EMPLOYEE BENEFIT PLANS

3 Months Ended

Mar. 31, 2012

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS

NOTE 13—EMPLOYEE BENEFIT PLANS

As of February 16, 2012, our defined benefit pension plans were closed to all new hires.

The following table shows the components of net periodic benefit cost (including amounts capitalized to our balance sheet) for our benefit plans for the three months ended March 31:

	Pension Benefits						Other Postretirement Benefits
(Millions)	2012			2011			2012			2011
Service cost	$	12.4		$	11.3		$	5.5		$	5.0
Interest cost	19.8			20.5			7.2			7.7
Expected return on plan assets	(27.1		)	(24.7		)	(7.0		)	(5.0		)
Amortization of transition obligation	—			—			0.1			0.1
Amortization of prior service cost (credit)	1.2			1.3			(0.9		)	(0.9		)
Amortization of net actuarial loss	8.3			4.7			1.6			1.1
Net periodic benefit cost	$	14.6		$	13.1		$	6.5		$	8.0

Transition obligations, prior service costs (credits), and net actuarial losses that have not yet been recognized as a component of net periodic benefit cost are included in accumulated OCI for our nonregulated entities and are recorded as net regulatory assets for our utilities.

We make contributions to our plans in accordance with legal and tax requirements. These contributions do not necessarily occur evenly throughout the year. We contributed $171.5 million to our pension plans and $75.1 million to our other postretirement benefit plans during the three months ended March 31, 2012. We expect to contribute an additional $3.8 million to our pension plans and $39.1 million to our other postretirement benefit plans during the remainder of 2012, dependent upon various factors affecting us, including our liquidity position and tax law changes.