Capital and Mandatorily Redeemable Capital Stock Schedule of Declared and Paid Quarterly Dividends (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Stockholders' Equity [Abstract]
Dividends, Common Stock, Cash	$ 81	$ 85	$ 80	$ 65	$ 166	$ 145
Common Stock Dividend-Annualized Rate	6.54%	6.47%	5.78%	5.16%	6.50%	5.35%