Consolidated Statement of Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income from Continuing Operations	$ 296	$ 307	$ 546	$ 469
Other Comprehensive Income (Loss), Net of Taxes
Pension and other postretirement benefit plan activity, net of income taxes (benefit)		(5)	3	5
Comprehensive Income from Continuing Operations	296	302	549	474
Less: Comprehensive Income from Continuing Operations Attributable to Noncontrolling Interests	2	2	5	5
Comprehensive Income from Continuing Operations Attributable to Ameren Corporation	294	300	544	469
Loss from Discontinued Operations, Net of Taxes	(1)	(3)	(3)	(212)
Other Comprehensive Loss from Discontinued Operations, Net of Taxes		(5)		(16)
Comprehensive Loss from Discontinued Operations Attributable to Ameren Corporation	(1)	(8)	(3)	(228)
Comprehensive Income	$ 293	$ 292	$ 541	$ 241