Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Summary of Significant Accounting Policies [Abstract]

Allowance for Doubtful Accounts Activity

	For the Year Ended December 31,
	2018			2017			2016
Balance at beginning of period	$	12.1		$	11.3		$	12.1
Charged to costs and expenses		0.7			2.7			2.3
Deductions		(1.3	)		(1.9	)		(3.1	)
Balance at end of period	$	11.5		$	12.1		$	11.3

Cash, Cash Equivalents and Restricted Cash

	December 31,
	2018		2017
Cash and cash equivalents	$	344.8	$	5.1
Restricted cash		65.3		65.2
Total cash, cash equivalents and restricted cash shown in the    Statements of Consolidated Cash Flows	$	410.1	$	70.3

Environmental Reserves Activity

	For the Year Ended December 31,
	2018			2017			2016
Balance at beginning of period	$	11.6		$	11.9		$	13.0
Charged to costs and expenses		8.2			12.1			7.0
Acquisition-related additions and other		1.7			1.7			0.5
Deductions		(14.6	)		(14.1	)		(8.6	)
Balance at end of period	$	6.9		$	11.6		$	11.9