The following table presents the impact on Ameren Missouri and Ameren Illinois of related party transactions for the three months ended March 31, 2013, and 2012. It is based primarily on the agreements discussed above and in Note 14 - Related Party Transactions under Part II, Item 8, of the Form 10-K, and the money pool arrangements discussed in Note 4 - Short-term Debt and Liquidity of this report.



			Three Months ended March 31
Agreement	Income Statement Line Item		Ameren Missouri		Ameren Illinois
Ameren Missouri power supply	Operating Revenues	2013	$	1	$ (a)
agreements with Ameren Illinois		2012	(b)		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2013	5		(b)
rent and facility services		2012	5		(b)
Ameren Missouri and Genco gas	Operating Revenues	2013	(b)		(a)
transportation agreement		2012	(b)		(a)
Transmission services agreement	Operating Revenues	2013	(a)		6
with Marketing Company		2012	(a)		2
Total Operating Revenues		2013	$	6	$	6
		2012	5		2
Ameren Illinois power supply	Purchased Power	2013	$ (a)		$	26
agreements with Marketing Company		2012	(a)		87
Ameren Illinois power supply	Purchased Power	2013	(a)		1
agreements with Ameren Missouri		2012	(a)		(b)
Total Purchased Power		2013	$ (a)		$	27
		2012	(a)		87
Ameren Services support services	Other Operations and Maintenance	2013	$	31	$	25
agreement		2012	28		23
Insurance premiums^(c)	Other Operations and Maintenance	2013	(b)		(a)
		2012	(b)		(a)
Total Other Operations and		2013	$	31	$	25
Maintenance Expenses		2012	28		23
Money pool borrowings (advances)	Interest Charges	2013	$ (b)		$ (b)
		2012	—		(b)


(a)	Not applicable.


(b)	Amount less than $1 million.


(c)	Represents insurance premiums paid to Missouri Energy Risk Assurance Company, an affiliate for replacement power, property damage and terrorism coverage