Investments - Schedule of Maturities for Fixed Income Securities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Amortized cost, net
Due in one year or less	$ 1,544	$ 3,422
Due after one year through five years	22,889	23,218
Due after five years through ten years	17,431	12,553
Due after ten years	10,526	8,717
Subtotal	52,390	47,910
ABS	1,226	1,739
Amortized cost, net	53,616	49,649
Fair value
Due in one year or less	1,531	3,374
Due after one year through five years	22,595	22,614
Due after five years through ten years	17,130	12,273
Due after ten years	10,250	8,859
Subtotal	51,506	47,120
ABS	1,241	1,745
Fair value	$ 52,747	$ 48,865