Contingencies (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Nov. 30, 2012 company	Sep. 30, 2014 USD ($) company	Jun. 30, 2015 USD ($)	Dec. 31, 1992 defendant
Environmental litigation with respect to Lowry Landfill site
Contingencies
Approximate number of other companies named in a lawsuit with respect to Lowry Landfill | defendant				38
Waste Management litigation
Contingencies
Response cost related to site, minimum before the company may be asked to make payments			$ 319
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 additional potentially responsible parties (PRPs) | company		20
Expected future remediation costs			$ 342
Site cleanup costs		$ 100
Number of companies whose data is under review | company	30
Period over which data is reviewed	2 years
Environmental litigation with respect to Lower Duwamish site | Minimum
Contingencies
Number of potentially responsible parties (PRPs) | company	50
Number of potentially responsible parties (PRP) groups whose data is under review | company	2