Summary Of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2014

Summary Of Nonvested Shares Related To Long-Term Incentive Plan

A summary of nonvested performance share units at March 31, 2014, and changes during the three months ended March 31, 2014, under the 2006 Plan are presented below:



	Performance Share Units
	Share Units		Weighted-average Fair Value Per Unit at Grant Date
Nonvested at January 1, 2014	1,218,544		$	33.23
Granted^(a)	680,606		38.90
Forfeitures	(46,758	)	33.29
Vested^(b)	(116,297	)	38.81
Nonvested at March 31, 2014	1,736,095		$	35.08


(a)	Includes performance share units (share units) granted to certain executive and nonexecutive officers and other eligible employees in 2014 under the 2006 Plan.


(b)	Share units vested due to the attainment of retirement eligibility by certain employees. Actual shares issued for retirement-eligible employees will vary depending on actual performance over the three-year measurement period.

Schedule Of Amortization Expense Based On Usage Of Renewable Energy Credits And Emission Allowances

The following table presents amortization expense based on usage of renewable energy credits and emission allowances, net of gains from sales, for Ameren, Ameren Missouri and Ameren Illinois, during the three months ended March 31, 2014, and 2013:



	Three Months
	2014			2013
Ameren Missouri	$	6	^(a)	$	(b)
Ameren Illinois		3			4
Ameren	$	9		$	4


(a)	Includes higher priced renewable energy credits.


(b)	Less than $1 million.

Schedule of Excise Taxes

The following table presents excise taxes recorded in “Operating Revenues - Electric,” “Operating Revenues - Gas” and “Operating Expenses - Taxes other than income taxes” for the three months ended March 31, 2014, and 2013:



	Three months
	2014		2013
Ameren Missouri	$	34	$	33
Ameren Illinois	26		22
Ameren	$	60	$	55

Schedule of Unrecognized Tax Benefits

The following table presents the amount of unrecognized tax benefits (detriments) as of March 31, 2014, and December 31, 2013:



	March 31, 2014			December 31, 2013
	March 31, 2014			December 31, 2013
Ameren	$	92		$	90
Ameren Missouri	32			31
Ameren Illinois	(1		)	(1		)

Schedule of Unrecognized Tax Benefits That Would Impact Effective Tax Rate

The following table presents the amount of unrecognized tax benefits (detriments) as of March 31, 2014, and 2013, that would impact the effective tax rate, if recognized:



	March 31, 2014			December 31, 2013
	March 31, 2014			December 31, 2013
Ameren	$	55		$	54
Ameren Missouri	2			3
Ameren Illinois	(1		)	—

Equity Changes Attributable To Noncontrolling Interest

A reconciliation of the equity changes attributable to the noncontrolling interests at Ameren for the three months ended March 31, 2014, and 2013, are shown below:



	Three Months
	2014			2013
Noncontrolling interests, beginning of period	$	142		$	151		^(a)
Net income from continuing operations attributable to noncontrolling interests	2			2
Dividends paid to noncontrolling interest holders	(2		)	(2		)
Noncontrolling interests, end of period	$	142		$	151		^(a)

(a)

Included the 20% EEI ownership interest not owned by Ameren prior to the divestiture of New AER to IPH. Prior to the divestiture of New AER, the assets and liabilities of EEI were consolidated in Ameren’s balance sheet at a 100% ownership level and were included in “Assets of discontinued operations” and “Liabilities of discontinued operations.” The divestiture of New AER, which included EEI, was completed in the fourth quarter of 2013. See Note 12 - Divestiture Transactions and Discontinued Operations for additional information.