Retirement Plans (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plans [Member]
Retirement Plans (Textuals) [Abstract]
Total expense for all defined contribution retirement plans	$ 267.0	$ 278.0	$ 272.0
Other Postretirement Benefit Plans [Member]
Retirement Plans (Textuals) [Abstract]
Total net benefit (expense)	8.0	8.0	$ 0.4
Defined benefit plans, unfunded status	$ 706.0	$ 640.0