Retirement Benefits (Tables)

12 Months Ended

Dec. 31, 2014

Summary Of Benefit Liability Recorded

The following table presents the net benefit liability recorded on the balance sheets of each of the Ameren Companies as of December 31, 2014 and 2013:

	2014		2013
Ameren(a)	$	710	$	461
Ameren Missouri	277		191
Ameren Illinois	278		159

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

Funded Status Of Benefit Plans And Amounts Included In Regulatory Assets And OCI

The following table presents the funded status of Ameren's pension and postretirement benefit plans as of December 31, 2014 and 2013. It also provides the amounts included in regulatory assets and accumulated OCI at December 31, 2014 and 2013, that have not been recognized in net periodic benefit costs.

	2014						2013
	Pension Benefits(a)				Postretirement Benefits(a)		Pension Benefits(a)				Postretirement Benefits(a)
Accumulated benefit obligation at end of year	$	4,176		$	(b)		$	3,698		$	(b)
Change in benefit obligation:
Net benefit obligation at beginning of year	$	3,900		$	1,096		$	4,051		$	1,157
Service cost	79				19		91				22
Interest cost	183				50		163				46
Participant contributions	—				16		—				16
Actuarial (gain) loss	462				84		(207		)		(76	)
Curtailment gain(c)	—				—		—				(3	)
Settlement(d)	—				—		—				(5	)
Benefits paid	(214		)		(65	)	(198		)		(64	)
Federal subsidy on benefits paid	(b)				3		(b)				3
Net benefit obligation at end of year	4,410				1,203		3,900				1,096
Change in plan assets:
Fair value of plan assets at beginning of year	3,461				1,074		3,127				938
Actual return on plan assets	448				75		376				156
Employer contributions	99				6		156				25
Federal subsidy on benefits paid	(b)				3		(b)				3
Participant contributions	—				16		—				16
Benefits paid	(214		)		(65	)	(198		)		(64	)
Fair value of plan assets at end of year	3,794				1,109		3,461				1,074
Funded status – deficiency	616				94		439				22
Accrued benefit cost at December 31	$	616		$	94		$	439		$	22
Amounts recognized in the balance sheet consist of:
Noncurrent asset(e)	$	—		$	—		$	—		$	(9	)
Current liability(f)	3				2		3				1
Noncurrent liability	613				92		436				30
Net liability recognized	$	616		$	94		$	439		$	22
Amounts recognized in regulatory assets consist of:
Net actuarial (gain) loss	$	452		$	(7	)	$	282		$	(71	)
Prior service cost (credit)	(6		)		(16	)	(7		)		(20	)
Amounts (pretax) recognized in accumulated OCI consist of:
Net actuarial (gain) loss	29				(5	)	17				(12	)
Prior service cost (credit)	—				(1	)	—				(1	)
Total	$	475		$	(29	)	$	292		$	(104	)

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

(b) Not applicable.

Assumptions Used To Determine Benefit Obligations

The following table presents the assumptions used to determine our benefit obligations at December 31, 2014 and 2013:

	Pension Benefits				Postretirement Benefits
	2014		2013		2014		2013
Discount rate at measurement date	4.00	%	4.75	%	4.00	%	4.75	%
Increase in future compensation	3.50		3.50		3.50		3.50
Medical cost trend rate (initial)	(a)		(a)		5.00		5.00
Medical cost trend rate (ultimate)	(a)		(a)		5.00		5.00
Years to ultimate rate	(a)		(a)		—		—

Schedule Of Cash Contributions Made To Benefit Plans

The following table presents the cash contributions made to our defined benefit retirement plan and to our postretirement plans during 2014, 2013, and 2012:

	Pension Benefits						Postretirement Benefits
	2014		2013		2012		2014		2013		2012
Ameren Missouri	$	41	$	60	$	52	$	3	$	10	$	9
Ameren Illinois	39		50		46		2		11		35
Other	19		46		30		1		4		1
Ameren(a)	99		156		128		6		25		45

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

Target Allocation Of The Plans' Asset Categories

The following table presents our target allocations for 2015 and our pension and postretirement plans’ asset categories as of December 31, 2014 and 2013:

Asset Category	Target Allocation 2015	Percentage of Plan Assets at December  31,
		2014		2013
Pension Plan:
Cash and cash equivalents	0% - 5%	2	%	2	%
Equity securities:
U.S. large-capitalization	29% - 39%	34	%	36	%
U.S. small- and mid-capitalization	2% - 12%	7	%	8	%
International and emerging markets	9% - 19%	12	%	14	%
Total equity	50% - 60%	53	%	58	%
Debt securities	35% - 45%	41	%	36	%
Real estate	0% -   9%	4	%	4	%
Private equity	0% -   4%	(a)		(a)
Total		100	%	100	%
Postretirement Plans:
Cash and cash equivalents	0% - 10%	4	%	4	%
Equity securities:
U.S. large-capitalization	33% - 43%	40	%	41	%
U.S. small- and mid-capitalization	3% - 13%	7	%	8	%
International	10% - 20%	13	%	14	%
Total equity	55% - 65%	60	%	63	%
Debt securities	30% - 40%	36	%	33	%
Total		100	%	100	%

Changes In The Fair Value Of Plan Assets Classified As Level 3

The following table summarizes the changes in the fair value of the pension plan assets classified as Level 3 in the fair value hierarchy for each of the years ended December 31, 2014 and 2013:

	Beginning Balance at January 1,		Actual Return on Plan Assets Related to Assets Still Held at the Reporting Date			Actual Return on Plan Assets Related to Assets Sold During the Period		Purchases, Sales, and Settlements, Net			Net Transfers into (out of) of Level 3		Ending Balance at December 31,
2014:
Real estate	$	131	$	11		$	—	$	5		$	—	$	147
Private equity	15		(9		)	10		(3		)	—		13
2013:
Real estate	$	118	$	9		$	—	$	4		$	—	$	131
Private equity	19		(9		)	11		(6		)	—		15

Components Of Net Periodic Benefit Cost

The following table presents the components of the net periodic benefit cost of our pension and postretirement benefit plans during 2014, 2013, and 2012:

	Pension Benefits Ameren(a)			Postretirement Benefits Ameren(a)
2014
Service cost	$	79		$	19
Interest cost	183			50
Expected return on plan assets	(229		)	(65		)
Amortization of:
Prior service credit	(1		)	(5		)
Actuarial (gain) loss	49			(7		)
Net periodic benefit cost (benefit)	$	81		$	(8	)
2013
Service cost	$	91		$	22
Interest cost	163			46
Expected return on plan assets	(218		)	(62		)
Amortization of:
Prior service credit	(2		)	(6		)
Actuarial loss	87			8
Curtailment gain	(12		)	(7		)
Net periodic benefit cost(b)	$	109		$	1
2012
Service cost	$	81		$	22
Interest cost	166			47
Expected return on plan assets	(208		)	(56		)
Amortization of:
Transition obligation	—			2
Prior service credit	(3		)	(6		)
Actuarial loss	75			5
Net periodic benefit cost(c)	$	111		$	14

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

Summary Of Estimated Amortizable Amounts From Regulatory Assets and Accumulated OCI Into Net Periodic Benefit Cost

The estimated amounts that will be amortized from regulatory assets and accumulated OCI into net periodic benefit cost in 2015 are as follows:

	Pension Benefits Ameren(a)			Postretirement Benefits Ameren(a)
Regulatory assets:
Prior service credit	$	(1	)	$	(4	)
Net actuarial loss	86			15
Accumulated OCI:
Net actuarial (gain) loss	2			(2		)
Total	$	87		$	9

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

Summary Of Benefit Plan Costs Incurred

The Ameren Companies are responsible for their share of the pension and postretirement benefit costs. The following table presents the pension costs and the postretirement benefit costs incurred and included in continuing operations for the years ended December 31, 2014, 2013, and 2012:

	Pension Costs						Postretirement Costs
	2014		2013		2012		2014			2013		2012
Ameren Missouri	$	50	$	69	$	63	$	3		$	8	$	10
Ameren Illinois	30		41		37		(9		)	—		4
Other	1		5		2		(2		)	—		—
Ameren(a)	81		115		102		(8		)	8		14

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

Schedule Of Expected Payments From Qualified Trust And Company Funds

The expected pension and postretirement benefit payments from qualified trust and company funds, which reflect expected future service, as of December 31, 2014, are as follows:

	Pension Benefits				Postretirement Benefits
	Paid from Qualified Trust		Paid from          Company       Funds		Paid from          Qualified       Trust		Paid from          Company       Funds
2015	$	253	$	3	$	58	$	2
2016	256		3		61		2
2017	257		4		64		2
2018	260		3		68		2
2019	260		3		70		2
2020 - 2024	1,273		11		388		11

Assumptions Used To Determine Net Periodic Benefit Cost

The following table presents the assumptions used to determine net periodic benefit cost for our pension and postretirement benefit plans for the years ended December 31, 2014, 2013, and 2012:

	Pension Benefits						Postretirement Benefits
	2014		2013		2012		2014		2013		2012
Discount rate at measurement date	4.75	%	4.00	%	4.50	%	4.75	%	4.00	%	4.50	%
Expected return on plan assets	7.25		7.50		7.75		7.00		7.25		7.50
Increase in future compensation	3.50		3.50		3.50		3.50		3.50		3.50
Medical cost trend rate (initial)	(a)		(a)		(a)		5.00		5.00		5.50
Medical cost trend rate (ultimate)	(a)		(a)		(a)		5.00		5.00		5.00
Years to ultimate rate	(a)		(a)		(a)		—		—		1 year

Schedule Of Potential Changes In Key Assumptions

The table below reflects the sensitivity of Ameren’s plans to potential changes in key assumptions:

	Pension Benefits					Postretirement Benefits
	Service Cost and Interest Cost			Projected     Benefit      Obligation		Service Cost     and Interest     Cost			Postretirement       Benefit        Obligation
0.25% decrease in discount rate	$	(1	)	$	138	$	1		$	39
0.25% increase in salary scale	2			13		—			—
1.00% increase in annual medical trend	—			—		3			36
1.00% decrease in annual medical trend	—			—		(2		)	(33		)

Schedule Of Matching Contributions

The following table presents the portion of the matching contribution to the Ameren 401(k) plan attributable to the continuing operations for each of the Ameren Companies for the years ended December 31, 2014, 2013, and 2012:

	2014		2013		2012
Ameren Missouri	$	16	$	16	$	16
Ameren Illinois	11		10		9
Other	1		1		1
Ameren(a)	28		27		26

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

Pension Benefits

Target Allocation Of The Plans' Asset Categories

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the pension plan assets measured at fair value as of December 31, 2014:

	Quoted Prices in Active Markets for Identified Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Total
Cash and cash equivalents	$	—	$	38	$	—	$	38
Equity securities:
U.S. large-capitalization	—		1,331		—		1,331
U.S. small- and mid-capitalization	270		—		—		270
International and emerging markets	134		360		—		494
Debt securities:
Corporate bonds	—		1,026		—		1,026
Municipal bonds	—		175		—		175
U.S. treasury and agency securities	6		366		—		372
Other	—		31		—		31
Real estate	—		—		147		147
Private equity	—		—		13		13
Derivative assets	1		—		—		1
Total	$	411	$	3,327	$	160	$	3,898
Less: Medical benefit assets at December 31(a)							(125		)
Plus: Net receivables at December 31(b)							21
Fair value of pension plans assets at year end							$	3,794

(a) Medical benefit (health and welfare) component for accounts maintained in accordance with Section 401(h) of the Internal Revenue Code to fund a portion of the postretirement obligation.

(b) Receivables related to pending security sales, offset by payables related to pending security purchases.

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the pension plan assets measured at fair value as of December 31, 2013:

	Quoted Prices in Active Markets for Identified Assets or Liabilities (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Total
Cash and cash equivalents	$	5		$	39	$	—	$	44
Equity securities:
U.S. large-capitalization	107			1,162		—		1,269
U.S. small- and mid-capitalization	273			—		—		273
International and emerging markets	143			372		—		515
Debt securities:
Corporate bonds	—			860		—		860
Municipal bonds	—			149		—		149
U.S. treasury and agency securities	—			256		—		256
Other	—			27		—		27
Real estate	—			—		131		131
Private equity	—			—		15		15
Derivative assets	1			—		—		1
Derivative liabilities	(1		)	—		—		(1		)
Total	$	528		$	2,865	$	146	$	3,539
Less: Medical benefit assets at December 31(a)								(112		)
Plus: Net receivables at December 31(b)								34
Fair value of pension plans assets at year end								$	3,461

(a) Medical benefit (health and welfare) component for accounts maintained in accordance with Section 401(h) of the Internal Revenue Code to fund a portion of the postretirement obligation.

(b) Receivables related to pending security sales, offset by payables related to pending security purchases.

Postretirement Benefits

Target Allocation Of The Plans' Asset Categories

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the postretirement benefit plans assets measured at fair value as of December 31, 2014:

	Quoted Prices in Active Markets for Identified Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Total
Cash and cash equivalents	$	89	$	—	$	—	$	89
Equity securities:
U.S. large-capitalization	291		101		—		392
U.S. small- and mid-capitalization	70		—		—		70
International	37		94		—		131
Other	—		7				7
Debt securities:
Corporate bonds	—		105		—		105
Municipal bonds	—		111		—		111
U.S. treasury and agency securities	—		89		—		89
Other	—		44		—		44
Total	$	487	$	551	$	—	$	1,038
Plus: Medical benefit assets at December 31(a)							125
Less: Net payables at December 31(b)							(54		)
Fair value of postretirement benefit plans assets at year end							$	1,109

(a) Medical benefit (health and welfare) component for 401(h) accounts to fund a portion of the postretirement obligation. These 401(h) assets are included in the pension plan assets shown above.

(b) Payables related to pending security purchases, offset by interest receivables and receivables related to pending security sales.

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the postretirement benefit plans assets measured at fair value as of December 31, 2013:

	Quoted Prices in Active Markets for Identified Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Total
Cash and cash equivalents	$	77	$	—	$	—	$	77
Equity securities:
U.S. large-capitalization	297		101		—		398
U.S. small- and mid-capitalization	77		—		—		77
International	39		96		—		135
Other	—		2		—		2
Debt securities:
Corporate bonds	—		97		—		97
Municipal bonds	—		103		—		103
U.S. treasury and agency securities	—		72		—		72
Other	—		40		—		40
Total	$	490	$	511	$	—	$	1,001
Plus: Medical benefit assets at December 31(a)							112
Less: Net payables at December 31(b)							(39		)
Fair value of postretirement benefit plans assets at year end							$	1,074

(a) Medical benefit (health and welfare) component for 401(h) accounts to fund a portion of the postretirement obligation. These 401(h) assets are included in the pension plan assets shown above.

(b) Payables related to pending security purchases, offset by Medicare, interest receivables, and receivables related to pending security sales.