Name:	hum_DepreciationAndAmortizationIncomeStatement
Namespace Prefix:	hum_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The total amount of expense recognized during the period for future policy benefits, claims and claims adjustment costs, and for selling, general and administrative costs.

Name:	us-gaap_BenefitsLossesAndExpenses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment.

No definition available.

Name:	us-gaap_GainLossOnSaleOfBusiness
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Name:	us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Name:	us-gaap_InterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities.

Name:	us-gaap_InvestmentIncomeInterestAndDividend
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The net result for the period of deducting operating expenses from operating revenues.

No definition available.

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount, after effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred for health insurance contracts.

Name:	us-gaap_PolicyholderBenefitsAndClaimsIncurredHealthCare
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.1)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(c))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.12-17)
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

Name:	us-gaap_PremiumsEarnedNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

Name:	us-gaap_SalesRevenueServicesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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.

No definition available.

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

The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=68048583&loc=d3e3636-108311

Name:	us-gaap_SellingGeneralAndAdministrativeExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	us-gaap_MajorCustomersAxis=hum_MedicareAdvantageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_GroupMedicareAdvantageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_MedicareStandAlonePrescriptionDrugPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_MedicareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_FullyInsuredMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_SpecialtyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_MedicaidAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_ProviderMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_ASOAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_MajorCustomersAxis=hum_PharmacyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=hum_RetailMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=hum_GroupAndSpecialtyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=hum_HealthcareServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=hum_IndividualCommercialSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_MaterialReconcilingItemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_IntersegmentEliminationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ProductOrServiceAxis=hum_ServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: