Postretirement Benefits Schedule of Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	[1]	Jul. 01, 2017	[1]	Apr. 01, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Settlement Loss	$ 96.6		$ 0.0		$ 0.0		$ 0.0		$ 0.0	$ 96.6	[1]	$ 55.1
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest Cost									22.6	28.4		35.8
Expected Return on Plan Assets									(24.8)	(33.5)		(38.5)
Amortization of Prior Service Credits									0.0	0.0		0.0
Amortization of Net Actuarial Losses									9.9	14.4		17.4
Settlement Loss									0.0	96.6		55.1
Net Pension and Other Benefit Costs									7.7	105.9		69.8
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest Cost									1.1	1.2		1.4
Expected Return on Plan Assets									0.0	0.0		0.0
Amortization of Prior Service Credits									(0.7)	(0.7)		(0.7)
Amortization of Net Actuarial Losses									0.0	0.0		0.0
Settlement Loss									0.0	0.0		0.0
Net Pension and Other Benefit Costs									$ 0.4	$ 0.5		$ 0.7

[1] (I) Pension settlement charges are discussed in Note 18 – Postretirement Benefits.