2.2.0.7 true Investments (Fair Value of Available-for-sale Investments with Gross Unrealized Losses by Investment Type and Length of Time That Individual Securities Have Been in a Continuous Unrealized Loss Position) (Details) (USD $) 40206 - Disclosure - Investments (Fair Value of Available-for-sale Investments with Gross Unrealized Losses by Investment Type and Length of Time That Individual Securities Have Been in a Continuous Unrealized Loss Position) (Details) true false In Millions false false 1 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 2 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 1 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 1 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 2 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 2 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 true true false false 417000000 417 false false false 2 true true false false 1622000000 1622 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 3 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false true false false -2000000 -2 false false false 2 false true false false -24000000 -24 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 4 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 18000000 18 false false false 2 false true false false 261000000 261 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 5 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false true false false -1000000 -1 false false false 2 false true false false -12000000 -12 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 6 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 435000000 435 false false false 2 false true false false 1883000000 1883 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 7 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 false true false false -3000000 -3 false false false 2 false true false false -36000000 -36 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 8 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 3 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false Non-U.S. Agency Mortgage-backed Securities us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 9 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 134000000 134 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 10 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -1000000 -1 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 11 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 86000000 86 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 12 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -4000000 -4 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 13 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 220000000 220 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 14 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -5000000 -5 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 15 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 4 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false U.S. Government and Agency Obligations us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_USTreasuryAndGovernmentMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 16 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 437000000 437 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 17 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -11000000 -11 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 18 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 4000000 4 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 19 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false 0 0 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 20 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 441000000 441 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 21 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -11000000 -11 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 22 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 5 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false State and Municipal Obligations us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_USStatesAndPoliticalSubdivisionsMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false State and Municipal Obligations us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_USStatesAndPoliticalSubdivisionsMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 23 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 145000000 145 false false false 2 false true false false 392000000 392 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 24 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false true false false -1000000 -1 false false false 2 false true false false -6000000 -6 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 25 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 18000000 18 false false false 2 false true false false 100000000 100 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 26 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false true false false -1000000 -1 false false false 2 false true false false -5000000 -5 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 27 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 163000000 163 false false false 2 false true false false 492000000 492 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 28 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 false true false false -2000000 -2 false false false 2 false true false false -11000000 -11 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 29 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 7 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false Corporate Obligations us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_CorporateDebtSecuritiesMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 8 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false Corporate Obligations us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_CorporateDebtSecuritiesMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 30 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 272000000 272 false false false 2 false true false false 304000000 304 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 31 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false true false false -1000000 -1 false false false 2 false true false false -3000000 -3 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 32 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 0 0 false false false 2 false true false false 69000000 69 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 33 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false true false false 0 0 false false false 2 false true false false -3000000 -3 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 34 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 272000000 272 false false false 2 false true false false 373000000 373 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 35 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 false true false false -1000000 -1 false false false 2 false true false false -6000000 -6 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 36 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 9 USD true false false false Debt Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_DebtSecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember false false U.S. Agency Mortgage-backed Securities us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 37 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 355000000 355 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 38 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -3000000 -3 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 39 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 2000000 2 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 40 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false 0 0 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 41 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 357000000 357 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 42 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -3000000 -3 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 43 0 na true na na No definition available. false true false false false false false false false false false http://www.unitedhealthgroup.com/taxonomy/role/disclosurefairvalueofavailableforsaleinvestmentswithgrossunrealizedlossesbyinvestmenttypeandlengthoftimethatindividualsecuritieshavebeeninacontinuousunrealizedlossposition false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 10 USD true false false false Equity Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_EquitySecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 11 USD true false false false Equity Securities us-gaap_InvestmentSecondaryCategorizationAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_EquitySecuritiesMember us-gaap_InvestmentSecondaryCategorizationAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 44 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 202000000 202 false false false 2 false true false false 169000000 169 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 45 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossLessThanTwelveMonths unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. false false false false false false false false false false true negated false 1 false true false false -13000000 -13 false false false 2 false true false false -13000000 -13 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Less than Twelve Months. No authoritative reference available. false 46 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 11000000 11 false false false 2 false true false false 1000000 1 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 47 2 unh_AvailableForSaleSecuritiesContinuousUnrealizedLossTwelveMonthsOrLonger unh false credit instant Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. false false false false false false false false false false true negated false 1 false true false false -1000000 -1 false false false 2 false true false false -1000000 -1 false false false xbrli:monetaryItemType monetary Available-for-sale Securities, Continuous Unrealized Losses, Twelve Months or Longer. No authoritative reference available. false 48 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 213000000 213 false false false 2 false true false false 170000000 170 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 49 2 unh_AvailableForSaleSecuritiesUnrealizedLosses unh false credit instant This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading... false false false false false false false false false false true negated false 1 true true false false -14000000 -14 false false false 2 true true false false -14000000 -14 false false false xbrli:monetaryItemType monetary This item represents the unrealized losses on debt or equity securities categorized neither as held-to-maturity nor trading securities. No authoritative reference available. false 2 49 false Millions UnKnown UnKnown false true