Advances Outstanding by the Earlier of Contractual Maturity or Next Put Date (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Advances by Earlier of Contractual Maturity or Next Put Date [Line Items]
Deposit Liabilities Reclassified as Loans Receivable	$ 12	$ 7,682
Federal Home Loan Bank Advances, Earlier of Contractual Maturity or Next Put Date, Due within Next Rolling Twelve Months	10,580,359	11,193,533
Federal Home Loan Bank Advances, Earlier of Contractual Maturity or Next Put Date, Due In Rolling Year Two	1,181,230	1,876,203
Federal Home Loan Bank Advances, Earlier of Contractual Maturity or Next Put Date, Due In Rolling Year Three	724,530	786,691
Federal Home Loan Bank Advances, Earlier of Contractual Maturity or Next Put Date, Due In Rolling Year Four	658,358	392,021
Federal Home Loan Bank Advances, Earlier of Contractual Maturity or Next Put Date, Due In Rolling Year Five	432,730	601,359
Federal Home Loan Bank Advances, Earlier of Contractual Maturity or Next Put Date, Due After Rolling Year Five	799,314	751,229
Federal Home Loan Bank Advances, Maturities, Amortizing Advances at Balance Sheet Date	2,035,515	2,319,538
Federal Home Loan Bank Advances Par Value	$ 16,412,048	$ 17,928,256