Basis of Presentation (Details) (Health and Well-Being Services [Member], USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Health and Well-Being Services [Member]
Depreciation and amortization expense	$ 7.3	$ 4.9	$ 16.7	$ 8.8

Name:

hum_DepreciationAndAmortizationClassifiedAsBenefitExpense

Namespace Prefix:

hum

Data Type:

xbrli:monetaryItemType

Balance Type:

debit

Period Type:

duration