Acquisitions, Research Collaborations and License Agreements - Narrative (Details) $ / shares in Units, € in Millions, shares in Millions, $ in Millions		1 Months Ended														12 Months Ended
	Apr. 01, 2019 USD ($)	Dec. 31, 2021 USD ($)	Nov. 30, 2021 USD ($)	Apr. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jan. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 EUR (€)	Jul. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	May 31, 2020 USD ($)	Jan. 31, 2020 USD ($)	Jul. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Nov. 19, 2021 USD ($)	Jan. 16, 2020 USD ($)
Business Acquisition [Line Items]
Research and development																$ 12,245.0	$ 13,397.0	$ 9,724.0
Research and development expenses																1,556.0	0.0	0.0
Inventories		$ 5,953.0					$ 5,554.0									5,953.0	5,554.0
Contingent consideration		777.0					841.0									777.0	841.0	767.0
Goodwill		21,264.0					18,882.0									21,264.0	18,882.0	18,069.0
IPR&D impairment charges																		172.0
Business combination, contingent consideration arrangements, change in amount of contingent consideration liability																(57.0)	(83.0)
Pandion Therapeutics
Business Acquisition [Line Items]
Consideration paid				$ 1,900.0
Transaction costs				147.0
Other net assets (liabilities)				$ 156.0
Research and development																1,700.0
OncoImmune
Business Acquisition [Line Items]
Consideration paid							423.0
Other net assets (liabilities)							(22.0)										$ (22.0)
Payments to acquire investment							$ 50.0
Equity method, ownership percentage							20.00%										20.00%
Investments							$ 33.0										$ 33.0
Premium on shares acquired							17.0
Research and development expenses																	462.0
VelosBio
Business Acquisition [Line Items]
Consideration paid		47.0					2,800.0
Other net assets (liabilities)		$ 90.0					180.0									90.0	180.0
Research and development																43.0	2,700.0
Dunboyne
Business Acquisition [Line Items]
Consideration paid								$ 302.0	€ 256
Other net assets (liabilities)								13.0
Property, plant and equipment								289.0
Peloton
Business Acquisition [Line Items]
Consideration paid														$ 1,200.0
Other net assets (liabilities)														4.0
Research and development																		$ 993.0
Cash														157.0
Deferred tax liabilities														52.0
Research and development
Business Acquisition [Line Items]
Premium on shares acquired																	16.0
Sentinel
Business Acquisition [Line Items]
Consideration paid										$ 410.0
Inventories										9.0
Sentinel | Products and product rights
Business Acquisition [Line Items]
Finite-lived intangible assets acquired										$ 401.0
COVID-19
Business Acquisition [Line Items]
Research and development																	45.0
Charges related to program discontinuation																207.0	305.0
IPR&D impairment charges																	90.0
Business combination, contingent consideration arrangements, change in amount of contingent consideration liability																	45.0
Inventory and fixed assets write-offs																	260.0
nemtabrutinib
Business Acquisition [Line Items]
IPR&D impairment charges																275.0
Gilead Sciences | Oral and Injectable Formulations | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Profit share by counterparty					60.00%
Profit share					40.00%
Gilead Sciences | Oral Formulation | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Profit share by counterparty					65.00%
Profit share					35.00%
Sales threshold					$ 2,000.0
Gilead Sciences | Injectable Formulation | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Profit share by counterparty					65.00%
Profit share					35.00%
Sales threshold					$ 3,500.0
Artiva Biotherapeutics, Inc. | Licensing Agreements
Business Acquisition [Line Items]
Upfront and milestone payments						$ 30.0
Upfront and milestone payments to be made						$ 15.0
Artiva Biotherapeutics, Inc. | Minimum | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate, percentage						7.00%
Artiva Biotherapeutics, Inc. | Maximum | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate, percentage						14.00%
Seagen
Business Acquisition [Line Items]
Contingent payments collaborative arrangement								2,600.0
Research and development																	616.0
Upfront and milestone payments								600.0
Payments to acquire investment								$ 1,000.0
Forward contract indexed to issuer's equity, indexed shares (in shares) | shares								5
Share price (in dollars per share) | $ / shares								$ 200
Seagen | Tukysa
Business Acquisition [Line Items]
Upfront and milestone payments								$ 210.0
Seagen | Tukysa | Minimum
Business Acquisition [Line Items]
Royalty rate, percentage								20.00%	20.00%
Seagen | Tukysa | Maximum
Business Acquisition [Line Items]
Royalty rate, percentage								33.00%	33.00%
Sentinel | Products and product rights
Business Acquisition [Line Items]
Estimated useful life of intangible assets, acquired										15 years
IAVI
Business Acquisition [Line Items]
Upfront and milestone payments												$ 6.5
Bristol Myers Squibb | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate, percentage			22.00%
Royalty rate, deduction, percentage			50.00%
Bristol Myers Squibb | Minimum | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate, percentage			20.00%
Bristol Myers Squibb | Maximum | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate, percentage			24.00%
Acceleron Pharma Inc.
Business Acquisition [Line Items]
Cash paid for acquisition of business			$ 11,500.0
Transaction costs			$ 280.0
Estimated useful life of intangible assets, acquired			12 years
In-process research and development (IPR&D)																			$ 6,380.0
Cash and cash equivalents																			340.0
Other assets and (liabilities), net																			89.0
Goodwill																			$ 2,422.0
Themis
Business Acquisition [Line Items]
Cash paid for acquisition of business											$ 366.0
Potential future milestone payments, maximum							450.0				740.0						450.0
Contingent consideration											85.0
In-process research and development (IPR&D)											113.0
Cash and cash equivalents											59.0
Deferred tax assets											72.0
Other assets and (liabilities), net											(32.0)
Goodwill											$ 239.0
Themis | COVID-19
Business Acquisition [Line Items]
IPR&D impairment charges																	90.0
Business combination, contingent consideration arrangements, change in amount of contingent consideration liability																	45.0
ArQule
Business Acquisition [Line Items]
Cash paid for acquisition of business													$ 2,700.0
Transaction costs													95.0
In-process research and development (IPR&D)																				$ 2,280.0
Cash and cash equivalents																				145.0
Other assets and (liabilities), net																				34.0
Goodwill																				$ 512.0
Share-based compensation payments to settle equity awards attributable to precombination service													$ 138.0
Antelliq
Business Acquisition [Line Items]
Cash paid for acquisition of business	$ 2,300.0
Transaction costs	47.0
Debt assumed	1,300.0
Property, plant and equipment	60.0
Cash and cash equivalents	31.0
Other assets and (liabilities), net	(82.0)
Goodwill	$ 1,376.0
Immune Design
Business Acquisition [Line Items]
Cash paid for acquisition of business															$ 301.0
Other net assets															42.0
In-process research and development (IPR&D)															156.0
Cash and cash equivalents															83.0
Goodwill															$ 20.0
Development Milestones | Artiva Biotherapeutics, Inc. | Licensing Agreements
Business Acquisition [Line Items]
Contingent payments collaborative arrangement						$ 217.5
Development Milestones | Seagen
Business Acquisition [Line Items]
Contingent payments collaborative arrangement								$ 850.0
Development Milestones | Themis
Business Acquisition [Line Items]
Potential future milestone payments, maximum							60.0										60.0
Regulatory Milestones | Peloton
Business Acquisition [Line Items]
Contingent consideration														50.0
Regulatory Milestones | Artiva Biotherapeutics, Inc. | Licensing Agreements
Business Acquisition [Line Items]
Contingent payments collaborative arrangement						570.0
Regulatory Milestones | Seagen | Tukysa
Business Acquisition [Line Items]
Contingent payments collaborative arrangement								65.0
Regulatory Milestones | Bristol Myers Squibb | Licensing Agreements
Business Acquisition [Line Items]
Contingent payments collaborative arrangement			$ 20.0
Regulatory Milestones | Themis
Business Acquisition [Line Items]
Potential future milestone payments, maximum							196.0										196.0
Commercial Milestone | Peloton
Business Acquisition [Line Items]
Contingent consideration																$ 50.0
Sales-Based Milestones | Peloton
Business Acquisition [Line Items]
Contingent consideration														$ 1,050.0
Sales-Based Milestones | Artiva Biotherapeutics, Inc. | Licensing Agreements
Business Acquisition [Line Items]
Contingent payments collaborative arrangement						$ 1,050.0
Sales-Based Milestones | Seagen
Business Acquisition [Line Items]
Contingent payments collaborative arrangement								$ 1,750.0
Sales-Based Milestones | Bristol Myers Squibb | Licensing Agreements
Business Acquisition [Line Items]
Contingent payments collaborative arrangement			$ 80.0
Sales-Based Milestones | Themis
Business Acquisition [Line Items]
Potential future milestone payments, maximum							$ 194.0										$ 194.0