Capital Retained Earnings (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Banking Regulation, Total Capital [Abstract]
Quarterly Net Income Allocated to Restricted Retained Earnings	20.00%
Percent of Average Balance of Outstanding Consolidated Obligations Prescribed per the Joint Capital Enhancement Agreement For Each Previous Quarter	1.00%
Retained Earnings, Appropriated	$ 522	$ 504

A segregation of retained earnings which is unavailable for dividend distribution. Includes also retained earnings appropriated for loss contingencies.

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