Capital (Narrative) (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) $ / shares
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Stock, Par or Stated Value Per Share | $ / shares	$ 100		$ 100
Number of Subclasses of Capital Stock	2
Redemption Period Under FHLBank Capital Plan	5 years
Written Notice Period Required to Repurchase Excess Membership Capital Stock	15 days
Banking Regulation, Total Risk-Based Capital, Excess, Actual	$ 0		$ 0
Minimum Capital Stock Required to be Held by Members as a Percent of Total Assets at Preceeding Fiscal Year End, Subject to Cap and Floor	0.12%
Activity Based Capital Stock Required by Members as a Percent of Total Advances and Mortgage Loans Oustanding as Disclosed in the Statement of Condition	4.00%
Interest Expense, Capital Securities	$ 3,000,000	$ 3,000,000
Maximum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Federal Home Loan Banks, Membership Requirements, Capital Stock	10,000,000
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Federal Home Loan Banks, Membership Requirements, Capital Stock	$ 10,000