Pension And Other Benefit Plans - (Components of Net Periodic Benefit Cost of Defined Benefit Pension Pans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (9.1)	$ (10.0)	$ (8.0)
Net periodic pension cost	(7.6)	(7.3)	$ (7.9)
Defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(9.1)	(10.0)
Interest cost	(2.4)	(2.0)
Expected return on plan assets	3.2	3.8
Amortization of initial net obligation	(0.2)	(0.2)
Amortization of prior service credit	0.0	0.1
Amortization of actuarial loss	(0.4)	(0.8)
Settlement gain	1.3	1.8
Net periodic pension cost	$ (7.6)	$ (7.3)