Advances Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
Advances Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Advances [Line Items]
Percent Of Fixed Rate Advances Swapped To Adjustable Rate	63.00%		66.00%
Gross Prepayment Fees on Advances Received	$ 7,237	$ 328
Federal Home Loan Bank Advances Par Value	44,305,556		$ 50,840,265
USAA Federal Savings Bank
Advances [Line Items]
Federal Home Loan Bank advances, par value	$ 6,000,000
percentage of outstanding advances	13.50%
American General Life Insurance Company
Advances [Line Items]
Federal Home Loan Bank advances, par value	$ 4,422,993
Institutions affiliated with American General Life Insurance Company
Advances [Line Items]
Federal Home Loan Bank advances, par value	$ 909,000
American General Life Insurance Company and affiliated institutions
Advances [Line Items]
percentage of outstanding advances	12.00%
Minimum [Member]
Advances [Line Items]
Federal Home Loan Bank Advances, Interest Rate	0.54%		0.54%
Maximum [Member]
Advances [Line Items]
Federal Home Loan Bank Advances, Interest Rate	6.46%		6.46%
Federal Home Loan Bank Advances Callable Option [Member]
Advances [Line Items]
Federal Home Loan Bank Advances Par Value	$ 6,140,342		$ 6,096,106
Federal Home Loan Bank Advances Putable Option [Member]
Advances [Line Items]
Federal Home Loan Bank Advances Par Value	4,278,750		4,798,750
Federal Home Loan Bank Advances Receivable [Member]
Advances [Line Items]
Financing Receivable, Accrued Interest, after Allowance for Credit Loss	$ 114,257		$ 137,161