Share-Based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share based compensation expense	$ 28.1	$ 31.5
Tax benefit	(6.8)	(7.6)
After-tax expense	21.3	23.9
Stock Options [Member]
Share based compensation expense	9.7	11.8
Restricted Stock Units (RSUs) [Member]
Share based compensation expense	11.0	13.0
Performance Shares [Member]
Share based compensation expense	7.8	4.4
Deferred Compensation [Member]
Share based compensation expense	1.4	0.9
Other share based compensation [Member]
Share based compensation expense	(1.8)	1.4
Continuing Operations [Member]
After-tax expense	20.3	21.2
Discontinued Operations [Member]
After-tax expense	$ 1.0	$ 2.7