Segment Information

9 Months Ended

Sep. 30, 2014

Segment Reporting [Abstract]

SEGMENT INFORMATION

SEGMENT INFORMATION

Ameren has two reportable segments: Ameren Missouri and Ameren Illinois. The Ameren Missouri segment for both Ameren and Ameren Missouri includes all of the operations of Ameren Missouri’s business as described in Note 1 - Summary of Significant Accounting Policies. The Ameren Illinois segment for both Ameren and Ameren Illinois includes all of the operations of Ameren Illinois’ business as described in Note 1 - Summary of Significant Accounting Policies. The category called Other primarily includes Ameren (parent) activities, Ameren Services, and ATXI. In 2013, the Other category also included certain corporate activities previously included in the Merchant Generation segment.

The following table presents information about the reported revenues and specified items reflected in Ameren’s net income attributable to Ameren Corporation from continuing operations for the three and nine months ended September 30, 2014, and 2013, and total assets of continuing operations as of September 30, 2014, and December 31, 2013.

Three Months	Ameren Missouri		Ameren Illinois		Other			Intersegment Eliminations			Ameren
2014
External revenues	$	1,089	$	572	$	9		$	—		$	1,670
Intersegment revenues	8		—		2			(10		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	222		75		(3		)	—			294
2013
External revenues	$	1,088	$	547	$	3		$	—		$	1,638
Intersegment revenues	5		—		1			(6		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	238		77		(10		)	—			305
Nine Months
2014
External revenues	$	2,793	$	1,864	$	26		$	—		$	4,683
Intersegment revenues	21		1		3			(25		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	395		156		(10		)	—			541
2013
External revenues	$	2,760	$	1,744	$	12		$	—		$	4,516
Intersegment revenues	18		3		2			(23		)	—
Net income (loss) attributable to Ameren Corporation from continuing operations	362		139		(37		)	—			464
As of September 30, 2014:
Total assets	$	13,179	$	7,983	$	810		$	(111	)	$	21,861	(a)
As of December 31, 2013:
Total assets	$	12,904	$	7,454	$	752		$	(233	)	$	20,877	(a)

(a)    Excludes total assets from discontinued operations of $15 million and $165 million as of September 30, 2014, and December 31, 2013, respectively.