Consolidated Obligations (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Short-term and Long-term Debt [Line Items]
Percent of Fixed Rate Long Term Debt Swapped to An Adjustable Rate	89.00%	91.00%
Percent of Variable Rate Long Term Debt Swapped to a Different Variable Rate Index or Hedged With Interest Rate Swap Offsetting an Interest Rate Cap Embedded in the Bonds	1.00%	16.00%
Federal Home Loan Bank, Consolidated Obligations	$ 28,555,825	$ 32,682,314
FHLBanks [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Debt, Gross	721,000,000	688,000,000
FHL Bank of Dallas [Member]
Schedule of Short-term and Long-term Debt [Line Items]
Federal Home Loan Bank, Consolidated Obligations	$ 28,600,000	$ 32,600,000