Contingencies (Details) $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	Jan. 31, 2015 USD ($)	Nov. 30, 2012 item	Sep. 30, 2015 a	Sep. 30, 2014 USD ($) item	Dec. 31, 2015 USD ($)	Dec. 31, 1992 entity
Contingencies
Brazil Governmental assessments					$ 7.5
Environmental litigation with respect to Lowry Landfill site
Contingencies
Approximate number of other companies named in a lawsuit with respect to Lowry Landfill | entity						38
Waste Management litigation
Contingencies
Response cost related to site, minimum before the company may be asked to make payments					$ 319.0
Projects costs to date	$ 140.0
Period before projected completion of project when response cost is expected to exceed minimum amount					3 years
Estimated additional cleanup costs					$ 10.0
Estimated additional site costs for the potentially responsible party (PRP) group					$ 1.0
Environmental litigation with respect to Lower Duwamish site
Contingencies
Number of potentially responsible parties (PRPs) | item		50
Number of additional potentially responsible parties (PRPs) | item				20
Expected future remediation costs				$ 342.0
Expected future remediation of area of river bottom | a			200
Site cleanup costs				$ 100.0
Number of companies whose data is under review | item		30
Number of potentially responsible parties (PRP) groups whose data is under review | item		2
Period over which data is reviewed		2 years