Revenue (Disaggregation of Revenue by Product) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 6,772.8	$ 5,740.6	$ 20,318.5	$ 17,099.8
U.S.
Disaggregation of Revenue [Line Items]
Revenue	3,989.6	3,161.4	11,635.1	9,631.4
Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	2,783.3	2,579.3	8,683.4	7,468.5
Diabetes
Disaggregation of Revenue [Line Items]
Revenue	3,274.1	2,783.0	9,560.6	8,530.9
Diabetes | U.S.
Disaggregation of Revenue [Line Items]
Revenue	2,143.0	1,798.5	6,284.0	5,663.0
Diabetes | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	1,131.1	984.5	3,276.6	2,868.0
Trulicity®
Disaggregation of Revenue [Line Items]
Revenue	1,600.1	1,106.6	4,588.2	3,565.7
Trulicity® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	1,201.4	791.2	3,465.7	2,673.2
Trulicity® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	398.8	315.4	1,122.5	892.5
Humalog®
Disaggregation of Revenue [Line Items]
Revenue	626.7	656.9	1,851.3	1,907.8
Humalog® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	347.3	390.1	1,009.0	1,070.4
Humalog® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	279.4	266.9	842.3	837.4
Jardiance
Disaggregation of Revenue [Line Items]
Revenue	390.4	310.8	1,058.9	840.3
Jardiance | U.S.
Disaggregation of Revenue [Line Items]
Revenue	221.2	163.3	566.8	453.0
Jardiance | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	169.2	147.5	492.1	387.3
Humulin®
Disaggregation of Revenue [Line Items]
Revenue	286.7	305.9	923.8	935.2
Humulin® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	193.4	214.0	633.5	642.5
Humulin® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	93.4	91.9	290.3	292.7
Basaglar®
Disaggregation of Revenue [Line Items]
Revenue	192.8	248.2	650.1	842.3
Basaglar® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	114.7	178.5	423.3	638.7
Basaglar® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	78.1	69.7	226.8	203.7
Other Diabetes
Disaggregation of Revenue [Line Items]
Revenue	177.4	154.6	488.3	439.6
Other Diabetes | U.S.
Disaggregation of Revenue [Line Items]
Revenue	65.0	61.4	185.7	185.2
Other Diabetes | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	112.2	93.1	302.6	254.4
Oncology
Disaggregation of Revenue [Line Items]
Revenue	1,406.1	1,333.4	4,332.4	3,803.5
Oncology | U.S.
Disaggregation of Revenue [Line Items]
Revenue	730.9	682.5	2,201.7	2,023.1
Oncology | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	675.3	650.9	2,130.7	1,780.4
Alimta®
Disaggregation of Revenue [Line Items]
Revenue	457.0	578.0	1,626.6	1,677.2
Alimta® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	297.2	291.9	911.9	933.4
Alimta® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	159.8	286.1	714.7	743.8
Verzenio®
Disaggregation of Revenue [Line Items]
Revenue	335.5	234.4	945.8	631.1
Verzenio® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	199.6	158.9	582.1	430.0
Verzenio® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	135.9	75.5	363.7	201.1
Cyramza®
Disaggregation of Revenue [Line Items]
Revenue	253.4	252.7	762.5	748.4
Cyramza® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	84.8	94.5	266.3	277.6
Cyramza® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	168.6	158.2	496.3	470.8
Erbitux®
Disaggregation of Revenue [Line Items]
Revenue	134.3	136.4	403.7	396.7
Erbitux® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	114.0	122.5	357.7	356.1
Erbitux® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	20.3	14.0	45.9	40.6
Tyvyt® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	0.0	0.0	0.0	0.0
Tyvyt® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	125.6	84.4	340.2	205.9
Other Oncology
Disaggregation of Revenue [Line Items]
Revenue	100.3	47.5	253.6	144.2
Other Oncology | U.S.
Disaggregation of Revenue [Line Items]
Revenue	35.3	14.7	83.7	26.0
Other Oncology | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	65.1	32.7	169.9	118.2
Immunology
Disaggregation of Revenue [Line Items]
Revenue	1,004.9	627.1	2,404.2	1,761.2
Immunology | U.S.
Disaggregation of Revenue [Line Items]
Revenue	616.2	346.8	1,323.3	995.1
Immunology | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	388.7	280.3	1,080.9	766.1
Taltz®
Disaggregation of Revenue [Line Items]
Revenue	593.1	454.5	1,565.4	1,293.2
Taltz® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	422.2	326.2	1,071.6	942.9
Taltz® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	170.9	128.3	493.8	350.3
Olumiant® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	194.0	14.5	236.5	39.0
Olumiant® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	212.9	147.5	572.6	407.7
Other Immunology
Disaggregation of Revenue [Line Items]
Revenue	4.9	10.6	29.7	21.3
Other Immunology | U.S.
Disaggregation of Revenue [Line Items]
Revenue	0.0	6.1	15.2	13.2
Other Immunology | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	4.9	4.5	14.5	8.1
Neuroscience
Disaggregation of Revenue [Line Items]
Revenue	450.2	470.7	1,427.8	1,356.7
Neuroscience | U.S.
Disaggregation of Revenue [Line Items]
Revenue	144.6	140.4	453.1	354.7
Neuroscience | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	305.5	330.3	974.7	1,002.0
Emgality®
Disaggregation of Revenue [Line Items]
Revenue	140.0	91.5	415.7	252.9
Emgality® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	99.9	81.4	313.5	229.3
Emgality® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	40.1	10.1	102.2	23.6
Cymbalta®
Disaggregation of Revenue [Line Items]
Revenue	132.0	186.6	484.3	576.9
Cymbalta® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	7.0	11.1	30.3	30.5
Cymbalta® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	125.1	175.5	454.0	546.5
Zyprexa®
Disaggregation of Revenue [Line Items]
Revenue	101.7	112.7	292.8	307.7
Zyprexa® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	13.0	21.2	28.3	41.5
Zyprexa® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	88.7	91.5	264.5	266.2
Other Neuroscience
Disaggregation of Revenue [Line Items]
Revenue	76.5	79.9	235.0	219.2
Other Neuroscience | U.S.
Disaggregation of Revenue [Line Items]
Revenue	24.7	26.7	81.0	53.4
Other Neuroscience | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	51.6	53.2	154.0	165.7
Other
Disaggregation of Revenue [Line Items]
Revenue	637.7	526.4	2,593.5	1,647.5
Other | U.S.
Disaggregation of Revenue [Line Items]
Revenue	354.9	193.2	1,373.0	595.5
Other | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	282.7	333.2	1,220.5	1,052.0
COVID-19 Antibodies
Disaggregation of Revenue [Line Items]
Revenue		0.0	1,176.2	0.0
COVID-19 Antibodies | U.S.
Disaggregation of Revenue [Line Items]
Revenue	215.5	0.0	949.5	0.0
COVID-19 Antibodies | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	1.6	0.0	226.7	0.0
Forteo®
Disaggregation of Revenue [Line Items]
Revenue	200.9	266.9	617.8	791.9
Forteo® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	109.6	144.6	330.1	386.7
Forteo® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	91.3	122.3	287.7	405.2
Cialis®
Disaggregation of Revenue [Line Items]
Revenue	130.9	162.5	538.7	486.2
Cialis® | U.S.
Disaggregation of Revenue [Line Items]
Revenue	(6.5)	15.1	(3.1)	64.6
Cialis® | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	137.4	147.3	541.8	421.6
Other
Disaggregation of Revenue [Line Items]
Revenue	88.8	97.0	260.8	369.4
Other | U.S.
Disaggregation of Revenue [Line Items]
Revenue	36.3	33.5	96.5	144.2
Other | Outside U.S.
Disaggregation of Revenue [Line Items]
Revenue	$ 52.4	$ 63.6	$ 164.3	$ 225.2