Health Care Costs Payable - Components of Change in Health Care Costs Payable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of period	$ 12,049
Less: Reinsurance recoverables	5
Less: Impact of discount rate on long-duration insurance reserves	(23)
Health care costs payable, beginning of period, net	12,067
Acquisition, net	0	$ 1,098
Add: Components of incurred health care costs
Current year	115,774	86,639
Prior years	(947)	(685)
Total incurred health care costs	114,827	85,954
Less: Claims paid
Current year	101,583	75,529
Prior years	10,327	9,585
Total claims paid	111,910	85,114
Health care costs payable, end of period, net	14,984	12,067
Add: Reinsurance recoverables	81	5
Add: Impact of discount rate on long-duration insurance reserves	(1)	(23)
Health care costs payable, end of period	15,064	12,049
Health Care Benefits
Less: Claims paid
Health care costs recorded in other insurance liabilities	107	83	$ 79
Corporate/ Other
Less: Claims paid
Health care costs recorded in other insurance liabilities	187	210	249
Health Insurance Product Line
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of period		10,142	8,678
Less: Reinsurance recoverables		5	8
Less: Impact of discount rate on long-duration insurance reserves		8	0
Health care costs payable, beginning of period, net		$ 10,129	8,670
Acquisition, net			0
Add: Components of incurred health care costs
Current year			71,399
Prior years			(654)
Total incurred health care costs			70,745
Less: Claims paid
Current year			61,640
Prior years			7,646
Total claims paid			69,286
Health care costs payable, end of period, net			10,129
Add: Reinsurance recoverables	$ 81		5
Add: Impact of discount rate on long-duration insurance reserves			8
Health care costs payable, end of period			$ 10,142