Retirement Benefits

3 Months Ended

Mar. 31, 2012

Retirement Benefits

NOTE 12 - RETIREMENT BENEFITS

Ameren's pension and postretirement plans are funded in compliance with income tax regulations and to achieve 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 December 31, 2011, its estimated investment performance through March 31, 2012, and its pension funding policy, Ameren expects to make annual contributions of $90 million to $150 million in each of the next five years, with aggregate estimated contributions of $580 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 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, 2012, and 2011:

	Pension  Benefits(a)						Postretirement  Benefits(a)
	Three Months						Three Months
	2012			2011			2012			2011
Service cost	$	21		$	20		$	6		$	6
Interest cost		43			45			14			15
Expected return on plan assets		(54	)		(54	)		(14	)		(14	)
Amortization of:
Prior service cost (benefit)		—			—			(1	)		(2	)
Actuarial loss		20			11			4			1
Net periodic benefit cost	$	30		$	22		$	9		$	6

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

Ameren Missouri, Ameren Illinois and Genco 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, 2012, and 2011:

	Pension Costs				Postretirement Costs
	Three Months				Three Months
	2012		2011		2012		2011
Ameren Missouri	$	16	$	14	$	5	$	3
Ameren Illinois		10		5		2		2
Genco		3		2		2		1
Other		1		1		—		—
Ameren(a)	$	30	$	22	$	9	$	6

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

Ameren Illinois Company [Member]

Retirement Benefits

NOTE 12 - RETIREMENT BENEFITS

Ameren's pension and postretirement plans are funded in compliance with income tax regulations and to achieve 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 December 31, 2011, its estimated investment performance through March 31, 2012, and its pension funding policy, Ameren expects to make annual contributions of $90 million to $150 million in each of the next five years, with aggregate estimated contributions of $580 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 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, 2012, and 2011:

	Pension  Benefits(a)						Postretirement  Benefits(a)
	Three Months						Three Months
	2012			2011			2012			2011
Service cost	$	21		$	20		$	6		$	6
Interest cost		43			45			14			15
Expected return on plan assets		(54	)		(54	)		(14	)		(14	)
Amortization of:
Prior service cost (benefit)		—			—			(1	)		(2	)
Actuarial loss		20			11			4			1
Net periodic benefit cost	$	30		$	22		$	9		$	6

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

Ameren Missouri, Ameren Illinois and Genco 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, 2012, and 2011:

	Pension Costs				Postretirement Costs
	Three Months				Three Months
	2012		2011		2012		2011
Ameren Missouri	$	16	$	14	$	5	$	3
Ameren Illinois		10		5		2		2
Genco		3		2		2		1
Other		1		1		—		—
Ameren(a)	$	30	$	22	$	9	$	6

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

Ameren Energy Generating Company [Member]

Retirement Benefits

NOTE 12 - RETIREMENT BENEFITS

Ameren's pension and postretirement plans are funded in compliance with income tax regulations and to achieve 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 December 31, 2011, its estimated investment performance through March 31, 2012, and its pension funding policy, Ameren expects to make annual contributions of $90 million to $150 million in each of the next five years, with aggregate estimated contributions of $580 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 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, 2012, and 2011:

	Pension  Benefits(a)						Postretirement  Benefits(a)
	Three Months						Three Months
	2012			2011			2012			2011
Service cost	$	21		$	20		$	6		$	6
Interest cost		43			45			14			15
Expected return on plan assets		(54	)		(54	)		(14	)		(14	)
Amortization of:
Prior service cost (benefit)		—			—			(1	)		(2	)
Actuarial loss		20			11			4			1
Net periodic benefit cost	$	30		$	22		$	9		$	6

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

Ameren Missouri, Ameren Illinois and Genco 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, 2012, and 2011:

	Pension Costs				Postretirement Costs
	Three Months				Three Months
	2012		2011		2012		2011
Ameren Missouri	$	16	$	14	$	5	$	3
Ameren Illinois		10		5		2		2
Genco		3		2		2		1
Other		1		1		—		—
Ameren(a)	$	30	$	22	$	9	$	6

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

Union Electric Company [Member]

Retirement Benefits

NOTE 12 - RETIREMENT BENEFITS

Ameren's pension and postretirement plans are funded in compliance with income tax regulations and to achieve 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 December 31, 2011, its estimated investment performance through March 31, 2012, and its pension funding policy, Ameren expects to make annual contributions of $90 million to $150 million in each of the next five years, with aggregate estimated contributions of $580 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 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, 2012, and 2011:

	Pension  Benefits(a)						Postretirement  Benefits(a)
	Three Months						Three Months
	2012			2011			2012			2011
Service cost	$	21		$	20		$	6		$	6
Interest cost		43			45			14			15
Expected return on plan assets		(54	)		(54	)		(14	)		(14	)
Amortization of:
Prior service cost (benefit)		—			—			(1	)		(2	)
Actuarial loss		20			11			4			1
Net periodic benefit cost	$	30		$	22		$	9		$	6

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

Ameren Missouri, Ameren Illinois and Genco 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, 2012, and 2011:

	Pension Costs				Postretirement Costs
	Three Months				Three Months
	2012		2011		2012		2011
Ameren Missouri	$	16	$	14	$	5	$	3
Ameren Illinois		10		5		2		2
Genco		3		2		2		1
Other		1		1		—		—
Ameren(a)	$	30	$	22	$	9	$	6

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