Health Care Costs Payable - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Liability for Claims and Claims Adjustment Expense [Line Items]
Decrease in prior years' healthcare costs payable	$ 685
Health Care Benefits
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for IBNR plus expected development on reported claims	$ 8,700