Employee Benefits WRAP Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
WRAP Plan Liabilities	$ 25.5	$ 26.8
Rabbi Trust Marketable Securities	23.4	23.1
Deferred Compensation Mark To Market Adjustments	1.0	2.3	$ (3.9)
Unrealized (gains) losses on marketable securities	$ (3.2)	$ (3.9)	$ 1.2