Consolidated Statement Of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income from Continuing Operations	$ 518	$ 522	$ 437
Pension and other postretirement activity, net of income taxes (benefit)	30	(8)	(19)
Comprehensive Income (Loss) from Continuing Operations	548	514	418
Less: Comprehensive Income from Continuing Operations Attributable to Noncontrolling Interests	6	6	6
Comprehensive Income from Continuing Operations Attributable to Ameren Corporation	542	508	412
Income (Loss) from Discontinued Operations, Net of Tax (Note 16)	(223)	(1,496)	89
Comprehensive Income from Continuing Operations Attributable to Ameren Corporation	(18)	58	(20)
Comprehensive Income (Loss) from Discontinued Operations	(241)	(1,438)	69
Less: Comprehensive Income from Discontinuing Operations Attributable to Noncontrolling Interest	1	2	(5)
Comprehensive Income (Loss) from Discontinued Operations Attributable to Ameren Corporation	(242)	(1,440)	74
Comprehensive Income (Loss)	300	(932)	486
Ameren Illinois Company
Pension and other postretirement activity, net of income taxes (benefit)	(3)	(3)	(3)
Comprehensive Income (Loss)	$ 160	$ 141	$ 193