Mortgage Loans Held for Portfolio Delinquency Statistics (Details) - Conventional Mortgage Loan - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Originated Five or More Years before Latest Fiscal Year	$ 2,999
Originated, Current Fiscal Year and Preceeding Four Preceeding Fiscal Years	243
Total Amortized Cost	3,242
In process of foreclosure, included above	1	$ 0
Nonaccrual loans	$ 7	$ 7
Serious delinquencies as a percentage of total mortgage loans outstanding	0.22%	0.22%
Total past due		$ 24
Total current loans		3,310
Total MPF Recorded Investment		3,334
Financing Receivable, Nonaccrual, No Allowance	$ 6
30 – 59 days delinquent
Financing Receivable, Past Due [Line Items]
Originated Five or More Years before Latest Fiscal Year	12
Originated, Current Fiscal Year and Preceeding Four Preceeding Fiscal Years	3
Total Amortized Cost	15
Total past due		15
60 – 89 days delinquent
Financing Receivable, Past Due [Line Items]
Originated Five or More Years before Latest Fiscal Year	3
Originated, Current Fiscal Year and Preceeding Four Preceeding Fiscal Years	2
Total Amortized Cost	5
Total past due		2
90 days or more delinquent
Financing Receivable, Past Due [Line Items]
Originated Five or More Years before Latest Fiscal Year	3
Originated, Current Fiscal Year and Preceeding Four Preceeding Fiscal Years	4
Total Amortized Cost	7
Total past due		$ 7
Nonperforming
Financing Receivable, Past Due [Line Items]
Originated Five or More Years before Latest Fiscal Year	18
Originated, Current Fiscal Year and Preceeding Four Preceeding Fiscal Years	9
Total Amortized Cost	27
Current Performing Loan
Financing Receivable, Past Due [Line Items]
Originated Five or More Years before Latest Fiscal Year	2,981
Originated, Current Fiscal Year and Preceeding Four Preceeding Fiscal Years	234
Total Amortized Cost	$ 3,215