Identifiable Intangible Assets and Goodwill - Finite-lived and Indefinite-lived Intangible Assets (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount		$ 76,759	$ 75,058
Finite-lived intangible assets, accumulated amortization	[1]	(52,862)	(48,941)
Finite-lived intangible assets, less accumulated amortization		23,896	26,117
Indefinite-lived Intangible Assets [Line Items]
Total indefinite-lived intangible assets		4,575	7,819
Intangible assets, gross carrying amount	[1]	81,334	82,877
Identifiable Intangible Assets, less Accumulated Amortization	[1]	28,471	33,936
Brands [Member]
Indefinite-lived Intangible Assets [Line Items]
Total indefinite-lived intangible assets		827	827
IPR&D [Member]
Indefinite-lived Intangible Assets [Line Items]
Total indefinite-lived intangible assets	[2]	3,175	5,919
Licensing Agreements and Other [Member]
Indefinite-lived Intangible Assets [Line Items]
Total indefinite-lived intangible assets	[3]	573	1,073
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount	[4]	73,545	72,449
Finite-lived intangible assets, accumulated amortization	[4]	(50,902)	(47,092)
Finite-lived intangible assets, less accumulated amortization	[4]	22,643	25,357
Brands [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount		922	922
Finite-lived intangible assets, accumulated amortization		(774)	(741)
Finite-lived intangible assets, less accumulated amortization		148	181
Licensing Agreements and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount	[3]	2,292	1,687
Finite-lived intangible assets, accumulated amortization	[3]	(1,186)	(1,108)
Finite-lived intangible assets, less accumulated amortization	[3]	$ 1,106	$ 579

[1] The decrease is primarily due to amortization, impairments, and measurement period adjustments related to the acquisition of Array, partially offset by the capitalization of an upfront payment to Myovant (see Note 2E).

[2] The decrease in the gross carrying amount primarily reflects a decrease from a $1.2 billion measurement period adjustment related to the acquisition of Array, a $900 million impairment of IPR&D (see Note 4), and the transfer of $600 million from IPR&D to Developed technology rights to reflect the approval of Braftovi in combination with Erbitux® (cetuximab), for the treatment of BRAFV600E-mutant mCRC after prior therapy.

[3] The changes in the gross carrying amounts primarily reflect the transfer of $600 million from indefinite-lived Licensing agreements and other to finite-lived Licensing agreements and other to reflect the approval in the U.S. of several products subject to out-licensing arrangements acquired from Array, as well as measurement period adjustments related to the acquisition of Array.

[4] The increase in the gross carrying amount primarily reflects the transfer of $600 million from IPR&D to Developed technology rights to reflect the approval of Braftovi in combination with Erbitux® (cetuximab), for the treatment of BRAFV600E-mutant mCRC after prior therapy, as well as a $499 million capitalized portion of an upfront payment to Myovant (see Note 2E) and an increase from a $200 million measurement period adjustment related to the acquisition of Array (see Note 2A), partially offset by a $528 million impairment of Eucrisa (see Note 4) and a $263 million impairment of certain generic sterile injectables acquired in connection with our acquisition of Hospira (see Note 4).