Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=hum_InterestRateSwapMaturing2033Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=hum_InterestRateSwapMaturing2053Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=hum_InterestRateSwapMaturing2049Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=hum_InterestRateSwapMaturing2034Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=hum_InterestRateSwapMaturing2054Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=hum_A5875PercentSeniorNotesDueMarch2033Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=hum_A550PercentSeniorNotesDueMarch2053Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=hum_A395PercentSeniorNotesDueAugust2049Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=hum_A5.950PercentSeniorNotesDueMarch2034Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=hum_A5.750PercentSeniorNotesDueApril2054Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

FAIR VALUE - Fair Value of Swap Agreements (Details) - USD ($)	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Interest Rate Swap Maturing 2033 \| Securities lending invested collateral
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, notional amount	$ 650,000,000		$ 650,000,000
Interest Rate Swap Maturing 2053 \| Securities lending invested collateral
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, notional amount	700,000,000		300,000,000
Interest Rate Swap Maturing 2049 \| Securities lending invested collateral
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, notional amount	450,000,000		450,000,000
Interest Rate Swap Maturing 2034 \| Securities lending invested collateral
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, notional amount	800,000,000		400,000,000
Interest Rate Swap Maturing 2054 \| Securities lending invested collateral
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, notional amount	400,000,000		$ 0
$750 million, 5.875% due March 1, 2033 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal	$ 750,000,000
Stated interest rate (percent)	5.875%
$750 million, 5.500% due March 15, 2053 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal	$ 750,000,000
Stated interest rate (percent)	5.50%
$500 million, 3.950% due August 15, 2049 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal	$ 500,000,000
Stated interest rate (percent)	3.95%
$850 million, 5.950% due March 15, 2034 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal	$ 850,000,000
Stated interest rate (percent)	5.95%
$1,000 million, $5.750% due April 15, 2054 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal	$ 1,000,000,000	$ 1,000,000,000
Stated interest rate (percent)	5.75%	5.75%