Employee Benefit Plans (Schedule of Underfunded Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plan [Member]
Change in benefit obligation:
Benefit obligation, beginning balance	$ 49.7	$ 40.4
Service cost	1.3	1.1	$ 1.2
Interest cost	1.8	1.8	1.6
Change in plan provisions	0.0	0.0
Benefits paid	(1.2)	(1.2)
Actuarial (gain) loss	(1.0)	7.6
Benefit obligation, ending balance	50.6	49.7	40.4
Change in fair value of plan assets:
Plan assets, beginning balance	0.0	0.0
Employer contribution	1.2	1.2
Benefits paid	(1.2)	(1.2)
Plan assets, ending balance	0.0	0.0	0.0
Underfunded status, end of year	(50.6)	(49.7)
Other Benefits [Member]
Change in benefit obligation:
Benefit obligation, beginning balance	28.8	24.1
Service cost	0.2	0.3	0.4
Interest cost	1.1	1.1	1.0
Change in plan provisions	0.0	0.0
Benefits paid	(0.9)	(1.1)
Actuarial (gain) loss	(5.3)	4.4
Benefit obligation, ending balance	23.9	28.8	24.1
Change in fair value of plan assets:
Plan assets, beginning balance	0.0	0.0
Employer contribution	0.9	1.1
Benefits paid	(0.9)	(1.1)
Plan assets, ending balance	0.0	0.0	$ 0.0
Underfunded status, end of year	$ (23.9)	$ (28.8)