Landfill and Environmental Remediation Liabilities (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010	Dec. 31, 2009
Liabilities for landfill and environmental remediation costs
Current (in accrued liabilities)	$ 146	$ 148
Long-term	1,436	1,402
Total	1,582	1,550
Landfill Liabilities [Member]
Liabilities for landfill and environmental remediation costs
Current (in accrued liabilities)	104	105
Long-term	1,203	1,161
Total	1,307	1,266	1,267
Environmental Remediation Liabilities [Member]
Liabilities for landfill and environmental remediation costs
Current (in accrued liabilities)	42	43
Long-term	233	241
Total	$ 275	$ 284