Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OPERATING ACTIVITIES:
Net income	$ 63,510	$ 57,693
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,860	7,715
Change in net fair value adjustment on derivative and hedging activities	7,804	28,814
Net change in fair value adjustments on trading securities	(1)	8,880
Net change in fair value adjustments on Consolidated Obligation Bonds held at fair value	(532)	(2,621)
Other adjustments	(2,502)	1,400
Net change in:
Accrued interest receivable	139	(14,742)
Other assets	2,264	2,559
Accrued interest payable	14,296	(7,195)
Other liabilities	2,451	15,279
Total adjustments	27,779	40,089
Net cash provided by operating activities	91,289	97,782
Net change in:
Interest-bearing deposits	32,288	64,965
Securities purchased under agreements to resell	850,000	(2,600,000)
Federal funds sold	(250,000)	(785,000)
Premises, software, and equipment	(797)	(179)
Trading securities:
Net increase in short-term	0	(231,230)
Proceeds from maturities of long-term	83	48
Available-for-sale securities:
Net increase in short-term	(500,000)	(91,183)
Held-to-maturity securities:
Net decrease (increase) in short-term	659	(1,180,072)
Proceeds from maturities of long-term	773,803	856,409
Purchases of long-term	(1,698,350)	(452,601)
Advances:
Proceeds	204,371,433	143,651,562
Made	(208,746,435)	(142,476,529)
Mortgage loans held for portfolio:
Principal collected	652,170	615,805
Purchases	(339,823)	(980,998)
Net cash used in investing activities	(4,854,969)	(3,609,003)
FINANCING ACTIVITIES:
Net (decrease) increase in deposits and pass-through reserves	(76,190)	150,870
Net payments on derivative contracts with financing elements	(11,562)	(44,433)
Net proceeds from issuance of Consolidated Obligations:
Discount Notes	47,052,712	48,407,843
Bonds	5,368,244	5,206,868
Payments for maturing and retiring Consolidated Obligations:
Discount Notes	(43,820,701)	(47,468,707)
Bonds	(3,762,062)	(4,742,556)
Proceeds from issuance of capital stock	474,153	30,712
Payments for redemption of mandatorily redeemable capital stock	(95,098)	(20,471)
Cash dividends paid	(38,454)	(35,316)
Net cash provided by financing activities	5,091,042	1,484,810
Net increase (decrease) in cash and cash equivalents	327,362	(2,026,411)
Cash and cash equivalents at beginning of the period	16,423	2,033,944
Cash and cash equivalents at end of the period	343,785	7,533
Supplemental Disclosures:
Interest paid	129,497	171,508
AHP payments, net	$ 2,395	$ 2,454