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

Amount of member co-share amounts and government subsidies that are excluded from benefits expense because the health plans do not bear responsibility.

No definition available.

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

Health Care Reform, Premium Deficiency Reserve

No definition available.

Name:	hum_HealthCareReformPremiumDeficiencyReserve
Namespace Prefix:	hum_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long Term Insurance Reserve Strengthening Expense

No definition available.

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

Percentage Of Total Premium And Services Revenues Derived From Contracts With The Federal Government

No definition available.

Name:	hum_PercentageOfTotalPremiumAndServicesRevenuesDerivedFromContractsWithFederalGovernment
Namespace Prefix:	hum_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Premiums Reduction, Write Off Of Risk Corridor Receivables

No definition available.

Name:	hum_PremiumsReductionWriteOffOfRiskCorridorReceivables
Namespace Prefix:	hum_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_EntityWideInformationRevenueFromExternalCustomerLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.