Health Care Costs Payable - Incurred and Paid Health Care Claims Development (Details) - Health Insurance Product Line - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Claims Development [Line Items]
Incurred Health Care Claims, Net of Reinsurance	$ 116,634
Cumulative Paid Health Care Claims, Net of Reinsurance	108,190
All outstanding liabilities for health care costs payable prior to 2020, net of reinsurance	130
Total outstanding liabilities for health care costs payable, net of reinsurance	8,574
2020
Claims Development [Line Items]
Incurred Health Care Claims, Net of Reinsurance	53,804	$ 54,529
Cumulative Paid Health Care Claims, Net of Reinsurance	53,590	$ 47,567
2021
Claims Development [Line Items]
Incurred Health Care Claims, Net of Reinsurance	62,830
Cumulative Paid Health Care Claims, Net of Reinsurance	$ 54,600