Advances Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Advances Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Advances [Line Items]
Percent Of Fixed Rate Advances Swapped To Adjustable Rate	56.00%		56.00%		66.00%
Gross Prepayment Fees on Advances Received	$ 312	$ 576	$ 7,549	$ 904
Federal Home Loan Bank Advances Par Value	47,560,940		47,560,940		$ 50,840,265
USAA Federal Savings Bank
Advances [Line Items]
Federal Home Loan Bank advances, par value	$ 5,250,000		$ 5,250,000
percentage of outstanding advances	11.00%		11.00%
American General Life Insurance Company
Advances [Line Items]
Federal Home Loan Bank advances, par value	$ 4,419,393		$ 4,419,393
Institutions affiliated with American General Life Insurance Company
Advances [Line Items]
Federal Home Loan Bank advances, par value	$ 909,000		$ 909,000
American General Life Insurance Company and affiliated institutions
Advances [Line Items]
percentage of outstanding advances	11.20%		11.20%
Minimum [Member]
Advances [Line Items]
Federal Home Loan Bank Advances, Interest Rate	0.54%		0.54%		0.54%
Maximum [Member]
Advances [Line Items]
Federal Home Loan Bank Advances, Interest Rate	6.46%		6.46%		6.46%
Federal Home Loan Bank Advances Callable Option [Member]
Advances [Line Items]
Federal Home Loan Bank Advances Par Value	$ 6,415,468		$ 6,415,468		$ 6,096,106
Federal Home Loan Bank Advances Putable Option [Member]
Advances [Line Items]
Federal Home Loan Bank Advances Par Value	4,529,250		4,529,250		4,798,750
Federal Home Loan Bank Advances Receivable [Member]
Advances [Line Items]
Financing Receivable, Accrued Interest, after Allowance for Credit Loss	$ 114,205		$ 114,205		$ 137,161