Pension And Other Benefit Plans - Components of Net Periodic Benefit Cost Reflected in the Consolidated Condensed Statement of Earnings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ (10.3)	$ (9.1)	$ (10.0)
Other net periodic pension costs:
Nonoperating income (expense)	(0.9)	1.5	2.7
Net periodic pension cost	$ (11.2)	$ (7.6)	$ (7.3)