2.2.0.25falsefalse40702 - Disclosure - Medical Costs and Medical Costs Payable (The Components of the Change in Medical Costs Payable) (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010
USD ($)
USD ($) / shares
$Duration_1_1_2010_To_12_31_2010http://www.sec.gov/CIK0000731766duration2010-01-01T00:00:002010-12-31T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2falsefalseUSDfalsefalse1/1/2009 - 12/31/2009
USD ($)
USD ($) / shares
$Duration_1_1_2009_To_12_31_20092http://www.sec.gov/CIK0000731766duration2009-01-01T00:00:002009-12-31T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$3falsefalseUSDfalsefalse1/1/2008 - 12/31/2008
USD ($)
USD ($) / shares
$Duration_1_1_2008_To_12_31_20082http://www.sec.gov/CIK0000731766duration2008-01-01T00:00:002008-12-31T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0unh_MedicalCostsAndMedicalCostsPayableAbstractunhfalsenadurationMedical Costs And Medical Costs Payable [Abstract]falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringMedical Costs And Medical Costs Payable [Abstract]falsefalse3false0us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalsefalseperiodstartlabel1truefalsefalse93620000009362falsetruefalsefalsefalse2truefalsefalse86640000008664falsetruefalsefalsefalse3truefalsefalse83310000008331falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
-Subparagraph b
falsefalse4false0unh_LiabilityForClaimsAndClaimsAdjustmentExpenseRelatedToAcquisitionsunhfalsecreditinstantThe amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse00falsefalsefalsefalsefalse2truefalsefalse252000000252falsefalsefalsefalsefalse3truefalsefalse331000000331falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date at the date of acquisition, whether or not reported to the insurer at that date.No authoritative reference available.falsefalse5false0us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsCurrentYearus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse6964100000069641falsefalsefalsefalsefalse2truefalsefalse6559900000065599falsefalsefalsefalsefalse3truefalsefalse6058900000060589falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAmount of provision in the period for claims incurred in the reporting period and related claims settlement costs.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Financial Reporting Release (FRR)
-Number 403
-Paragraph 04
-Subparagraph b
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
-Subparagraph b
falsefalse6false0us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsPriorYearsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-800000000-800falsefalsefalsefalsefalse2truefalsefalse-310000000-310falsefalsefalsefalsefalse3truefalsefalse-230000000-230falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAmount of provision in the period for claims incurred in prior reporting periods and related claims settlement costs.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Financial Reporting Release (FRR)
-Number 403
-Paragraph 04
-Subparagraph b
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
-Subparagraph b
falsefalse7false0us-gaap_PolicyholderBenefitsAndClaimsIncurredHealthCareus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse6884100000068841falsefalsefalsefalsefalse2truefalsefalse6528900000065289falsefalsefalsefalsefalse3truefalsefalse6035900000060359falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryProvision for benefits, claims and claims settlement expenses incurred during the period for health care insurance contracts net of the effects of contracts assumed and ceded.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 5
-Article 7
truefalse8false0us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYearus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-60949000000-60949falsefalsefalsefalsefalse2truefalsefalse-57109000000-57109falsefalsefalsefalsefalse3truefalsefalse-52872000000-52872falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAmount of payments made in the reporting period to settle claims incurred in the current period and related claims settlement costs.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Financial Reporting Release (FRR)
-Number 403
-Paragraph 04
-Subparagraph b
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
-Subparagraph c
falsefalse9false0us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYearsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-8034000000-8034falsefalsefalsefalsefalse2truefalsefalse-7734000000-7734falsefalsefalsefalsefalse3truefalsefalse-7485000000-7485falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAmount of payments made in the reporting period to settle claims incurred in prior periods and related claims settlement costs.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Financial Reporting Release (FRR)
-Number 403
-Paragraph 04
-Subparagraph b
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
-Subparagraph c
falsefalse10false0us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-68983000000-68983falsefalsefalsefalsefalse2truefalsefalse-64843000000-64843falsefalsefalsefalsefalse3truefalsefalse-60357000000-60357falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal amount of payments made during the reporting period to settle insured claims and pay costs incurred in the claims settlement process.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Financial Reporting Release (FRR)
-Number 403
-Paragraph 04
-Subparagraph b
truefalse11false0us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsetruefalseperiodendlabel1truefalsefalse92200000009220falsetruefalsefalsefalse2truefalsefalse93620000009362falsetruefalsefalsefalse3truefalsefalse86640000008664falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 94-5
-Paragraph 11
-Subparagraph b
falsefalse310Medical Costs and Medical Costs Payable (The Components of the Change in Medical Costs Payable) (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
