Collaborations and Other Arrangements (Net Product Revenue) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 6,114.0	$ 5,476.6	$ 5,636.7	$ 5,092.2	$ 5,637.6	$ 5,306.9	$ 5,585.0	$ 4,963.8	$ 22,319.5	$ 21,493.3	$ 19,973.8
Basaglar®
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue									1,112.6	801.2	432.1
Jardiance
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue									944.2	658.3	447.5
Trajenta®
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue									$ 590.6	$ 574.7	$ 537.9