Document and Entity Information Document Information [Table] Class of Stock [Axis] Class of Stock [Domain] Shares Represents the 0.5% Senior Unsecured Exchangeable Bonds, which are exchangeable into shares of the entity's stock. 0.50% Exchangeable Bonds due January 2023 Document Information [Line Items] Document and Entity Information Document Type Document Period End Date Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, Postal Zip Code Entity Address, Country City Area Code Local Phone Number Written Communications Soliciting Material Pre-commencement Tender Offer Pre-commencement Issuer Tender Offer Title of 12(b) Security Trading Symbol Security Exchange Name Entity Emerging Growth Company Entity Central Index Key Amendment Flag