Fair Value Measurements (Financial Assets And Liabilities Carried At Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets:
Available-for-sale securities	$ 195.4	$ 170.1
Liabilities:
Deferred compensation plans	55.6	52.2
Quoted Prices in Active Market (Level 1)
Assets:
Available-for-sale securities	146.2	117.8
Liabilities:
Deferred compensation plans	0.0	0.0
Significant Other Observable Inputs (Level 2)
Assets:
Available-for-sale securities	49.2	52.3
Liabilities:
Deferred compensation plans	55.6	52.2
Significant Unobservable Inputs (Level 3)
Assets:
Available-for-sale securities	0.0	0.0
Liabilities:
Deferred compensation plans	$ 0.0	$ 0.0