Investments - Total Investment Schedule (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Total Investments [Line Items]
Current	$ 2,805	$ 3,259
Long-term	28,939	23,019
Total	31,744	26,278
Debt securities available for sale
Total Investments [Line Items]
Current	2,633	3,131
Long-term	23,857	18,582
Total	26,490	21,713
Mortgage loans
Total Investments [Line Items]
Current	172	128
Long-term	1,315	1,183
Total	1,487	1,311
Other investments
Total Investments [Line Items]
Current	0	0
Long-term	3,767	3,254
Total	$ 3,767	$ 3,254