Health Care Costs Payable - Components of Change in Health Care Costs Payable (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of the period	$ 12,049
Less: Reinsurance recoverables	5
Less: Impact of discount rate on long-duration insurance reserves	(23)
Health care costs payable, beginning of the period, net	12,067
Acquisitions, net	0	$ 1,098
Add: Components of incurred health care costs
Current year	85,541	64,183
Prior years	(845)	(679)
Total incurred health care costs	84,696	63,504
Less: Claims paid
Current year	71,356	52,952
Prior years	10,886	9,207
Total claims paid	82,242	62,159
Health care costs payable, end of the period, net	14,521	12,572
Add: Premium deficiency reserve	670	0
Add: Reinsurance recoverables	65	4
Add: Impact of discount rate on long-duration insurance reserves	(19)	(26)
Health care costs payable, end of the period	15,237	12,550
Health Care Benefits
Less: Claims paid
Benefit costs recorded in other insurance liabilities	70	62
Corporate/ Other
Less: Claims paid
Benefit costs recorded in other insurance liabilities	$ 142	163
Health Insurance Product Line
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of the period		10,142
Less: Reinsurance recoverables		5
Less: Impact of discount rate on long-duration insurance reserves		8
Health care costs payable, beginning of the period, net		$ 10,129