XML 72 R65.htm IDEA: XBRL DOCUMENT v2.4.1.9
Commercial Paper and Long-Term Debt (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Debt Instrument [Line Items]    
Par Value $ 17,347us-gaap_DebtInstrumentFaceAmount $ 16,952us-gaap_DebtInstrumentFaceAmount
Carrying Value 17,256us-gaap_DebtInstrumentCarryingAmount 16,739us-gaap_DebtInstrumentCarryingAmount
Fair Value 19,034us-gaap_LongTermDebtFairValue 17,596us-gaap_LongTermDebtFairValue
Commercial Paper [Member]    
Debt Instrument [Line Items]    
Par Value 321us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CommercialPaperMember		 1,115us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CommercialPaperMember
Commercial Paper 321us-gaap_CommercialPaper
/ us-gaap_DebtInstrumentAxis
= us-gaap_CommercialPaperMember		 1,115us-gaap_CommercialPaper
/ us-gaap_DebtInstrumentAxis
= us-gaap_CommercialPaperMember
Debt Instrument, Fair Value Disclosure 321us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= us-gaap_CommercialPaperMember		 1,115us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= us-gaap_CommercialPaperMember
4.750% Notes Due February 2014 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member		  
Par Value 0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member		 172us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member
Carrying Value 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member		 173us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member
Fair Value 0us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member		 173us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenFiveSeniorUnsecuredNotesDueFebruray2014Member
5.000% Notes Due August 2014 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member		  
Par Value 0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member		 389us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member
Carrying Value 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member		 397us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member
Fair Value 0us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member		 400us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePercentSeniorUnsecuredNotesDueAugust2014Member
Floating-rate Notes Due August 2014 [Member]    
Debt Instrument [Line Items]    
Par Value 0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SeniorUnsecuredFloatingRateNotesDueAugust2014Member		 250us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SeniorUnsecuredFloatingRateNotesDueAugust2014Member
Carrying Value 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SeniorUnsecuredFloatingRateNotesDueAugust2014Member		 250us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SeniorUnsecuredFloatingRateNotesDueAugust2014Member
Fair Value 0us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SeniorUnsecuredFloatingRateNotesDueAugust2014Member		 250us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SeniorUnsecuredFloatingRateNotesDueAugust2014Member
4.875% Notes Due March 2015 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		  
Par Value 416us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		 [1] 416us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		 [1]
Carrying Value 419us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		 [1] 431us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		 [1]
Fair Value 419us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		 [1] 436us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointEightSevenFivePercentSeniorUnsecuredNotesDueMarch2015Member		 [1]
0.850% Notes due October 2015 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 0.85%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		  
Par Value 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		 [1] 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		 [1]
Carrying Value 625us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		 [1] 624us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		 [1]
Fair Value 627us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		 [1] 628us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A0850SeniorUnsecuredNotesDueOctober2015Member		 [1]
5.375% Notes Due March 2016 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		  
Par Value 601us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		 [1] 601us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		 [1]
Carrying Value 623us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		 [1] 641us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		 [1]
Fair Value 634us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		 [1] 657us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2016Member		 [1]
1.875% Notes Due November 2016 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 1.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		  
Par Value 400us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		 [1] 400us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		 [1]
Carrying Value 397us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		 [1] 398us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		 [1]
Fair Value 406us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		 [1] 408us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_OnePointEightSevenFivePercentSeniorUnsecuredNotesDueNovember2016Member		 [1]
5.360% Notes Due November 2016 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.36%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member		  
Par Value 95us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member		 95us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member
Carrying Value 95us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member		 95us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member
Fair Value 103us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member		 107us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointThreeSixPercentSeniorUnsecuredNotesDueNovember2016Member
6.000% Notes Due June 2017 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		  
Par Value 441us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		 [1] 441us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		 [1]
Carrying Value 466us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		 [1] 479us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		 [1]
Fair Value 489us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		 [1] 506us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPercentSeniorUnsecuredNotesDueJuneTwoThousandSeventeenMember		 [1]
1.400% Notes due October 2017 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 1.40%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		  
Par Value 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		 [1] 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		 [1]
Carrying Value 616us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		 [1] 613us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		 [1]
Fair Value 624us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		 [1] 617us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A1400SeniorUnsecuredNotesDueOctober2017Member		 [1]
6.000% Notes Due November 2017 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		  
Par Value 156us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		 [1] 156us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		 [1]
Carrying Value 164us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		 [1] 168us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		 [1]
Fair Value 175us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		 [1] 178us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroPercentSeniorUnsecuredNotesDueNovember2017Member		 [1]
1.400% Notes Due December 2017 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 1.40%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		  
Par Value 750us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		 [1] 0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		 [1]
Carrying Value 745us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		 [1] 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		 [1]
Fair Value 749us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		 [1] 0us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A1.400SeniorUnsecuredNotesDueDecember2017Member		 [1]
6.000% Notes Due February 2018 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		  
Par Value 1,100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		 [1] 1,100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		 [1]
Carrying Value 1,106us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		 [1] 1,116us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		 [1]
Fair Value 1,238us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		 [1] 1,271us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointZeroSeniorUnsecuredNotesDueFebruaryTwoThousandEighteenMember		 [1]
1.625% Notes Due March 2019 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 1.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		  
Par Value 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		 [1] 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		 [1]
Carrying Value 496us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		 [1] 489us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		 [1]
Fair Value 493us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		 [1] 481us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A1625SeniorUnsecuredNotesDueMarch2019Member		 [1]
2.300% Notes Due December 2019 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		  
Par Value 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		 [1] 0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		 [1]
Carrying Value 496us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		 [1] 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		 [1]
Fair Value 502us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		 [1] 0us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2.300SeniorUnsecuredNotesDueDecember2019Member		 [1]
3.875% Notes Due October 2020 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 3.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		  
Par Value 450us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		 [1] 450us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		 [1]
Carrying Value 450us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		 [1] 435us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		 [1]
Fair Value 477us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		 [1] 474us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueOctober2020Member		 [1]
4.700% Notes Due February 2021 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.70%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		  
Par Value 400us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		 [1] 400us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		 [1]
Carrying Value 413us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		 [1] 416us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		 [1]
Fair Value 450us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		 [1] 436us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSevenPercentageSeniorUnsecuredNotesDueFebruaryTwoThousandTwentyOneMember		 [1]
3.375% Notes Due November 2021 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 3.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		  
Par Value 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		 [1] 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		 [1]
Carrying Value 496us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		 [1] 472us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		 [1]
Fair Value 519us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		 [1] 494us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_ThreePointThreeSevenFivePercentSeniorUnsecuredNotesDueNovember2021Member		 [1]
2.875% Notes Due December 2021 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		  
Par Value 750us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		 [1] 0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		 [1]
Carrying Value 748us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		 [1] 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		 [1]
Fair Value 759us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		 [1] 0us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2.875SeniorUnsecuredNotesDueDecember2021Member		 [1]
2.875% Notes Due March 2022 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		  
Par Value 1,100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		 [1] 1,100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		 [1]
Carrying Value 1,042us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		 [1] 981us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		 [1]
Fair Value 1,104us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		 [1] 1,046us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_TwoPointEightSevenFiveSeniorUnsecuredNotesDueMarch2022Member		 [1]
0.000% Notes Due November 2022 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember		  
Par Value 15us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember		 15us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember
Carrying Value 10us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember		 9us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember
Fair Value 11us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember		 10us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_ZeroCouponSeniorUnsecuredNotesDueNovemberTwoThousandTwentyTwoMember
2.750% Notes due February 2023 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		  
Par Value 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		 [1] 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		 [1]
Carrying Value 604us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		 [1] 563us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		 [1]
Fair Value 613us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		 [1] 572us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2750SeniorUnsecuredNotesDueFebruary2023Member		 [1]
2.875% Notes due March 2023 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		  
Par Value 750us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		 [1] 750us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		 [1]
Carrying Value 777us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		 [1] 729us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		 [1]
Fair Value 745us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		 [1] 698us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A2875SeniorUnsecuredNotesDueMarch2023Member		 [1]
5.800% Notes Due March 2036 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.80%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember		  
Par Value 850us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember		 850us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember
Carrying Value 845us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember		 845us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember
Fair Value 1,052us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember		 935us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointEightPercentSeniorUnsecuredNotesDueMarchTwoThousandThirtySixMember
6.500% Notes Due June 2037 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 6.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember		  
Par Value 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember		 500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember
Carrying Value 495us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember		 495us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember
Fair Value 670us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember		 593us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointFivePercentSeniorUnsecuredNotesDueJuneTwoThousandThirtySevenMember
6.625% Notes Due November 2037 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 6.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member		  
Par Value 650us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member		 650us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member
Carrying Value 646us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member		 645us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member
Fair Value 888us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member		 786us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2037Member
6.875% Notes Due February 2038 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 6.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member		  
Par Value 1,100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member		 1,100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member
Carrying Value 1,085us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member		 1,084us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member
Fair Value 1,544us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member		 1,370us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_SixPointEightSevenFivePercentSeniorUnsecuredNotesDueFebruray2038Member
5.700% Notes Due October 2040 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.70%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember		  
Par Value 300us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember		 300us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember
Carrying Value 298us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember		 298us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember
Fair Value 378us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember		 329us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointSevenPercentSeniorUnsecuredNotesDueOctoberTwoThousandFortyMember
5.950% Notes Due February 2041 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.95%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member		  
Par Value 350us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member		 350us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member
Carrying Value 348us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member		 348us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member
Fair Value 455us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member		 397us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FivePointNineFiveSeniorUnsecuredNotesDueFebrurary2041Member
4.625% Notes Due November 2041 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member		  
Par Value 600us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member		 600us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member
Carrying Value 593us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member		 593us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member
Fair Value 646us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member		 567us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointSixTwoFivePercentSeniorUnsecuredNotesDueNovember2041Member
4.375% Notes Due March 2042 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member		  
Par Value 502us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member		 502us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member
Carrying Value 486us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member		 486us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member
Fair Value 536us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member		 459us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_FourPointThreeSevenFivePercentSeniorUnsecuredNotesDueMarch2042Member
3.950% Notes due October 2042 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 3.95%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member		  
Par Value 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member		 625us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member
Carrying Value 611us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member		 611us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member
Fair Value 621us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member		 530us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A3950SeniorUnsecuredNotesDueOctober2042Member
4.250% Notes due March 2043 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member		  
Par Value 750us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member		 750us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member
Carrying Value 740us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member		 740us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member
Fair Value $ 786us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member		 $ 673us-gaap_LongTermDebtFairValue
/ us-gaap_DebtInstrumentAxis
= unh_A4250SeniorUnsecuredNotesDueMarch2043Member
[1] Fixed-rate debt instruments hedged with interest rate swap contracts. See below for more information on the Company’s interest rate swaps.