Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Estimated useful lives of our property and equipment

The estimated useful lives of our property and equipment are as follows:


	Estimated Useful Lives
Buildings and improvements		7 - 40 years
Vehicles		5 - 12 years
Landfill equipment		7 - 10 years
Other equipment		3 - 15 years
Furniture and fixtures		5 - 12 years

Allowance for Doubtful Accounts [Member]

Valuation Allowance [Line Items]

Activity in allowance for doubtful accounts

The following table reflects the activity in our allowance for doubtful accounts for the years ended December 31, 2011, 2010 and 2009:


	2011			2010			2009
Balance at beginning of year	$	50.9		$	55.2		$	65.7
Additions charged to expense		21.0			23.6			27.3
Accounts written-off		(23.8	)		(27.9	)		(37.8	)

Balance at end of year	$	48.1		$	50.9		$	55.2

- Definition

Tabular disclosure of valuation allowances to reduce deferred tax assets to net realizable value, including identification of the deferred tax asset more likely than not will not be fully realized and the corresponding amount of the valuation allowance.

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