Consolidated Balance Sheet - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents		$ 9	$ 292
Accounts receivable - trade (less allowance for doubtful accounts)		437	388
Unbilled revenue		295	239
Miscellaneous accounts and notes receivable		63	98
Inventories		527	538
Current regulatory assets		149	260
Other current assets		98	88
Assets of discontinued operations (Note 1)		15	14
Total current assets		1,593	1,917
Property, Plant and Equipment, Net	[1]	20,113	18,799
Investments and Other Assets:
Nuclear decommissioning trust fund		607	556
Goodwill		411	411
Regulatory assets		1,437	1,382
Other assets		538	575
Total investments and other assets		2,993	2,924
TOTAL ASSETS		24,699	23,640
Current Liabilities:
Current maturities of long-term debt		681	395
Short-term debt		558	301
Accounts and wages payable		805	777
Taxes accrued		46	43
Interest accrued		93	89
Customer deposits		107	100
Current regulatory liabilities		110	80
Other current liabilities		248	279
Liabilities of discontinued operations (Note 1)		26	29
Total current liabilities		2,674	2,093
Long-term Debt, Net		6,595	6,880
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net		4,264	3,885
Accumulated deferred investment tax credits		55	60
Regulatory liabilities		1,985	1,905
Asset retirement obligations		635	618
Pension and other postretirement benefits		769	580
Other deferred credits and liabilities		477	531
Total deferred credits and other liabilities		8,185	7,579
Commitments and Contingencies (Notes 2, 10, 14 and 15)
Stockholders' Equity:
Common stock		2	2
Other paid-in capital, principally premium on common stock		5,556	5,616
Retained earnings		1,568	1,331
Accumulated other comprehensive income (loss)		(23)	(3)
Total stockholders' equity		7,103	6,946
Noncontrolling Interests		142	142
Total equity		7,245	7,088
TOTAL LIABILITIES AND EQUITY		24,699	23,640
Union Electric Company
Current Assets:
Cash and cash equivalents		0	199
Advances to money pool		161	36
Accounts receivable - trade (less allowance for doubtful accounts)		187	174
Accounts receivable - affiliates		12	54
Unbilled revenue		154	128
Miscellaneous accounts and notes receivable		14	78
Inventories		392	387
Current regulatory assets		35	89
Other current assets		49	41
Total current assets		1,004	1,186
Property, Plant and Equipment, Net	[1]	11,478	11,183
Investments and Other Assets:
Nuclear decommissioning trust fund		607	556
Regulatory assets		619	605
Other assets		327	321
Total investments and other assets		1,553	1,482
TOTAL ASSETS		14,035	13,851
Current Liabilities:
Current maturities of long-term debt		431	266
Accounts and wages payable		444	417
Accounts payable - affiliates		68	56
Taxes accrued		30	31
Interest accrued		54	59
Current regulatory liabilities		12	28
Other current liabilities		123	120
Total current liabilities		1,162	977
Long-term Debt, Net		3,563	3,844
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net		3,013	2,844
Accumulated deferred investment tax credits		53	58
Regulatory liabilities		1,215	1,172
Asset retirement obligations		629	612
Pension and other postretirement benefits		291	234
Other deferred credits and liabilities		19	28
Total deferred credits and other liabilities		5,220	4,948
Commitments and Contingencies (Notes 2, 10, 14 and 15)
Stockholders' Equity:
Common stock		511	511
Other paid-in capital, principally premium on common stock		1,828	1,822
Preferred stock not subject to mandatory redemption		80	80
Retained earnings		1,671	1,669
Total stockholders' equity		4,090	4,082
TOTAL LIABILITIES AND EQUITY		14,035	13,851
Ameren Illinois Company
Current Assets:
Cash and cash equivalents		0	71
Accounts receivable - trade (less allowance for doubtful accounts)		242	204
Accounts receivable - affiliates		10	22
Unbilled revenue		141	111
Miscellaneous accounts and notes receivable		22	19
Inventories		135	151
Current regulatory assets		108	167
Other current assets		25	15
Total current assets		683	760
Property, Plant and Equipment, Net		7,469	6,848
Investments and Other Assets:
Goodwill		411	411
Regulatory assets		816	771
Other assets		95	113
Total investments and other assets		1,322	1,295
TOTAL ASSETS		9,474	8,903
Current Liabilities:
Current maturities of long-term debt		250	129
Short-term debt		51	0
Accounts and wages payable		264	249
Accounts payable - affiliates		63	66
Taxes accrued		16	13
Interest accrued		33	28
Customer deposits		69	69
Mark-to-market derivative liabilities		15	45
Environmental remediation		38	28
Current regulatory liabilities		78	39
Other current liabilities		94	86
Total current liabilities		971	752
Long-term Debt, Net		2,338	2,342
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net		1,631	1,480
Accumulated deferred investment tax credits		2	2
Regulatory liabilities		768	732
Pension and other postretirement benefits		346	271
Accrued Environmental Loss Contingencies, Noncurrent		162	205
Other deferred credits and liabilities		222	222
Total deferred credits and other liabilities		3,131	2,912
Commitments and Contingencies (Notes 2, 10, 14 and 15)
Stockholders' Equity:
Common stock		0	0
Other paid-in capital, principally premium on common stock		2,005	2,005
Preferred stock not subject to mandatory redemption		62	62
Retained earnings		967	825
Accumulated other comprehensive income (loss)		0	5
Total stockholders' equity		3,034	2,897
TOTAL LIABILITIES AND EQUITY		$ 9,474	$ 8,903

[1] (a)Amounts in Ameren and Ameren Missouri include two CTs under separate capital lease agreements. The gross cumulative asset value of those agreements was $232 million and $233 million at December 31, 2016 and 2015, respectively. The total accumulated depreciation associated with the two CTs was $77 million and $72 million at December 31, 2016 and 2015, respectively. In addition, Ameren Missouri has investments in debt securities, classified as held-to-maturity and recorded in "Other assets" that are related to the two CTs from the city of Bowling Green and Audrain County. As of December 31, 2016 and 2015, the carrying value of these debt securities was $282 million and $288 million, respectively.