Advances (Redemption Terms) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Advances [Abstract]
Overdrawn demand deposit accounts	$ 5	$ 1
Weighted Average Interest Rate on Overdrawn Demand Deposit	1.36%	2.73%
Due in one year or less	$ 33,669	$ 35,432
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Next Twelve Rolling Months	1.05%	1.97%
Due after one year through two years	$ 19,305	$ 21,959
Federal Home Loan Bank Advances, Weighted Average Interest Rate, Maturing in Rolling Year Two	1.71%	2.23%
Due after two years through three years	$ 10,264	$ 8,693
Federal Home Loan Bank Advances, Weighted Average Interest Rate, Maturing in Rolling Year Three	2.07%	2.33%
Due after three years through four years	$ 5,244	$ 5,109
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Four	2.36%	2.51%
Due after four years through five years	$ 7,231	$ 5,978
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Five	1.93%	2.17%
Thereafter	$ 3,441	$ 3,013
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing after Rolling Year Five	2.43%	2.72%
Federal Home Loan Bank, Advances, Par Value	$ 79,159	$ 80,185
Federal Home Loan Bank, Advances, Weighted Average Interest Rate	1.57%	2.16%
Premiums	$ 24	$ 25
Discounts	(5)	(6)
Fair value hedging adjustments	579	156
Total	79,757	80,360
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Next Rolling Twelve Months	48,177	53,156
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Next Rolling Twelve Months	34,633	36,278
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Two	12,855	11,967
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Two	19,360	22,101
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Three	6,617	5,427
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Three	10,320	8,730
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Four	3,924	3,802
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Four	5,036	5,004
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, in Rolling Year Five	4,558	3,461
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, in Rolling Year Five	6,375	5,069
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, after Rolling Year Five	3,023	2,371
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, after Rolling Year Five	$ 3,430	$ 3,002