Guarantees Outstanding

No definition available.

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- Definition

Impairment and Other Charges

+ References

No definition available.

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
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Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
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-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

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- Definition

Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and other assets expected to be realized or consumed within one year or normal operating cycle, if longer.

+ References

No definition available.

+ Details

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- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 958
-SubTopic 225
-Section 45
-Paragraph 11
-Subparagraph (a)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Impairment
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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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- Definition

The cash inflow from amounts received from issuance of long-term debt that is wholly or partially secured by collateral. Excludes proceeds from tax exempt secured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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Balance Type:	debit
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- Definition

The cash outflow attributable to repayments of borrowings not otherwise defined in the taxonomy (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Glossary Financing Activities
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Balance Type:	credit
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- Definition

Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
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-Paragraph 15A
-Subparagraph (a)(3)
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Schedule I - Condensed Financial Information Of Parent (Impairment and Other Charges) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	May. 31, 2014	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impairment and Other Charges [Line Items]
Deferred Income Taxes and Other Assets, Current				$ 352
Repayments of Other Long-term Debt			$ 120	697	$ 399
Parent Company
Impairment and Other Charges [Line Items]
Deferred Income Taxes and Other Assets, Current				143
Guarantees Outstanding		$ 36	36
Repayments of Other Long-term Debt			0	425	0
Parent Company \| Merchant Generation
Impairment and Other Charges [Line Items]
Impairment charge on long-lived assets and related charges					$ 201
New Ameren Energy Resources Company, LLC
Impairment and Other Charges [Line Items]
Loss Contingency Accrual		25	25
New Ameren Energy Resources Company, LLC \| Parent Company
Impairment and Other Charges [Line Items]
Loss Contingency Accrual		$ 25	$ 25
Senior Unsecured Notes8875 Due2014 [Member] \| Parent Company
Impairment and Other Charges [Line Items]
Repayments of Other Long-term Debt	$ 425
Long-term debt interest rate	8.875%
Senior Unsecured Notes270 due 2020 [Member] \| Parent Company
Impairment and Other Charges [Line Items]
Long-term debt interest rate		2.70%	2.70%
Senior Unsecured Notes365 due 2026 [Member] \| Parent Company
Impairment and Other Charges [Line Items]
Long-term debt interest rate		3.65%	3.65%
Unsecured Debt [Member] \| Senior Unsecured Notes270 due 2020 [Member] \| Parent Company
Impairment and Other Charges [Line Items]
Debt instrument face amount		$ 350	$ 350	0
Proceeds from issuance of secured debt		$ 348
Long-term debt interest rate		2.70%	2.70%
Unsecured Debt [Member] \| Senior Unsecured Notes365 due 2026 [Member] \| Parent Company
Impairment and Other Charges [Line Items]
Debt instrument face amount		$ 350	$ 350	$ 0
Proceeds from issuance of secured debt		$ 347
Long-term debt interest rate		3.65%	3.65%
2013 Tax Year [Member] \| Parent Company
Impairment and Other Charges [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities			$ 53