Segment Information (Details) $ in Millions		12 Months Ended
		Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment		2
Adjusted Net Interest Income		$ 563	$ 611	$ 559
Amortization of Basis Adjustments	[1]	34	(1)	0
Income/(Expense) on Economic Hedges	[2]	(16)	(13)	(40)
Interest Expense on Mandatorily Redeemable Capital Stock	[3]	14	24	32
Net Interest Income After Mortgage Loan Loss Provision		531	601	567
Other Income/ (Loss)		21	(11)	78
Other Expense		187	187	224
Income Before AHP Assessment		365	403	421
OTTI PLRMBS, Total accretion or amortization recognized in interest income		78	81	93
Net OTTI loss, credit-related		11	11	16
Assets		106,842	109,326	123,385
Advances- Related Business
Segment Reporting Information [Line Items]
Adjusted Net Interest Income		307	320	234
Assets		85,709	88,272	103,426
Mortgage- Related Business
Segment Reporting Information [Line Items]
Adjusted Net Interest Income	[4]	256	291	325
Assets		$ 21,133	$ 21,054	$ 19,959

[1] Represents amortization of amounts deferred for adjusted net interest income purposes only

[2] The Bank includes income and expense associated with net settlements from economic hedges in adjusted net interest income in its analysis of financial performance for its two operating segments. For financial reporting purposes, the Bank does not include these amounts in net interest income in the Statements of Income, but instead records them in other income in “Net gain/(loss) on derivatives and hedging activities.”

[3] The Bank excludes interest expense on mandatorily redeemable capital stock from adjusted net interest income in its analysis of financial performance for its two operating segments

[4] The mortgage-related business includes total accretion or amortization associated with other-than-temporarily impaired PLRMBS, which are recognized in interest income totaled $78, $81, and $93 for the years ended December 31, 2019, 2018, and 2017, respectively. The mortgage-related business does not include credit-related OTTI losses of $11, $11, and $16 for the years ended December 31, 2019, 2018, and 2017, respectively.