Goodwill and Other Intangible Assets (Narrative) (Details) $ in Millions		3 Months Ended		12 Months Ended
	Jun. 30, 2023	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Apr. 01, 2023 USD ($)
Intangible Assets Excluding Goodwill [Line Items]
Finite-lived intangible assets, net		$ 18,861.7	$ 22,566.9	$ 18,861.7	$ 22,566.9
In-process research and development		319.4	40.2	319.4	40.2
Goodwill		9,867.1	10,425.8	9,867.1	10,425.8	$ 12,113.7
Goodwill, Derecognized				919.7
Impairment of goodwill				(581.0)	(117.0)	0.0
Goodwill, Transfers				(189.0)
Intangible assets, net		19,181.1	22,607.1	$ 19,181.1	22,607.1
Europe Segment
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Decrease In Fair Value During Period, Percentage				10.00%
North America Segment
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Decrease In Fair Value During Period, Percentage				10.00%
Greater China
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Decrease In Fair Value During Period, Percentage				10.00%
JANZ
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Decrease In Fair Value During Period, Percentage				15.00%
Emerging Markets
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Decrease In Fair Value During Period, Percentage				15.00%
Disposal Group, Held-for-sale, Not Discontinued Operations
Intangible Assets Excluding Goodwill [Line Items]
Property, plant and equipment, net		262.2	0.0	$ 262.2	0.0
Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations
Intangible Assets Excluding Goodwill [Line Items]
Intangible assets, net		1,930.0		1,930.0
Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations | API
Intangible Assets Excluding Goodwill [Line Items]
Goodwill, Transfers		120.0
Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations | Women's Healthcare Business
Intangible Assets Excluding Goodwill [Line Items]
Goodwill, Transfers				69.0
In-process research and development
Intangible Assets Excluding Goodwill [Line Items]
IPR&D intangible asset impairment charges				0.0	0.6	19.4
Product rights and licenses
Intangible Assets Excluding Goodwill [Line Items]
Finite-lived intangible assets, net		$ 18,861.0	22,565.9	18,861.0	22,565.9
Finite-lived intangible asset disposal & impairment charges			172.9	$ 32.0	172.9	83.4
Europe Segment
Intangible Assets Excluding Goodwill [Line Items]
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount							$ 535.0
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		3.90%		3.90%
Good will, After Amortization Expense, Before Reclassification		$ 4,470.0		$ 4,470.0
North America Segment
Intangible Assets Excluding Goodwill [Line Items]
Good will, After Amortization Expense, Before Reclassification		3,150.0		3,150.0
JANZ
Intangible Assets Excluding Goodwill [Line Items]
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount		$ 145.0		$ 145.0
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		5.50%		5.50%
Goodwill		$ 645.7	689.0	$ 645.7	689.0	776.3
Impairment of goodwill				(30.0)
Goodwill, Transfers				0.0
Good will, After Amortization Expense, Before Reclassification		680.0		680.0
JANZ | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input, Term	10 years
JANZ | Product rights and licenses
Intangible Assets Excluding Goodwill [Line Items]
Finite-lived intangible assets, net		1,177.2	1,325.5	1,177.2	1,325.5
Greater China
Intangible Assets Excluding Goodwill [Line Items]
Goodwill		932.8	940.6	932.8	940.6	969.5
Impairment of goodwill				0.0
Goodwill, Transfers				0.0
Good will, After Amortization Expense, Before Reclassification		940.0		940.0
Greater China | Product rights and licenses
Intangible Assets Excluding Goodwill [Line Items]
Finite-lived intangible assets, net		5,216.5	5,642.9	5,216.5	5,642.9
Emerging Markets
Intangible Assets Excluding Goodwill [Line Items]
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount		$ 513.0		$ 513.0
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		7.70%		7.70%
Goodwill		$ 1,181.2	1,334.7	$ 1,181.2	1,334.7	$ 1,644.5
Goodwill, Transfers				(137.0)
Good will, After Amortization Expense, Before Reclassification		1,340.0		1,340.0
Emerging Markets | Disposal Group, Held-for-sale, Not Discontinued Operations | Upjohn Distributor Markets
Intangible Assets Excluding Goodwill [Line Items]
Impairment of goodwill			(117.0)	(7.0)
Emerging Markets | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input, Term	10 years
Emerging Markets | Product rights and licenses
Intangible Assets Excluding Goodwill [Line Items]
Finite-lived intangible assets, net		$ 3,035.7	$ 3,386.4	$ 3,035.7	$ 3,386.4
Measurement Input, Discount Rate | In-process research and development | Minimum
Intangible Assets Excluding Goodwill [Line Items]
Rate used to discount net cash inflows to present values		0.100		0.100		0.070
Measurement Input, Discount Rate | In-process research and development | Maximum
Intangible Assets Excluding Goodwill [Line Items]
Rate used to discount net cash inflows to present values		0.240	0.105	0.240	0.105	0.090
Measurement Input, Discount Rate | Europe Segment | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.110		0.110
Measurement Input, Discount Rate | Europe Segment | Minimum | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input Increase		1.00%		1.00%
Measurement Input, Discount Rate | Europe Segment | Maximum | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input Increase		4.50%		4.50%
Measurement Input, Discount Rate | JANZ | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.070		0.070
Measurement Input, Discount Rate | Emerging Markets | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.115		0.115
Measurement Input, Long-term Revenue Growth Rate | Europe Segment
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.024		0.024
Measurement Input, Long-term Revenue Growth Rate | JANZ
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.020		0.020
Measurement Input, Long-term Revenue Growth Rate | Emerging Markets
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.018		0.018
Measurement Input, Estimated Tax Rate | Europe Segment | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.149		0.149
Measurement Input, Estimated Tax Rate | JANZ | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.306		0.306
Measurement Input, Estimated Tax Rate | Emerging Markets | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.174		0.174
Measurement Input, Terminal Year Revenue Growth Rate | Europe Segment | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.020		0.020
Measurement Input, Terminal Year Revenue Growth Rate | JANZ | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.015		0.015
Measurement Input, Terminal Year Revenue Growth Rate | Emerging Markets | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.020		0.020
Measurement Input, Reduction in Terminal Year Revenue Growth Rate | Europe Segment | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.010		0.010
Measurement Input, Reduction in Terminal Year Revenue Growth Rate | JANZ | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.005		0.005
Measurement Input, Reduction in Terminal Year Revenue Growth Rate | Emerging Markets | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.025		0.025
Measurement Input, Increase in Discount Rate | Europe Segment | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.005		0.005
Measurement Input, Increase in Discount Rate | JANZ | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.005		0.005
Measurement Input, Increase in Discount Rate | Emerging Markets | Valuation Technique, Discounted Cash Flow
Intangible Assets Excluding Goodwill [Line Items]
Goodwill Impairment, Measurement Input		0.010		0.010