v2.4.1.9
Borrowings (Details) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Aug. 31, 2014
Feb. 28, 2014
Commercial Paper   $ 2,680,600,000us-gaap_CommercialPaper $ 0us-gaap_CommercialPaper      
Short-term borrowings and current maturities of long-term debt   2,688,700,000us-gaap_DebtCurrent 1,012,600,000us-gaap_DebtCurrent      
Short-term Debt, Weighted Average Interest Rate   0.18%us-gaap_ShortTermDebtWeightedAverageInterestRate        
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum   1.95%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum        
Repayments of Long-term Debt 1,000,000,000us-gaap_RepaymentsOfLongTermDebt 1,034,800,000us-gaap_RepaymentsOfLongTermDebt 10,500,000us-gaap_RepaymentsOfLongTermDebt 1,511,100,000us-gaap_RepaymentsOfLongTermDebt    
Notes Payable   4,887,300,000us-gaap_NotesPayable 4,887,300,000us-gaap_NotesPayable      
Other Notes Payable   33,100,000us-gaap_OtherNotesPayable 27,100,000us-gaap_OtherNotesPayable      
Long-term Debt, Fair Value Adjustment   455,400,000lly_LongTermDebtFairValueAdjustment 298,500,000lly_LongTermDebtFairValueAdjustment      
Debt, Long-term and Short-term, Combined Amount   8,056,400,000us-gaap_DebtLongtermAndShorttermCombinedAmount 5,212,900,000us-gaap_DebtLongtermAndShorttermCombinedAmount      
Long-term debt   5,367,700,000us-gaap_LongTermDebtNoncurrent 4,200,300,000us-gaap_LongTermDebtNoncurrent      
Description of Derivative Activity Volume Percent   55.00%lly_DescriptionOfDerivativeActivityVolumePercent        
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months   8,100,000us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths        
Long-term Debt, Maturities, Repayments of Principal in Year Two   208,500,000us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo        
Long-term Debt, Maturities, Repayments of Principal in Year Three   1,010,000,000us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree        
Long-term Debt, Maturities, Repayments of Principal in Year Four   203,800,000us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour        
Long-term Debt, Maturities, Repayments of Principal in Year Five   601,000,000us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive        
Line of Credit Facility, Remaining Borrowing Capacity   3,310,000,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity        
Line of Credit Facility, Amount Outstanding   0us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding        
Interest Paid, Net   140,400,000us-gaap_InterestPaidNet 139,700,000us-gaap_InterestPaidNet 171,900,000us-gaap_InterestPaidNet    
Debt Instrument, Interest Rate, Effective Percentage   3.69%us-gaap_DebtInstrumentInterestRateEffectivePercentage 3.10%us-gaap_DebtInstrumentInterestRateEffectivePercentage      
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum   7.13%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum        
Maturity Date, 2019 [Member]            
Debt Instrument, Interest Rate, Stated Percentage           1.95%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= lly_MaturityDate2019Member
Long-term Debt           600,000,000us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= lly_MaturityDate2019Member
Line of Credit Facility, Maximum Borrowing Capacity         1,200,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= lly_MaturityDate2019Member
 
Maturity Date, 2015 [Member]            
Line of Credit Facility, Maximum Borrowing Capacity         2,000,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= lly_MaturityDate2015Member
 
Maturity Date, 2044 [Member]            
Debt Instrument, Interest Rate, Stated Percentage           4.65%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= lly_MaturityDate2044Member
Long-term Debt           $ 400,000,000us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= lly_MaturityDate2044Member