Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 26	$ 30
Accounts receivable - trade (less allowance for doubtful accounts)	553	404
Unbilled revenue	236	304
Miscellaneous accounts and notes receivable	201	196
Materials and supplies	424	526
Current regulatory assets	220	156
Current accumulated deferred income taxes, net	95	106
Other current assets	70	85
Assets of discontinued operations (Note 12)	15	165
Total current assets	1,840	1,972
Property and Plant, Net	16,425	16,205
Investments and Other Assets:
Nuclear decommissioning trust fund	503	494
Goodwill	411	411
Intangible assets	17	22
Regulatory assets	1,251	1,240
Other assets	719	698
Total investments and other assets	2,901	2,865
TOTAL ASSETS	21,166	21,042
Current Liabilities:
Current maturities of long-term debt	648	534
Short-term Debt	700	368
Accounts and wages payable	559	806
Taxes accrued	89	55
Interest accrued	104	86
Current regulatory liabilities	248	216
Other current liabilities	344	351
Liabilities of discontinued operations (Note 12)	33	45
Total current liabilities	2,725	2,461
Long-term Debt, Net	5,226	5,504
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	3,340	3,250
Accumulated deferred investment tax credits	62	63
Regulatory liabilities	1,751	1,705
Asset retirement obligations	373	369
Pension and other postretirement benefits	480	466
Other deferred credits and liabilities	554	538
Total deferred credits and other liabilities	6,560	6,391
Commitments and Contingencies
Stockholders' Equity:
Common Stock	2	2
Other paid-in capital	5,602	5,632
Retained earnings	906	907
Accumulated other comprehensive income (loss)	3	3
Stockholder's equity	6,513	6,544
Noncontrolling Interest	142	142
Total equity	6,655	6,686
TOTAL LIABILITIES AND EQUITY	21,166	21,042
Union Electric Company
Current Assets:
Cash and cash equivalents		1
Accounts receivable - trade (less allowance for doubtful accounts)	218	191
Accounts receivable - affiliates	1	1
Unbilled revenue	129	168
Miscellaneous accounts and notes receivable	67	57
Materials and supplies	338	352
Current regulatory assets	145	118
Other current assets	50	71
Total current assets	948	959
Property and Plant, Net	10,499	10,452
Investments and Other Assets:
Nuclear decommissioning trust fund	503	494
Intangible assets	17	22
Regulatory assets	539	534
Other assets	442	443
Total investments and other assets	1,501	1,493
TOTAL ASSETS	12,948	12,904
Current Liabilities:
Current maturities of long-term debt	223	109
Short-term Debt	290
Borrowings from money pool		105
Accounts and wages payable	183	387
Accounts payable - affiliates	38	30
Taxes accrued	252	220
Interest accrued	47	57
Current regulatory liabilities	47	57
Other current liabilities	87	82
Total current liabilities	1,167	1,047
Long-term Debt, Net	3,535	3,648
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	2,551	2,524
Accumulated deferred investment tax credits	58	59
Regulatory liabilities	1,062	1,041
Asset retirement obligations	371	366
Pension and other postretirement benefits	198	189
Other deferred credits and liabilities	43	37
Total deferred credits and other liabilities	4,283	4,216
Commitments and Contingencies
Stockholders' Equity:
Common Stock	511	511
Other paid-in capital	1,560	1,560
Preferred stock not subject to mandatory redemption	80	80
Retained earnings	1,812	1,842
Stockholder's equity	3,963	3,993
TOTAL LIABILITIES AND EQUITY	12,948	12,904
Ameren Illinois Company
Current Assets:
Cash and cash equivalents	1	1
Accounts receivable - trade (less allowance for doubtful accounts)	328	201
Unbilled revenue	107	135
Miscellaneous accounts and notes receivable	8	13
Materials and supplies	86	174
Current regulatory assets	75	38
Current accumulated deferred income taxes, net	52	45
Other current assets	20	26
Total current assets	677	633
Property and Plant, Net	5,731	5,589
Investments and Other Assets:
Goodwill	411	411
Regulatory assets	706	701
Other assets	115	120
Total investments and other assets	1,232	1,232
TOTAL ASSETS	7,640	7,454
Current Liabilities:
Borrowings from money pool	242	56
Accounts and wages payable	230	243
Accounts payable - affiliates	28	18
Taxes accrued	22	23
Customer deposits	80	79
Current environmental remediation	46	43
Current regulatory liabilities	201	159
Other current liabilities	153	150
Total current liabilities	1,002	771
Long-term Debt, Net	1,692	1,856
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	1,158	1,116
Accumulated deferred investment tax credits	4	4
Regulatory liabilities	689	664
Pension and other postretirement benefits	200	197
Environmental remediation	222	232
Other deferred credits and liabilities	173	166
Total deferred credits and other liabilities	2,446	2,379
Commitments and Contingencies
Stockholders' Equity:
Common Stock	0	0
Other paid-in capital	1,965	1,965
Preferred stock not subject to mandatory redemption	62	62
Retained earnings	463	410
Accumulated other comprehensive income (loss)	10	11
Stockholder's equity	2,500	2,448
TOTAL LIABILITIES AND EQUITY	$ 7,640	$ 7,454