Fair Values - Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Investment securities:
Equity securities	$ 46	$ 48
Debt securities	997	1,192
Derivatives, gross	174	1,006
Total Assets	1,216	2,246
Liabilities
Derivatives, gross	1,120	131
Total Liabilities	1,120	131
Fair Value, Inputs, Level 1
Investment securities:
Equity securities	46	48
Debt securities	0	0
Derivatives, gross	0	0
Total Assets	46	48
Liabilities
Derivatives, gross	0	0
Total Liabilities	0	0
Fair Value, Inputs, Level 2
Investment securities:
Equity securities	0	0
Debt securities	916	1,115
Derivatives, gross	164	975
Total Assets	1,080	2,090
Liabilities
Derivatives, gross	1,120	131
Total Liabilities	1,120	131
Fair Value, Inputs, Level 3
Investment securities:
Equity securities	0	0
Debt securities	81	77
Derivatives, gross	10	31
Total Assets	91	108
Liabilities
Derivatives, gross	0	0
Total Liabilities	$ 0	$ 0