Contingencies - Environmental (Details) $ in Millions		1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Nov. 04, 2011	Jan. 31, 2015 USD ($)	Nov. 30, 2012 item	Sep. 30, 2014 item	Sep. 30, 2017 USD ($) a action	Dec. 31, 2003	Dec. 31, 1992 USD ($) company
Environmental remediation
Estimated potential liability for all environmental matters					$ 45
Waste Disposal Remediation | Lowry Landfill Site
Environmental remediation
Number of actions in which the company is actively involved | action					0
Waste Disposal Remediation | Lowry Landfill Site | Waste Management
Environmental remediation
Project 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
Waste Disposal Remediation | Lowry Landfill Site | Waste Management | Minimum
Environmental remediation
Site contingency response cost							$ 319
Waste Disposal Remediation | Lowry Landfill Site | Denver And Waste Management Litigation
Environmental remediation
Loss Contingency, Number of Defendants | company							38
Waste Disposal Remediation | Lower Duwamish Site
Environmental remediation
Project costs to date					$ 100
Potential period for data review					1 year
Number of additional potentially responsible parties (PRPs) | item				20
Total site remediation costs expected to cover river bottom area in excess of amount spent to date					$ 342
Area of river bottom to be remediated (in acres) | a					200
Waste Disposal Remediation | Lower Duwamish Site | Minimum
Environmental remediation
Number of potentially responsible parties (PRPs) | item			50
Number of industrial companies and governmental entities under review | item			30
Number of PRP groups discussing allocation proposals | item			2
Waste Disposal Remediation | Crown Vantage Landfill Site | Georgia Pacific and International Paper Claims
Environmental remediation
Project costs to date					$ 14
Amount of liability for site clean up by Rexam to successor (as a percentage)	50.00%
Waste Disposal Remediation | Curtis Paper Superfund Site | Georgia Pacific And International Paper
Environmental remediation
Project costs to date					30
Rexam | Waste Disposal Remediation | Crown Vantage Landfill Site | Georgia Pacific and International Paper Claims | Georgia Pacific And International Paper
Environmental remediation
Amount of liability for site clean up costs by Rexam to successor					$ 7