2.2.0.25truefalse40201 - Disclosure - Basis of Presentation, Use of Estimates and Significant Accounting Policies (Narrative) (Details)truefalsefalse1falsefalseUSDfalsefalse1/1/2011 - 12/31/2011
USD ($)
$Duration_1_1_2011_To_12_31_2011http://www.sec.gov/CIK0000731766duration2011-01-01T00:00:002011-12-31T00:00:00Unit12Standardhttp://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$2falsefalseUSDfalsefalse1/1/2010 - 12/31/2010
USD ($)
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$3falsefalseUSDfalsefalse1/1/2009 - 12/31/2009
USD ($)
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$2false0unh_ChecksOutstandingInExcessOfBankDepositsunhfalsedebitdurationCarrying value as of the balance sheet date of bank checks outstanding in excess of bank deposits.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse13000000001300000000falsetruefalsefalsefalse3truefalsefalse12000000001200000000falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCarrying value as of the balance sheet date of bank checks outstanding in excess of bank deposits.No authoritative reference available.falsefalse3false0us-gaap_GoodwillImpairmentLossus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse172000000172000000falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLoss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph e(2)
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 43
Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 47
-Subparagraph b
Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 20
falsefalse4false0us-gaap_ReinsuranceRecoverablesus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse20000000002000000000falsefalsefalsefalsefalse3truefalsefalse20000000002000000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe known and estimated amount recoverable as of the balance sheet date from reinsurers for claims paid or incurred by the ceding insurer and associated claims settlement expenses, including estimated amounts for claims incurred but not reported, and policy benefits, net of any related valuation allowance.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 6
-Article 7
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 113
-Paragraph 14, 16, 27, 113
falsefalse5false0unh_MedicarePartDInitialCoverageLimitunhfalsecreditdurationMedicare Part D initial coverage limit.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse28400000002840000000falsefalsefalsefalsefalse3truefalsefalse28300000002830000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryMedicare Part D initial coverage limit.No authoritative reference available.falsefalse6false0unh_MedicarePartDCatastrophicCoverageunhfalsecreditinstantMedicare Part D catastrophic coverage.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse64480000006448000000falsefalsefalsefalsefalse3truefalsefalse64400000006440000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryMedicare Part D catastrophic coverage.No authoritative reference available.falsefalse7false0unh_MedicarePartDAnnualOutOfPocketMaximumunhfalsecreditdurationMedicare Part D annual out of pocket maximum.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse45500000004550000000falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryMedicare Part D annual out of pocket maximum.No authoritative reference available.falsefalse8false0unh_CatastrophicReinsuranceSubsidyCoverageunhfalsenadurationCatastrophic reinsurance subsidy coverage.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsetruefalse00falsefalsefalsefalsefalse2truetruefalse0.80.8falsefalsefalsefalsefalse3falsetruefalse00falsefalsefalsefalsefalseOtherus-types:percentItemTypepureCatastrophic reinsurance subsidy coverage.No authoritative reference available.falsefalse9false0unh_VarianceOfRiskShareunhfalsenadurationVariance Of Risk Sharefalsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsetruefalse00falsefalsefalsefalsefalse2truetruefalse0.050.05falsefalsefalsefalsefalse3falsetruefalse00falsefalsefalsefalsefalseOtherus-types:percentItemTypepureVariance Of Risk ShareNo authoritative reference available.falsefalse10false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.unitedhealthgroup.com/taxonomy/role/disclosurebasisofpresentationuseofestimatesandsignificantaccountingpoliciesnarrativedetails1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalseUSDtruefalse{unh_ReinsuranceReceivablesByBalanceSheetLocationAxis} : Other Current Receivables [Member]
12/31/2010
USD ($)
$As_Of_12_31_2010227http://www.sec.gov/CIK0000731766instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseOther Current Receivables [Member]unh_ReinsuranceReceivablesByBalanceSheetLocationAxisxbrldihttp://xbrl.org/2006/xbrldiunh_OtherCurrentReceivablesMemberunh_ReinsuranceReceivablesByBalanceSheetLocationAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5falsefalseUSDtruefalse{unh_ReinsuranceReceivablesByBalanceSheetLocationAxis} : Other Current Receivables [Member]
12/31/2009
USD ($)
$As_Of_12_31_200923http://www.sec.gov/CIK0000731766instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseOther Current Receivables [Member]unh_ReinsuranceReceivablesByBalanceSheetLocationAxisxbrldihttp://xbrl.org/2006/xbrldiunh_OtherCurrentReceivablesMemberunh_ReinsuranceReceivablesByBalanceSheetLocationAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse11false0unh_ReinsuranceRecoverablesCurrentunhfalsedebitinstantThe current portion of the known and estimated amount recoverable as of the balance sheet date from reinsurers for claims...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse126000000126000000falsefalsefalsefalsefalse3truefalsefalse139000000139000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe current portion of the known and estimated amount recoverable as of the balance sheet date from reinsurers for claims paid or incurred by the ceding insurer and associated claims settlement expenses, including estimated amounts for claims incurred but not reported, and policy benefits, net of any related valuation allowance.No authoritative reference available.falsefalse12false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.unitedhealthgroup.com/taxonomy/role/disclosurebasisofpresentationuseofestimatesandsignificantaccountingpoliciesnarrativedetails1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse6falsefalseUSDtruefalse{unh_ReinsuranceReceivablesByBalanceSheetLocationAxis} : Other Assets
12/31/2010
USD ($)
$As_Of_12_31_2010228http://www.sec.gov/CIK0000731766instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseOther Assetsunh_ReinsuranceReceivablesByBalanceSheetLocationAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_OtherAssetsMemberunh_ReinsuranceReceivablesByBalanceSheetLocationAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$7falsefalseUSDtruefalse{unh_ReinsuranceReceivablesByBalanceSheetLocationAxis} : Other Assets
12/31/2009
USD ($)
$As_Of_12_31_200924http://www.sec.gov/CIK0000731766instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseOther Assetsunh_ReinsuranceReceivablesByBalanceSheetLocationAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_OtherAssetsMemberunh_ReinsuranceReceivablesByBalanceSheetLocationAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse13false0unh_ReinsuranceRecoverablesNoncurrentunhfalsedebitinstantThe non-current portion of the known and estimated amount recoverable as of the balance sheet date from reinsurers for claims...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse19000000001900000000falsetruefalsefalsefalse3truefalsefalse19000000001900000000falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe non-current portion of the known and estimated amount recoverable as of the balance sheet date from reinsurers for claims paid or incurred by the ceding insurer and associated claims settlement expenses, including estimated amounts for claims incurred but not reported, and policy benefits, net of any related valuation allowance.No authoritative reference available.falsefalse312Basis of Presentation, Use of Estimates and Significant Accounting Policies (Narrative) (Details) (USD $)NoRoundingUnKnownUnKnownUnKnowntruetrue
