Capital (By Redemption Period) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount [Abstract]
Within 1 year		$ 135	$ 0
After 1 year through 2 years		0	224
Past contractual redemption date because of remaining activity	[1]	3	3
Total		$ 138	$ 227	$ 309	$ 457

[1] Represents mandatorily redeemable capital stock that is past the end of the contractual redemption period because of outstanding activity.