Fair Values - Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Investment securities:
Equity securities	$ 43	$ 46
Debt securities	5,074
Derivative, gross, assets	564	174
Liabilities
Derivatives, gross, liabilities	149	1,120
Fair Value, Recurring
Investment securities:
Equity securities	43	46
Debt securities	5,074	997
Derivative, gross, assets	564	174
Total Assets	5,681	1,216
Liabilities
Derivatives, gross, liabilities	149	1,120
Total Liabilities	149	1,120
Level 1 | Fair Value, Recurring
Investment securities:
Equity securities	43	46
Debt securities	0	0
Derivative, gross, assets	0	0
Total Assets	43	46
Liabilities
Derivatives, gross, liabilities	0	0
Total Liabilities	0	0
Level 2 | Fair Value, Recurring
Investment securities:
Equity securities	0	0
Debt securities	4,994	916
Derivative, gross, assets	564	164
Total Assets	5,558	1,080
Liabilities
Derivatives, gross, liabilities	149	1,120
Total Liabilities	149	1,120
Level 3 | Fair Value, Recurring
Investment securities:
Equity securities	0	0
Debt securities	80	81
Derivative, gross, assets	0	10
Total Assets	80	91
Liabilities
Derivatives, gross, liabilities	0	0
Total Liabilities	$ 0	$ 0