Pension And Other Postretirement Benefits
3 Months Ended
Mar. 31, 2016
Pension and Other Postretirement Benefit Expense [Abstract]  
Pension And Other Postretirement Benefits
Pension and Other Postretirement Benefits
CPG provides defined contribution plans and noncontributory defined benefit retirement plans that cover employees of subsidiaries of Columbia OpCo. Prior to the Separation, employees of subsidiaries of Columbia OpCo were covered by defined contribution plans and noncontributory defined benefit retirement plans provided by NiSource. Benefits under the defined benefit retirement plans reflect the employees’ compensation, years of service and age at retirement. Additionally, CPG provides health care and life insurance benefits for certain retired employees of subsidiaries of Columbia OpCo. The majority of employees may become eligible for these benefits if they reach retirement age while working for subsidiaries of Columbia OpCo. The expected cost of such benefits is accrued during the employees’ years of service. Current rates charged to customers of subsidiaries of Columbia OpCo include postretirement benefit costs. Cash contributions are remitted to grantor trusts.
Subsidiaries of Columbia OpCo are participants in the consolidated CPG defined benefit retirement plans (the "Plans") and, therefore, subsidiaries of Columbia OpCo are allocated a ratable portion of CPG’s grantor trusts for the Plans in which its employees and retirees participate. As a result, the Partnership follows multiple employer accounting under the provisions of GAAP.
The following table provides the components of the subsidiaries of Columbia OpCo's allocation of net periodic benefits cost for the three months ended March 31, 2016 and 2015:

Pension Benefits
 
Other Postretirement
Benefits
Three Months Ended March 31, (in millions)
2016
 
2015
 
2016
 
2015
Components of Net Periodic Benefit Cost (Income)
 
 
 
 
 
 
 
Service cost
$
1.3

 
$
1.3

 
$
0.2

 
$
0.3

Interest cost
3.2

 
3.1

 
1.0

 
1.0

Expected return on assets
(5.5
)
 
(6.1
)
 
(3.8
)
 
(4.3
)
Amortization of prior service credit
(0.2
)
 
(0.2
)
 

 

Recognized actuarial loss
2.5

 
2.0

 

 

Total Net Periodic Benefit Cost (Income)
$
1.3

 
$
0.1

 
$
(2.6
)
 
$
(3.0
)