Summary of significant accounting policies (Policies)	9 Months Ended
Summary of significant accounting policies (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Business	Business Amgen Inc. (including its subsidiaries, referred to as “Amgen,” “the Company,” “we,” “our” or “us”) is a global biotechnology pioneer that discovers, develops, manufactures and delivers innovative human therapeutics. We operate in one business segment: human therapeutics.
Basis of presentation	Basis of presentation The financial information for the three and nine months ended September 30, 2021 and 2020, is unaudited but includes all adjustments (consisting of only normal, recurring adjustments unless otherwise indicated), which Amgen considers necessary for a fair presentation of its condensed consolidated results of operations for those periods. Interim results are not necessarily indicative of results for the full fiscal year. The condensed consolidated financial statements should be read in conjunction with our consolidated financial statements and the notes thereto contained in our Annual Report on Form 10-K for the year ended December 31, 2020, and with our condensed consolidated financial statements and the notes thereto contained in our Quarterly Reports on Form 10-Q for the periods ended March 31, 2021 and June 30, 2021.
Principles of consolidation	Principles of consolidation The condensed consolidated financial statements include the accounts of Amgen as well as its majority-owned subsidiaries. We do not have any significant interests in any variable interest entities. All material intercompany transactions and balances have been eliminated in consolidation.
Use of estimates	Use of estimates The preparation of condensed consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results may differ from those estimates.
Property, plant and equipment, net	Property, plant and equipment, net Property, plant and equipment is recorded at historical cost, net of accumulated depreciation and amortization of $9.2 billion and $9.0 billion as of September 30, 2021 and December 31, 2020, respectively.
Other recent accounting pronouncements	Recent accounting pronouncements In March 2020, the Financial Accounting Standards Board (FASB) issued a new accounting standard to ease the financial reporting burdens caused by the expected market transition from the London Interbank Offered Rate (LIBOR) and other interbank offered rates to alternative reference rates, commonly referred to as reference rate reform. The new standard provides temporary optional expedients and exceptions to current GAAP guidance on contract modifications and hedge accounting. Specifically, a modification to transition to an alternative reference rate is treated as an event that does not require contract remeasurement or reassessment of a previous accounting treatment. Moreover, for all types of hedging relationships, an entity is permitted to change the reference rate without having to dedesignate the hedging relationship. The standard is generally effective for all contract modifications made and hedging relationships evaluated through December 31, 2022. In January 2021, the FASB issued a new accounting standard to expand on the scope of the original March 2020 standard to include derivative instruments on discounting transactions. We are currently evaluating the impacts that the two standards will have on our condensed consolidated financial statements.