Investments - Scheduled maturities for fixed income securities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Amortized cost, net
Due in one year or less	$ 3,754	$ 2,870
Due after one year through five years	24,766	26,546
Due after five years through ten years	11,461	11,035
Due after ten years	5,161	3,731
Subtotal	45,142	44,182
ABS	978	1,188
Amortized cost, net	46,120	45,370
Fair value
Due in one year or less	3,697	2,836
Due after one year through five years	23,771	25,217
Due after five years through ten years	10,697	9,870
Due after ten years	4,981	3,405
Subtotal	43,146	41,328
ABS	957	1,157
Total	$ 44,103	$ 42,485