Retirement Benefits

3 Months Ended

Mar. 31, 2013

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

Ameren’s pension and postretirement plans are funded in compliance with income tax regulations and to meet federal funding or regulatory requirements. As a result, Ameren expects to fund its pension plans at a level equal to the greater of the pension expense or the legally required minimum contribution. Considering Ameren’s assumptions at March 31, 2013, its estimated investment performance through March 31, 2013, and its pension funding policy, Ameren expects to make annual contributions of $60 million to $150 million in each of the next five years, with aggregate estimated contributions of $550 million. These amounts are estimates which may change with actual investment performance, changes in interest rates, any pertinent changes in government regulations, and any voluntary contributions. Our policy for postretirement benefits is primarily to fund the voluntary employee’s beneficiary association (VEBA) trusts to match the annual postretirement expense.

The following table presents the components of the net periodic benefit cost for Ameren’s pension and postretirement benefit plans for the three months ended March 31, 2013, and 2012:

	Pension Benefits						Postretirement Benefits
	Three Months						Three Months
	2013			2012			2013			2012
Service cost	$	24		$	21		$	6		$	6
Interest cost	40			42			12			13
Expected return on plan assets	(54		)	(52		)	(16		)	(14		)
Amortization of:
Prior service cost (benefit)	(1		)	(1		)	(1		)	(1		)
Actuarial loss	22			19			2			3
Net periodic benefit cost	$	31		$	29		$	3		$	7

Ameren Missouri and Ameren Illinois are responsible for their share of the pension and postretirement costs. The following table presents the pension costs and the postretirement benefit costs incurred for the three months ended March 31, 2013, and 2012:

	Pension Costs				Postretirement Costs
	Three Months				Three Months
	2013		2012		2013		2012
Ameren Missouri	$	18	$	16	$	2	$	5
Ameren Illinois	10		10		1		2
Other	3		3		—		—
Ameren(a)	$	31	$	29	$	3	$	7

(a) Includes amounts for Ameren registrants and nonregistrant subsidiaries.