Retirement Benefits (Net Amounts Included In Accumulated Other Comprehensive Loss (Income) That Have Not Been Recognized As Components Of Net Periodic Benefit Costs) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 635.0	$ 563.7
Prior service credit	(0.1)	(2.2)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	635.0	563.7
Prior service credit	(0.1)	(2.2)
Net amount before tax at December 31	634.9	561.5
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	162.7	211.2
Prior service credit	(73.5)	(88.0)
Net amount before tax at December 31	$ 89.2	$ 123.2