Segment Reporting - Reconciliation of Financial Measures of Segments to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Revenues from external customers	$ 84,944	$ 76,658
Net investment income (loss)	334	168
Total revenues	85,278	76,826
Adjusted operating income (loss)	4,370	4,607
Operating Segments | Health Care Benefits
Segment Reporting Information [Line Items]
Revenues from external customers	25,692	22,985
Net investment income (loss)	164	89
Total revenues	25,877	23,094
Adjusted operating income (loss)	1,824	1,861
Operating Segments | Health Services
Segment Reporting Information [Line Items]
Revenues from external customers	40,811	36,311
Net investment income (loss)	0	0
Total revenues	44,591	39,615
Adjusted operating income (loss)	1,680	1,471
Copayments	4,100	3,800
Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Revenues from external customers	18,426	17,331
Net investment income (loss)	(3)	(16)
Total revenues	27,922	25,898
Adjusted operating income (loss)	1,134	1,573
Corporate/ Other
Segment Reporting Information [Line Items]
Revenues from external customers	15	31
Net investment income (loss)	173	95
Total revenues	188	126
Adjusted operating income (loss)	(268)	(298)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(13,300)	(11,907)
Net investment income (loss)	0	0
Total revenues	(13,300)	(11,907)
Adjusted operating income (loss)	0	0
Intersegment Eliminations | Health Care Benefits
Segment Reporting Information [Line Items]
Intersegment revenues	21	20
Intersegment Eliminations | Health Services
Segment Reporting Information [Line Items]
Intersegment revenues	3,780	3,304
Intersegment Eliminations | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Intersegment revenues	$ 9,499	$ 8,583