Pension And Other Postretirement Benefits (Tables)
 3 Months Ended
Mar. 31, 2015
Pension and Other Postretirement Benefit Expense [Abstract]  
Components Of The Plans' Net Periodic Benefits Cost
 

Pension Benefits
 
Other Postretirement
Benefits
Three Months Ended March 31, (in millions)
2015
 
2014
 
2015
 
2014
 
 
 
Predecessor
 
 
 
Predecessor
Components of Net Periodic Benefit Cost (Income)
 
 
 
 
 
 
 
Service cost
$
1.3

 
$
1.2

 
$
0.3

 
$
0.3

Interest cost
3.1

 
3.4

 
1.0

 
1.2

Expected return on assets
(6.1
)
 
(5.9
)
 
(4.3
)
 
(4.1
)
Amortization of prior service credit
(0.2
)
 
(0.2
)
 
—

 
—

Recognized actuarial loss
2.0

 
1.6

 
—

 
—

Total Net Periodic Benefit Cost (Income)
$
0.1

 
$
0.1

 
$
(3.0
)
 
$
(2.6
)