Fair Values - Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Investment securities:
Equity securities	$ 48	$ 66
Debt securities	1,192	2,120
Derivatives, gross	1,006	80
Total Assets	2,246	2,266
Liabilities
Derivatives, gross	131	977
Total Liabilities	131	977
Fair Value, Inputs, Level 1
Investment securities:
Equity securities	48	66
Debt securities	0	0
Derivatives, gross	0	0
Total Assets	48	66
Liabilities
Derivatives, gross	0	0
Total Liabilities	0	0
Fair Value, Inputs, Level 2
Investment securities:
Equity securities	0	0
Debt securities	1,115	2,046
Derivatives, gross	975	62
Total Assets	2,090	2,108
Liabilities
Derivatives, gross	131	977
Total Liabilities	131	977
Fair Value, Inputs, Level 3
Investment securities:
Equity securities	0	0
Debt securities	77	74
Derivatives, gross	31	18
Total Assets	108	92
Liabilities
Derivatives, gross	0	0
Total Liabilities	$ 0	$ 0