Health Care Costs Payable - Components of Change in Health Care Costs Payable (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Health care costs payable, beginning of the period, net	$ 8,808
Less: Claims paid
Health care costs payable, end of the period, net	10,400
Health Care Benefits
Less: Claims paid
Benefit costs recorded in other insurance liabilities	37	$ 27
Corporate / Other
Less: Claims paid
Benefit costs recorded in other insurance liabilities	221	99
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	35,960	32,183
Prior years	(666)	(709)
Total incurred health care costs	35,294	31,474
Less: Claims paid
Current year	26,971	24,600
Prior years	6,732	6,409
Total claims paid	33,703	31,009
Add: Premium deficiency reserve	5	5
Health care costs payable, end of the period, net	10,396	8,396
Add: Reinsurance recoverables	4	18
Health care costs payable, end of the period	10,400	8,414
Premium deficiency reserve	$ 5	$ 5