Acquisitions, Divestitures, Equity-Method Investments, Licensing Arrangements and Collaborative Arrangements - Acquisitions (Details) - USD ($) $ / shares in Units, $ in Millions									1 Months Ended	3 Months Ended		11 Months Ended	12 Months Ended
		Dec. 31, 2022	Oct. 05, 2022	Oct. 03, 2022	Jun. 09, 2022	Mar. 11, 2022	Nov. 17, 2021	Jul. 30, 2019	Nov. 30, 2021	Dec. 31, 2022	Apr. 03, 2022	Nov. 16, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Business acquisition, cash payment, net of cash acquired													$ 22,997	$ 0	$ 0
Goodwill	[1]	$ 51,375								$ 51,375			51,375	49,208	49,556
Acquired in-process research and development expenses	[2]												$ 953	3,469	684
Finite-lived intangible asset, useful life													9 years
Collaborative Arrangement [Member]
Business Acquisition [Line Items]
Acquired in-process research and development expenses	[3]												$ 339	$ 1,056	179
Biohaven Ltd [Member] | Collaborative Arrangement [Member]
Business Acquisition [Line Items]
Tiered royalties, annual net sales threshold				$ 5,250
Potential milestone payments				$ 1,100
Biohaven Ltd [Member]
Business Acquisition [Line Items]
Ownership percentage		1.50%
Biohaven [Member]
Business Acquisition [Line Items]
Ownership percentage									2.60%
Trillium [Member]
Business Acquisition [Line Items]
Ownership percentage												2.00%
ReViral [Member]
Business Acquisition [Line Items]
Asset acquisition, consideration transferred					$ 536
Payments to acquire asset					436
Payment for asset acquisition, base payment					425
Asset acquisition, contingent consideration					100
Acquired in-process research and development expenses					$ 426
Trillium [Member]
Business Acquisition [Line Items]
Asset acquisition, consideration transferred							$ 2,000
Acquired in-process research and development expenses							$ 2,100
Asset acquisition, share price (in dollars per share)							$ 18.50
Asset acquisition, assets acquired							$ 256
Asset acquisition, liabilities assumed							$ 81
GBT [Member]
Business Acquisition [Line Items]
Business acquisition, per share in cash (in dollars per share)			$ 68.50
Business acquisition, cash payment, gross			$ 5,700
Business acquisition, cash payment, net of cash acquired			5,200
Intangible assets			4,400
Goodwill			1,100
Inventory			$ 681
Acquired inventory, selling period			3 years
Net deferred tax liabilities			$ 570
Assumed long-term debt, paid in full			331
GBT [Member] | Restructuring Charges And Acquisition-Related Costs [Member]
Business Acquisition [Line Items]
Post closing compensation expense			136							$ 136
Biohaven [Member]
Business Acquisition [Line Items]
Business acquisition, per share in cash (in dollars per share)				$ 148.50
Business acquisition, cash payment, gross				$ 11,500
Intangible assets				12,100
Goodwill				797
Inventory				$ 817
Acquired inventory, selling period				2 years
Net deferred tax liabilities				$ 566
Assumed long-term debt, paid in full				1,400
Repayment of assumed debt				863
Business acquisition, equity consideration				495
Consideration transferred, including equity interest held prior to business combination				11,800
Fair value of previously held equity interest in acquiree				300
Trade accounts receivable				398
Other current liabilities				477
Arena [Member]
Business Acquisition [Line Items]
Business acquisition, per share in cash (in dollars per share)						$ 100
Business acquisition, cash payment, gross						$ 6,600
Business acquisition, cash payment, net of cash acquired						6,200
Intangible assets						5,500
Goodwill						1,000
Net deferred tax liabilities						506
Arena [Member] | Restructuring Charges And Acquisition-Related Costs [Member]
Business Acquisition [Line Items]
Post closing compensation expense						138					$ 138
Array [Member]
Business Acquisition [Line Items]
Business acquisition, per share in cash (in dollars per share)								$ 48
Business acquisition, cash payment, gross								$ 11,200
Business acquisition, cash payment, net of cash acquired								10,900
Intangible assets								6,300
Goodwill								6,100
Net deferred tax liabilities								1,100
Assumed long-term debt, paid in full								451
Array [Member] | Restructuring Charges And Acquisition-Related Costs [Member]
Business Acquisition [Line Items]
Post closing compensation expense								$ 157
Developed Technology Rights [Member]
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life													8 years
Developed Technology Rights [Member] | GBT [Member]
Business Acquisition [Line Items]
Intangible assets			$ 1,400
Acquired intangible assets, useful life			6 years
Developed Technology Rights [Member] | Biohaven [Member]
Business Acquisition [Line Items]
Intangible assets				$ 11,600
Acquired intangible assets, useful life				11 years
Developed Technology Rights [Member] | Array [Member]
Business Acquisition [Line Items]
Acquired intangible assets, useful life								16 years
Identifiable intangible assets								$ 2,000
IPR&D [Member] | GBT [Member]
Business Acquisition [Line Items]
Intangible assets			$ 3,000
IPR&D [Member] | Biohaven [Member]
Business Acquisition [Line Items]
Intangible assets				$ 450
IPR&D [Member] | Arena [Member]
Business Acquisition [Line Items]
Intangible assets						5,000
IPR&D [Member] | Array [Member]
Business Acquisition [Line Items]
Identifiable intangible assets								2,800
Reduction in intangible assets due to measurement period adjustments															$ 900
Licensing Agreements [Member] | Arena [Member]
Business Acquisition [Line Items]
Intangible assets						$ 460
Licensing Agreements [Member] | Array [Member]
Business Acquisition [Line Items]
Intangible assets								1,500
Licensing Agreements, Technology In Development [Member] | Array [Member]
Business Acquisition [Line Items]
Intangible assets								1,200
Licensing Agreements, Developed Technology [Member] | Array [Member]
Business Acquisition [Line Items]
Identifiable intangible assets								$ 360
Finite-lived intangible asset, useful life								10 years

[1] As a result of the organizational changes to the commercial structure within the Biopharma operating segment effective in the third quarter of 2022 (see Note 1A), our goodwill was required to be reallocated amongst impacted reporting units. The allocation of goodwill is a complex process that requires, among other things, that we determine the fair value of each reporting unit under our old and new organizational structure and the portions being transferred. We completed this re-allocation during the fourth quarter 2022 and concluded that none of our goodwill was impaired. Our goodwill balance continues to be assigned within the Biopharma reportable segment.

[2] See Note 1L.

[3] Primarily relates to upfront payments to our partners as well as premiums paid on our equity investments in the common stock of our partners.