Lease Commitments (Schedule Of Rental Expense For Premises, Net Of Sublease Income, And Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Rental expense	$ 36.6	$ 43.8	$ 30.5
Premises
Property, Plant and Equipment [Line Items]
Rental expense	34.9	42.1	28.7
Equipment
Property, Plant and Equipment [Line Items]
Rental expense	$ 1.7	$ 1.7	$ 1.8