Segment Information (Financial Data By Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Reportable segments operating revenues	$ 37,886	$ 32,098
Operating gain (loss)	2,447	2,161
Commercial & Specialty [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	1,082	1,268
Government Business [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	789	478
IngenioRx Segment [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	398	407
Other [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	178	8
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	(6,045)	(4,908)
Unaffiliated
Segment Reporting Information [Line Items]
Reportable segments operating revenues	37,886	32,098
Unaffiliated | Commercial & Specialty [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	10,269	9,491
Unaffiliated | Government Business [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	23,758	19,283
Unaffiliated | IngenioRx Segment [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	3,301	2,738
Unaffiliated | Other [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	558	586
Affiliated [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	0	0
Affiliated [Member] | Commercial & Specialty [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues		0
Affiliated [Member] | Government Business [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues		0
Affiliated [Member] | IngenioRx Segment [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	3,382	3,124
Affiliated [Member] | Other [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	$ 2,663	$ 1,784