Investments - Schedule of Maturities for Fixed Income Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Amortized cost, net
Due in one year or less	$ 3,422	$ 2,870
Due after one year through five years	23,218	26,546
Due after five years through ten years	12,553	11,035
Due after ten years	8,717	3,731
Subtotal	47,910	44,182
ABS	1,739	1,188
Amortized cost, net	49,649	45,370
Fair value
Due in one year or less	3,374	2,836
Due after one year through five years	22,614	25,217
Due after five years through ten years	12,273	9,870
Due after ten years	8,859	3,405
Subtotal	47,120	41,328
ABS	1,745	1,157
Fair value	$ 48,865	$ 42,485