Fair Values - Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Investment securities:
Equity securities	$ 45	$ 48
Debt securities	1,213	1,192
Derivative, gross, assets	141	1,006
Total Assets	1,399	2,246
Liabilities
Derivatives, gross, liabilities	1,206	131
Total Liabilities	1,206	131
Level 1
Investment securities:
Equity securities	45	48
Debt securities	0	0
Derivative, gross, assets	0	0
Total Assets	45	48
Liabilities
Derivatives, gross, liabilities	0	0
Total Liabilities	0	0
Level 2
Investment securities:
Equity securities	0	0
Debt securities	1,132	1,115
Derivative, gross, assets	134	975
Total Assets	1,266	2,090
Liabilities
Derivatives, gross, liabilities	1,206	131
Total Liabilities	1,206	131
Level 3
Investment securities:
Equity securities	0	0
Debt securities	81	77
Derivative, gross, assets	7	31
Total Assets	88	108
Liabilities
Derivatives, gross, liabilities	0	0
Total Liabilities	$ 0	$ 0