Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Allowance for Doubtful Accounts Activity

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

	For the Year Ended December 31,
	2017			2016			2015
Balance at beginning of period	$	11.3		$	12.1		$	13.9
Charged to costs and expenses		2.7			2.3			0.8
Deductions		(1.9	)		(3.1	)		(2.6	)
Balance at end of period	$	12.1		$	11.3		$	12.1

Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash and cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the amounts shown in the Statements of Consolidated Cash Flows.

	December 31,
	2017		2016
Cash and cash equivalents	$	5.1	$	63.1
Restricted cash		65.2		354.5
Total cash, cash equivalents and restricted cash shown in the    Statements of Consolidated Cash Flows	$	70.3	$	417.6

Environmental Reserves Activity

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

	For the Year Ended December 31,
	2017			2016			2015
Balance at beginning of period	$	11.9		$	13.0		$	15.6
Charged to costs and expenses		12.1			7.0			6.4
Acquisition-related additions and other		1.7			0.5			1.1
Deductions		(14.1	)		(8.6	)		(10.1	)
Balance at end of period	$	11.6		$	11.9		$	13.0