Advances - Narratives (Details) $ in Billions	12 Months Ended
	Dec. 31, 2019 Borrowers	Dec. 31, 2018 USD ($) Borrowers	Dec. 31, 2017 USD ($)
Credit Risk Exposure and Security Terms [Abstract]
Total outstanding advances greater than $1.0 billion per borrower, amount		$ 12.3	$ 16.4
Minimum amount of advances outstanding per borrower		$ 1.0
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	35.60%	37.90%
Minimum [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank Advances Maturities	1 day
Interest rates of advances outstanding	(0.35%)	0.00%
Maximum [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank Advances Maturities	30 years
Interest rates of advances outstanding	7.72%	7.72%