Retirement Benefits (Components Of Net Periodic Benefit (Credit) Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 13.1	$ 13.0	$ 14.2
Interest cost	68.2	74.1	67.8
Expected return on assets	(143.2)	(137.5)	(133.1)
Recognized actuarial loss	25.7	21.0	28.3
Amortization of prior service credit	(0.6)	(0.8)	(0.8)
Settlement loss	6.5	5.2	11.0
Net periodic benefit cost (credit)	(30.3)	(25.0)	(12.6)
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	3.2	6.7
Interest cost	23.4	26.3	22.4
Expected return on assets	(23.7)	(23.4)	(22.1)
Recognized actuarial loss	15.3	9.4	11.2
Amortization of prior service credit	(14.4)	(14.4)	(13.3)
Net periodic benefit cost (credit)	$ 2.7	$ 1.1	$ 4.9