Health Care Costs Payable - Components of Change in Health Care Costs Payable (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of the period	$ 15,064	$ 12,049
Less: Reinsurance recoverables	81	5
Less: Impact of discount rate on long-duration insurance reserves	(1)	(23)
Health care costs payable, beginning of the period, net	14,984	12,067
Add: Components of incurred health care costs
Current year	30,293	28,212
Prior years	(1,651)	(479)
Total incurred health care costs	28,642	27,733
Less: Claims paid
Current year	19,312	16,263
Prior years	9,749	9,150
Total claims paid	29,061	25,413
Health care costs payable, end of the period, net	14,565	14,387
Add: Premium deficiency reserve	431	0
Add: Reinsurance recoverables	114	4
Add: Impact of discount rate on long-duration insurance reserves	2	(23)
Health care costs payable, end of the period	15,112	14,368
Health Care Benefits
Less: Claims paid
Benefit costs recorded in other insurance liabilities	16	23
Corporate/ Other
Less: Claims paid
Benefit costs recorded in other insurance liabilities	$ 46	$ 47