SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Premiums	$ 22,266	$ 19,978	$ 44,969	$ 40,102
Services revenue:	1,349	491	2,613	957
Total external revenues	23,615	20,469	47,582	41,059
Total intersegment revenues	0	0	0	0
Investment income	47	176	50	254
Total revenues	23,662	20,645	47,632	41,313
Benefits	19,099	17,149	38,724	34,445
Operating costs	3,173	2,116	6,059	4,123
Depreciation and amortization	175	144	345	286
Total operating expenses	22,447	19,409	45,128	38,854
Income (loss) from operations	1,215	1,236	2,504	2,459
Interest expense	101	79	191	147
Other (income) expense, net	(8)	419	(29)	534
Income (loss) before income taxes and equity in net earnings	1,122	738	2,342	1,778
Equity in net earnings (losses)	2	33	(2)	54
Segment earnings (loss)	1,124	771	2,340	1,832
Less: noncontrolling interests	(1)		(1)
Segment earnings (loss) attributable to Humana	1,123		2,339
Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	16,692	14,585	33,744	29,400
Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	1,857	1,775	3,732	3,530
Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	606	662	1,245	1,326
Total Medicare
Segment Reporting Information [Line Items]
Premiums	19,155	17,022	38,721	34,256
Fully-insured
Segment Reporting Information [Line Items]
Premiums	1,128	1,260	2,282	2,537
Specialty
Segment Reporting Information [Line Items]
Premiums	427	432	856	866
Medicaid and other
Segment Reporting Information [Line Items]
Premiums	1,556	1,264	3,110	2,443
Home solutions
Segment Reporting Information [Line Items]
Services revenue:	752	25	1,478	49
Provider services
Segment Reporting Information [Line Items]
Services revenue:	137	97	250	188
ASO and other
Segment Reporting Information [Line Items]
Services revenue:	204	206	405	401
Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue:	256	163	480	319
Services
Segment Reporting Information [Line Items]
Total intersegment revenues	0	0	0	0
Products
Segment Reporting Information [Line Items]
Total intersegment revenues	0	0	0	0
Operating segments | Retail
Segment Reporting Information [Line Items]
Premiums	20,896	18,468	42,198	37,059
Services revenue:	8	12	14	17
Total external revenues	20,904	18,480	42,212	37,076
Total intersegment revenues	0	0	0	0
Investment income	42	65	85	117
Total revenues	20,946	18,545	42,297	37,193
Benefits	18,182	16,068	36,932	32,367
Operating costs	1,712	1,533	3,406	2,984
Depreciation and amortization	131	108	254	212
Total operating expenses	20,025	17,709	40,592	35,563
Income (loss) from operations	921	836	1,705	1,630
Interest expense	0	0	0	0
Other (income) expense, net	0	0	0	0
Income (loss) before income taxes and equity in net earnings	921	836	1,705	1,630
Equity in net earnings (losses)	8	0	8	0
Segment earnings (loss)	929	836	1,713	1,630
Less: noncontrolling interests	0		0
Segment earnings (loss) attributable to Humana	929		1,713
Operating segments | Retail | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	16,692	14,585	33,744	29,400
Operating segments | Retail | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	1,857	1,775	3,732	3,530
Operating segments | Retail | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	606	662	1,245	1,326
Operating segments | Retail | Total Medicare
Segment Reporting Information [Line Items]
Premiums	19,155	17,022	38,721	34,256
Operating segments | Retail | Fully-insured
Segment Reporting Information [Line Items]
Premiums	185	182	367	360
Operating segments | Retail | Specialty
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Retail | Medicaid and other
Segment Reporting Information [Line Items]
Premiums	1,556	1,264	3,110	2,443
Operating segments | Retail | Home solutions
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Retail | Provider services
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Retail | ASO and other
Segment Reporting Information [Line Items]
Services revenue:	8	12	14	17
Operating segments | Retail | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Retail | Services
Segment Reporting Information [Line Items]
Total intersegment revenues	0	0	0	0
Operating segments | Retail | Products
Segment Reporting Information [Line Items]
Total intersegment revenues	0	0	0	0
Operating segments | Group and Specialty
Segment Reporting Information [Line Items]
Premiums	1,370	1,510	2,771	3,043
Services revenue:	196	194	391	384
Total external revenues	1,566	1,704	3,162	3,427
Total intersegment revenues	14	10	28	20
Investment income	4	4	7	8
Total revenues	1,584	1,718	3,197	3,455
Benefits	1,045	1,247	2,091	2,392
Operating costs	415	409	828	806
Depreciation and amortization	23	22	45	43
Total operating expenses	1,483	1,678	2,964	3,241
Income (loss) from operations	101	40	233	214
Interest expense	0	0	0	0
Other (income) expense, net	0	0	0	0
Income (loss) before income taxes and equity in net earnings	101	40	233	214
Equity in net earnings (losses)	0	0	0	0
Segment earnings (loss)	101	40	233	214
Less: noncontrolling interests	0		0
Segment earnings (loss) attributable to Humana	101		233
Operating segments | Group and Specialty | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Group and Specialty | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Group and Specialty | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Group and Specialty | Total Medicare
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Group and Specialty | Fully-insured
Segment Reporting Information [Line Items]
Premiums	943	1,078	1,915	2,177
Operating segments | Group and Specialty | Specialty
Segment Reporting Information [Line Items]
Premiums	427	432	856	866
Operating segments | Group and Specialty | Medicaid and other
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Group and Specialty | Home solutions
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Group and Specialty | Provider services
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Group and Specialty | ASO and other
Segment Reporting Information [Line Items]
Services revenue:	196	194	391	384
Operating segments | Group and Specialty | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Group and Specialty | Services
Segment Reporting Information [Line Items]
Total intersegment revenues	14	10	28	20
Operating segments | Group and Specialty | Products
Segment Reporting Information [Line Items]
Total intersegment revenues	0	0	0	0
Operating segments | Healthcare Services
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Services revenue:	1,145	285	2,208	556
Total external revenues	1,145	285	2,208	556
Total intersegment revenues	7,816	7,238	15,439	14,164
Investment income	1	1	3	2
Total revenues	8,962	7,524	17,650	14,722
Benefits	0	0	0	0
Operating costs	8,469	7,205	16,654	14,115
Depreciation and amortization	50	41	103	81
Total operating expenses	8,519	7,246	16,757	14,196
Income (loss) from operations	443	278	893	526
Interest expense	0	0	0	0
Other (income) expense, net	0	0	0	0
Income (loss) before income taxes and equity in net earnings	443	278	893	526
Equity in net earnings (losses)	(6)	33	(10)	54
Segment earnings (loss)	437	311	883	580
Less: noncontrolling interests	(1)		(1)
Segment earnings (loss) attributable to Humana	436		882
Operating segments | Healthcare Services | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Total Medicare
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Fully-insured
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Specialty
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Medicaid and other
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Operating segments | Healthcare Services | Home solutions
Segment Reporting Information [Line Items]
Services revenue:	752	25	1,478	49
Operating segments | Healthcare Services | Provider services
Segment Reporting Information [Line Items]
Services revenue:	137	97	250	188
Operating segments | Healthcare Services | ASO and other
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Operating segments | Healthcare Services | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue:	256	163	480	319
Operating segments | Healthcare Services | Services
Segment Reporting Information [Line Items]
Total intersegment revenues	5,327	4,977	10,504	9,751
Operating segments | Healthcare Services | Products
Segment Reporting Information [Line Items]
Total intersegment revenues	2,489	2,261	4,935	4,413
Eliminations/ Corporate
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Services revenue:	0	0	0	0
Total external revenues	0	0	0	0
Total intersegment revenues	(7,830)	(7,248)	(15,467)	(14,184)
Investment income	0	106	(45)	127
Total revenues	(7,830)	(7,142)	(15,512)	(14,057)
Benefits	(128)	(166)	(299)	(314)
Operating costs	(7,423)	(7,031)	(14,829)	(13,782)
Depreciation and amortization	(29)	(27)	(57)	(50)
Total operating expenses	(7,580)	(7,224)	(15,185)	(14,146)
Income (loss) from operations	(250)	82	(327)	89
Interest expense	101	79	191	147
Other (income) expense, net	(8)	419	(29)	534
Income (loss) before income taxes and equity in net earnings	(343)	(416)	(489)	(592)
Equity in net earnings (losses)	0	0	0	0
Segment earnings (loss)	(343)	(416)	(489)	(592)
Less: noncontrolling interests	0		0
Segment earnings (loss) attributable to Humana	(343)		(489)
Eliminations/ Corporate | Individual Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Group Medicare Advantage
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Medicare stand-alone PDP
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Total Medicare
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Fully-insured
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Specialty
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Medicaid and other
Segment Reporting Information [Line Items]
Premiums	0	0	0	0
Eliminations/ Corporate | Home solutions
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Eliminations/ Corporate | Provider services
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Eliminations/ Corporate | ASO and other
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Eliminations/ Corporate | Pharmacy solutions
Segment Reporting Information [Line Items]
Services revenue:	0	0	0	0
Eliminations/ Corporate | Services
Segment Reporting Information [Line Items]
Total intersegment revenues	(5,341)	(4,987)	(10,532)	(9,771)
Eliminations/ Corporate | Products
Segment Reporting Information [Line Items]
Total intersegment revenues	$ (2,489)	$ (2,261)	$ (4,935)	$ (4,413)