Related Party Transactions (Tables)

6 Months Ended

Jun. 30, 2012

Ameren Missouri [Member]

Schedule of Related Party Transactions

			Three Months									Six Months
Agreement	Income Statement Line Item		Ameren Missouri			Ameren Illinois			Genco			Ameren Missouri			Ameren Illinois			Genco
Genco and EEI power supply	Operating Revenues	2012	$	(a	)	$	(a	)	$	193		$	(a	)	$	(a	)	$	386
agreements with Marketing Company		2011		(a	)		(a	)		242			(a	)		(a	)		482
Ameren Missouri and Ameren Illinois	Operating Revenues	2012		4			(b	)		(a	)		8			(b	)		(a	)
rent and facility services		2011		4			(b	)		(a	)		8			(b	)		(a	)
Ameren Missouri and Genco gas	Operating Revenues	2012		(b	)		(a	)		(b	)		(b	)		(a	)		(b	)
transportation agreement		2011		(b	)		(a	)		(b	)		(b	)		(a	)		(b	)
Total Operating Revenues		2012	$	4		$	(b	)	$	193		$	8		$	(b	)	$	386
		2011		4			(b	)		242			8			(b	)		482
Ameren Illinois power supply	Purchased Power	2012	$	(a	)	$	72		$	(a	)	$	(a	)	$	160		$	(a	)
agreements with Marketing Company		2011		(a	)		48			(a	)		(a	)		94			(a	)
EEI power supply agreement with	Purchased Power	2012		(a	)		(a	)		(b	)		(a	)		(a	)		(b	)
Marketing Company		2011		(a	)		(a	)		12			(a	)		(a	)		12
Total Purchased Power		2012	$	(a	)	$	72		$	(b	)	$	(a	)	$	160		$	(b	)
		2011		(a	)		48			12			(a	)		94			12
Ameren Services support services	Other Operations	2012	$	27		$	22		$	5		$	55		$	45		$	10
agreement	and Maintenance	2011		28			21			4			59			45			10
Insurance premiums(c)	Other Operations	2012		(b	)		(a	)		(a	)		(b	)		(a	)		(a	)
	and Maintenance	2011		(b	)		(a	)		(a	)		(b	)		(a	)		(a	)
Total Other Operations and		2012	$	27		$	22		$	5		$	55		$	45		$	10
Maintenance Expenses		2011		28			21			4			59			45			10
Money pool borrowings (advances)	Interest Charges	2012	$	-		$	(b	)	$	(b	)	$	-		$	(b	)	$	(b	)
		2011		-			-			(b	)		-			-			(b	)

(a) Not applicable.

(b) Amount less than $1 million.

(c) Represents insurance premiums paid to an affiliate for replacement power, property damage and terrorism coverage.

Ameren Illinois Company [Member]

Schedule of Related Party Transactions

			Three Months									Six Months
Agreement	Income Statement Line Item		Ameren Missouri			Ameren Illinois			Genco			Ameren Missouri			Ameren Illinois			Genco
Genco and EEI power supply	Operating Revenues	2012	$	(a	)	$	(a	)	$	193		$	(a	)	$	(a	)	$	386
agreements with Marketing Company		2011		(a	)		(a	)		242			(a	)		(a	)		482
Ameren Missouri and Ameren Illinois	Operating Revenues	2012		4			(b	)		(a	)		8			(b	)		(a	)
rent and facility services		2011		4			(b	)		(a	)		8			(b	)		(a	)
Ameren Missouri and Genco gas	Operating Revenues	2012		(b	)		(a	)		(b	)		(b	)		(a	)		(b	)
transportation agreement		2011		(b	)		(a	)		(b	)		(b	)		(a	)		(b	)
Total Operating Revenues		2012	$	4		$	(b	)	$	193		$	8		$	(b	)	$	386
		2011		4			(b	)		242			8			(b	)		482
Ameren Illinois power supply	Purchased Power	2012	$	(a	)	$	72		$	(a	)	$	(a	)	$	160		$	(a	)
agreements with Marketing Company		2011		(a	)		48			(a	)		(a	)		94			(a	)
EEI power supply agreement with	Purchased Power	2012		(a	)		(a	)		(b	)		(a	)		(a	)		(b	)
Marketing Company		2011		(a	)		(a	)		12			(a	)		(a	)		12
Total Purchased Power		2012	$	(a	)	$	72		$	(b	)	$	(a	)	$	160		$	(b	)
		2011		(a	)		48			12			(a	)		94			12
Ameren Services support services	Other Operations	2012	$	27		$	22		$	5		$	55		$	45		$	10
agreement	and Maintenance	2011		28			21			4			59			45			10
Insurance premiums(c)	Other Operations	2012		(b	)		(a	)		(a	)		(b	)		(a	)		(a	)
	and Maintenance	2011		(b	)		(a	)		(a	)		(b	)		(a	)		(a	)
Total Other Operations and		2012	$	27		$	22		$	5		$	55		$	45		$	10
Maintenance Expenses		2011		28			21			4			59			45			10
Money pool borrowings (advances)	Interest Charges	2012	$	-		$	(b	)	$	(b	)	$	-		$	(b	)	$	(b	)
		2011		-			-			(b	)		-			-			(b	)

(a) Not applicable.

(b) Amount less than $1 million.

(c) Represents insurance premiums paid to an affiliate for replacement power, property damage and terrorism coverage.

Ameren Energy Generating Company [Member]

Schedule of Related Party Transactions

			Three Months									Six Months
Agreement	Income Statement Line Item		Ameren Missouri			Ameren Illinois			Genco			Ameren Missouri			Ameren Illinois			Genco
Genco and EEI power supply	Operating Revenues	2012	$	(a	)	$	(a	)	$	193		$	(a	)	$	(a	)	$	386
agreements with Marketing Company		2011		(a	)		(a	)		242			(a	)		(a	)		482
Ameren Missouri and Ameren Illinois	Operating Revenues	2012		4			(b	)		(a	)		8			(b	)		(a	)
rent and facility services		2011		4			(b	)		(a	)		8			(b	)		(a	)
Ameren Missouri and Genco gas	Operating Revenues	2012		(b	)		(a	)		(b	)		(b	)		(a	)		(b	)
transportation agreement		2011		(b	)		(a	)		(b	)		(b	)		(a	)		(b	)
Total Operating Revenues		2012	$	4		$	(b	)	$	193		$	8		$	(b	)	$	386
		2011		4			(b	)		242			8			(b	)		482
Ameren Illinois power supply	Purchased Power	2012	$	(a	)	$	72		$	(a	)	$	(a	)	$	160		$	(a	)
agreements with Marketing Company		2011		(a	)		48			(a	)		(a	)		94			(a	)
EEI power supply agreement with	Purchased Power	2012		(a	)		(a	)		(b	)		(a	)		(a	)		(b	)
Marketing Company		2011		(a	)		(a	)		12			(a	)		(a	)		12
Total Purchased Power		2012	$	(a	)	$	72		$	(b	)	$	(a	)	$	160		$	(b	)
		2011		(a	)		48			12			(a	)		94			12
Ameren Services support services	Other Operations	2012	$	27		$	22		$	5		$	55		$	45		$	10
agreement	and Maintenance	2011		28			21			4			59			45			10
Insurance premiums(c)	Other Operations	2012		(b	)		(a	)		(a	)		(b	)		(a	)		(a	)
	and Maintenance	2011		(b	)		(a	)		(a	)		(b	)		(a	)		(a	)
Total Other Operations and		2012	$	27		$	22		$	5		$	55		$	45		$	10
Maintenance Expenses		2011		28			21			4			59			45			10
Money pool borrowings (advances)	Interest Charges	2012	$	-		$	(b	)	$	(b	)	$	-		$	(b	)	$	(b	)
		2011		-			-			(b	)		-			-			(b	)

(a) Not applicable.

(b) Amount less than $1 million.

(c) Represents insurance premiums paid to an affiliate for replacement power, property damage and terrorism coverage.