Identifiable Intangible Assets and Goodwill - Finite-lived and Indefinite-lived Intangible Assets (Detail) - USD ($) $ in Millions		Sep. 30, 2018	Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		$ 9,294	$ 12,179
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount		96,187	93,595
Finite-lived intangible assets, accumulated amortization	[1]	(60,175)	(57,033)
Finite-lived intangible assets, net		36,012	36,562
Intangible assets, gross carrying amount	[1]	105,481	105,774
Finite-lived intangible assets, accumulated amortization	[1]	(60,175)	(57,033)
Identifiable Intangible Assets, less Accumulated Amortization	[1],[2]	45,306	48,741
Brands [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		6,909	6,929
In Process Research and Development [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	[3]	2,385	5,249
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount	[3]	92,123	89,550
Finite-lived intangible assets, accumulated amortization	[3]	(57,786)	(54,785)
Finite-lived intangible assets, net	[3]	34,337	34,765
Finite-lived intangible assets, accumulated amortization	[3]	(57,786)	(54,785)
Brands [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount		2,126	2,134
Finite-lived intangible assets, accumulated amortization		(1,228)	(1,152)
Finite-lived intangible assets, net		898	982
Finite-lived intangible assets, accumulated amortization		(1,228)	(1,152)
License Agreements and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount		1,938	1,911
Finite-lived intangible assets, accumulated amortization		(1,160)	(1,096)
Finite-lived intangible assets, net		777	815
Finite-lived intangible assets, accumulated amortization		$ (1,160)	$ (1,096)

[1] The decrease in Identifiable intangible assets, less accumulated amortization, is primarily due to amortization, partially offset by additions, mainly consisting of $240 million of Developed technology rights recorded in connection with the EU approval of Mylotarg (see Note 7E).

[2] Amounts may not add due to rounding.

[3] 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).