2.2.0.25truefalse40202 - Disclosure - Basis of Presentation, Use of Estimates and Significant Accounting Policies (Consolidated Balance Sheet) (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse12/31/2010
USD ($)
USD ($) / shares
$As_Of_12_31_20103http://www.sec.gov/CIK0000731766instant2010-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2falsefalseUSDfalsefalse12/31/2009
USD ($)
USD ($) / shares
$As_Of_12_31_20093http://www.sec.gov/CIK0000731766instant2009-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2false0us-gaap_OtherReceivablesus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse16430000001643falsetruefalsefalsefalse2truefalsefalse18380000001838falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCarrying amounts due as of the balance sheet date from parties or arising from transactions not otherwise specified in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 8
-Article 5
falsefalse3false0us-gaap_OtherPolicyholderFundsus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse39790000003979falsefalsefalsefalsefalse2truefalsefalse31370000003137falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLiability as of the balance sheet date to the policyholders for funds held that are returnable under the terms of insurance contracts that were not separately reported.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 14
-Article 7
falsefalse4false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.unitedhealthgroup.com/taxonomy/role/disclosurebasisofpresentationuseofestimatesandsignificantaccountingpoliciesconsolidatedbalancesheetdetails1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalseUSDtruefalse{us-gaap_SubsequentEventTypeAxis} : CMS Subsidies [Member]
12/31/2010
USD ($)
$As_Of_12_31_201022282http://www.sec.gov/CIK0000731766instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseCMS Subsidies [Member]us-gaap_SubsequentEventTypeAxisxbrldihttp://xbrl.org/2006/xbrldiunh_CmsSubsidiesMemberus-gaap_SubsequentEventTypeAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4falsefalseUSDtruefalse{us-gaap_SubsequentEventTypeAxis} : CMS Subsidies [Member]
12/31/2009
USD ($)
$As_Of_12_31_2009523219http://www.sec.gov/CIK0000731766instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseCMS Subsidies [Member]us-gaap_SubsequentEventTypeAxisxbrldihttp://xbrl.org/2006/xbrldiunh_CmsSubsidiesMemberus-gaap_SubsequentEventTypeAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse5false0us-gaap_OtherReceivablesus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse00[1]falsefalsefalsefalsefalse2truefalsefalse271000000271[1]falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCarrying amounts due as of the balance sheet date from parties or arising from transactions not otherwise specified in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 8
-Article 5
falsefalse6false0us-gaap_OtherPolicyholderFundsus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse475000000475[1]falsefalsefalsefalsefalse2truefalsefalse00[1]falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLiability as of the balance sheet date to the policyholders for funds held that are returnable under the terms of insurance contracts that were not separately reported.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 14
-Article 7
falsefalse7false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.unitedhealthgroup.com/taxonomy/role/disclosurebasisofpresentationuseofestimatesandsignificantaccountingpoliciesconsolidatedbalancesheetdetails1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse5falsefalseUSDtruefalse{us-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxis} : Risk Share [Member]
12/31/2010
USD ($)
$As_Of_12_31_201022283http://www.sec.gov/CIK0000731766instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseRisk Share [Member]us-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxisxbrldihttp://xbrl.org/2006/xbrldiunh_RiskShareMemberus-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6falsefalseUSDtruefalse{us-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxis} : Risk Share [Member]
12/31/2009
USD ($)
$As_Of_12_31_2009523220http://www.sec.gov/CIK0000731766instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseRisk Share [Member]us-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxisxbrldihttp://xbrl.org/2006/xbrldiunh_RiskShareMemberus-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse8false0us-gaap_OtherReceivablesus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse00falsefalsefalsefalsefalse2truefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCarrying amounts due as of the balance sheet date from parties or arising from transactions not otherwise specified in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 8
-Article 5
falsefalse9false0us-gaap_OtherPolicyholderFundsus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse265000000265falsetruefalsefalsefalse2truefalsefalse268000000268falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLiability as of the balance sheet date to the policyholders for funds held that are returnable under the terms of insurance contracts that were not separately reported.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 14
-Article 7
falsefalse1Includes the Catastrophic Reinsurance Subsidy and the Low-Income Member Cost Sharing Subsidy. 28Basis of Presentation, Use of Estimates and Significant Accounting Policies (Consolidated Balance Sheet) (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue