Consolidated Statement Of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income from Continuing Operations	$ 529	$ 659	$ 585
Pension and other postretirement activity, net of income taxes (benefit)	5	(20)	6
Comprehensive Income from Continuing Operations	534	639	591
Less: Comprehensive Income from Continuing Operations Attributable to Noncontrolling Interests	6	6	6
Comprehensive Income from Continuing Operations Attributable to Ameren Corporation	528	633	585
Comprehensive Income from Discontinued Operations Attributable to Ameren Common shareholders	0	0	51
Comprehensive Income	$ 528	$ 633	$ 636

Comprehensive Income (Loss) from Continuing Operations, Net of Tax, Attributable to Noncontrolling Interest

No definition available.

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- Definition

Comprehensive Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest

+ References

No definition available.

+ Details

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- Definition

Comprehensive Income (Loss) from Continuing Operations, Net of Tax, Portion Attributable to Parent

+ References

No definition available.

+ Details

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- Definition

Comprehensive Income (Loss) from Discontinued Operations, Net of Tax, Portion Attributable to Parent

+ References

No definition available.

+ Details

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- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831270

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831223

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e557-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=51831255

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- Definition

Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=68079674&loc=SL4569616-111683

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- Definition

Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (i-k)
-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669646-108580

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