Advances (Redemption Terms) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Advances [Abstract]
Overdrawn Demand Deposit Accounts	$ 1	$ 2
Advances, Maturing in Next Rolling Twelve Months	35,432	50,561
Advances, Maturing in Rolling Year Two	21,959	23,946
Advances, Maturing in Rolling Year Three	8,693	17,582
Advances, Maturing in Rolling Year Four	5,109	4,091
Advances, Maturing in Rolling Year Five	5,978	6,814
Advances, Maturing after Rolling Year Five	3,013	3,417
Advances, Par Value	$ 80,185	$ 106,413
Advances, Weighted Average Interest Rate on Overdrawn Demand Deposit	2.73%	3.63%
Advances, Weighted Average Interest Rate, Maturing in Next Twelve Rolling Months	1.97%	2.61%
Advances, Weighted Average Interest Rate, Maturing in Rolling Year Two	2.23%	2.61%
Advances, Weighted Average Interest Rate, Maturing in Rolling Year Three	2.33%	2.73%
Advances, Weighted Average Interest Rate, Maturing in Rolling Year Four	2.51%	2.73%
Advances, Weighted Average Interest Rate, Maturing in Rolling Year Five	2.17%	2.76%
Advances, Weighted Average Interest Rate, Maturing after Rolling Year Five	2.72%	2.96%
Advances, Weighted Average Interest Rate	2.16%	2.66%
Premiums	$ 25	$ 38
Discounts	(6)	(8)
Federal Home Loan Bank, Advances, Valuation Adjustments for Hedging Activities	156	(120)
Total Advances	80,360	106,323
Advances, Earlier of Contractual Maturity or Next Call Date, in Next Rolling Twelve Months	53,156	77,931
Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Two	11,967	11,087
Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Three	5,427	10,423
Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Four	3,802	2,357
Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Five	3,461	2,444
Advances, Earlier of Contractual Maturity or Next Call Date, after Rolling Year Five	2,371	2,169
Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Next Rolling Twelve Months	36,278	50,617
Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Two	22,101	24,060
Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Three	8,730	17,628
Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Four	5,004	4,078
Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Five	5,069	6,722
Advances, Earlier of Contractual Maturity or Next Put or Convert Date, after Rolling Year Five	$ 3,002	$ 3,306