Consolidated Statement of Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income from Continuing Operations	$ 99	$ 56
Other Comprehensive Income, Net of Taxes
Other Comprehensive Income, Net of Taxes	0	0
Comprehensive Income from Continuing Operations	99	56
Less: Comprehensive Income from Continuing Operations Attributable to Noncontrolling Interests	2	2
Comprehensive Income from Continuing Operations Attributable to Ameren Corporation	97	54
Loss from Discontinued Operations, Net of Taxes	(1)	(199)
Other Comprehensive Loss from Discontinued Operations, Net of Taxes	0	(7)
Comprehensive Loss from Discontinued Operations Attributable to Ameren Corporation	(1)	(206)
Comprehensive Income (Loss)	$ 96	$ (152)