Acquisitions and Other Transactions (Narrative) (Details) $ / shares in Units, $ in Millions		3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Nov. 07, 2022 USD ($)	Sep. 30, 2023 USD ($) right $ / shares	Jun. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2023 USD ($) right $ / shares	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Revenue				$ 4,083.8			$ 12,399.7
Business Acquisition, Pro Forma Net Income (Loss)		$ 338.3		313.7		$ 852.9	915.1
Goodwill		10,278.1				10,278.1		$ 10,425.8
Contingent consideration		371.1				371.1		375.0
Payments to Acquire Businesses, Net of Cash Acquired						667.7	0.0
Revenues		3,941.9		4,078.2		11,589.6	12,386.7
Net earnings attributable to Viatris Inc. common shareholders		331.6		$ 354.3		820.3	$ 1,067.4
Prepaid expenses and other current assets		1,784.7				1,784.7		1,811.2
In Process Research And Development, Fair value Measurement Input, Discount Rate	23.90%
Defined benefit plans, estimated benefit payments, in current fiscal year						108.5
Estimated employer contributions in current year		51.3				51.3
Famy Life Sciences
Business Acquisition [Line Items]
Equity Securities, FV-NI										$ 25.0
Gain (Loss) on Disposition of Stock in Subsidiary or Equity Method Investee						18.9
Mapi Pharma Ltd. | Variable Interest Entity, Not Primary Beneficiary
Business Acquisition [Line Items]
Variable Interest Entity, Maximum Milestone Payments		90.0				90.0
Equity Securities, FV-NI, Unrealized Gain (Loss)			$ 45.6
Other Assets		132.1				132.1		56.4
Gain (Loss) on Investments						62.1		16.5
Prepaid expenses and other current assets		$ 52.5				$ 52.5		$ 42.5
Variable Interest Entity, Financial or Other Support, Amount			$ 30.0
Product Rights And Licenses
Business Acquisition [Line Items]
Finite-lived intangible assets, estimated useful life, in years		10 years				10 years
Oyster Point Pharma Acquisition
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs						$ 21.4
Goodwill		$ 5.9				5.9
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory						29.3
Business Combination, Consideration Transferred						$ 427.4
Business Acquisition, Share Price | $ / shares		$ 11				$ 11
Business Acquisition, Non-Transferable Contingent Value Right, Number Of Rights | right		1				1
Business Acquisition, Contingent Consideration Per Share | $ / shares		$ 2				$ 2
Contingent consideration		$ 60.0				$ 60.0
Business Acquisition, Provisional Information, Initial Accounting Incomplete, Adjustment, Amortization		7.3				22.0
Payments to Acquire Businesses, Net of Cash Acquired		392.7				392.7
Revenues					$ 26.9
Net earnings attributable to Viatris Inc. common shareholders					$ 119.8
Oyster Point Pharma Acquisition | Product Rights And Licenses
Business Acquisition [Line Items]
Acquired intangible assets		$ 334.0				$ 334.0
Famy Life Sciences Acquisition
Business Acquisition [Line Items]
Goodwill	$ 89.3
Business Combination, Consideration Transferred	281.0
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value	43.9
Payments to Acquire Businesses, Net of Cash Acquired	325.0
Famy Life Sciences Acquisition | In Process Research and Development
Business Acquisition [Line Items]
Acquired intangible assets	$ 290.0
Famy Life Sciences Acquisition | In Process Research and Development | Scenario, Forecast
Business Acquisition [Line Items]
Acquired intangible assets									$ 120.0
Viatris Inc.
Business Acquisition [Line Items]
Subsidiary, Ownership Percentage, Noncontrolling Owner										13.50%