Illinois Power Generating 10-K 26 Feb 10 2009 FY Annual report Financial data

Statement Of Income Alternative

Statement Of Income Alternative (USD $)
In Millions, except Per Share data	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
Operating Revenues:
Electric	$5,909	$6,367	$6,283
Gas	1,181	1,472	1,279
Total operating revenues	7,090	7,839	7,562
Operating Expenses:
Fuel	1,141	1,275	1,167
Purchased power	909	1,210	1,387
Gas purchased for resale	749	1,057	900
Other operations and maintenance	1,738	1,857	1,687
Depreciation and amortization	725	685	681
Taxes other than income taxes	412	393	381
Total operating expenses	5,674	6,477	6,203
Operating Income	1,416	1,362	1,359
Other Income and Expenses:
Miscellaneous income	71	80	75
Miscellaneous expense	(23)	(31)	(25)
Total other income	48	49	50
Interest Charges	508	440	423
Income Before Income Taxes	956	971	986
Income Taxes	332	327	330
Net Income	624	644	656
Less: Net Income Attributable to Noncontrolling Interests	12	39	38
Net Income Attributable to Ameren Corporation	$612	$605	$618
Earnings per Common Share - Basic and Diluted	2.78	2.88	2.98
Dividends per Common Share	1.54	2.54	2.54
Average Common Shares Outstanding	220.4	210.1	207.4

Statement Of Financial Position

Statement Of Financial Position Classified (USD $)
In Millions	Dec. 31, 2009	Dec. 31, 2008
Current Assets:
Cash and cash equivalents	$622	$92
Accounts receivable - trade (less allowance for doubtful accounts of $24 and $28, respectively)	434	516
Unbilled revenue	367	427
Miscellaneous accounts and notes receivable	308	315
Materials and supplies	782	842
Mark-to-market derivative assets	121	207
Other current assets	208	209
Total current assets	2,842	2,608
Property and Plant, Net	17,610	16,567
Investments and Other Assets:
Nuclear decommissioning trust fund	293	239
Goodwill	831	831
Intangible assets	129	167
Regulatory assets	1,430	1,653
Other assets	655	606
Total investments and other assets	3,338	3,496
TOTAL ASSETS	23,790	22,671
Current Liabilities:
Current maturities of long-term debt	204	380
Short-term debt	20	1,174
Accounts and wages payable	694	813
Taxes accrued	54	54
Interest accrued	110	107
Customer deposits	101	126
Mark-to-market derivative liabilities	109	155
Other current liabilities	419	268
Total current liabilities	1,711	3,077
Credit Facility Borrowings	830	0
Long-term Debt, Net	7,113	6,554
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	2,554	2,131
Accumulated deferred investment tax credits	94	100
Regulatory liabilities	1,338	1,291
Asset retirement obligations	429	406
Pension and other postretirement benefits	1,165	1,495
Other deferred credits and liabilities	496	438
Total deferred credits and other liabilities	6,076	5,861
Ameren Corporation Stockholders' Equity:
Common stock, $.01 par value, 400.0 shares authorized - shares outstanding of 237.4 and 212.3, respectively	2	2
Other paid-in capital, principally premium on common stock	5,412	4,780
Retained earnings	2,455	2,181
Accumulated other comprehensive loss	(16)	0
Total Ameren Corporation stockholders' equity	7,853	6,963
Noncontrolling Interests	207	216
Total equity	8,060	7,179
TOTAL LIABILITIES AND EQUITY	$23,790	$22,671

1_Statement Of Financial Positi

Statement Of Financial Position Classified (Parenthetical) (USD $)
In Millions, except Per Share data	Dec. 31, 2009	Dec. 31, 2008
Accounts receivable - trade, allowance for doubtful accounts	$24	$28
Common stock, par value	0.01	0.01
Common stock, shares authorized	400	400
Common stock, shares outstanding	237.4	212.3

Statement Of Cash Flows Indirec

Statement Of Cash Flows Indirect (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
Cash Flows From Operating Activities:
Net income	$624	$644	$656
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of emission allowances	(6)	(8)	(8)
Loss on asset impairments	7	14	0
Net mark-to-market gain on derivatives	(23)	(3)	(3)
Depreciation and amortization	748	705	735
Amortization of nuclear fuel	53	37	37
Amortization of debt issuance costs and premium/discounts	25	20	19
Deferred income taxes and investment tax credits, net	402	167	(28)
Other	(17)	(9)	9
Changes in assets and liabilities:
Receivables	21	12	(172)
Materials and supplies	67	(100)	(88)
Accounts and wages payable	(42)	57	0
Taxes accrued	0	(30)	21
Assets, other	(66)	83	42
Liabilities, other	103	113	(44)
Pension and other postretirement benefits	(9)	(4)	27
Counterparty collateral, net	(17)	(25)	(39)
Taum Sauk costs, net of insurance recoveries	107	(149)	(56)
Net cash provided by operating activities	1,977	1,524	1,108
Cash Flows From Investing Activities:
Capital expenditures	(1,704)	(1,896)	(1,381)
Nuclear fuel expenditures	(80)	(173)	(68)
Purchases of securities - nuclear decommissioning trust fund	(383)	(520)	(142)
Sales of securities - nuclear decommissioning trust fund	380	497	128
Purchases of emission allowances	(4)	(14)	(24)
Sales of emission allowances	0	6	5
Other	2	3	14
Net cash used in investing activities	(1,789)	(2,097)	(1,468)
Cash Flows From Financing Activities:
Dividends on common stock	(338)	(534)	(527)
Capital issuance costs	(65)	(12)	(4)
Short-term and credit facility borrowings, net	(324)	(298)	860
Dividends paid to noncontrolling interest holders	(21)	(40)	(32)
Redemptions, repurchases, and maturities:
Long-term debt	(631)	(842)	(488)
Preferred stock	0	(16)	(1)
Issuances:
Common stock	634	154	91
Long-term debt	1,021	1,879	674
Generator advances received for construction, net	66	19	5
Net cash provided by financing activities	342	310	578
Net change in cash and cash equivalents	530	(263)	218
Cash and cash equivalents at beginning of year	92	355	137
Cash and cash equivalents at end of year	622	92	355
Cash Paid During the Year:
Interest (net of $40, $41, and $31 capitalized, respectively)	478	409	391
Income taxes, net	$9	$106	$283

2_Statement Of Cash Flows Indir

Statement Of Cash Flows Indirect (Parenthetical) (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
Interest, capitalized	$40	$41	$31

Statement Of Shareholders Equit

Statement Of Shareholders Equity And Other Comprehensive Income (USD $)
In Millions				Derivative financial instruments	Deferred retirement benefit costs	Accumulated other comprehensive income (loss)	Total Ameren Corporation Stockholders' Equity			Total
Beginning of year at Dec. 31, 2006									206.6
Beginning of year at Dec. 31, 2006	$2	$4,495	$2,024	$60	$2			$211
Net income			618					38		656
Shares issued	0	91
Change in derivative financial instruments				(51)
Dividends			(527)
Dividends paid to noncontrolling interest holders								(32)
Stock-based compensation cost		18
Adjustment to adopt new accounting standard			(5)
Change in deferred retirement benefit costs					25
Shares issued									1.7
End of year at Dec. 31, 2007	2	4,604	2,110	9	27	36	6,752	217		6,969
End of year at Dec. 31, 2007									208.3
Net income			605					39		644
Shares issued	0	154
Change in derivative financial instruments				39
Dividends			(534)
Dividends paid to noncontrolling interest holders								(40)
Stock-based compensation cost		22
Adjustment to adopt new accounting standard			0
Change in deferred retirement benefit costs					(75)
Shares issued									4
End of year at Dec. 31, 2008	2	4,780	2,181	48	(48)	0	6,963	216		7,179
End of year at Dec. 31, 2008									212.3	212.3
Net income			612					12		624
Shares issued	0	617
Change in derivative financial instruments				(38)
Dividends			(338)
Dividends paid to noncontrolling interest holders								(21)
Stock-based compensation cost		15
Adjustment to adopt new accounting standard			0
Change in deferred retirement benefit costs					22
Shares issued									25.1
End of year at Dec. 31, 2009	$2	$5,412	$2,455	$10	($26)	($16)	$7,853	$207		$8,060
End of year at Dec. 31, 2009									237.4	237.4

3_Statement Of Shareholders Equ

Statement Of Shareholders Equity And Other Comprehensive Income (Parenthetical) (USD $)
In Millions
Shares issued, issuance costs	$0
Unrealized net gain (loss) on derivative hedging instruments, income taxes (benefit)		(7)
Reclassification adjustments for derivative (gains) included in net income, income taxes		22
Reclassification adjustment due to implementation of FAC, income taxes		0
Pension and other postretirement activity, taxes (benefit)		1
Shares issued, issuance costs	0
Unrealized net gain (loss) on derivative hedging instruments, income taxes (benefit)		65
Reclassification adjustments for derivative (gains) included in net income, income taxes		43
Reclassification adjustment due to implementation of FAC, income taxes		0
Pension and other postretirement activity, taxes (benefit)		(45)
Shares issued, issuance costs	17
Unrealized net gain (loss) on derivative hedging instruments, income taxes (benefit)		78
Reclassification adjustments for derivative (gains) included in net income, income taxes		82
Reclassification adjustment due to implementation of FAC, income taxes		18
Pension and other postretirement activity, taxes (benefit)		$22

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	12 Months Ended Dec. 31, 2009 USD / shares
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 1 SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES General Ameren, headquartered in St. Louis, Missouri, is a public utility holding company under PUHCA 2005, administered by FERC. Amerens primary assets are the common stock of its subsidiaries. Amerens subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. These subsidiaries operate, as the case may be, rate-regulated electric generation, transmission and distribution businesses, rate-regulated natural gas transmission and distribution businesses, and merchant electric generation businesses in Missouri and Illinois. Dividends on Amerens common stock and the payment of other expenses by Ameren depend on distributions made to it by its subsidiaries. Amerens principal subsidiaries are listed below. Also see the Glossary of Terms and Abbreviations at the front of this report. UE, or Union Electric Company, also known as AmerenUE, operates a rate-regulated electric generation, transmission and distribution business, and a rate-regulated natural gas transmission and distribution business in Missouri. UE was incorporated in Missouri in 1922 and is successor to a number of companies, the oldest of which was organized in 1881. It is the largest electric utility in the state of Missouri. It supplies electric and natural gas service to a 24,000-square-mile area located in central and eastern Missouri. This area has an estimated population of 2.8million and includes the Greater St. Louis area. UE supplies electric service to 1.2million customers and natural gas service to 126,000 customers. CIPS, or Central Illinois Public Service Company, also known as AmerenCIPS, operates a rate-regulated electric and natural gas transmission and distribution business in Illinois. CIPS was incorporated in Illinois in 1923 and is successor to a number of companies, the oldest of which was organized in 1902. It supplies electric and natural gas utility service to portions of central, west central and southern Illinois having an estimated population of 1.1million in an area of 20,500 square miles. CIPS supplies electric service to 383,000 customers and natural gas service to 182,000 customers. Genco, or Ameren Energy Generating Company, operates a merchant electric generation business in Illinois and Missouri. Genco was incorporated in Illinois in March 2000. Gencos coal, and natural gas and oil-fired electric generating facilities, are expected to have capacity of 3,454, 1,578, and 169 megawatts, respectively, at the time of the 2010 peak summer electrical demand. CILCO, or Central Illinois Light Company, also known as AmerenCILCO, operates a rate-regulated electric transmission and distribution business, a merchant electric generation business (through its subsidiary AERG), and a rate-regulated natural gas transmission and distribution business, all in Illinois. CILCO was incorporated in Illinois in 1913. It supplies electric and natural gas utility service to portions of central and east central Illinois in areas of 3,700 and 4,500 square miles, respectively, with an estimated population of 0.6million. CILCO supplies e

RATE AND REGULATORY MATTERS

RATE AND REGULATORY MATTERS
	12 Months Ended Dec. 31, 2009 USD / shares
RATE AND REGULATORY MATTERS	NOTE 2 RATE AND REGULATORY MATTERS Below is a summary of significant regulatory proceedings and related lawsuits. We are unable to predict theultimate outcome of these matters, the timing of the final decisions of the various agencies and courts, or the impact on our results of operations, financial position, or liquidity. Missouri 2009 Electric Rate Order In January 2009, the MoPSC issued an order approving an increase for UE in annual revenues of approximately $162 million for electric service and the implementation of a FAC and a vegetation management and infrastructure inspection cost tracking mechanism, among other things. The rate changes necessary to implement the provisions of the MoPSC order were effective March1, 2009. In February 2009, Noranda, UEs largest electric customer, and the Missouri Office of Public Counsel appealed certain aspects of the MoPSC decision to the Circuit Court of Pemiscot County, Missouri, the Circuit Court of Stoddard County, Missouri, and the Circuit Court of Cole County, Missouri. In September 2009, the Circuit Court of Pemiscot County granted Norandas request to stay the electric rate increase granted by the January 2009 MoPSC order as it applies specifically to Norandas electric service account until the court renders its decision on the appeal. The merits of the appeal continue to be briefed by the parties. A decision is likely to be issued by the Circuit Court of Pemiscot County in the second quarter of 2010. During the stay, Noranda will pay into the court registry the contested portion of its monthly billings, approximately $0.5 million per month based on current usage levels. If UE wins the appeal, it will receive those monthly payments plus interest. Pending Electric Rate Case UE filed a request with the MoPSC in July 2009 to increase its annual revenues for electric service by $402million. Included in this increase request was approximately $227 million of anticipated increases in normalized net fuel costs in excess of the net fuel costs included in base rates previously authorized by the MoPSC in its January 2009 electric rate order, which, absent initiation of this general rate proceeding, would have been eligible for recovery through UEs existing FAC. The balance of the increase request is based primarily on investments made to continue systemwide reliability improvements for customers, increases in costs essential to generating and delivering electricity, and higher financing costs. The initial electric rate increase request was based on an 11.5% return on equity, a capital structure composed of 47.4% equity, a rate base for UE of $6.0 billion, and a test year ended March31, 2009, with certain pro-forma adjustments through the anticipated true-up date of January31, 2010. In February 2010, UE filed rebuttal testimony relating to certain positions taken by interveners in the rate case and modified its recommended return on equity to 10.8%. UEs initial filing included a request for interim rate relief, which would have placed into effect approximately $37 million of the requested increase prior to completion of the full rate case. In January 2010, the MoPSC denied UEs reques

PROPERTY AND PLANT, NET

PROPERTY AND PLANT, NET
	12 Months Ended Dec. 31, 2009 USD / shares
PROPERTY AND PLANT, NET	NOTE 3 PROPERTY AND PLANT, NET The following table presents property and plant, net, for each of the Ameren Companies at December31, 2009 and 2008: Ameren(a)(b) UE(b) CIPS Genco CILCO (Illinois Regulated) CILCO (AERG) IP 2009: Property and plant, at original cost: Electric $ 22,486 $ 13,627 $ 1,796 $ 2,730 $ 987 $ 1,251 $ 1,966 Gas 1,583 363 374 - 520 - 603 Other 406 85 6 6 3 2 21 24,475 14,075 2,176 2,736 1,510 1,253 2,590 Less: Accumulated depreciation and amortization 8,787 5,760 923 1,032 730 295 176 15,688 8,315 1,253 1,704 780 958 2,414 Construction work in progress: Nuclear fuel in process 271 271 - - - - - Other 1,651 999 15 431 12 39 36 Property and plant, net $ 17,610 $ 9,585 $ 1,268 $ 2,135 $ 792 $ 997 $ 2,450 2008: Property and plant, at original cost: Electric $ 21,244 $ 13,214 $ 1,744 $ 2,451 $ 954 $ 948 $ 1,840 Gas 1,505 347 365 - 506 - 565 Other 381 76 6 6 3 2 21 23,130 13,637 2,115 2,457 1,463 950 2,426 Less: Accumulated depreciation and amortization 8,499 5,539 915 1,013 721 329 152 14,631 8,098 1,200 1,444 742 621 2,274 Construction work in progress: Nuclear fuel in process 190 190 - - - - - Other 1,746 707 12 506 12 359 55 Property and plant, net $ 16,567 $ 8,995 $ 1,212 $ 1,950 $ 754 $ 980 $ 2,329 (a) Includes amounts for Ameren registrant and nonregistrant subsidiaries as well as intercompany eliminations. (b) Amounts in Ameren and UE include two electric generation CTs under two separate capital lease agreements with a gross asset value of $226million and $222 million at December31, 2009 and 2008, respectively. The total accumulated depreciation associated with the two CTs was $41 million and $36 million at December31, 2009 and 2008, respectively. The following table provides accrued capital expenditures at December31, 2009, 2008, and 2007, which represent noncash investing activity excluded from the statements of cash flows: Ameren(a) UE CIPS Genco CILCO IP 2009 $ 143 $ 86 $ 7 $ 23 $ 6 $ 18 2008 213 110 3 41 45 14 2007 153 76 3 28 35 7 (a) Includes amounts for Ameren registrant and nonregistrant subsidiaries.

CREDIT FACILITY BORROWINGS AND

CREDIT FACILITY BORROWINGS AND LIQUIDITY
	12 Months Ended Dec. 31, 2009 USD / shares
CREDIT FACILITY BORROWINGS AND LIQUIDITY	NOTE 4 CREDIT FACILITY BORROWINGS AND LIQUIDITY The liquidity needs of the Ameren Companies are typically supported through the use of available cash, short-term intercompany borrowings, or drawings under committed bank credit facilities. The following table summarizes the borrowing activity and relevant interest rates under the $1.15 billion credit facility described below for the years ended December31, 2009 and 2008, respectively, and excludes letters of credit issued under the credit facility: 2009 Multiyear Credit Agreement ($1.15 billion)(a) Ameren (Parent) UE Genco Total 2009: Average daily borrowings outstanding during 2009 $ 307 $ 266 $ 54 $ 627 Outstanding credit facility borrowings at period end 646 - - 646 Weighted-average interest rate during 2009 2.15 % 1.72 % 2.70 % 2.02 % Peak credit facility borrowings during 2009(b) $ 699 $ 457 $ 133 $ 940 Peak interest rate during 2009 5.50 % 5.50 % 3.56 % 5.50 % Prior $1.15 Billion Credit Facility 2008: Average daily borrowings outstanding during 2008 $ 389 $ 154 $ 41 $ 584 Outstanding credit facility borrowings at period end 275 251 - 526 Weighted-average interest rate during 2008 3.58 % 3.25 % 3.97 % 3.52 % Peak credit facility borrowings during 2008 $ 675 $ 493 $ 150 $ 1,068 Peak interest rate during 2008 7.25 % 5.65 % 5.53 % 7.25 % (a) The 2009 Multiyear Credit Agreement amended and restated the Prior $1.15 Billion Credit Facility. Therefore, information in this table includes borrowing activity under the Prior $1.15 Billion Credit Facility. (b) The timing of peak credit facility borrowings varies by company. Therefore, the amounts presented by company might not equal the total peak credit facility borrowings for the period. The simultaneous peak credit facility borrowings under all credit facilities during 2009 were $1 billion. The following table summarizes the borrowing activity and relevant interest rates under the $150 million Supplemental Agreement described below for the year ended December31, 2009: Supplemental Agreement ($150 million) Ameren (Parent) UE Genco Total 2009: Average daily borrowings outstanding during 2009 $ 42 $ 20 $ 12 $ 74 Outstanding credit facility borrowings at period end 84 - - 84 Weighted-average interest rate during 2009 3.58 % 3.62 % 3.52 % 3.56 % Peak credit facility borrowings during 2009(a) $ 91 $ 53 $ 17 $ 109 Peak interest rate during 2009 5.50 % 5.50 % 3.56 % 5.50 % (a) The timing of peak credit facility borrowings varies by company and therefore the amounts presented by company might not equal the total peak credit facility borrowings for t

LONG-TERM DEBT AND EQUITY FINAN

LONG-TERM DEBT AND EQUITY FINANCINGS
	12 Months Ended Dec. 31, 2009 USD / shares
LONG-TERM DEBT AND EQUITY FINANCINGS	NOTE 5 LONG-TERM DEBT AND EQUITY FINANCINGS The following table presents long-term debt outstanding for the Ameren Companies as of December31, 2009 and 2008: 2009 2008 Ameren (Parent): 8.875% Senior unsecured notes due 2014 $ 425 $ - Less: Unamortized discount and premium (2 ) - Long-term debt, net $ 423 $ - UE: First mortgage bonds:(a) 5.25% Senior secured notes due 2012(b) $ 173 $ 173 4.65% Senior secured notes due 2013(b) 200 200 5.50% Senior secured notes due 2014(b) 104 104 4.75% Senior secured notes due 2015(b) 114 114 5.40% Senior secured notes due 2016(b) 260 260 6.40% Senior secured notes due 2017(b) 425 425 6.00% Senior secured notes due 2018(b) 250 250 5.10% Senior secured notes due 2018(b) 200 200 6.70% Senior secured notes due 2019(b) 450 450 5.10% Senior secured notes due 2019(b) 300 300 5.00% Senior secured notes due 2020(b) 85 85 5.45% Series due 2028(c) 44 44 5.50% Senior secured notes due 2034(b) 184 184 5.30% Senior secured notes due 2037(b) 300 300 8.45% Senior secured notes due 2039(b) 350 - Environmental improvement and pollution control revenue bonds:(a)(b)(c)(d) 1992 Series due 2022 47 47 1998 Series A due 2033 60 60 1998 Series B due 2033 50 50 1998 Series C due 2033 50 50 Subordinated deferrable interest debentures: 7.69% Series A due 2036(e) 66 66 Capital lease obligations: City of Bowling Green capital lease (Peno Creek CT) 78 82 Audrain County capital lease (Audrain County CT) 240 240 Total long-term debt, gross 4,030 3,684 Less: Unamortized discount and premium (8 ) (7 ) Less: Maturities due within one year (4 ) (4 ) Long-term debt, net $ 4,018 $ 3,673 CIPS: First mortgage bonds:(a) 6.625% Senior secured notes due 2011(b) $ 150 $ 150 7.61% Series 1997-2 due 2017 40 40 6.125% Senior secured notes due 2028(b) 60 60 6.70% Senior secured notes due 2036(b) 61 61 Environmental improvement and pollution control revenue bonds: 2000 Series A 5.50% due 2014 51 51 1993 Series C-1 5.95% due 2026 35 35 1993 Series C-2 5.70% due 2026 8 8 1993 Series B-1 due 2028(d) 17 17 Total long-term debt, gross 422 422 Less: Unamortized discount and premium (1 ) (1 ) Long-term debt, net $ 421 $ 421 Genco: Unsecured notes: Senior notes Series D 8.35% due 2010 $ 200 $ 200 Senior notes Series F 7.95% due 2032 275 275 Senior notes Series H 7.00% due 2018 300 300 Senior notes Series I 6.30% due 2020 250 - Total long-term de

OTHER INCOME AND EXPENSES

OTHER INCOME AND EXPENSES
	12 Months Ended Dec. 31, 2009 USD / shares
OTHER INCOME AND EXPENSES	NOTE 6 OTHER INCOME AND EXPENSES The following table presents Other Income and Expenses for each of the Ameren Companies for the years ended December31, 2009, 2008, and 2007: 2009 2008 2007 Ameren:(a) Miscellaneous income: Interest and dividend income $ 2 $ 15 $ 27 Interest income on industrial development revenue bonds 28 28 28 Allowance for equity funds used during construction 36 28 5 Other 5 9 15 Total miscellaneous income $ 71 $ 80 $ 75 Miscellaneous expense: Donations $ (12 ) $ (13 ) $ (13 ) Other (11 ) (18 ) (12 ) Total miscellaneous expense $ (23 ) $ (31 ) $ (25 ) UE: Miscellaneous income: Interest and dividend income $ 1 $ 5 $ 4 Interest income on industrial development revenue bonds 28 28 28 Allowance for equity funds used during construction 33 28 4 Other 1 1 2 Total miscellaneous income $ 63 $ 62 $ 38 Miscellaneous expense: Donations $ (3 ) $ (3 ) $ (2 ) Other (4 ) (6 ) (5 ) Total miscellaneous expense $ (7 ) $ (9 ) $ (7 ) CIPS: Miscellaneous income: Interest and dividend income $ 5 $ 9 $ 16 Other 3 2 1 Total miscellaneous income $ 8 $ 11 $ 17 Miscellaneous expense: Donations $ (1 ) $ (2 ) $ (2 ) Other (1 ) (1 ) (1 ) Total miscellaneous expense $ (2 ) $ (3 ) $ (3 ) Genco: Miscellaneous income: Interest and dividend income $ - $ 1 $ - Total miscellaneous income $ - $ 1 $ - Miscellaneous expense: Other $ - $ (1 ) $ - Total miscellaneous expense $ - $ (1 ) $ - CILCO: Miscellaneous income: Interest and dividend income $ 1 $ 1 $ 4 Other - 1 1 Total miscellaneous income $ 1 $ 2 $ 5 Miscellaneous expense: Donations $ (1 ) $ (2 ) $ (1 ) Other (4 ) (3 ) (5 ) Total miscellaneous expense $ (5 ) $ (5 ) $ (6 ) IP: Miscellaneous income: Interest and dividend income $ - $ 5 $ 8 Allowance for equity funds used during construction 2 - - Other 1 6 6 Total miscellaneous income $ 3 $ 11 $ 14 Miscellaneous expense: Donations $ (2 ) $ (3 ) $ (3 ) Other (1 ) (2 ) (2 ) Total miscellaneous expense $ (3 ) $ (5 ) $ (5 ) (a) Includes amounts for Ameren regis

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS
	12 Months Ended Dec. 31, 2009 USD / shares
DERIVATIVE FINANCIAL INSTRUMENTS	NOTE 7 DERIVATIVE FINANCIAL INSTRUMENTS We use derivatives principally to manage the risk of changes in market prices for natural gas, coal, diesel, electricity, uranium, and emission allowances. Such price fluctuations may cause the following: an unrealized appreciation or depreciation of our contracted commitments to purchase or sell when purchase or sale prices under the commitments are compared with current commodity prices; market values of coal, natural gas, and uranium inventories or emission allowances that differ from the cost of those commodities in inventory; and actual cash outlays for the purchase of these commodities that differ from anticipated cash outlays. The derivatives that we use to hedge these risks are governed by our risk management policies for forward contracts, futures, options, and swaps. Our net positions are continually assessed within our structured hedging programs to determine whether new or offsetting transactions are required. The goal of the hedging program is generally to mitigate financial risks while ensuring that sufficient volumes are available to meet our requirements. Contracts we enter into as part of our risk management program may be settled financially, settled by physical delivery, or net settled with the counterparty. The following table presents open gross derivative volumes by commodity type as of December31, 2009: Quantity Commodity NPNS Contracts(a) Cash Flow Hedges(b) Other Derivatives(c) DerivativesSubjectto Regulatory Deferral(d) Coal (in tons) Ameren(e) 114,747,000 (f ) (f ) (f ) UE 80,540,000 (f ) (f ) (f ) Genco 17,403,000 (f ) (f ) (f ) CILCO 7,782,000 (f ) (f ) (f ) Natural gas (in mmbtu) Ameren(e) 164,843,000 (f ) 28,104,000 136,266,000 UE 21,683,000 (f ) 5,390,000 20,730,000 CIPS 27,625,000 (f ) (f ) 22,228,000 Genco (f ) (f ) 7,383,000 (f ) CILCO 49,580,000 (f ) (f ) 36,368,000 IP 65,956,000 (f ) (f ) 56,941,000 Heating oil (in gallons) Ameren(e) (f ) (f ) 94,254,000 117,300,000 UE (f ) (f ) (f ) 117,300,000 Genco (f ) (f ) 48,126,000 (f ) CILCO (f ) (f ) 21,286,000 (f ) Power (in megawatthours) Ameren(e) 75,948,000 32,136,000 22,182,000 35,871,000 UE 3,579,000 (f ) 608,000 4,071,000 CIPS (f ) (f ) (f ) 10,494,000 CILCO (f ) (f ) (f ) 5,406,000 IP (f ) (f ) (f ) 15,900,000 Uranium (in pounds) Ameren (f ) (f ) (f ) 250,000 UE (f ) (f ) (f ) 250,000 (a) Contracts through December 2013,March 2015, and September 2035 for coal, natural gas, and power, respectively. (b) Contracts through December 2012 for power. (c) Contracts through April 2012,December 2013, and May 2013 for natural gas, heating oil, and power,

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS
	12 Months Ended Dec. 31, 2009 USD / shares
FAIR VALUE MEASUREMENTS	NOTE 8 FAIR VALUE MEASUREMENTS Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. We use various methods to determine fair value, including market, income, and cost approaches. With these approaches, we adopt certain assumptions that market participants would use in pricing the asset or liability, including assumptions about market risk or the risks inherent in the inputs to the valuation. Inputs to valuation can be readily observable, market-corroborated, or unobservable. We use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. Authoritative accounting guidance established a fair value hierarchy that prioritizes the inputs used to measure fair value. All financial assets and liabilities carried at fair value are classified and disclosed in one of the following three hierarchy levels: Level 1: Inputs based on quoted prices in active markets for identical assets or liabilities. Level 1 assets and liabilities are primarily exchange-traded derivatives and assets, including U.S. treasury securities and listed equity securities, such as those held in UEs Nuclear Decommissioning Trust Fund. Level 2: Market-based inputs corroborated by third-party brokers or exchanges based on transacted market data. Level 2 assets and liabilities include certain assets held in UEs Nuclear Decommissioning Trust Fund, including corporate bonds and other fixed-income securities, and certain over-the-counter derivative instruments, including natural gas swaps and financial power transactions. Derivative instruments classified as Level 2 are valued using corroborated observable inputs, such as pricing services or prices from similar instruments that trade in liquid markets. Our development and corroboration process entails obtaining multiple quotes or prices from outside sources. To derive our forward view to price our derivative instruments at fair value, we average the midpoints of the bid/ask spreads. To validate forward prices obtained from outside parties, we compare the pricing to recently settled market transactions. Additionally, a review of all sources is performed to identify any anomalies or potential errors. Further, we consider the volume of transactions on certain trading platforms in our reasonableness assessment of the averaged midpoint. Level 3: Unobservable inputs that are not corroborated by market data. Level 3 assets and liabilities are valued based on internally developed models and assumptions or methodologies that use significant unobservable inputs. Level 3 assets and liabilities include derivative instruments that trade in less liquid markets, where pricing is largely unobservable, including the financial contracts entered into between the Ameren Illinois Utilities and Marketing Company. We value Level 3 instruments by using pricing models with inputs that are often unobservable in the market, as well as certain internal assumptions. Our development

NUCLEAR DECOMMISSIONING TRUST F

NUCLEAR DECOMMISSIONING TRUST FUND INVESTMENTS
	12 Months Ended Dec. 31, 2009 USD / shares
NUCLEAR DECOMMISSIONING TRUST FUND INVESTMENTS	NOTE 9 NUCLEAR DECOMMISSIONING TRUST FUND INVESTMENTS UE has investments in debt and equity securities that are held in a trust fund for the purpose of funding the decommissioning of its Callaway nuclear plant. See Note16 Callaway Nuclear Plant for additional information. We have classified these investments as available for sale, and we have recorded all such investments at their fair market value at December31, 2009, and 2008. Investments in the nuclear decommissioning trust fund have a target allocation of 60% to 70% in equity securities, with the balance invested in debt securities. Due to market conditions in 2008, the equity securities weighting was less than targeted levels at December31, 2008. In January 2009, UE rebalanced its investments to align with its targeted equity securities weighting. The following table presents proceeds from the sale of investments in UEs nuclear decommissioning trust fund and the gross realized gains and losses resulting from those sales for the years ended December31, 2009, 2008, and 2007: 2009 2008 2007 Proceeds from sales $ 380 $ 497 $ 128 Gross realized gains 5 5 4 Gross realized losses 10 8 3 Net realized and unrealized gains and losses are deferred and recorded as regulatory assets or regulatory liabilities on Amerens and UEs Consolidated Balance Sheets. This reporting is consistent with the method used to account for the decommissioning costs recovered in rates. Gains or losses associated with assets in the trust fund could result in lower or higher funding requirements for decommissioning costs, which are expected to be reflected in electric rates paid by UEs customers. See Note2 Rate and Regulatory Matters. The following table presents the costs and fair values of investments in debt and equity securities in UEs nuclear decommissioning trust fund at December31, 2009 and 2008: Security Type Cost GrossUnrealizedGain GrossUnrealizedLoss FairValue 2009: Debt securities $ 95 $ 3 $ 1 $ 97 Equity securities 137 72 14 195 Cash (a ) - - (a ) Other(b) 1 - - 1 Total $ 233 $ 75 $ 15 $ 293 2008: Debt securities $ 109 $ 5 $ 3 $ 111 Equity securities 123 40 29 134 Cash 2 - - 2 Other(b) (8 ) - - (8 ) Total $ 226 $ 45 $ 32 $ 239 (a) Amount less than $1 million. (b) Represents payables relating to pending security purchases, net of receivables related to pending securities sales and interest receivables. The following table presents the costs and fair values of investments in debt securities in UEs nuclear decommissioning trust fund according to their contractual maturities at December31, 2009: Cost FairValue Less than 5 years $ 50 $ 51 5 years to 10 years 25 26 Due after 10 years 20 20 Total $ 95 $ 97 We have unrea

PREFERRED STOCK

PREFERRED STOCK
	12 Months Ended Dec. 31, 2009 USD / shares
PREFERRED STOCK	NOTE 10 PREFERRED STOCK All classes of UEs, CIPS, CILCOs and IPs preferred stock are entitled to cumulative dividends and have voting rights. The following table presents the outstanding preferred stock of UE, CIPS, CILCO and IP that is not subject to mandatory redemption. The preferred stock is redeemable, at the option of the issuer, at the prices presented as of December31, 2009 and 2008: RedemptionPrice(pershare) 2009 2008 UE: Without par value and stated value of $100 per share, 25million shares authorized $3.50 Series 130,000 shares $110.00 $ 13 $ 13 $3.70 Series 40,000 shares 104.75 4 4 $4.00 Series 150,000 shares 105.625 15 15 $4.30 Series 40,000 shares 105.00 4 4 $4.50 Series 213,595 shares 110.00(a) 21 21 $4.56 Series 200,000 shares 102.47 20 20 $4.75 Series 20,000 shares 102.176 2 2 $5.50 Series A 14,000 shares 110.00 1 1 $7.64 Series 330,000 shares 101.27(b) 33 33 Total $ 113 $ 113 CIPS: With par value of $100 per share, 2million shares authorized 4.00% Series 150,000 shares $ 101.00 $ 15 $ 15 4.25% Series 50,000 shares 102.00 5 5 4.90% Series 75,000 shares 102.00 8 8 4.92% Series 50,000 shares 103.50 5 5 5.16% Series 50,000 shares 102.00 5 5 6.625% Series 125,000 shares 100.00 12 12 Total $ 50 $ 50 CILCO: With par value of $100 per share, 1.5million shares authorized 4.50% Series 111,264 shares $ 110.00 $ 11 $ 11 4.64% Series 79,940 shares 102.00 8 8 Total $ 19 $ 19 IP: With par value of $50 per share, 5million shares authorized 4.08% Series 225,510 shares $ 51.50 $ 12 $ 12 4.20% Series 143,760 shares 52.00 7 7 4.26% Series 104,280 shares 51.50 5 5 4.42% Series 102,190 shares 51.50 5 5 4.70% Series 145,170 shares 51.50 7 7 7.75% Series 191,765 shares 50.00 10 10 Total $ 46 $ 46 Less: Shares of IP preferred stock owned by Ameren (33 ) (33 ) Total Ameren $ 195 $ 195 (a) In the event of voluntary liquidation, $105.50. (b) Redemption price as of December31, 2009. Declining to $100 per share in 2012. In addition, the Ameren Companies have classes of preferred stock that are authorized but no shares of which are outstanding. Ameren has 100million shares of $0.01 par value preferred stock authorized, with no shares outstanding. CIPS has 2.6million shares of no par value preferred stock authorized, with no shares outstanding. UE has 7.5million shares of $1 par value preference stock authorized, with no such preference stock outstanding. CILCO has 2million shares

RETIREMENT BENEFITS

RETIREMENT BENEFITS
	12 Months Ended Dec. 31, 2009 USD / shares
RETIREMENT BENEFITS	NOTE 11 RETIREMENT BENEFITS The primary objective of the Ameren retirement plan and postretirement benefit plans is to provide eligible employees with pension and postretirement health care and life insurance benefits. We offer defined benefit and postretirement benefit plans covering substantially all employees of UE, CIPS, CILCO, IP, EEI, and Ameren Services and certain employees of Resources Company and its subsidiaries, including Genco. Ameren uses a measurement date of December31 for its pension and postretirement benefit plans. The following table presents the benefit liability recorded on the balance sheets of each of the Ameren Companies as of December31, 2009: Ameren(a) $ 1,171 UE 403 CIPS 59 Genco 51 CILCO 194 IP 238 (a) Includes amounts for Ameren registrant and nonregistrant subsidiaries. Ameren recognizes the underfunded status of its pension and postretirement plans as a liability on its balance sheet, with offsetting entries to accumulated OCI and regulatory assets, in accordance with authoritative accounting guidance. The following table presents the funded status of our pension and postretirement benefit plans as of December31, 2009 and 2008. It also provides the amounts included in regulatory assets and accumulated OCI at December31, 2009 and 2008, that have not been recognized in net periodic benefit costs. 2009 2008 PensionBenefits(a) Postretirement Benefits(a) PensionBenefits(a) Postretirement Benefits(a) Accumulated benefit obligation at end of year $ 3,041 $ (b ) $ 3,051 $ (b ) Change in benefit obligation: Net benefit obligation at beginning of year $ 3,303 $ 1,182 $ 3,076 $ 1,253 Service cost 68 19 60 18 Interest cost 186 66 186 70 Plan amendments - - 2 - Participant contributions - 17 - 14 Actuarial (gain) loss (133 ) (74 ) 145 (105 ) Benefits paid (169 ) (72 ) (166 ) (73 ) Federal subsidy on benefits paid (b ) 5 (b ) 5 Net benefit obligation at end of year 3,255 1,143 3,303 1,182 Change in plan assets: Fair value of plan assets at beginning of year 2,393 593 2,698 787 Actual return on plan assets 172 140 (205 ) (187 ) Employer contributions 99 49 66 47 Federal subsidy on benefits paid - 5 - 5 Participant contributions - 17 - 14 Benefits paid (169 ) (72 ) (166 ) (73 ) Fair value of plan assets at end of year 2,495 732 2,393 593 Funded status deficiency 760 411 910 589 Accrued benefit cost at December31 $ 760 $ 411 $ 910 $ 589 Amounts recognized in the balance sheet consist of: Current liability $ 3

Stock-Based Compensation

Stock-Based Compensation
	12 Months Ended Dec. 31, 2009 USD / shares
Stock-Based Compensation	NOTE 12 Stock-Based Compensation Amerens long-term incentive plan for eligible employees, called the Long-term Incentive Plan of 1998 (1998 Plan), was replaced prospectively by the 2006 Omnibus Incentive Compensation Plan (2006 Plan) effective May2, 2006. The 2006 Plan provides for a maximum of 4million common shares to be available for grant to eligible employees and directors. No new awards may be granted under the 1998 Plan; however, previously granted awards continue to vest or to be exercisable in accordance with their original terms and conditions. The 2006 Plan awards may be stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance share units, cash-based awards, and other stock-based awards. A summary of nonvested shares as of December31, 2009, and changes during the year ended December31, 2009, under the 1998 Plan and the 2006 Plan are presented below: PerformanceShareUnits Restricted Shares ShareUnits Weighted-average FairValueperUnit Shares Weighted-average FairValueperShare Nonvested at January1, 2009 675,977 $ 43.28 213,683 $ 47.46 Granted(a) 741,738 15.52 - - Dividends - - 7,934 25.39 Unearned or forfeited(b) (247,065 ) 57.15 (3,644 ) 48.30 Earned and vested(c) (225,313 ) 25.66 (82,277 ) 45.15 Nonvested at December31, 2009 945,337 $ 22.07 135,696 $ 48.92 (a) Includes performance share units (share units) granted to certain executive and nonexecutive officers and other eligible employees in March 2009 under the 2006 Plan. (b) Includes share units granted in 2007 that were not earned based on performance provisions of the award grants. (c) Includes share units granted in 2007 that vested as of December31, 2009, that were earned pursuant to the provisions of the award grants. Also includes share units that vested due to attainment of retirement eligibility by certain employees. Actual shares issued for retirement-eligible employees will vary depending on actual performance over the three-year measurement period. Ameren recorded compensation expense of $15million, $22 million, and $18 million for the years ended December31, 2009, 2008, and 2007, respectively, and a related tax benefit of $6 million, $8 million, and $7million for the years ended December31, 2009, 2008, and 2007, respectively. As of December31, 2009, total compensation cost of $8 million related to nonvested awards not yet recognized is expected to be recognized over a weighted-average period of 16 months. Performance Share Units Performance share unit awards were granted under the 2006 Plan each year since 2006. A share unit will vest and entitle an employee to receive shares of Ameren common stock (plus accumulated dividends) if, at the end of the three-year performance period, certain specified performance or market conditions have been met and the individual remains employed by Ameren. The exact number of shares issued pursuant to a share unit will vary from 0% to 200% of the target award, depending o

INCOME TAXES

INCOME TAXES
	12 Months Ended Dec. 31, 2009 USD / shares
INCOME TAXES	NOTE 13 INCOME TAXES The following table presents the principal reasons why the effective income tax rate differed from the statutory federal income tax rate for the years ended December31, 2009, 2008 and 2007: Ameren UE CIPS Genco CILCO IP 2009: Statutory federal income tax rate: 35 % 35 % 35 % 35 % 35 % 35 % Increases (decreases) from: Permanent items(a) (1 ) - - (1 ) (3 ) - Depreciation differences (1 ) (3 ) (1 ) - - - Amortization of investment tax credit (1 ) (1 ) (4 ) - - - State tax 5 3 5 4 4 5 Reserve for uncertain tax positions (1 ) - 1 - (1 ) - Other(b) (1 ) (1 ) - - - - Effective income tax rate 35 % 33 % 36 % 38 % 35 % 40 % 2008: Statutory federal income tax rate: 35 % 35 % 35 % 35 % 35 % 35 % Increases (decreases) from: Permanent items(a) (1 ) 1 (1 ) (2 ) (1 ) 7 Depreciation differences - (1 ) (2 ) - (1 ) - Amortization of investment tax credit (1 ) (1 ) (10 ) - (1 ) - State tax 4 3 5 5 5 5 Reserve for uncertain tax positions (1 ) (1 ) (1 ) (1 ) - 2 Other(c) (2 ) - (1 ) (1 ) (1 ) 1 Effective income tax rate 34 % 36 % 25 % 36 % 36 % 50 % 2007: Statutory federal income tax rate: 35 % 35 % 35 % 35 % 35 % 35 % Increases (decreases) from: Permanent items(a) (2 ) (2 ) 2 (1 ) (2 ) 1 Depreciation differences - - 3 - (1 ) (3 ) Amortization of investment tax credit (1 ) (1 ) (6 ) (1 ) (1 ) - State tax 4 4 6 5 3 5 Reserve for uncertain tax positions (1 ) (1 ) - - - - Other(d) (1 ) (2 ) (4 ) - - (1 ) Effective income tax rate 34 % 33 % 36 % 38 % 34 % 37 % (a) Permanent items are treated differently for book and tax purposes and primarily include Internal Revenue Code Section199 production activity deductions for Ameren, UE, Genco and CILCO, company-owned life insurance for Ameren and CILCO, impacts of Medicare Part D for Ameren, UE, Genco and CILCO, employee stock ownership plan dividends for Ameren, and nondeductible expenses for IP. (b) Primarily includes low-income housing tax credits and research credits for Ameren and UE. (c) Primarily includes settlements with state taxing authorities for Ameren, state apportionment changes for Ameren, CIPS, Genco, and CILCO, research credits for Ameren, Genco, and CILCO and low-income housing tax credits for Ameren and CIPS. (d) Primarily includes low-income housing tax credits for Ameren, UE, CIPS and IP. The following table presents the components of inco

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS
	12 Months Ended Dec. 31, 2009 USD / shares
RELATED PARTY TRANSACTIONS	NOTE 14 RELATED PARTY TRANSACTIONS The Ameren Companies have engaged in, and may in the future engage in, affiliate transactions in the normal course of business. These transactions primarily consist of gas and power purchases and sales, services received or rendered, and borrowings and lendings. Transactions between affiliates are reported as intercompany transactions on their financial statements, but are eliminated in consolidation for Amerens financial statements. Below are the material related party agreements. 2007 Illinois Electric Settlement Agreement As part of the 2007 Illinois Electric Settlement Agreement, the Ameren Illinois Utilities, Genco, and AERG agreed to make aggregate contributions of $150 million over four years as part of a comprehensive program to provide $1 billion of funding for rate relief to certain Illinois electric customers, including customers of the Ameren Illinois Utilities. At December31, 2009, CIPS, CILCO and IP had receivable balances from Genco for reimbursement of customer rate relief of less than $1 million each. Also at December31, 2009, CIPS, CILCO and IP had receivable balances from AERG for reimbursement of customer rate relief of less than $1 million each. During the year ended December31, 2009, Genco incurred charges to earnings of $10 million for customer rate relief contributions and program funding reimbursements to the Ameren Illinois Utilities (CIPS $3 million, CILCO $2 million, IP $5million), and AERG incurred charges to earnings of $5million (CIPS $2 million, CILCO $1 million, and IP $2 million). The Ameren Illinois Utilities recorded most of the reimbursements received from Genco and AERG as electric revenue. An immaterial amount was recorded as miscellaneous revenue. Electric Power Supply Agreements The following table presents the amount of physical gigawatthour sales under related party electric power supply agreements for the years ended December31, 2009, 2008, and 2007: December31, 2009 2008 2007 Genco sales to Marketing Company(a) 13,372 16,551 17,425 AERG sales to Marketing Company(a) 6,817 6,677 5,316 Marketing Company sales to CIPS(b) 1,283 2,050 2,396 Marketing Company sales to CILCO(b) 556 909 1,167 Marketing Company sales to IP(b) 1,690 2,870 3,493 (a) Both Genco and AERG have a power supply agreement with Marketing Company whereby Genco and AERG sell and Marketing Company purchases all the capacity and energy available from Gencos and AERGs generation fleets. (b) Marketing Company contracted with CIPS, CILCO, and IP to provide power based on the results of the September 2006 Illinois power procurement auction. The values in this table reflect the physical sales volumes provided in that agreement. In December 2006, Genco and AERG entered into two separate power supply agreements (PSA) with Marketing Company, whereby Genco and AERG agreed to sell and Marketing Company agreed to purchase all of the capacity available from Gencos and AERGs generation fleets and all of the associated energy. In March 2008, Genco and AERG entered into an amendment to their

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES
	12 Months Ended Dec. 31, 2009 USD / shares
COMMITMENTS AND CONTINGENCIES	NOTE 15 COMMITMENTS AND CONTINGENCIES We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in these notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity. See also Note 1 Summary of Significant Accounting Policies, Note 2 Rate and Regulatory Matters, Note 14 Related Party Transactions and Note 16 Callaway Nuclear Plant in this report. Callaway Nuclear Plant The following table presents insurance coverage at UEs Callaway nuclear plant at December31, 2009. The property coverage and the nuclear liability coverage must be renewed on October1 and January1, respectively, of each year. Type and Source of Coverage MaximumCoverages MaximumAssessmentsforSingleIncidents Public liability and nuclear worker liability: American Nuclear Insurers $300(a) $ - Pool participation 12,219(b) 118(c) $12,519(d) $118 Property damage: Nuclear Electric Insurance Ltd. $2,750(e) $ 23 Replacement power: Nuclear Electric Insurance Ltd. $490(f) $ 9 Energy Risk Assurance Company $64(g) $ - (a) Effective January1, 2010, limit was increased to $375 million. (b) Provided through mandatory participation in an industry-wide retrospective premium assessment program. (c) Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $300million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year. (d) Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors. (e) Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage. (f) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear plant. Weekly indemnity of $4.5million for 52 weeks, which commences after the first eight weeks of an outage, plus $3.6 million per week for 71.1 weeks thereafter. (g) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear plant. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week se

CALLAWAY NUCLEAR PLANT

CALLAWAY NUCLEAR PLANT
	12 Months Ended Dec. 31, 2009 USD / shares
CALLAWAY NUCLEAR PLANT	NOTE 16 CALLAWAY NUCLEAR PLANT Under the Nuclear Waste Policy Act of 1982, the DOE is responsible for the permanent storage and disposal of spent nuclear fuel. The DOE currently charges one mill, or 1/10 of one cent, per nuclear-generated kilowatthour sold for future disposal of spent fuel. Pursuant to this act, UE collects one mill from its electric customers for each kilowatthour of electricity that it generates and sells from its Callaway nuclear plant. Electric utility rates charged to customers provide for recovery of such costs. The DOEs last announced date of when it expects a permanent storage facility for spent fuel to be available was 2020, and the DOE continues to evaluate permanent storage alternatives. UE has sufficient installed storage capacity at its Callaway nuclear plant until 2020. It has the capability for additional storage capacity through the licensed life of the plant. The delayed availability of the DOEs disposal facility is not expected to adversely affect the continued operation of the Callaway nuclear plant through its currently licensed life. UE intends to submit a license extension application with the NRC to extend its Callaway nuclear plants operating license from 2024 to 2044. If the Callaway nuclear plants license is extended, additional spent fuel storage will be required. UE is evaluating the installation of a dry spent fuel storage facility at its Callaway nuclear plant. Electric utility rates charged to customers provide for the recovery of the Callaway nuclear plants decommissioning costs, which include decontamination, dismantling, and site restoration costs, over an assumed 40-year life of the plant, ending with the expiration of the plants operating license in 2024. It is assumed that the Callaway nuclear plant site will be decommissioned based on the immediate dismantlement method and removed from service. Ameren and UE have recorded an ARO for the Callaway nuclear plant decommissioning costs at fair value, which represents the present value of estimated future cash outflows. Decommissioning costs are included in the costs of service used to establish electric rates for UEs customers. These costs amounted to $7 million in each of the years 2009, 2008, and 2007. Every three years, the MoPSC requires UE to file an updated cost study for decommissioning its Callaway nuclear plant. Electric rates may be adjusted at such times to reflect changed estimates. The latest cost study, filed in September 2008, included minor tritium contamination discovered on the Callaway nuclear plant site, which did not result in a significant increase in the decommissioning cost estimate. Costs collected from customers are deposited in an external trust fund to provide for the Callaway nuclear plants decommissioning. If the assumed return on trust assets is not earned, we believe that it is probable that any such earnings deficiency will be recovered in rates. The fair value of the nuclear decommissioning trust fund for UEs Callaway nuclear plant is reported as Nuclear Decommissioning Trust Fund in Amerens Consolidated Balance Sheet and UEs Balance Sheet. This amount is legally restricted and may be used only to

GOODWILL

GOODWILL
	12 Months Ended Dec. 31, 2009 USD / shares
GOODWILL	NOTE 17 GOODWILL We evaluate goodwill for impairment as of October31 of each year, or more frequently if events and circumstances indicate that the asset might be impaired. Goodwill impairment testing is a two-step process. The first step involves a comparison of the estimated fair value of a reporting unit with its carrying amount. If the estimated fair value of the reporting unit exceeds the carrying value, goodwill of the reporting unit is considered unimpaired. If the carrying amount of the reporting unit exceeds its estimated fair value, a second step is performed to measure the amount of impairment, if any. The second step of the goodwill impairment test compares the implied fair value of the reporting units goodwill with the carrying amount of that goodwill. The implied fair value of goodwill is determined by allocating the estimated fair value of the reporting unit to the estimated fair value of its existing assets and liabilities in a manner similar to a purchase price allocation. The unallocated portion of the estimated fair value of the reporting unit is the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount, an impairment loss equivalent to the difference is recorded as a reduction of goodwill and a charge to operating expense. During the first quarter of 2009, we concluded that events had occurred and circumstances had changed which required us to perform an interim goodwill impairment test. The following events triggered this impairment test: A significant decline in Amerens market capitalization. The continuing decline in market prices for electricity. A decrease in observable industry market multiples. The fair value of Amerens and IPs reporting units was estimated based on a risk-adjusted, probability-weighted discounted cash flow model that considered multiple operating scenarios. Key assumptions in the determination of fair value included the use of an appropriate discount rate, estimated five-year cash flows, and an exit value based on observable industry market multiples. We use our best estimates in making these evaluations. We consider various factors, including forward price curves for energy and fuel costs, the regulatory environment, and operating costs. For the interim test conducted as of March31, 2009, the discount rate used was 3.8%, based on the 20-year treasury yield. To assess the reasonableness of the estimated reporting unit fair values, the sum of the estimated fair values of the Ameren reporting units is reconciled to our current market capitalization plus an estimated control premium. Amerens reporting units and IPs reporting unit did not require a second step assessment; the results of the step one tests indicated no impairment of goodwill as of March31, 2009. The annual impairment test, conducted as of October31, 2009, did not result in a second step assessment; the test indicated no impairment of Amerens or IPs goodwill. The annual test was conducted in a manner similar to the interim test described above. Amerens market capitalization was less than the book value of its equity as of the October 31, 200

SEGMENT INFORMATION

SEGMENT INFORMATION
	12 Months Ended Dec. 31, 2009 USD / shares
SEGMENT INFORMATION	NOTE 18 SEGMENT INFORMATION Ameren has three reportable segments: Missouri Regulated, Illinois Regulated, and Merchant Generation. The Missouri Regulated segment for Ameren includes all the operations of UEs business as described in Note 1 Summary of Significant Accounting Policies, except for UEs 40% interest in EEI (which in February 2008 was transferred to Resources Company through an internal reorganization). The Illinois Regulated segment for Ameren consists of the regulated electric and gas transmission and distribution businesses of CIPS, CILCO, and IP, as described in Note 1 Summary of Significant Accounting Policies, and AITC. The Merchant Generation segment for Ameren consists primarily of the operations or activities of Genco, the CILCORP parent company, AERG, EEI, Medina Valley and Marketing Company. The category called Other primarily includes Ameren parent company activities. UE has one reportable segment: Missouri Regulated. The Missouri Regulated segment for UE includes all the operations of UEs business as described in Note 1 Summary of Significant Accounting Policies, except for UEs former 40% interest in EEI. CILCO has two reportable segments: Illinois Regulated and Merchant Generation. The Illinois Regulated segment for CILCO consists of the regulated electric and gas transmission and distribution businesses of CILCO. The Merchant Generation segment for CILCO consists of the generation business of AERG. Other comprises minor activities not reported in the Illinois Regulated or Merchant Generation segments. The following tables present information about the reported revenues and specified items included in net income of Ameren, UE, and CILCO for the years ended December31, 2009, 2008 and 2007, and total assets as of December31, 2009, 2008 and 2007. Ameren Missouri Regulated Illinois Regulated Merchant Generation Other Intersegment Eliminations Consolidated 2009 External revenues $ 2,847 $ 2,912 $ 1,322 $ 9 $ - $ 7,090 Intersegment revenues 27 27 390 19 (463 ) - Depreciation and amortization 357 216 126 26 - 725 Interest and dividend income 29 5 - 33 (37 ) 30 Interest charges 229 153 119 48 (41 ) 508 Income taxes (benefit) 128 77 151 (24 ) - 332 Net income (loss) attributable to Ameren Corporation(a) 259 124 247 (18 ) - 612 Capital expenditures 872 415 408 9 - 1,704 Total assets 12,301 7,344 4,921 1,657 (2,433 ) 23,790 2008 External revenues $ 2,922 $ 3,433 $ 1,482 $ 2 $ - $ 7,839 Intersegment revenues 38 45 455 18 (556 ) - Depreciation and amortization 329 219 109 28 - 685 Interest and dividend income 33 15 3 30 (38 ) 43 Interest charges 193 144 99

SELECTED QUARTERLY INFORMATION

SELECTED QUARTERLY INFORMATION
	12 Months Ended Dec. 31, 2009 USD / shares
SELECTED QUARTERLY INFORMATION	SELECTED QUARTERLY INFORMATION (Unaudited) (In millions, except per share amounts) Quarter Ended(a) Operating Revenues Operating Income Net Income Attributableto AmerenCorporation EarningsperCommon Share - Basic and Diluted Ameren March31, 2009 $ 1,916 $ 321 $ 141 $ 0.66 March31, 2008 2,081 321 138 0.66 June30, 2009 1,684 365 165 0.77 June30, 2008 1,790 444 206 0.98 September30, 2009 1,815 485 227 1.04 September30, 2008 2,060 428 204 0.97 December31, 2009 1,675 245 79 0.34 December31, 2008 1,908 169 57 0.27 (a) The sum of quarterly amounts, including per share amounts, may not equal amounts reported for year-to-date periods. This is due to the effects of rounding and changes in the number of weighted-average shares outstanding each period. Quarter Ended Operating Revenues Operating Income(Loss) NetIncome(Loss) NetIncome(Loss) AvailabletoCommon Stockholder UE March31, 2009 $ 655 $ 75 $ 22 $ 21 March31, 2008 724 111 64 63 June30, 2009 752 173 84 82 June30, 2008 771 232 124 122 September30, 2009 836 257 142 141 September30, 2008 875 195 99 98 December31, 2009 631 61 17 15 December31, 2008 590 (24 ) (36 ) (38 ) CIPS March31, 2009 $ 265 $ 16 $ 7 $ 6 March31, 2008 290 8 3 2 June30, 2009 196 6 1 1 June30, 2008 207 3 (3 ) (3 ) September30, 2009 208 35 18 17 September30, 2008 217 14 7 6 December31, 2009 200 11 3 2 December31, 2008 268 17 8 7 Genco(a) March31, 2009 $ 225 $ 90 $ 47 $ 47 March31, 2008 233 83 46 46 June30, 2009 218 84 46 46 June30, 2008 196 133 74 74 September30, 2009 212 63 27 27 September30, 2008 238 46 20 20 December31, 2009 195 73 35 35 December31, 2008 241 68 35 35 CILCO March31, 2009 $ 311 $ 59 $ 33 $ 33 March31, 2008 345 48 26 26 June30, 2009 232 59 31 31 June30, 2008 232 22 12 11 September30, 2009 251 69 37 36 September30, 2008 264 43 24 24 December31, 2009 288 65 34 34 December31, 2008 306 19 7 7 IP March31, 2009 $ 472 $ 49 $ 14 $ 13 March31, 200

SCHEDULE I - CONDENSED FINANCIA

SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT
	12 Months Ended Dec. 31, 2009 USD / shares
SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT	SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT AMEREN CORPORATION CONDENSED STATEMENT OF INCOME For the Years Ended December31, 2009, 2008 and 2007 (In millions) 2009 2008 2007 Operating revenue $ - $ - $ - Operating expenses 20 22 18 Operating loss (20 ) (22 ) (18 ) Equity in earnings of subsidiaries 625 610 614 Miscellaneous income 32 16 30 Interest and other charges 37 22 25 Income tax expense (12 ) (23 ) (17 ) Net income $ 612 $ 605 $ 618 SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT AMEREN CORPORATION CONDENSED BALANCE SHEET (In millions) December31,2009 December31,2008 Assets: Cash and equivalents $ 24 $ 22 Accounts and notes receivable 1,211 804 Total current assets 1,235 826 Investments in subsidiaries 7,882 6,764 Other 229 133 Total assets $ 9,346 $ 7,723 Liabilities and Stockholders Equity: Accounts payable $ 66 $ 50 Other current liabilities 915 632 Total current liabilities 981 682 Long-term debt 423 - Other deferred credits and other noncurrent liabilities 73 78 Stockholders equity 7,869 6,963 Total liabilities and stockholders equity $ 9,346 $ 7,723 SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT AMEREN CORPORATION CONDENSED STATEMENT OF CASH FLOWS For the Years Ended December31, 2009, 2008 and 2007 (In millions) 2009 2008 2007 Net cash flows from operating activities $ (442 ) $ 338 $ 682 Cash flows from investing activities: Money pool advances, net 300 (129 ) 131 Investments in subsidiaries (831 ) 67 (523 ) Net cash flows from investing activities (531 ) (62 ) (392 ) Cash flows from financing activities: Dividends on common stock (338 ) (534 ) (527 ) Short-term and credit facility borrowings, net 275 25 500 Redemptions, repurchases, and maturities of long-term debt - - (350 ) Issuances of: Long-term debt 423 - - Common stock 634 154 91 Other (19 ) (6 ) - Net cash flows from financing activities 975 (361 ) (286 ) Net change in cash and equivalents 2 (85 ) 4 Cash and equivalents at beginning of year 22 107 103 Cash and equivalents at the end of year 24 22 107 Cash dividends received from consolidated subsidiaries 338 534 527 AMEREN CORPORATION (parent company only) NOTES TO CONDENSED FINANCIAL STATEMENTS December31, 2009 NOTE 1 BASIS OF PRESENTATION Ameren Corporation (parent company only) has accounted for wholly owned subsidiaries using the

SCHEDULE II - VALUATION AND QUA

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS
	12 Months Ended Dec. 31, 2009 USD / shares
SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS	SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED DECEMBER 31, 2009, 2008 AND 2007 (In millions) Column A Column B Column C Column D Column E Description Balanceat Beginning of Period (1) ChargedtoCosts and Expenses (2) ChargedtoOther Accounts Deductions(a) BalanceatEnd of Period Ameren: Deducted from assets -allowance for doubtful accounts: 2009 $ 28 $ 37 $ - $ 41 $ 24 2008 22 63 - 57 28 2007 11 53 - 42 22 UE: Deducted from assets - allowance for doubtful accounts: 2009 $ 8 $ 8 $ - $ 10 $ 6 2008 6 14 - 12 8 2007 6 14 - 14 6 CIPS: Deducted from assets - allowance for doubtful accounts: 2009 $ 6 $ 7 $ - $ 8 $ 5 2008 5 13 - 12 6 2007 2 10 - 7 5 CILCO: Deducted from assets - allowance for doubtful accounts: 2009 $ 3 $ 6 $ - $ 6 $ 3 2008 2 9 - 8 3 2007 1 7 - 6 2 IP: Deducted from assets - allowance for doubtful accounts: 2009 $ 12 $ 14 $ - $ 17 $ 9 2008 9 27 - 24 12 2007 3 21 - 15 9 (a) Uncollectible accounts charged off, less recoveries.

Document Information

Document Information
	12 Months Ended Dec. 31, 2009 USD / shares
Document Type	10-K
Amendment Flag	false
Document Period End Date	2009-12-31

Entity Information

Entity Information (USD $)
	12 Months Ended Dec. 31, 2009	Jan. 29, 2010	Jun. 30, 2009
Trading Symbol	AEE
Entity Registrant Name	AMEREN CORP
Entity Central Index Key	0001002910
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		237,503,643
Entity Public Float			$5,332,141,765