Contingencies and commitments (Details Textual) $ in Millions												1 Months Ended				2 Months Ended	12 Months Ended
	Jan. 22, 2018 lawsuit	Oct. 18, 2017 patent	Oct. 06, 2017 patent	Oct. 05, 2017 defendants	Sep. 22, 2017 USD ($)	Sep. 14, 2017 lawsuit	Jan. 23, 2017 patent	Nov. 08, 2016 lawsuit	Nov. 01, 2016 lawsuit	Feb. 26, 2016 patent affiliate	Dec. 15, 2014 patent	Dec. 31, 2017 USD ($) lawsuit	Jun. 30, 2017 lawsuit	Sep. 30, 2016 lawsuit	Mar. 31, 2016	Oct. 02, 2015 lawsuit	Dec. 31, 2017 USD ($) actions plaintiffs lawsuit	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Future rental commitments for abandoned leases | $												$ 264					$ 264
Future rental income relating to noncancelable subleases of abandoned facilities | $												$ 205					205
Rental expense on operating leases | $																	$ 159	$ 134	$ 133
Sanofi/Regeneron Patent Litigation [Member]
Loss Contingencies [Line Items]
Number of patents allegedly infringed | patent											7
Length of trial															5 days
Loss contingency, number of defendants | defendants				2
Sensipar (cinacalcet) Patent Litigation [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit												4	4	14
KYPROLIS (carfilzomib) Patent Litigation [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit						3											10
Apotex NEUPOGEN/Neulasta [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit																2
ENBREL (etanercept) [Member]
Loss Contingencies [Line Items]
Number of patents allegedly infringed | patent										5
Gain contingency, number of affiliates | affiliate										2
Epoetin Alfa Litigation [Member]
Loss Contingencies [Line Items]
Number of patents allegedly infringed | patent							2
Length of trial					5 days
Aount awarded from other party | $					$ 70
Mvasi Patent Litigation, Genentech, Inc. (Genentech) and the City of Hope [Member]
Loss Contingencies [Line Items]
Number of patents allegedly infringed | patent			27
Loss contingency, patents allegedly infringed | patent		25	24
State Derivative Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency, number of plaintiffs | plaintiffs																	3
Loss contingency, number of lawsuits | actions																	1
Onyx Therapeutics, Inc [Member] | KYPROLIS (carfilzomib) Patent Litigation [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit								4	4
Subsequent event [Member] | Mvasi Patent Litigation, Genentech, Inc. (Genentech) and the City of Hope [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit	2