Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Premium and service revenues	$ 34,838	$ 33,968	$ 69,790	$ 68,200
Premium tax	2,770	1,968	6,707	4,921
Total external revenues	37,608	35,936	76,497	73,121
Revenues	37,608	35,936	76,497	73,121
Medical costs	29,347	27,312	58,781	55,150
Cost of services	877	2,099	1,747	4,087
Gross margin	4,614	4,557	9,262	8,963
Operating Segments
Segment Reporting Information [Line Items]
Revenues	3,789	5,986	7,656	12,436
Eliminations
Segment Reporting Information [Line Items]
Revenues	(3,789)	(5,986)	(7,656)	(12,436)
Premium
Segment Reporting Information [Line Items]
Premium and service revenues	33,713	31,510	67,538	63,399
Service
Segment Reporting Information [Line Items]
Premium and service revenues	1,125	2,458	2,252	4,801
Premium and service revenues
Segment Reporting Information [Line Items]
Premium and service revenues	34,838	33,968	69,790	68,200
Medicaid
Segment Reporting Information [Line Items]
Revenues	24,665	22,455	50,829	46,529
Medical costs	19,459	18,258	39,469	37,033
Cost of services	2	0	2	0
Gross margin	2,434	2,229	4,651	4,575
Medicaid | Operating Segments
Segment Reporting Information [Line Items]
Premium tax	2,770	1,968	6,707	4,921
Total external revenues	24,665	22,455	50,829	46,529
Revenues	0	0	0	0
Medicaid | Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Medicaid | Premium | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	21,895	20,488	44,122	41,609
Medicaid | Service | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	0	(1)	0	(1)
Medicaid | Premium and service revenues | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	21,895	20,487	44,122	41,608
Medicare
Segment Reporting Information [Line Items]
Revenues	5,665	5,639	11,541	11,396
Medical costs	4,884	4,826	9,892	9,872
Cost of services	0	0	0	0
Gross margin	781	813	1,649	1,524
Medicare | Operating Segments
Segment Reporting Information [Line Items]
Premium tax	0	0	0	0
Total external revenues	5,665	5,639	11,541	11,396
Revenues	0	0	0	0
Medicare | Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Medicare | Premium | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	5,665	5,639	11,541	11,396
Medicare | Service | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	0	0	0	0
Medicare | Premium and service revenues | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	5,665	5,639	11,541	11,396
Commercial
Segment Reporting Information [Line Items]
Revenues	5,734	4,555	10,986	8,687
Medical costs	4,644	3,529	8,649	6,803
Cost of services	0	0	0	0
Gross margin	1,090	1,026	2,337	1,884
Commercial | Operating Segments
Segment Reporting Information [Line Items]
Premium tax	0	0	0	0
Total external revenues	5,734	4,555	10,986	8,687
Revenues	0	0	0	0
Commercial | Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Commercial | Premium
Segment Reporting Information [Line Items]
Premium and service revenues	5,734	4,554	10,986	8,686
Commercial | Service | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	0	1	0	1
Commercial | Premium and service revenues | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	5,734	4,555	10,986	8,687
Other/Eliminations
Segment Reporting Information [Line Items]
Revenues	1,544	3,287	3,141	6,509
Medical costs	360	699	771	1,442
Cost of services	875	2,099	1,745	4,087
Gross margin	309	489	625	980
Other/Eliminations | Operating Segments
Segment Reporting Information [Line Items]
Premium tax	0	0	0	0
Total external revenues	1,544	3,287	3,141	6,509
Revenues	3,789	5,986	7,656	12,436
Other/Eliminations | Eliminations
Segment Reporting Information [Line Items]
Revenues	(3,789)	(5,986)	(7,656)	(12,436)
Other/Eliminations | Premium | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	419	829	889	1,708
Other/Eliminations | Service | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	1,125	2,458	2,252	4,801
Other/Eliminations | Premium and service revenues | Operating Segments
Segment Reporting Information [Line Items]
Premium and service revenues	$ 1,544	$ 3,287	$ 3,141	$ 6,509