Employee Benefit Plans Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 3.2	$ 3.5	$ 3.4
Interest cost	28.6	36.1	33.8
Expected asset return	(42.0)	(48.4)	(45.8)
Amortized actuarial loss	6.0	5.4	8.9
Amortized prior service cost (credit)	(0.1)	(0.1)	5.4
Defined Benefit Plan, Recognized Net Gain Due to Settlements	0.0	35.5	0.0
Net periodic benefit cost	(4.3)	32.0	5.7
Other Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.4	0.3	0.4
Interest cost	15.0	15.3	13.2
Expected asset return	0.0	0.0	0.0
Amortized actuarial loss	0.8	0.5	0.9
Amortized prior service cost (credit)	(2.7)	(2.7)	(1.8)
Defined Benefit Plan, Recognized Net Gain Due to Settlements	0.0	0.0	0.0
Other postretirement benefit expense	$ 13.5	$ 13.4	$ 12.7