of hedging activities recorded in (loss) gain on derivatives and hedging activities		$ 4,000		$ 4,000
[1]	Amortization of hedging activities includes $934,000 recorded in CO bond interest expense and $4,000
[2]	Amortization of hedging activities includes $4.3 million recorded in CO bond interest expense and $4,000
[3]	Recorded in other non-interest expenses in the statement of operations.
[4]	Recorded in net amount of impairment losses reclassified to accumulated other comprehensive loss in the statement of operations.

Fair Values Carrying Value and

Fair Values Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Mar. 31, 2018		Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 26,681		$ 261,673
Trading securities		942,874		191,510
Available-for-sale securities Fair Value		6,966,772		7,324,736
Held-to-maturity securities	[1],[2]	1,545,726		1,626,122
Held-to-maturity securities Fair Value		1,823,482		1,903,227
Loans to other FHLBanks		0		400,000
Accrued interest receivable		93,749		94,100
Derivative assets		30,079		34,786
Derivative Assets, Netting Adjustments and Cash Collateral	[3],[4]	9,166		(21,452)
Mandatorily redeemable capital stock		(36,113)		(35,923)
Accrued interest payable		(101,593)		(90,626)
Derivative liabilities		(260,565)		(300,450)
Derivative liability, Netting Adjustments and Cash Collateral	[3],[4]	58,925		46,902
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		26,681		261,673
Interest-bearing deposits		51,160		246
Securities purchased under agreements to resell		0		0
Federal funds sold		0		0
Trading securities		0	[5]	0
Available-for-sale securities Fair Value		0	[5]	0
Held-to-maturity securities Fair Value		0		0
Advances		0		0
Mortgage loans, net		0		0
Loans to other FHLBanks				0
Accrued interest receivable		0		0
Derivative assets		0	[5]	0
Other assets	[5]	12,031		9,726
Deposits		0		0
Mandatorily redeemable capital stock		(36,113)		(35,923)
Accrued interest payable		0		0
Derivative liabilities		0	[5]	0
Level 1 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 1 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 1 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0		0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		0		0
Interest-bearing deposits		0		0
Securities purchased under agreements to resell		2,998,981		5,348,898
Federal funds sold		6,224,991		3,449,981
Trading securities	[5]	942,874		191,510
Available-for-sale securities Fair Value	[5]	6,929,277		7,287,053
Held-to-maturity securities Fair Value		764,744		811,759
Advances		37,962,720		37,591,048
Mortgage loans, net		3,945,318		4,013,704
Loans to other FHLBanks	[6]			399,997
Accrued interest receivable		93,749		94,100
Derivative assets	[5]	20,913		56,238
Other assets	[5]	13,091		12,625
Deposits		(527,791)		(477,060)
Mandatorily redeemable capital stock		0		0
Accrued interest payable		(101,593)		(90,626)
Derivative liabilities	[5]	(319,490)		(347,352)
Level 2 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(3,829)		(3,817)
Level 2 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,148)		(1,100)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(29,465,498)		(27,719,598)
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		0		0
Interest-bearing deposits		0		0
Securities purchased under agreements to resell		0		0
Federal funds sold		0		0
Trading securities		0	[5]	0
Available-for-sale securities Fair Value	[5]	37,495		37,683
Held-to-maturity securities Fair Value		1,058,738		1,091,468
Advances		0		0
Mortgage loans, net		21,582		22,224
Loans to other FHLBanks				0
Accrued interest receivable		0		0
Derivative assets		0	[5]	0
Other assets		0	[5]	0
Deposits		0		0
Mandatorily redeemable capital stock		0		0
Accrued interest payable		0		0
Derivative liabilities		0	[5]	0
Level 3 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 3 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Level 3 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0		0
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		26,681		261,673
Interest-bearing deposits		51,160		246
Securities purchased under agreements to resell		2,999,000		5,349,000
Federal funds sold		6,225,000		3,450,000
Trading securities	[5]	942,874		191,510
Available-for-sale securities Fair Value	[5]	6,966,772		7,324,736
Held-to-maturity securities		1,545,726		1,626,122
Advances		37,987,775		37,565,967
Mortgage loans, net		4,026,998		4,004,737
Loans to other FHLBanks	[6]			400,000
Accrued interest receivable		93,749		94,100
Derivative assets	[5]	30,079		34,786
Other assets	[5]	25,122		22,351
Deposits		(527,832)		(477,069)
Mandatorily redeemable capital stock		(36,113)		(35,923)
Accrued interest payable		(101,593)		(90,626)
Derivative liabilities	[5]	(260,565)		(300,450)
Carrying Value [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0		0
Carrying Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,148)		(1,100)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(29,467,314)		(27,720,906)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		26,681		261,673
Interest-bearing deposits		51,160		246
Securities purchased under agreements to resell		2,998,981		5,348,898
Federal funds sold		6,224,991		3,449,981
Trading securities	[5]	942,874		191,510
Available-for-sale securities Fair Value	[5]	6,966,772		7,324,736
Held-to-maturity securities Fair Value		1,823,482		1,903,227
Advances		37,962,720		37,591,048
Mortgage loans, net		3,966,900		4,035,928
Loans to other FHLBanks	[6]			399,997
Accrued interest receivable		93,749		94,100
Derivative assets	[5]	30,079		34,786
Other assets	[5]	25,122		22,351
Deposits		(527,791)		(477,060)
Mandatorily redeemable capital stock		(36,113)		(35,923)
Accrued interest payable		(101,593)		(90,626)
Derivative liabilities	[5]	(260,565)		(300,450)
Total Fair Value [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(3,829)		(3,817)
Total Fair Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,148)		(1,100)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(29,465,498)		(27,719,598)
COs - bonds [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		0		0
COs - bonds [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		(27,005,475)		(28,353,945)
COs - bonds [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		0		0
COs - bonds [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		(27,125,212)		(28,344,623)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (27,005,475)		$ (28,353,945)
[1]	Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss.
[2]	Fair values of held-to-maturity securities were $ 1,823,482 and $1,903,227 at March 31, 2018 , and December 31, 2017
[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 $68.7 million and $25.8 million at March 31, 2018 , and December 31, 2017 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $601,000 and $350,000 at March 31, 2018 , and December 31, 2017 .
[4]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[5]	Carried at fair value on a recurring basis.
[6]	The Fair Value Summary table for December 31, 2017, has been revised to correct the omission of Loans to Other FHLBanks. This revision had no impact on the Statements of Condition, Statements of Operations, or Statements of Cash Flows.

Fair Values Fair Value of Asset

Fair Values Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands		Mar. 31, 2018		Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		$ 942,874		$ 191,510
Available-for-sale securities Fair Value		6,966,772		7,324,736
Derivative assets		30,079		34,786
Derivative Assets, Netting Adjustments and Cash Collateral	[1],[2]	9,166		(21,452)
Derivative liabilities		(260,565)		(300,450)
Derivative liability, Netting Adjustments and Cash Collateral	[1],[2]	58,925		46,902
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0	[3]	0
Available-for-sale securities Fair Value		0	[3]	0
Derivative assets		0	[3]	0
Other assets	[3]	12,031		9,726
Derivative liabilities		0	[3]	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	942,874		191,510
Available-for-sale securities Fair Value	[3]	6,929,277		7,287,053
Derivative assets	[3]	20,913		56,238
Other assets	[3]	13,091		12,625
Derivative liabilities	[3]	(319,490)		(347,352)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0	[3]	0
Available-for-sale securities Fair Value	[3]	37,495		37,683
Derivative assets		0	[3]	0
Other assets		0	[3]	0
Derivative liabilities		0	[3]	0
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[2]	9,166		(21,452)
Derivative liability, Netting Adjustments and Cash Collateral	[2]	58,925		46,902
Recurring [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Netting Adjustments and Cash Collateral	[2]	9,166		(21,452)
Derivative liability, Netting Adjustments and Cash Collateral	[2]	58,925		46,902
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Derivative assets		0		0
Other assets		12,031		9,726
Total assets at fair value		12,031		9,726
Total liabilities at fair value		0		0
Recurring [Member] | Level 1 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		942,874		191,510
Available-for-sale securities Fair Value		6,929,277		7,287,053
Derivative assets		20,913		56,238
Other assets		13,091		12,625
Total assets at fair value		7,906,155		7,547,426
Total liabilities at fair value		(319,490)		(347,352)
Recurring [Member] | Level 2 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		20,630		56,069
Derivative liabilities		(319,484)		(347,325)
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		37,495		37,683
Derivative assets		0		0
Other assets		0		0
Total assets at fair value		37,495		37,683
Total liabilities at fair value		0		0
Recurring [Member] | Level 3 [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	[3]	942,874		191,510
Available-for-sale securities Fair Value	[3]	6,966,772		7,324,736
Derivative assets	[3]	30,079		34,786
Other assets	[3]	25,122		22,351
Derivative liabilities	[3]	(260,565)		(300,450)
Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		942,874		191,510
Available-for-sale securities Fair Value		6,966,772		7,324,736
Derivative assets		30,079		34,786
Other assets		25,122		22,351
Total assets at fair value		7,964,847		7,573,383
Total liabilities at fair value		(260,565)		(300,450)
Estimate of Fair Value Measurement [Member] | Recurring [Member] | Interest-rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		29,796		34,617
Derivative liabilities		(260,559)		(300,423)
U.S. Treasury obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		749,578		0
U.S. Treasury obligations [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
U.S. Treasury obligations [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		749,578
U.S. Treasury obligations [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
U.S. Treasury obligations [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		749,578
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		7,170		0
Corporate bonds [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
Corporate bonds [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		7,170
Corporate bonds [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0
Corporate bonds [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		7,170
U.S. government-guaranteed - single-family MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		6,429		6,807
Available-for-sale securities Fair Value		92,228		95,777
U.S. government-guaranteed - single-family MBS [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
U.S. government-guaranteed - single-family MBS [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		6,429		6,807
Available-for-sale securities Fair Value		92,228		95,777
U.S. government-guaranteed - single-family MBS [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
U.S. government-guaranteed - single-family MBS [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		6,429		6,807
Available-for-sale securities Fair Value		92,228		95,777
U.S. government guaranteed - multifamily MBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		414,153		443,373
U.S. government guaranteed - multifamily MBS [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government guaranteed - multifamily MBS [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		414,153		443,373
U.S. government guaranteed - multifamily MBS [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government guaranteed - multifamily MBS [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		414,153		443,373
HFA securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		37,495		37,683
HFA securities [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
HFA securities [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
HFA securities [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		37,495		37,683
HFA securities [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		37,495		37,683
Supranational institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		406,730		418,285
Supranational institutions [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
Supranational institutions [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		406,730		418,285
Supranational institutions [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
Supranational institutions [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		406,730		418,285
U.S. government-owned corporations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		285,027		292,077
U.S. government-owned corporations [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government-owned corporations [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		285,027		292,077
U.S. government-owned corporations [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
U.S. government-owned corporations [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		285,027		292,077
GSEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		117,751		121,343
GSEs [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
GSEs [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		117,751		121,343
GSEs [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		0		0
GSEs [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities Fair Value		117,751		121,343
Single Family [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		275		346
Available-for-sale securities Fair Value		4,288,240		4,562,992
Single Family [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Single Family [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		275		346
Available-for-sale securities Fair Value		4,288,240		4,562,992
Single Family [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Single Family [Member] | Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		275		346
Available-for-sale securities Fair Value		4,288,240		4,562,992
Multifamily [Member] | Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		179,422		184,357
Available-for-sale securities Fair Value		1,325,148		1,353,206
Multifamily [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Multifamily [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		179,422		184,357
Available-for-sale securities Fair Value		1,325,148		1,353,206
Multifamily [Member] | Government Sponsored Enterprises [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Available-for-sale securities Fair Value		0		0
Multifamily [Member] | Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		179,422		184,357
Available-for-sale securities Fair Value		1,325,148		1,353,206
Mortgages [Member] | Recurring [Member] | Level 1 [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Mortgages [Member] | Recurring [Member] | Level 2 [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		283		169
Derivative liabilities		(6)		(27)
Mortgages [Member] | Recurring [Member] | Level 3 [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Mortgages [Member] | Estimate of Fair Value Measurement [Member] | Recurring [Member] | Mortgage-delivery commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		283		169
Derivative liabilities		$ (6)		$ (27)
[1]	Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $68.7 million and $25.8 million at March 31, 2018 , and December 31, 2017 , respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $601,000 and $350,000 at March 31, 2018 , and December 31, 2017 .
[2]	These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.
[3]	Carried at fair value on a recurring basis.

Estimated Fair Value Level 3 Re

Estimated Fair Value Level 3 Reconciliation - Roll Forward (Details) - Level 3 [Member] - Recurring [Member] - Available-for-sale Securities [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 37,683	$ 8,146
Unrealized (losses) gains included in other comprehensive income	(188)	38
Balance at end of period	$ 37,495	$ 8,184

Fair Value of Assets Measured a

Fair Value of Assets Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		$ 1,823,482	$ 1,903,227
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		0	0
Mortgage loans held for portfolio		0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		764,744	811,759
Mortgage loans held for portfolio		3,945,318	4,013,704
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		1,058,738	1,091,468
Mortgage loans held for portfolio		21,582	22,224
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	0	0
REO	[1]		0
Total assets recorded at fair value on a nonrecurring basis	[1]	0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	0	0
REO	[1]		0
Total assets recorded at fair value on a nonrecurring basis	[1]	0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	354	4,608
REO	[1]		784
Total assets recorded at fair value on a nonrecurring basis	[1]	2,244	7,362
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		1,823,482	1,903,227
Mortgage loans held for portfolio		3,966,900	4,035,928
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for portfolio	[1]	354	4,608
REO	[1]		784
Total assets recorded at fair value on a nonrecurring basis	[1]	2,244	7,362
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities		912,790	951,898
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[1]	0	0
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[1]	0	0
Residential Mortgage Backed Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[1]	1,890	1,970
Residential Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of held-to-maturity securities	[1]	$ 1,890	$ 1,970
[1]	The fair values presented are as of the date the fair value adjustment was recorded during the three months ended March 31, 2018 , and year ended December 31, 2017

Commitments and Contingencies84

Commitments and Contingencies (Details) - USD ($)		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Value of the guarantees related to standby letters of credit		$ 40,469,000	$ 45,619,000
Maximum term of commitments to invest in mortgage loans		45 days
Other FHLBanks [Member]
Loss Contingencies [Line Items]
Par value of other FHLBanks' outstanding COs for which we are jointly and severally liable		$ 962,600,000,000	978,200,000,000
Standby Letters of Credit Issuance Commitments [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 2,400,000	1,400,000
Off-balance-sheet Commitments Expiring After One Year			543,000
Maximum [Member]
Loss Contingencies [Line Items]
Standby letters of credit, original terms		20 years
Standby letters of credit, current terms		10 years
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[1]	$ 6,147,846,000	5,034,725,000
Off-balance-sheet Commitments Expiring After One Year	[1]	277,842,000	223,167,000
Total Off-balance Sheet Commitments	[1]	6,425,688,000	5,257,892,000
Value of the guarantees related to standby letters of credit		1,100,000	1,100,000
Commitments of unused lines of credit - advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year	[2]	1,207,681,000	1,216,592,000
Off-balance-sheet Commitments Expiring After One Year	[2]	0	0
Total Off-balance Sheet Commitments	[2]	$ 1,207,681,000	1,216,592,000
Commitments of unused lines of credit - advances [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Period for commitments for unused line-of-credit advances		12 months
Commitments to make additional advances [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		$ 40,228,000	18,851,000
Off-balance-sheet Commitments Expiring After One Year		52,427,000	63,488,000
Total Off-balance Sheet Commitments		92,655,000	82,339,000
Unsettled CO bonds, at par [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		25,000,000	52,550,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		25,000,000	52,550,000
Consolidated Obligations Discount Notes [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		1,762,000,000	0
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		1,762,000,000	0
Mortgages [Member] | Commitments to Invest in Mortgage Loans [Member]
Loss Contingencies [Line Items]
Off-balance-sheet Commitments Expiring Within One Year		32,756,000	42,918,000
Off-balance-sheet Commitments Expiring After One Year		0	0
Total Off-balance Sheet Commitments		$ 32,756,000	$ 42,918,000
[1]	The amount of standby letters of credit outstanding excludes commitments to issue standby letters of credit that expire within one year. At March 31, 2018 , and December 31, 2017 , these amounts totaled $ 2.4 million and $1.4 million , respectively. Also excluded are commitments to issue standby letters of credit that expire after one year totaling $543,000 at December 31, 2017
[2]	Commitments for unused line-of-credit advances are generally for periods of up to 12 months

Transactions with Shareholder85

Transactions with Shareholders (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Transactions with Shareholders [Line Items]
Capital Stock Outstanding		$ 2,323,891		$ 2,283,721
Par Value of Advances	[1]	38,116,365		37,647,166
Total Accrued Interest Receivable		93,749		94,100
Interest income on advances		177,450	$ 106,583
Fees on letters of credit		2,356	2,012
Citizens Bank, N.A. [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding		$ 253,348		$ 227,287
Percent of Total Capital Stock Outstanding		10.70%		9.80%
Par Value of Advances		$ 5,508,833		$ 4,858,592
Percentage of Total Par Value of Advances		14.50%		12.90%
Total Accrued Interest Receivable		$ 4,406		$ 2,558
Percent of Total Accrued Interest Receivable on Advances		9.10%		6.00%
Interest income on advances		$ 26,892	14,111
Fees on letters of credit		1,097	$ 745
Directors' Financial Institutions [Member]
Transactions with Shareholders [Line Items]
Capital Stock Outstanding		$ 112,214		$ 114,498
Percent of Total Capital Stock Outstanding		4.80%		4.90%
Par Value of Advances		$ 2,062,824		$ 2,133,374
Percentage of Total Par Value of Advances		5.40%		5.70%
Total Accrued Interest Receivable		$ 2,646		$ 2,466
Percent of Total Accrued Interest Receivable on Advances		5.50%		5.80%
Minimum [Member]
Transactions with Shareholders [Line Items]
Definition of shareholder concentration, minimum percent		10.00%
[1]	Also includes certain floating-rate advances that may be contractually prepaid by the borrower on a floating-rate reset date without incurring prepayment or termination fees.

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events (Details) - Common Class B [Member] - Subsequent Event [Member] - USD ($) $ in Millions	May 02, 2018	Apr. 20, 2018
Subsequent Event [Line Items]
Annualized rate of cash dividend		5.46%
Dividend, including dividends on mandatorily redeemable capital stock	$ 32.4