Contingencies (Details) $ in Millions		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Nov. 04, 2011 USD ($)	Jan. 31, 2015 USD ($)	Sep. 30, 2014 item	Sep. 30, 2016 USD ($) a item	Dec. 31, 1992 entity	Nov. 30, 2012 item
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
Number of actions in which the company is actively involved | item				0
Waste Management litigation
Contingencies
Response cost related to site, minimum before the company may be asked to make payments				$ 319
Projects costs to date		$ 140
Period before projected completion of project when response cost is expected to exceed minimum amount				3 years
Estimated additional cleanup costs				$ 10
Estimated additional site costs for the potentially responsible party (PRP) group				1
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
Expected future remediation of area of river bottom | a				200
Site cleanup costs				$ 100
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
Georgia Pacific and International Paper Claims
Contingencies
Past costs incurred by complainants	$ 14
Remediation costs	$ 30
Rexam | Georgia Pacific and International Paper Claims
Contingencies
Percentage of liability of clean up costs	50.00%
Share of past costs due	$ 7