Medical Claims Payable (Reconciliation of Net Incurred Medical Claims to Benefit Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Net Incurred Medical Claims to Benefit Expense [Line Items]
Net incurred medical claims	$ 112,545	$ 98,737	$ 84,457
Quality improvement and other claims expense	3,942	3,908	3,588
Benefit expense	116,487	102,645	88,045
Commercial and Specialty Business Segment [Member]
Reconciliation of Net Incurred Medical Claims to Benefit Expense [Line Items]
Net incurred medical claims	29,913	27,667	24,519
Government Business Segment [Member]
Reconciliation of Net Incurred Medical Claims to Benefit Expense [Line Items]
Net incurred medical claims	81,165	69,448	58,650
Other Segment [Member]
Reconciliation of Net Incurred Medical Claims to Benefit Expense [Line Items]
Net incurred medical claims	$ 1,467	$ 1,622	$ 1,288