Retirement Benefits (Details 9) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (credit)	$ (1.6)
Amortization of net actuarial loss	71.6
Amortization of accumulated other comprehensive loss	70.0
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (credit)	1.3
Amortization of net actuarial loss	62.6
Amortization of accumulated other comprehensive loss	63.9
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (credit)	(2.9)
Amortization of net actuarial loss	9.0
Amortization of accumulated other comprehensive loss	$ 6.1