Identifiable Intangible Assets and Goodwill - Finite-lived and Indefinite-lived Intangible Assets - Footnotes (Details) - USD ($) $ in Millions		Sep. 30, 2018	Apr. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net		$ 36,012		$ 36,562
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	[1]	34,337		$ 34,765
Xtandi [Member] | Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Transfer of intangible assets		2,700
EU [Member] | Mylotarg [Member] | Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net			$ 240
In Process Research and Development [Member] | Xtandi [Member]
Finite-Lived Intangible Assets [Line Items]
Transfer of intangible assets		$ (2,700)

[1] The changes in the gross carrying amount of Developed technology rights and IPR&D primarily reflect (i) the transfer of $2.7 billion from IPR&D to Developed technology rights to reflect the approval of Xtandi in the U.S. for the treatment of men with non-metastatic castration-resistant prostate cancer, which is being developed through a collaboration with Astellas, and (ii) $240 million of Developed technology rights recorded in connection with the EU approval of Mylotarg (see Note 7E).