Acquisitions of businesses (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations1 [Abstract]
Property, plant & equipment	$ 0	$ 1,000,000	$ 1,000,000
Currently marketed products	0	0	346,000,000
Acquired research & development	0	505,000,000	0
Deferred tax assets	0	28,000,000	12,000,000
Inventories	0	0	3,000,000
Trade receivables and other current assets	0	0	2,000,000
Cash and cash equivalents	0	6,000,000	5,000,000
Deferred tax liabilities	0	(121,000,000)	(78,000,000)
Trade payables and other liabilities	0	(1,000,000)	(4,000,000)
Net identifiable assets acquired	0	418,000,000	287,000,000
Acquired liquidity	0	(6,000,000)	(5,000,000)
Goodwill	0	6,000,000	4,000,000
Net assets recognized as a result of business combinations	$ 0	418,000,000	286,000,000
Goodwill expected to be deductible for tax purposes		$ 0	$ 0

Business Combinations1 [Abstract]

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Currently Marketed Products Intangible Asset Recognised As Of Acquisition Date

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Net Identifiable Assets Acquired (Liabilities Assumed), Excluding Cash Acquired

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Research And Development Intangible Assets Recognised As Of Acquisition Date

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No definition available.

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- Definition

The amount recognised as of the acquisition date for cash and cash equivalents acquired in a business combination. [Refer: Cash and cash equivalents; Business combinations [member]]

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The amount recognised as of the acquisition date for deferred tax assets acquired in a business combination. [Refer: Deferred tax assets; Business combinations [member]]

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The amount recognised as of the acquisition date for deferred tax liabilities assumed in a business combination. [Refer: Deferred tax liabilities; Business combinations [member]]

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- Definition

The fair value of receivables acquired in a business combination. [Refer: Business combinations [member]]

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- Definition

The amount of goodwill in a business combination that is expected to be deductible for tax purposes. [Refer: Goodwill; Business combinations [member]]

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The amount recognised as of the business combination's acquisition date for goodwill. [Refer: Goodwill; Business combinations [member]]

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The amount recognised as of the acquisition date for net identifiable assets acquired or liabilities assumed in a business combination. [Refer: Business combinations [member]]

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The amount recognised as of the acquisition date for inventory acquired in a business combination. [Refer: Inventories; Business combinations [member]]

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The amount recognised as of the acquisition date for plant, property and equipment acquired in a business combination. [Refer: Property, plant and equipment; Business combinations [member]]

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- Definition

The amount recognised as of the acquisition date for trade and other payables assumed in a business combination. [Refer: Trade and other payables; Business combinations [member]]

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