Investments - Schedule of Maturities for Fixed Income Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Amortized cost, net
Due in one year or less	$ 2,663	$ 3,422
Due after one year through five years	22,966	23,218
Due after five years through ten years	17,073	12,553
Due after ten years	9,572	8,717
Subtotal	52,274	47,910
ABS	1,173	1,739
Amortized cost, net	53,447	49,649
Fair value
Due in one year or less	2,641	3,374
Due after one year through five years	22,968	22,614
Due after five years through ten years	17,351	12,273
Due after ten years	9,817	8,859
Subtotal	52,777	47,120
ABS	1,184	1,745
Fair value	$ 53,961	$ 48,865