Segment Information (Tables)

6 Months Ended

Jun. 30, 2013

Segment Reporting [Abstract]

Schedule Of Segment Reporting Information By Segment

The following table presents information about the revenues and specified items included in net income attributable to Ameren Corporation from continuing operations for the three and six months ended June 30, 2013, and 2012, and total assets as of June 30, 2013, and December 31, 2012.

Three Months	Ameren Missouri		Ameren Illinois		Other			Intersegment Eliminations			Consolidated
2013
External revenues	$	883	$	514	$	6		$	—		$	1,403
Intersegment revenues	6		2		—			(8		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	84		31		(10		)	—			105
2012
External revenues	$	838	$	564	$	—		$	—		$	1,402
Intersegment revenues	6		—		1			(7		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	143		32		(14		)	—			161
Six Months
2013
External revenues	$	1,672	$	1,197	$	9		$	—		$	2,878
Intersegment revenues	13		3		1			(17		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	124		62		(27		)	—			159
2012
External revenues	$	1,524	$	1,288	$	2		$	—		$	2,814
Intersegment revenues	11		—		2			(13		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	164		59		(25		)	—			198
As of June 30, 2013:
Total assets	$	13,131	$	7,366	$	1,354		$	(1,061	)	$	20,790	(a)
As of December 31, 2012:
Total assets	$	13,043	$	7,282	$	1,228		$	(944	)	$	20,609	(a)

(a)    Excludes “Current assets of discontinued operations.” See Note 2 - Divestiture Transactions and Discontinued Operations for additional information.