Related Party Transactions (Tables)

3 Months Ended

Mar. 31, 2015

Related Party Transactions [Abstract]

Schedule of Related Party Transactions

The following table presents the impact on Ameren Missouri and Ameren Illinois of related party transactions for the three months ended March 31, 2015 and 2014.

				Three Months
Agreement	Income Statement Line Item			Ameren Missouri		Ameren Illinois
Ameren Missouri power supply	Operating Revenues	2015	$	1	$	(a)
agreements with Ameren Illinois		2014		(b)		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2015		6		1
rent and facility services		2014		5		(b)
Ameren Missouri and Ameren Illinois	Operating Revenues	2015		(b)		(b)
miscellaneous support services		2014		(b)		(b)
Total Operating Revenues		2015	$	7	$	1
		2014		5		(b)
Ameren Illinois power supply	Purchased Power	2015	$	(a)	$	1
agreements with Ameren Missouri		2014		(a)		(b)
Ameren Illinois transmission	Purchased Power	2015		(a)		1
services with ATXI		2014		(a)		1
Total Purchased Power		2015	$	(a)	$	2
		2014		(a)		1
Ameren Services support services	Other Operations and Maintenance	2015	$	34	$	29
agreement		2014		33		27
Total Other Operations and		2015	$	34	$	29
Maintenance Expenses		2014		33		27
Money pool borrowings (advances)	Interest Charges/ Miscellaneous	2015	$	(b)	$	(b)
	Income	2014		(b)		(b)

(a) Not applicable.

(b) Amount less than $1 million.