Business combinations (Aggregate Consideration Paid) (Details) - Kirin-Amgen, Inc. (K-A) [Member] $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Total cash paid to Kirin	$ 780
Fair value of contingent consideration obligation	45
Loss on settlement of preexisting relationship	(168)
Total consideration transferred to acquire K-A	657
Fair value of Amgen’s investment in K-A	825
Total acquisition date fair value	$ 1,482

Business Combination, Fair Value of Contingent Consideration Arrangements, Addition from Acquisitions

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
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Fair value at acquisition-date of the assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interests issued by the acquirer, including but not limited to, instruments or interests issued or issuable in consideration for the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

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In a business combination achieved in stages, this element represents the amount of loss recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

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No definition available.

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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