Consolidated Statement of Income (Loss) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Operating Revenues:
Electric	$ 1,235		$ 1,228		$ 2,341		$ 2,316
Gas	184		175		672		562
Total operating revenues	1,419		1,403		3,013		2,878
Operating Expenses:
Fuel	198		213		402		426
Purchased power	111		121		223		272
Gas purchased for resale	79		72		383		302
Other operations and maintenance	412		447		832		846
Depreciation and amortization	183		178		364		353
Taxes other than income taxes	114		111		241		233
Total operating expenses	1,097		1,142		2,445		2,432
Operating Income	322		261		568		446
Other Income and Expenses:
Miscellaneous income	21	[1]	16	[1]	39	[1]	31	[1]
Miscellaneous expense	4	[1]	5	[1]	13	[1]	13	[1]
Total other income (expense)	17		11		26		18
Interest Charges	89		100		181		201
Income Before Income Taxes	250		172		413		263
Income Taxes	99		66		163		101
Income from Continuing Operations	151		106		250		162
Loss from Discontinued Operations, Net of Taxes (Note 12)	(1)		(10)		(2)		(209)
Net Income (Loss)	150		96		248		(47)
Pension and other postretirement benefit plan activity, net of income taxes (benefit)	3		10		3		10
Comprehensive Income (Loss)	152		101		248		(51)
Less: Net Income (Loss) Attributable to Noncontrolling Interests:
Net Income from Continuing Operations Attributable to Noncontrolling Interests	1		1		3		3
Net Income (Loss):
Continuing Operations	150		105		247		159
Discontinued Operations	(1)		(10)		(2)		(209)
Net Income (Loss)	149		95		245		(50)
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.62		$ 0.44		$ 1.02		$ 0.66
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	$ (0.01)		$ (0.05)		$ (0.01)		$ (0.87)
Earnings Per Share, Basic	$ 0.61		$ 0.39		$ 1.01		$ (0.21)
Dividends per Common Share	$ 0.40		$ 0.40		$ 0.80		$ 0.80
Average Common Shares Outstanding - Basic	242.6		242.6		242.6		242.6
Union Electric Company
Operating Revenues:
Electric	871		860		1,620		1,592
Gas	28		29		96		93
Other	1				1
Total operating revenues	900		889		1,717		1,685
Operating Expenses:
Fuel	198		213		402		426
Purchased power	28		41		61		67
Gas purchased for resale	11		11		51		48
Other operations and maintenance	222		253		449		474
Depreciation and amortization	117		113		233		224
Taxes other than income taxes	81		79		159		156
Total operating expenses	657		710		1,355		1,395
Operating Income	243		179		362		290
Other Income and Expenses:
Miscellaneous income	16		14		30		28
Miscellaneous expense	2		3		6		8
Total other income (expense)	14		11		24		20
Interest Charges	54		56		106		116
Income Before Income Taxes	203		134		280		194
Income Taxes	76		49		105		68
Net Income (Loss)	127		85		175		126
Other Comprehensive Income	0		0		0		0
Comprehensive Income (Loss)	127		85		175		126
Net Income (Loss):
Net Income (Loss)	127		85		175		126
Preferred Stock Dividends	1		1		2		2
Net Income Available to Common Stockholder	126		84		173		124
Ameren Illinois Company
Operating Revenues:
Electric	364		368		717		728
Gas	155		146		576		470
Other			2				2
Total operating revenues	519		516		1,293		1,200
Operating Expenses:
Purchased power	86		80		167		207
Gas purchased for resale	67		61		331		254
Other operations and maintenance	195		196		395		372
Depreciation and amortization	64		62		127		123
Taxes other than income taxes	32		30		78		72
Total operating expenses	444		429		1,098		1,028
Operating Income	75		87		195		172
Other Income and Expenses:
Miscellaneous income	5		2		8		3
Miscellaneous expense	1		1		5		4
Total other income (expense)	4		1		3		(1)
Interest Charges	29		34		59		65
Income Before Income Taxes	50		54		139		106
Income Taxes	21		22		56		42
Net Income (Loss)	29		32		83		64
Pension and other postretirement benefit plan activity, net of income taxes (benefit)	(1)		(1)		(2)		(2)
Comprehensive Income (Loss)	28		31		81		62
Net Income (Loss):
Net Income (Loss)	29		32		83		64
Preferred Stock Dividends	1		1		2		2
Net Income Available to Common Stockholder	$ 28		$ 31		$ 81		$ 62

[1] Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.