Health Care Costs Payable - Components of Change in Health Care Costs Payable (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of the period	$ 8,808
Less: Claims paid
Health care costs payable, end of the period	10,351
Health Care Benefits
Less: Claims paid
Benefit costs recorded in other insurance liabilities	56	$ 45
Corporate / Other
Less: Claims paid
Benefit costs recorded in other insurance liabilities	274	168
Health Insurance Product Line
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of the period	8,808	7,936
Less: Reinsurance recoverables	8	10
Health care costs payable, beginning of the period, net	8,800	7,926
Add: Components of incurred health care costs
Current year	53,311	48,243
Prior years	(670)	(771)
Total incurred health care costs	52,641	47,472
Less: Claims paid
Current year	43,632	39,887
Prior years	7,468	6,639
Total claims paid	51,100	46,526
Add: Premium deficiency reserve	5	1
Health care costs payable, end of the period, net	10,346	8,873
Add: Reinsurance recoverables	5	4
Health care costs payable, end of the period	10,351	8,877
Premium deficiency reserve	$ 5	$ 1