Capital (Capital Requirements) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Capital Stock Requirement	1.00%
Membership Capital Stock Requirement, Cap	$ 15
Risk-Based Capital, Required	1,519	$ 1,899
Risk-Based Capital, Actual	6,605	6,522
Regulatory Capital, Required	4,274	4,373
Regulatory Capital, Actual	$ 6,605	$ 6,522
Regulatory Capital Ratio, Required	4.00%	4.00%
Regulatory Capital Ratio, Actual	6.18%	5.97%
Leverage Capital, Required	$ 5,342	$ 5,466
Leverage Capital, Actual	$ 9,908	$ 9,783
Leverage ratio - Required	5.00%	5.00%
Leverage Ratio, Actual	9.27%	8.95%
Multiplier for Determining Permanent Capital in Leverage Capital Calculation	1.5
Minimum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Capital Stock Requirement	0.50%
Membership Capital Stock Requirement, Cap	$ 10
Maximum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Capital Stock Requirement	1.50%
Membership Capital Stock Requirement, Cap	$ 50
Percentage of Total Advances Outstanding
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Activity Based Stock Requirement	2.70%
Percentage of Total Advances Outstanding \| Minimum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Activity Based Stock Requirement	2.00%
Percentage of Total Advances Outstanding \| Maximum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Activity Based Stock Requirement	5.00%
Mortgages
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Activity Based Stock Requirement	0.00%
Mortgages \| Minimum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Activity Based Stock Requirement	0.00%
Mortgages \| Maximum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Membership Activity Based Stock Requirement	5.00%

Leverage ratio requirement as defined in the regulations.

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- Definition

Membership activity-based stock requirement as a percentage of outstanding advances plus percentage of mortgage loans sold by the member and owned by the Bank

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Membership capital stock requirement, as a percentage of it's membership asset value.

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- Definition

Membership Capital Stock Requirement Cap

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- Definition

The weighting factor used for permanent capital when calculating total leverage capital.

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- Definition

Regulatory capital ratio requirement as defined in the regulations.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of leveraged capital of Federal Home Loan Bank (FHLBank), set by the Federal Housing Finance Agency (FHFA).

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Minimum amount of leverage capital required for Federal Home Loan Bank (FHLBank), set by the Federal Housing Finance Agency (FHFA).

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Leverage ratio of Federal Home Loan Bank (FHLBank), calculated per regulations of the Federal Housing Finance Agency (FHFA).

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Amount of regulatory capital of Federal Home Loan Bank (FHLBank), set by the Federal Housing Finance Agency (FHFA).

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Regulatory capital ratio of Federal Home Loan Bank (FHLBank), calculated per regulations of the Federal Housing Finance Agency (FHFA).

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Minimum amount of regulatory capital required for Federal Home Loan Bank (FHLBank), set by the Federal Housing Finance Agency (FHFA).

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Amount of risk-based capital of Federal Home Loan Bank (FHLBank), set by the Federal Housing Finance Agency (FHFA).

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Minimum amount of risk-based capital required for Federal Home Loan Bank (FHLBank), set by the Federal Housing Finance Agency (FHFA).

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