Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary of Significant Accounting Policies [Abstract]

Allowance for Doubtful Accounts Activity

The following table presents our allowance for doubtful accounts activity for the periods presented:

	For Year Ended December 31,
	2011			2010			2009
Balance at beginning of period	$	18.4		$	16.8		$	17.7
Charged to costs and expenses		0.8			2.6			0.1
Acquisition-related additions and other		--			1.1			--
Deductions (1)		(5.8	)		(2.1	)		(1.0	)
Balance at end of period	$	13.4		$	18.4		$	16.8
(1)   The 2011 deduction amount is primarily due to our reassessment of the allowance for doubtful accounts as a result of improved credit ratings of a significant customer, which reduced our exposure to potential uncollectibility.

Environmental Reserves Activity

The following table presents the activity of our environmental reserves for the periods presented:

	For Year Ended December 31,
	2011			2010			2009
Balance at beginning of period	$	12.4		$	16.7		$	22.3
Charged to costs and expenses		9.3			2.8			1.9
Acquisition-related additions and other		1.0			0.9			--
Deductions		(10.4	)		(8.0	)		(7.5	)
Balance at end of period	$	12.3		$	12.4		$	16.7

Natural Gas Imbalance Receivables and Payables

The following table presents our natural gas imbalance receivables and payables at the dates indicated:

	December 31,
	2011		2010
Natural gas imbalance receivables (1)	$	17.2	$	22.8
Natural gas imbalance payables (2)		24.0		31.9
(1)   Reflected as a component of “Accounts receivable – trade” on our Consolidated Balance Sheets. (2)   Reflected as a component of “Accrued product payables” on our Consolidated Balance Sheets.