Segment Reporting - Reconciliation of Financial Measures of Segments to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenues from external customers	$ 87,983	$ 84,944
Net investment income (loss)	454	334
Total revenues	88,437	85,278
Adjusted operating income (loss)	2,957	4,370
Operating Segments | Health Care Benefits
Segment Reporting Information [Line Items]
Revenues from external customers	31,865	25,692
Net investment income (loss)	353	164
Total revenues	32,236	25,877
Adjusted operating income (loss)	732	1,824
Operating Segments | Health Services
Segment Reporting Information [Line Items]
Revenues from external customers	36,466	40,811
Net investment income (loss)	0	0
Total revenues	40,285	44,591
Adjusted operating income (loss)	1,363	1,680
Co-payments	3,400	4,100
Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Revenues from external customers	19,638	18,426
Net investment income (loss)	0	(3)
Total revenues	28,725	27,922
Adjusted operating income (loss)	1,177	1,134
Corporate/ Other | Corporate/ Other
Segment Reporting Information [Line Items]
Revenues from external customers	14	15
Net investment income (loss)	101	173
Total revenues	115	188
Adjusted operating income (loss)	(315)	(268)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(12,924)	(13,300)
Net investment income (loss)	0	0
Total revenues	(12,924)	(13,300)
Adjusted operating income (loss)	0	0
Intersegment Eliminations | Health Care Benefits
Segment Reporting Information [Line Items]
Intersegment revenues	18	21
Intersegment Eliminations | Health Services
Segment Reporting Information [Line Items]
Intersegment revenues	3,819	3,780
Intersegment Eliminations | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Intersegment revenues	$ 9,087	$ 9,499