Segment Information

12 Months Ended

Dec. 31, 2011

Segment Information [Abstract]

Segment Information

NOTE 18 – SEGMENT INFORMATION

Ameren has three reportable segments: Ameren Missouri, Ameren Illinois, and Merchant Generation. The Ameren Missouri segment for Ameren and Ameren Missouri includes all the operations of Ameren Missouri's business as described in Note 1 – Summary of Significant Accounting Policies. The Ameren Illinois segment for Ameren and Ameren Illinois consists of all of the operations of Ameren Illinois as described in Note 1 – Summary of Significant Accounting Policies. The Merchant Generation segment for Ameren consists primarily of the operations or activities of Genco, including EEI, AERG, Medina Valley and Marketing Company. The category called Other primarily includes Ameren parent company activities, Ameren Services, and ATXI.

The following table presents information about the reported revenues and specified items reflected in Ameren's net income for the years ended December 31, 2011, 2010, and 2009, and total assets as of December 31, 2011, 2010, and 2009.

Ameren

	Ameren Missouri		Ameren Illinois Regulated Segment		Merchant Generation			Other			Intersegment Eliminations			Consolidated
2011
External revenues	$	3,358	$	2,774	$	1,394		$	5		$	-		$	7,531
Intersegment revenues		25		13		235			4			(277	)		-
Depreciation and amortization		408		215		143			19			-			785
Interest and dividend income		30		1		-			44			(43	)		32
Interest charges		209		136		105			44			(43	)		451
Income taxes (benefit)		161		127		32			(10	)		-			310
Net income (loss) attributable to Ameren Corporation(a)		287		193		45			(6	)		-			519
Capital expenditures		550		351		153			(24	)(b)		-			1,030
Total assets		12,757		7,213		3,833			1,211			(1,369	)		23,645
2010
External revenues	$	3,176	$	3,002	$	1,459		$	1		$	-		$	7,638
Intersegment revenues		21		12		234			13			(280	)		-
Depreciation and amortization		382		210		146			27			-			765
Interest and dividend income		31		1		1			25			(25	)		33
Interest charges		213		143		133			35			(27	)		497
Income taxes (benefit)		199		137		6			(17	)		-			325
Net income (loss) attributable to Ameren Corporation(a)		364		208		(409	)		(24	)		-			139
Capital expenditures		624		281		101			36			-			1,042
Total assets		12,504		7,406		3,934			1,354			(1,687	)		23,511
2009
External revenues	$	2,847	$	2,957	$	1,322		$	9		$	-		$	7,135
Intersegment revenues		27		27		390			19			(463	)		-
Depreciation and amortization		357		216		126			26			-			725
Interest and dividend income		29		6		-			33			(38	)		30
Interest charges		229		153		119			48			(41	)		508
Income taxes (benefit)		128		79		151			(26	)		-			332
Net income (loss) attributable to Ameren Corporation(a)		259		127		247			(21	)		-			612
Capital expenditures		882		352		408			68			-			1,710
Total assets		12,219		7,181		4,751			1,814			(2,263	)		23,702

(a) Represents net income (loss) available to common stockholders.

(b) Includes the elimination of intercompany transfers.