Advances (Interest-rate Payment Terms) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Advances [Abstract]
Fixed-rate, due in one year or less	$ 35,798	$ 40,578
Fixed-rate, due after one year	25,934	24,043
Total fixed-rate	61,732	64,621
Variable-rate, due in one year or less	28,448	31,755
Variable-rate, due after one year	10,802	12,038
Total variable-rate	39,250	43,793
Federal Home Loan Bank, Advances, Par Value	$ 100,982	$ 108,414