Consolidated Balance Sheet - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents		$ 292	$ 5
Accounts receivable - trade (less allowance for doubtful accounts)		388	423
Unbilled revenue		239	265
Miscellaneous accounts and notes receivable		98	81
Materials and supplies		538	524
Current regulatory assets		260	295
Other current assets		88	86
Assets of discontinued operations (Note 16)		14	15
Total current assets		1,917	1,694
Property, Plant and Equipment, Net	[1]	18,799	17,424
Investments and Other Assets:
Nuclear decommissioning trust fund		556	549
Goodwill		411	411
Regulatory assets		1,382	1,582
Other assets		575	629
Total investments and other assets		2,924	3,171
TOTAL ASSETS		23,640	22,289
Current Liabilities:
Current maturities of long-term debt		395	120
Short-term debt		301	714
Accounts and wages payable		777	711
Taxes accrued		43	46
Interest accrued		89	85
Current regulatory liabilities		80	106
Other current liabilities		379	434
Liabilities of discontinued operations (Note 16)		29	33
Total current liabilities		2,093	2,249
Long-term Debt, Net		6,880	6,085
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net		3,885	3,571
Accumulated deferred investment tax credits		60	64
Regulatory liabilities		1,905	1,850
Asset retirement obligations		618	396
Pension and other postretirement benefits		580	705
Other deferred credits and liabilities		531	514
Total deferred credits and other liabilities		$ 7,579	$ 7,100
Commitments and Contingencies (Notes 2, 10, 14 and 15)
Stockholders' Equity:
Common stock		$ 2	$ 2
Other paid-in capital, principally premium on common stock		5,616	5,617
Retained earnings		1,331	1,103
Accumulated other comprehensive income (loss)		(3)	(9)
Total stockholders' equity		6,946	6,713
Noncontrolling Interests		142	142
Total equity		7,088	6,855
TOTAL LIABILITIES AND EQUITY		23,640	22,289
Union Electric Company
Current Assets:
Cash and cash equivalents		199	1
Advances to money pool		36	0
Accounts receivable - trade (less allowance for doubtful accounts)		174	190
Accounts receivable - affiliates		54	65
Unbilled revenue		128	146
Miscellaneous accounts and notes receivable		78	35
Materials and supplies		387	347
Current regulatory assets		89	163
Other current assets		41	43
Total current assets		1,186	990
Property, Plant and Equipment, Net	[1]	11,183	10,867
Investments and Other Assets:
Nuclear decommissioning trust fund		556	549
Regulatory assets		605	695
Other assets		321	373
Total investments and other assets		1,482	1,617
TOTAL ASSETS		13,851	13,474
Current Liabilities:
Current maturities of long-term debt		266	120
Short-term debt		0	97
Accounts and wages payable		417	405
Accounts payable - affiliates		56	56
Taxes accrued		31	32
Interest accrued		59	58
Current regulatory liabilities		28	18
Other current liabilities		120	117
Total current liabilities		977	903
Long-term Debt, Net		3,844	3,861
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net		2,844	2,757
Accumulated deferred investment tax credits		58	61
Regulatory liabilities		1,172	1,147
Asset retirement obligations		612	389
Pension and other postretirement benefits		234	274
Other deferred credits and liabilities		28	30
Total deferred credits and other liabilities		$ 4,948	$ 4,658
Commitments and Contingencies (Notes 2, 10, 14 and 15)
Stockholders' Equity:
Common stock		$ 511	$ 511
Other paid-in capital, principally premium on common stock		1,822	1,569
Preferred stock not subject to mandatory redemption		80	80
Retained earnings		1,669	1,892
Total stockholders' equity		4,082	4,052
TOTAL LIABILITIES AND EQUITY		13,851	13,474
Ameren Illinois Company
Current Assets:
Cash and cash equivalents		71	1
Accounts receivable - trade (less allowance for doubtful accounts)		204	212
Accounts receivable - affiliates		22	22
Unbilled revenue		111	119
Miscellaneous accounts and notes receivable		19	9
Materials and supplies		151	177
Current regulatory assets		167	129
Other current assets		15	15
Total current assets		760	684
Property, Plant and Equipment, Net		6,848	6,165
Investments and Other Assets:
Goodwill		411	411
Regulatory assets		771	883
Other assets		113	61
Total investments and other assets		1,295	1,355
TOTAL ASSETS		8,903	8,204
Current Liabilities:
Current maturities of long-term debt		129	0
Short-term debt		0	32
Borrowings from money pool		0	15
Accounts and wages payable		249	207
Accounts payable - affiliates		66	50
Taxes accrued		13	17
Customer deposits		69	77
Mark-to-market derivative liabilities		45	42
Environmental remediation		28	52
Current regulatory liabilities		39	84
Other current liabilities		114	124
Total current liabilities		752	700
Long-term Debt, Net		2,342	2,224
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net		1,480	1,248
Accumulated deferred investment tax credits		2	3
Regulatory liabilities		732	703
Pension and other postretirement benefits		271	277
Accrued Environmental Loss Contingencies, Noncurrent		205	199
Other deferred credits and liabilities		222	189
Total deferred credits and other liabilities		$ 2,912	$ 2,619
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	1,980
Preferred stock not subject to mandatory redemption		62	62
Retained earnings		825	611
Accumulated other comprehensive income (loss)		5	8
Total stockholders' equity		2,897	2,661
TOTAL LIABILITIES AND EQUITY		$ 8,903	$ 8,204

[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 $233 million at December 31, 2015 and 2014. The total accumulated depreciation associated with the two CTs was $72 million and $66 million at December 31, 2015 and 2014, respectively. In addition, Ameren Missouri has investments in debt securities, which were classified as held-to-maturity and recorded in "Other assets", related to the two CTs from the city of Bowling Green and Audrain County. As of December 31, 2015 and 2014, the carrying value of these debt securities was $288 million and $294 million, respectively.