Summary Of Significant Accounting Policies Summary of Significant Accounting Policies (Activity in the LIFO Reserve) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
LIFO Reserve [Roll Forward]
Balance, beginning of year	$ 50.9	$ 33.8	$ 22.6
LIFO expense	31.3	18.6	10.5
Allocated to divested businesses	0.0	(1.5)	0.7
Balance, end of year	$ 50.9	$ 33.8	$ 22.6	$ 82.2