Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data	Sep. 30, 2011	Dec. 31, 2010
Current assets:
Allowance for doubtful accounts	$ 31	$ 26
Long-term assets
Accumulated depreciation and amortization	$ 15,107	$ 14,690
Waste Management, Inc. stockholders' equity:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	630,282,461	630,282,461
Treasury stock, shares	169,078,749	155,235,711