Schedule II - Valuation And Qualifying Accounts

12 Months Ended

Dec. 31, 2011

Valuation And Qualifying Accounts [Abstract]

Valuation And Qualifying Accounts

SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED DECEMBER 31, 2011, 2010 AND 2009
(in millions)
Column A	Column B		Column C				Column D		Column E
Description	Balance at Beginning of Period		(1) Charged to Costs and Expenses		(2) Charged to Other Accounts		Deductions(a)		Balance at End of Period
Ameren:
Deducted from assets – allowance for doubtful accounts:
2011	$	23	$	41	$	-	$	44	$	20
2010		24		33		-		34		23
2009		28		37		-		41		24
Ameren Missouri:
Deducted from assets – allowance for doubtful accounts:
2011	$	8	$	17	$	-	$	18	$	7
2010		6		14		-		12		8
2009		8		8		-		10		6
Ameren Illinois:
Deducted from assets – allowance for doubtful accounts:
2011	$	13	$	24	$	-	$	24	$	13
2010		17		18		-		22		13
2009		21		27		-		31		17

(a) Uncollectible accounts charged off, less recoveries.