Fair Values - Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Investment securities:
Equity securities	$ 41	$ 66
Debt securities	1,169	2,120
Derivative, gross, assets	316	80
Total Assets	1,526	2,266
Liabilities
Derivatives, gross, liabilities	209	977
Total Liabilities	209	977
Level 1
Investment securities:
Equity securities	41	66
Debt securities	0	0
Derivative, gross, assets	0	0
Total Assets	41	66
Liabilities
Derivatives, gross, liabilities	0	0
Total Liabilities	0	0
Level 2
Investment securities:
Equity securities	0	0
Debt securities	1,095	2,046
Derivative, gross, assets	299	62
Total Assets	1,394	2,108
Liabilities
Derivatives, gross, liabilities	209	977
Total Liabilities	209	977
Level 3
Investment securities:
Equity securities	0	0
Debt securities	74	74
Derivative, gross, assets	17	18
Total Assets	91	92
Liabilities
Derivatives, gross, liabilities	0	0
Total Liabilities	$ 0	$ 0