Pension Benefit Plans (Fair Values Of Pension Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 3,204.2	$ 2,911.1
Quoted Prices in Active Market (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	900.0	690.6
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	622.3	592.1
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Cash and equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	36.0	23.7
Cash and equivalents | Quoted Prices in Active Market (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	36.0	23.7
Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	515.8	370.9
Common Stock | Quoted Prices in Active Market (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	515.8	347.5
Common Stock | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	23.4
Preferred stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6.7	4.3
Preferred stock | Quoted Prices in Active Market (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6.7	4.3
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	138.4	62.9
Corporate bonds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	138.4	62.9
Government issued
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37.5	82.9
Government issued | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37.5	82.9
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	488.5	477.7
Mutual funds | Quoted Prices in Active Market (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	341.5	315.1
Mutual funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	147.0	162.6
Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	299.4	260.3
Insurance contracts | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	299.4	260.3
Total plan assets, excluding NAV assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,522.3	1,282.7
NAV assets, mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	239.6	289.1
NAV Assets, insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	72.1	70.2
NAV assets, common collective trusts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	774.0	697.8
NAV assets, venture capital, partnerships and other private investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 596.2	$ 571.3