v3.4.0.3
Employee Benefits
 3 Months Ended
Mar. 31, 2016
Compensation and Retirement Disclosure [Abstract]  
EMPLOYEE BENEFITS
EMPLOYEE BENEFITS

Defined Benefit Plans

The following tables show the components of net periodic pension and OPEB costs for our benefit plans. Our pension and OPEB costs for the three months ended March 31, 2016, include costs attributable to the Integrys pension and OPEB plans. The terms and conditions of the legacy company plans have not changed since the acquisition.
 
 
Pension Costs
 
 
Three Months Ended March 31
(in millions)
 
2016
 
2015
Service cost
 
$
11.3

 
$
3.9

Interest cost
 
33.2

 
15.2

Expected return on plan assets
 
(49.0
)
 
(25.8
)
Amortization of prior service cost
 
0.9

 
0.5

Amortization of net actuarial loss
 
20.5

 
11.6

Net periodic benefit cost
 
$
16.9

 
$
5.4


 
 
OPEB Costs
 
 
Three Months Ended March 31
(in millions)
 
2016
 
2015
Service cost
 
$
6.7

 
$
2.6

Interest cost
 
9.2

 
4.2

Expected return on plan assets
 
(13.1
)
 
(5.9
)
Amortization of prior service credit
 
(2.3
)
 
(0.3
)
Amortization of net actuarial loss
 
2.3

 
0.5

Net periodic benefit cost
 
$
2.8

 
$
1.1



We did not make any contributions to our qualified pension plans during the first three months of 2016. During the three months ended March 31, 2016, we made payments of $13.7 million related to our non-qualified pension plans and $1.4 million to our OPEB plans. We expect to make payments of $8.5 million to our pension plans and $10.8 million to our OPEB plans during the remainder of 2016, dependent upon various factors affecting us, including our liquidity position and possible tax law changes.