Health Care Costs Payable - Incurred and Paid Health Care Claims Development (Details) - Health Insurance Product Line - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Claims Development [Line Items]
Incurred Health Care Claims, Net of Reinsurance	$ 150,902
Cumulative Paid Health Care Claims, Net of Reinsurance	140,538
All outstanding liabilities for health care costs payable prior to 2022, net of reinsurance	171
Total outstanding liabilities for health care costs payable, net of reinsurance	10,535
2022
Claims Development [Line Items]
Incurred Health Care Claims, Net of Reinsurance	68,540	$ 69,185
Cumulative Paid Health Care Claims, Net of Reinsurance	68,363	$ 59,570
2023
Claims Development [Line Items]
Incurred Health Care Claims, Net of Reinsurance	82,362
Cumulative Paid Health Care Claims, Net of Reinsurance	$ 72,175