Disposal Group, Including Discontinued Operation, Buyer's Indemnification Guarantee Obligation

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- Definition

Disposal Group, Including Discontinued Operation, Buyer's Indemnification Guarantee Obligation, Period

+ References

No definition available.

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- Definition

Disposal Group, Including Discontinued Operation, Obligation to Provide Credit Support, Period

+ References

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- Definition

Related Party Transaction, Guarantees, Maximum Exposure

+ References

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- Definition

Related Party Transaction, Guarantees Outstanding

+ References

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- Definition

Related Party Transaction, Purchases of Financing Receivable, Discount

+ References

No definition available.

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- Definition

Amount for accounts payable to related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(k)(1))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph k

-Subparagraph 1

-Article 4

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 57

-Paragraph 2

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.17)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 17

-Article 7

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- Definition

The amount of any significant purchases of financing receivables during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953423-111524

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

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- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 57

-Paragraph 2

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Related Parties

-URI http://asc.fasb.org/extlink&oid=16382449

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.6-07.1(c))

-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 07

-Paragraph b

-Subparagraph 1

-Article 6

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Related Party Transactions (Narrative) (Detail) (USD $) In Millions, unless otherwise specified		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended				9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended			0 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Ameren Illinois Company	Sep. 30, 2012 Ameren Illinois Company	Sep. 30, 2013 Ameren Illinois Company	Sep. 30, 2012 Ameren Illinois Company	Sep. 30, 2013 Union Electric Company	Sep. 30, 2012 Union Electric Company	Sep. 30, 2013 Union Electric Company	Sep. 30, 2012 Union Electric Company	Sep. 30, 2013 Futures Commission Merchants	Sep. 30, 2013 Ameren Energy Marketing Company	Sep. 30, 2013 Ameren Energy Marketing Company Ameren Illinois Company	Sep. 30, 2013 Related Party One Ameren Illinois Company	Sep. 30, 2012 Related Party One Ameren Illinois Company	Sep. 30, 2013 Related Party One Ameren Illinois Company	Sep. 30, 2012 Related Party One Ameren Illinois Company	Sep. 30, 2013 Related Party One Union Electric Company	Sep. 30, 2012 Related Party One Union Electric Company	Sep. 30, 2013 Related Party One Union Electric Company	Sep. 30, 2012 Related Party One Union Electric Company	Sep. 30, 2013 Guarantee Type, Other	Mar. 14, 2013 New Ameren Energy Resources Company, LLC	Sep. 30, 2013 Miscellaneous Support Services Related Party One Ameren Illinois Company	Sep. 30, 2013 Miscellaneous Support Services Related Party One Union Electric Company	Sep. 30, 2013 Miscellaneous Support Services Related Party One Union Electric Company	Sep. 30, 2012 Miscellaneous Support Services Related Party One Union Electric Company
Related Party Transaction [Line Items]
Accounts payable, related parties												$ 17
Purchase of receivables from Marketing Company												115
Related Party Transaction, Purchases of Financing Receivable, Discount												2
Related Party Transaction, Guarantees Outstanding	192									25	154										13
Related Party Transaction, Guarantees, Maximum Exposure											25
Letters of Credit Outstanding, Amount	14
Obligation to provide credit support, period																						24 months
Buyer's indemnification guarantee obligation																						25
Buyer's indemnification guarantee obligation, period																						24 months
Revenue from Related Parties				$ 2.0		$ 1.0		$ 1.0	$ 1.0				$ 11.0	$ 5.0	$ 25.0	$ 12.0	$ 4.0	$ 5.0	$ 17.0	$ 15.0			$ 2.0	$ 1.0	$ 1.0	$ 1.0