Segment Reporting - Reconciliation of Financial Measures of Segments to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Revenues from external customers	$ 94,068	$ 87,983
Net investment income	520	454
Total revenues	94,588	88,437
Less: Net realized capital gains (losses)	(21)	(18)
Cost of products sold	51,057	48,073
Health care costs	29,135	27,803
Reconciliation of principal measure of segment performance to consolidated operating income:
Amortization of intangible assets	499	508
Net realized capital losses	21	18
Acquisition-related transaction and integration costs	45	60
Loss on Accountable Care assets	247
Office real estate optimization charges	6
Litigation charge	387	100
Operating income	3,374	2,271
Interest expense	785	716
Other income	(28)	(25)
Income before income tax provision	2,617	1,580
Depreciation and amortization	1,154	1,138
Health Care Benefits
Segment Reporting Information [Line Items]
Revenues from external customers	34,405	31,865
Net investment income	387	353
Reconciliation of principal measure of segment performance to consolidated operating income:
Depreciation and amortization	405	392
Health Services
Segment Reporting Information [Line Items]
Revenues from external customers	38,096	36,466
Net investment income	14	0
Reconciliation of principal measure of segment performance to consolidated operating income:
Loss on Accountable Care assets	247
Depreciation and amortization	261	261
Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Revenues from external customers	21,553	19,638
Net investment income	0	0
Reconciliation of principal measure of segment performance to consolidated operating income:
Depreciation and amortization	384	388
Corporate/ Other
Segment Reporting Information [Line Items]
Revenues from external customers	14	14
Net investment income	119	101
Reconciliation of principal measure of segment performance to consolidated operating income:
Depreciation and amortization	104	97
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net investment income	0	0
Total revenues	(15,729)	(12,924)
Intersegment Eliminations | Health Care Benefits
Segment Reporting Information [Line Items]
Total revenues	(18)	(18)
Intersegment Eliminations | Health Services
Segment Reporting Information [Line Items]
Total revenues	(5,352)	(3,819)
Intersegment Eliminations | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Total revenues	(10,359)	(9,087)
Operating Segments and Corporate/ Other
Segment Reporting Information [Line Items]
Total revenues	110,317	101,361
Adjusted operating income (loss)	4,579	2,957
Operating Segments | Health Care Benefits
Segment Reporting Information [Line Items]
Net investment income	387	353
Total revenues	34,810	32,236
Less: Net realized capital gains (losses)	(21)	(10)
Cost of products sold	0	0
Health care costs	28,637	27,458
Other segment items	4,201	4,056
Adjusted operating income (loss)	1,993	732
Reconciliation of principal measure of segment performance to consolidated operating income:
Net realized capital losses	21	10
Operating Segments | Health Services
Segment Reporting Information [Line Items]
Net investment income	14	0
Total revenues	43,462	40,285
Less: Net realized capital gains (losses)	15	0
Cost of products sold	40,115	37,532
Health care costs	1,047	701
Other segment items	682	689
Adjusted operating income (loss)	1,603	1,363
Reconciliation of principal measure of segment performance to consolidated operating income:
Net realized capital losses	(15)	0
Co-payments	3,700	3,400
Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Net investment income	0	0
Total revenues	31,912	28,725
Less: Net realized capital gains (losses)	0	0
Cost of products sold	25,804	22,760
Health care costs	0	0
Other segment items	4,795	4,788
Adjusted operating income (loss)	1,313	1,177
Reconciliation of principal measure of segment performance to consolidated operating income:
Net realized capital losses	0	0
Corporate/ Other | Corporate/ Other
Segment Reporting Information [Line Items]
Net investment income	119	101
Total revenues	133	115
Less: Net realized capital gains (losses)	(15)	(8)
Cost of products sold	0	0
Health care costs	46	47
Other segment items	432	391
Adjusted operating income (loss)	(330)	(315)
Reconciliation of principal measure of segment performance to consolidated operating income:
Net realized capital losses	$ 15	$ 8