2.2.0.7 true Investments (Amortized Cost and Fair Value of Available-for-sale Debt Securities by Contractual Maturity) (Details) (USD $) 40204 - Disclosure - Investments (Amortized Cost and Fair Value of Available-for-sale Debt Securities by Contractual Maturity) (Details) true false In Millions false false 1 USD false false Unit1 Standard http://www.xbrl.org/2003/instance shares xbrli 0 Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit14 Standard http://www.xbrl.org/2003/instance pure xbrli 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 true true false false 1638000000 1638 false false false xbrli:monetaryItemType monetary This item represents debt securities, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph a false 3 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 5094000000 5094 false false false xbrli:monetaryItemType monetary This item represents debt securities, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are expected to mature after one year and through five years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph b false 4 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 3601000000 3601 false false false xbrli:monetaryItemType monetary This item represents debt securities, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph c false 5 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 2171000000 2171 false false false xbrli:monetaryItemType monetary This item represents debt securities, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are expected to mature after ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph d false 6 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCost us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 14671000000 14671 false false false xbrli:monetaryItemType monetary This item represents the total of all debt securities grouped by maturity dates, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are classified neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 true 7 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 1648000000 1648 false false false xbrli:monetaryItemType monetary This item represents the fair value of debt securities which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph a false 8 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 5382000000 5382 false false false xbrli:monetaryItemType monetary This item represents the fair value of debt securities which are expected to mature after one year and through five years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph b false 9 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 3869000000 3869 false false false xbrli:monetaryItemType monetary This item represents the fair value of debt securities which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph c false 10 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 2314000000 2314 false false false xbrli:monetaryItemType monetary This item represents the fair value of debt securities which are expected to mature after ten years from the balance sheet date which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 -Subparagraph d false 11 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 15480000000 15480 false false false xbrli:monetaryItemType monetary This item represents the total of all debt securities grouped by maturity dates, at fair value, which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 true 14 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/disclosureinvestmentsamortizedcostandfairvalueofavailableforsaledebtsecuritiesbycontractualmaturitydetails false 1 false false false false 0 0 false false false false 2 USD true false 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 25 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost 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 458000000 458 false false false xbrli:monetaryItemType monetary This item represents debt securities, categorized neither as held-to-maturity nor trading securities, which do not have a single maturity date and which the Company has decided to disclose separately rather than allocating such cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, over several maturity groupings. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 false 26 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue 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 493000000 493 false false false xbrli:monetaryItemType monetary This item represents the fair value of debt securities, categorized neither as held-to-maturity nor trading securities, which do not have a single maturity date and which the Company has decided to disclose separately, rather than allocating such cost over several maturity groupings. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 false 27 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/disclosureinvestmentsamortizedcostandfairvalueofavailableforsaledebtsecuritiesbycontractualmaturitydetails false 1 false false false false 0 0 false false false false 3 USD true false 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 38 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost 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 1709000000 1709 false false false xbrli:monetaryItemType monetary This item represents debt securities, categorized neither as held-to-maturity nor trading securities, which do not have a single maturity date and which the Company has decided to disclose separately rather than allocating such cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, over several maturity groupings. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 false 39 2 us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue 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 1774000000 1774 false false false xbrli:monetaryItemType monetary This item represents the fair value of debt securities, categorized neither as held-to-maturity nor trading securities, which do not have a single maturity date and which the Company has decided to disclose separately, rather than allocating such cost over several maturity groupings. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 20 false 1 16 false Millions UnKnown UnKnown false true