Investments - Total Investment Schedule (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Total Investments [Line Items]
Current	$ 2,578	$ 2,407
Long-term	28,906	28,934
Total	31,484	31,341
Debt securities available for sale
Total Investments [Line Items]
Current	2,426	2,256
Long-term	23,618	23,777
Total	26,044	26,033
Mortgage loans
Total Investments [Line Items]
Current	152	151
Long-term	1,346	1,354
Total	1,498	1,505
Other investments
Total Investments [Line Items]
Current	0	0
Long-term	3,942	3,803
Total	$ 3,942	$ 3,803