Investments (Trading Major Security Types) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt and Equity Securities, FV-NI [Line Items]
Trading securities (includes $1,390 and $533 pledged as collateral that may by repledged)	$ 6,303	$ 4,720
US Treasury Securities
Debt and Equity Securities, FV-NI [Line Items]
Trading securities (includes $1,390 and $533 pledged as collateral that may by repledged)	6,104	4,508
U.S. Obligations [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities (includes $1,390 and $533 pledged as collateral that may by repledged)	57	59
US Government-sponsored Enterprises Debt Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities (includes $1,390 and $533 pledged as collateral that may by repledged)	48	47
Other [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading securities (includes $1,390 and $533 pledged as collateral that may by repledged)	$ 94	$ 106