SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Premiums	$ 101,272	$ 87,712	$ 79,822
Services revenue	4,033	4,776	3,055
Total revenues	106,374	92,870	83,064
Investment income	1,069	382	187
Benefits	88,394	75,690	69,199
Operating costs	13,188	12,671	10,121
Depreciation and amortization	779	709	596
Total operating expenses	102,361	89,070	79,916
Income (loss) from operations	4,013	3,800	3,148
Gain on sale of Gentiva Hospice	0	(237)	0
Interest expense	493	401	326
Other expense, net	137	68	(532)
Income (loss) before income taxes and equity in net earnings (losses)	3,383	3,568	3,354
Equity in net losses	(63)	(4)	65
Segment earnings (loss)	3,320	3,564	3,419
Net loss (income) attributable to noncontrolling interests	(5)	(4)	1
Segment earnings (loss) attributable to Humana	3,325	3,568	3,418
Products
Segment Reporting Information [Line Items]
Premiums	101,272	87,712	79,822
Services
Segment Reporting Information [Line Items]
Services revenue	4,033	4,776	3,055
External Revenues
Segment Reporting Information [Line Items]
Total revenues	105,305	92,488	82,877
Total Medicare | Products
Segment Reporting Information [Line Items]
Premiums	87,895	75,157	67,980
Individual Medicare Advantage | Products
Segment Reporting Information [Line Items]
Premiums	78,837	65,591	58,654
Group Medicare Advantage | Products
Segment Reporting Information [Line Items]
Premiums	6,869	7,297	6,955
Medicare stand-alone PDP | Products
Segment Reporting Information [Line Items]
Premiums	2,189	2,269	2,371
Commercial fully-insured | Products
Segment Reporting Information [Line Items]
Premiums	3,527	4,389	4,950
Specialty benefits | Products
Segment Reporting Information [Line Items]
Premiums	1,007	1,047	1,052
Medicare Supplement | Products
Segment Reporting Information [Line Items]
Premiums	735	743	731
State-based contracts and other | Products
Segment Reporting Information [Line Items]
Premiums	8,108	6,376	5,109
Home solutions | Services
Segment Reporting Information [Line Items]
Services revenue	1,342	2,333	1,166
Primary care | Services
Segment Reporting Information [Line Items]
Services revenue	842	568	413
Commercial ASO | Services
Segment Reporting Information [Line Items]
Services revenue	237	300	306
Military services and other | Services
Segment Reporting Information [Line Items]
Services revenue	763	550	547
Pharmacy solutions | Services
Segment Reporting Information [Line Items]
Services revenue	849	1,025	623
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Total revenues	102,854	88,841	80,930
Investment income	551	223	214
Benefits	89,100	75,934	69,639
Operating costs	10,408	9,251	8,340
Depreciation and amortization	692	634	539
Total operating expenses	100,200	85,819	78,518
Income (loss) from operations	2,654	3,022	2,412
Gain on sale of Gentiva Hospice		0
Interest expense	0	0	0
Other expense, net	0	0	0
Income (loss) before income taxes and equity in net earnings (losses)	2,654	3,022	2,412
Equity in net losses	(6)	18	0
Segment earnings (loss)	2,648	3,040	2,412
Net loss (income) attributable to noncontrolling interests	(6)	(5)	0
Segment earnings (loss) attributable to Humana	2,654	3,045	2,412
Operating Segments | Insurance | Products
Segment Reporting Information [Line Items]
Premiums	101,272	87,712	79,822
Operating Segments | Insurance | Services
Segment Reporting Information [Line Items]
Services revenue	1,000	850	853
Operating Segments | Insurance | External Revenues
Segment Reporting Information [Line Items]
Total revenues	102,272	88,562	80,675
Operating Segments | Insurance | Total Medicare | Products
Segment Reporting Information [Line Items]
Premiums	87,895	75,157	67,980
Operating Segments | Insurance | Individual Medicare Advantage | Products
Segment Reporting Information [Line Items]
Premiums	78,837	65,591	58,654
Operating Segments | Insurance | Group Medicare Advantage | Products
Segment Reporting Information [Line Items]
Premiums	6,869	7,297	6,955
Operating Segments | Insurance | Medicare stand-alone PDP | Products
Segment Reporting Information [Line Items]
Premiums	2,189	2,269	2,371
Operating Segments | Insurance | Commercial fully-insured | Products
Segment Reporting Information [Line Items]
Premiums	3,527	4,389	4,950
Operating Segments | Insurance | Specialty benefits | Products
Segment Reporting Information [Line Items]
Premiums	1,007	1,047	1,052
Operating Segments | Insurance | Medicare Supplement | Products
Segment Reporting Information [Line Items]
Premiums	735	743	731
Operating Segments | Insurance | State-based contracts and other | Products
Segment Reporting Information [Line Items]
Premiums	8,108	6,376	5,109
Operating Segments | Insurance | Home solutions | Services
Segment Reporting Information [Line Items]
Services revenue	0	0	0
Operating Segments | Insurance | Primary care | Services
Segment Reporting Information [Line Items]
Services revenue	0	0	0
Operating Segments | Insurance | Commercial ASO | Services
Segment Reporting Information [Line Items]
Services revenue	237	300	306
Operating Segments | Insurance | Military services and other | Services
Segment Reporting Information [Line Items]
Services revenue	763	550	547
Operating Segments | Insurance | Pharmacy solutions | Services
Segment Reporting Information [Line Items]
Services revenue	0	0	0
Operating Segments | CenterWell
Segment Reporting Information [Line Items]
Total revenues	18,405	17,307	14,058
Investment income	0	8	4
Benefits	0	0	0
Operating costs	16,791	15,835	12,968
Depreciation and amortization	210	181	152
Total operating expenses	17,001	16,016	13,120
Income (loss) from operations	1,404	1,291	938
Gain on sale of Gentiva Hospice		(237)
Interest expense	3	0	0
Other expense, net	0	0	0
Income (loss) before income taxes and equity in net earnings (losses)	1,401	1,528	938
Equity in net losses	(57)	(22)	65
Segment earnings (loss)	1,344	1,506	1,003
Net loss (income) attributable to noncontrolling interests	1	1	1
Segment earnings (loss) attributable to Humana	1,343	1,505	1,002
Operating Segments | CenterWell | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Services
Segment Reporting Information [Line Items]
Services revenue	3,033	3,926	2,202
Operating Segments | CenterWell | External Revenues
Segment Reporting Information [Line Items]
Total revenues	3,033	3,926	2,202
Operating Segments | CenterWell | Total Medicare | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Individual Medicare Advantage | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Group Medicare Advantage | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Medicare stand-alone PDP | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Commercial fully-insured | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Specialty benefits | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Medicare Supplement | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | State-based contracts and other | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0
Operating Segments | CenterWell | Home solutions | Services
Segment Reporting Information [Line Items]
Services revenue	1,342	2,333	1,166
Operating Segments | CenterWell | Primary care | Services
Segment Reporting Information [Line Items]
Services revenue	842	568	413
Operating Segments | CenterWell | Commercial ASO | Services
Segment Reporting Information [Line Items]
Services revenue	0	0	0
Operating Segments | CenterWell | Military services and other | Services
Segment Reporting Information [Line Items]
Services revenue	0	0	0
Operating Segments | CenterWell | Pharmacy solutions | Services
Segment Reporting Information [Line Items]
Services revenue	849	1,025	623
Eliminations/ Corporate
Segment Reporting Information [Line Items]
Total revenues	(14,885)	(13,278)	(11,924)
Investment income	518	151	(31)
Benefits	(706)	(244)	(440)
Operating costs	(14,011)	(12,415)	(11,187)
Depreciation and amortization	(123)	(106)	(95)
Total operating expenses	(14,840)	(12,765)	(11,722)
Income (loss) from operations	(45)	(513)	(202)
Gain on sale of Gentiva Hospice		0
Interest expense	490	401	326
Other expense, net	137	68	(532)
Income (loss) before income taxes and equity in net earnings (losses)	(672)	(982)	4
Equity in net losses	0	0	0
Segment earnings (loss)	(672)	(982)	4
Net loss (income) attributable to noncontrolling interests	0	0	0
Segment earnings (loss) attributable to Humana	(672)	(982)	4
Eliminations/ Corporate | Insurance
Segment Reporting Information [Line Items]
Total revenues	31	56	41
Eliminations/ Corporate | Insurance | Products
Segment Reporting Information [Line Items]
Total revenues	0	0	0
Eliminations/ Corporate | Insurance | Services
Segment Reporting Information [Line Items]
Total revenues	31	56	41
Eliminations/ Corporate | CenterWell
Segment Reporting Information [Line Items]
Total revenues	15,372	13,373	11,852
Eliminations/ Corporate | CenterWell | Products
Segment Reporting Information [Line Items]
Total revenues	10,451	9,841	9,024
Eliminations/ Corporate | CenterWell | Services
Segment Reporting Information [Line Items]
Total revenues	4,921	3,532	2,828
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues	(15,403)	(13,429)	(11,893)
Intersegment Eliminations | Products
Segment Reporting Information [Line Items]
Total revenues	(10,451)	(9,841)	(9,024)
Intersegment Eliminations | Services
Segment Reporting Information [Line Items]
Total revenues	$ (4,952)	$ (3,588)	$ (2,869)