Related party transactions	12 Months Ended
Dec. 31, 2018
Related Party Transactions [Abstract]
Related party transactions	Related party transactions As of December 31, 2017, we owned a 50% interest in K-A, a corporation formed in 1984 with Kirin for the development and commercialization of certain products based on advanced biotechnology. All of our rights to manufacture and market certain products including pegfilgrastim, filgrastim, darbepoetin alfa, recombinant human erythropoietin and romiplostim are pursuant to exclusive licenses from K-A, which we currently market under the brand names Neulasta^®, NEUPOGEN^®(filgrastim)/GRANULOKINE^®, Aranesp^®, EPOGEN^®and Nplate^®(romiplostim), respectively. During the first quarter of 2018, we acquired the remaining 50% ownership of K-A from Kirin, making K-A a wholly owned subsidiary of Amgen. The transaction was accounted for as a business combination. K-A’s results of operations are now included in our consolidated financial statements, and as a result, transactions between us and K-A are eliminated in consolidation. See Note 3, Business combinations. License agreements with Kirin and Johnson & Johnson (J&J) remain in place. Prior to the share acquisition, we accounted for our interest in K-A using the equity method and included our share of K-A’s profits or losses in Selling, general and administrative expense in the Consolidated Statements of Income. Our share of K-A’s profits was insignificant for the period January 1, 2018 through the 2018 share acquisition date. For the years ended December 31, 2017 and 2016, our share of K-A’s profits was $68 million and $58 million, respectively. The carrying value of our equity method investment in K-A was $570 million as of December 31, 2017, and is included in Other assets in the Consolidated Balance Sheets. K-A’s revenues consist of royalty income related to its licensed technology rights. Prior to the share acquisition, K-A received royalty income from us. K-A also received and continues to receive royalty income from Kirin and J&J under separate product license contracts for certain geographic areas outside the United States. Royalties earned by K-A from us were insignificant for the period January 1, 2018 through the 2018 share acquisition date. During the years ended December 31, 2017 and 2016, K-A earned royalties from us of $221 million and $239 million, respectively. These amounts are included in Cost of sales in the Consolidated Statements of Income. K-A’s expenses consist primarily of costs related to R&D activities conducted on its behalf by us through the 2018 share acquisition and by Kirin. Payment for these services is based on negotiated rates. Revenues from K-A for certain R&D activities performed on K-A’s behalf were insignificant for the period January 1, 2018 through the 2018 share acquisition date. During the years ended December 31, 2017 and 2016, we earned revenues from K-A of $28 million and $31 million, respectively, for certain R&D activities performed on K-A’s behalf. These amounts were recognized as Other revenues in the Consolidated Statements of Income. Cost recoveries from K-A recorded during the period January 1, 2018 through the 2018 share acquisition date and the years ended December 31, 2017 and 2016, were insignificant. These amounts are included in Research and development expense in the Consolidated Statements of Income. As of December 31, 2017, we owed K-A $80 million, which is included in Accrued liabilities in the Consolidated Balance Sheets.

Related party transactions

As of December 31, 2017, we owned a 50% interest in K-A, a corporation formed in 1984 with Kirin for the development and commercialization of certain products based on advanced biotechnology. All of our rights to manufacture and market certain products including pegfilgrastim, filgrastim, darbepoetin alfa, recombinant human erythropoietin and romiplostim are pursuant to exclusive licenses from K-A, which we currently market under the brand names Neulasta^®, NEUPOGEN^®(filgrastim)/GRANULOKINE^®, Aranesp^®, EPOGEN^®and Nplate^®(romiplostim), respectively. During the first quarter of 2018, we acquired the remaining 50% ownership of K-A from Kirin, making K-A a wholly owned subsidiary of Amgen. The transaction was accounted for as a business combination. K-A’s results of operations are now included in our consolidated financial statements, and as a result, transactions between us and K-A are eliminated in consolidation. See Note 3, Business combinations. License agreements with Kirin and Johnson & Johnson (J&J) remain in place.

Prior to the share acquisition, we accounted for our interest in K-A using the equity method and included our share of K-A’s profits or losses in Selling, general and administrative expense in the Consolidated Statements of Income. Our share of K-A’s profits was insignificant for the period January 1, 2018 through the 2018 share acquisition date. For the years ended December 31, 2017 and 2016, our share of K-A’s profits was $68 million and $58 million, respectively. The carrying value of our equity method investment in K-A was $570 million as of December 31, 2017, and is included in Other assets in the Consolidated Balance Sheets.

K-A’s revenues consist of royalty income related to its licensed technology rights. Prior to the share acquisition, K-A received royalty income from us. K-A also received and continues to receive royalty income from Kirin and J&J under separate product license contracts for certain geographic areas outside the United States. Royalties earned by K-A from us were insignificant for the period January 1, 2018 through the 2018 share acquisition date. During the years ended December 31, 2017 and 2016, K-A earned royalties from us of $221 million and $239 million, respectively. These amounts are included in Cost of sales in the Consolidated Statements of Income.

K-A’s expenses consist primarily of costs related to R&D activities conducted on its behalf by us through the 2018 share acquisition and by Kirin. Payment for these services is based on negotiated rates. Revenues from K-A for certain R&D activities performed on K-A’s behalf were insignificant for the period January 1, 2018 through the 2018 share acquisition date. During the years ended December 31, 2017 and 2016, we earned revenues from K-A of $28 million and $31 million, respectively, for certain R&D activities performed on K-A’s behalf. These amounts were recognized as Other revenues in the Consolidated Statements of Income. Cost recoveries from K-A recorded during the period January 1, 2018 through the 2018 share acquisition date and the years ended December 31, 2017 and 2016, were insignificant. These amounts are included in Research and development expense in the Consolidated Statements of Income.

As of December 31, 2017, we owed K-A $80 million, which is included in Accrued liabilities in the Consolidated Balance Sheets.