SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Premiums	$ 27,951	$ 25,099	$ 84,354	$ 76,144
Services revenue	1,103	1,016	3,265	2,993
Total revenues	29,397	26,423	88,548	79,912
Investment income	343	308	929	775
Benefits	25,120	21,745	75,283	65,612
Operating costs	3,339	3,271	9,529	9,361
Depreciation and amortization	210	201	631	578
Total operating expenses	28,669	25,217	85,443	75,551
Income from operations	728	1,206	3,105	4,361
Interest expense	169	114	496	347
Other expense (income), net	(92)	(6)	26	40
Income (loss) before income taxes and equity in net losses	651	1,098	2,583	3,974
Equity in net losses	(16)	(12)	(57)	(39)
Segment earnings (loss)	635	1,086	2,526	3,935
Net loss (income) attributable to noncontrolling interests	0	2	3	6
Segment earnings (loss) attributable to Humana	635	1,088	2,529	3,941
Products
Segment Reporting Information [Line Items]
Premiums	27,951	25,099	84,354	76,144
Products | Total Medicare
Segment Reporting Information [Line Items]
Premiums	24,490	21,825	74,768	66,064
Products | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	21,856	19,637	66,519	59,195
Products | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	1,913	1,695	5,840	5,192
Products | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	721	493	2,409	1,677
Products | Commercial fully-insured
Segment Reporting Information [Line Items]
Premiums	85	842	493	2,810
Products | Specialty benefits
Segment Reporting Information [Line Items]
Premiums	238	252	717	758
Products | Medicare Supplement
Segment Reporting Information [Line Items]
Premiums	217	185	620	546
Products | State-based contracts and other
Segment Reporting Information [Line Items]
Premiums	2,921	1,995	7,756	5,966
Services
Segment Reporting Information [Line Items]
Services revenue	1,103	1,016	3,265	2,993
Services | Home solutions
Segment Reporting Information [Line Items]
Services revenue	326	342	996	997
Services | Primary care
Segment Reporting Information [Line Items]
Services revenue	319	214	882	605
Services | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue	232	203	672	661
Services | Commercial ASO
Segment Reporting Information [Line Items]
Services revenue	12	55	44	190
Services | Military services and other
Segment Reporting Information [Line Items]
Services revenue	214	202	671	540
Total external revenues
Segment Reporting Information [Line Items]
Total revenues	29,054	26,115	87,619	79,137
Operating segments | Insurance
Segment Reporting Information [Line Items]
Total revenues	28,370	25,511	85,594	77,289
Investment income	192	154	522	385
Benefits	25,319	21,976	75,752	66,096
Operating costs	2,595	2,634	7,354	7,597
Depreciation and amortization	182	179	553	516
Total operating expenses	28,096	24,789	83,659	74,209
Income from operations	274	722	1,935	3,080
Interest expense	0	0	0	0
Other expense (income), net	0	0	0	0
Income (loss) before income taxes and equity in net losses	274	722	1,935	3,080
Equity in net losses	(1)	0	(2)	(2)
Segment earnings (loss)	273	722	1,933	3,078
Net loss (income) attributable to noncontrolling interests	0	3	3	7
Segment earnings (loss) attributable to Humana	273	725	1,936	3,085
Operating segments | Insurance | Products
Segment Reporting Information [Line Items]
Premiums	27,951	25,099	84,354	76,144
Operating segments | Insurance | Products | Total Medicare
Segment Reporting Information [Line Items]
Premiums	24,490	21,825	74,768	66,064
Operating segments | Insurance | Products | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	21,856	19,637	66,519	59,195
Operating segments | Insurance | Products | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	1,913	1,695	5,840	5,192
Operating segments | Insurance | Products | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	721	493	2,409	1,677
Operating segments | Insurance | Products | Commercial fully-insured
Segment Reporting Information [Line Items]
Premiums	85	842	493	2,810
Operating segments | Insurance | Products | Specialty benefits
Segment Reporting Information [Line Items]
Premiums	238	252	717	758
Operating segments | Insurance | Products | Medicare Supplement
Segment Reporting Information [Line Items]
Premiums	217	185	620	546
Operating segments | Insurance | Products | State-based contracts and other
Segment Reporting Information [Line Items]
Premiums	2,921	1,995	7,756	5,966
Operating segments | Insurance | Services
Segment Reporting Information [Line Items]
Services revenue	226	257	715	730
Operating segments | Insurance | Services | Home solutions
Segment Reporting Information [Line Items]
Services revenue	0	0	0	0
Operating segments | Insurance | Services | Primary care
Segment Reporting Information [Line Items]
Services revenue	0	0	0	0
Operating segments | Insurance | Services | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue	0	0	0	0
Operating segments | Insurance | Services | Commercial ASO
Segment Reporting Information [Line Items]
Services revenue	12	55	44	190
Operating segments | Insurance | Services | Military services and other
Segment Reporting Information [Line Items]
Services revenue	214	202	671	540
Operating segments | Insurance | Total external revenues
Segment Reporting Information [Line Items]
Total revenues	28,177	25,356	85,069	76,874
Operating segments | CenterWell
Segment Reporting Information [Line Items]
Total revenues	5,041	4,660	14,806	13,695
Investment income	0	0	0	0
Benefits	0	0	0	0
Operating costs	4,602	4,207	13,638	12,526
Depreciation and amortization	57	53	166	152
Total operating expenses	4,659	4,260	13,804	12,678
Income from operations	382	400	1,002	1,017
Interest expense	2	1	4	2
Other expense (income), net	0	0	0	0
Income (loss) before income taxes and equity in net losses	380	399	998	1,015
Equity in net losses	(15)	(12)	(55)	(37)
Segment earnings (loss)	365	387	943	978
Net loss (income) attributable to noncontrolling interests	0	(1)	0	(1)
Segment earnings (loss) attributable to Humana	365	386	943	977
Operating segments | CenterWell | Products
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Total Medicare
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Commercial fully-insured
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Specialty benefits
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | Medicare Supplement
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Products | State-based contracts and other
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | CenterWell | Services
Segment Reporting Information [Line Items]
Services revenue	877	759	2,550	2,263
Operating segments | CenterWell | Services | Home solutions
Segment Reporting Information [Line Items]
Services revenue	326	342	996	997
Operating segments | CenterWell | Services | Primary care
Segment Reporting Information [Line Items]
Services revenue	319	214	882	605
Operating segments | CenterWell | Services | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue	232	203	672	661
Operating segments | CenterWell | Services | Commercial ASO
Segment Reporting Information [Line Items]
Services revenue	0	0	0	0
Operating segments | CenterWell | Services | Military services and other
Segment Reporting Information [Line Items]
Services revenue	0	0	0	0
Operating segments | CenterWell | Total external revenues
Segment Reporting Information [Line Items]
Total revenues	877	759	2,550	2,263
Eliminations/ Corporate
Segment Reporting Information [Line Items]
Total revenues	(4,014)	(3,748)	(11,852)	(11,072)
Investment income	151	154	407	390
Benefits	(199)	(231)	(469)	(484)
Operating costs	(3,858)	(3,570)	(11,463)	(10,762)
Depreciation and amortization	(29)	(31)	(88)	(90)
Total operating expenses	(4,086)	(3,832)	(12,020)	(11,336)
Income from operations	72	84	168	264
Interest expense	167	113	492	345
Other expense (income), net	(92)	(6)	26	40
Income (loss) before income taxes and equity in net losses	(3)	(23)	(350)	(121)
Equity in net losses	0	0	0	0
Segment earnings (loss)	(3)	(23)	(350)	(121)
Net loss (income) attributable to noncontrolling interests	0	0	0	0
Segment earnings (loss) attributable to Humana	(3)	(23)	(350)	(121)
Eliminations/ Corporate | Insurance
Segment Reporting Information [Line Items]
Total revenues	1	1	3	30
Eliminations/ Corporate | Insurance | Products
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Eliminations/ Corporate | Insurance | Services
Segment Reporting Information [Line Items]
Total revenues	1	1	3	30
Eliminations/ Corporate | CenterWell
Segment Reporting Information [Line Items]
Total revenues	4,164	3,901	12,256	11,432
Eliminations/ Corporate | CenterWell | Products
Segment Reporting Information [Line Items]
Total revenues	2,701	2,594	7,963	7,848
Eliminations/ Corporate | CenterWell | Services
Segment Reporting Information [Line Items]
Total revenues	1,463	1,307	4,293	3,584
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues	(4,165)	(3,902)	(12,259)	(11,462)
Intersegment Eliminations | Products
Segment Reporting Information [Line Items]
Total revenues	(2,701)	(2,594)	(7,963)	(7,848)
Intersegment Eliminations | Services
Segment Reporting Information [Line Items]
Total revenues	$ (1,464)	$ (1,308)	$ (4,296)	$ (3,614)