GUARANTEES (Details) $ in Millions	Jun. 30, 2015 USD ($)
Guarantees
Total guarantees	$ 253.1
Guarantees expiring in less than 1 year	117.3
Guarantees expiring within 1 to 3 years	0.2
Guarantees with expiration over 3 years	135.6
Guarantees supporting commodity transactions of subsidiaries
Guarantees
Total guarantees	156.4
Guarantees expiring in less than 1 year	83.4
Guarantees expiring within 1 to 3 years	0.0
Guarantees with expiration over 3 years	73.0
Guarantees supporting commodity transactions of subsidiaries \| WBS
Guarantees
Total guarantees	5.0
Guarantees supporting commodity transactions of subsidiaries \| PDL
Guarantees
Total guarantees	6.0
Guarantees supporting commodity transactions of subsidiaries \| ITF
Guarantees
Total guarantees	1.1
Guarantees supporting commodity transactions of subsidiaries \| MERC
Guarantees
Total guarantees	109.3
Guarantees supporting commodity transactions of subsidiaries \| MGU
Guarantees
Total guarantees	35.0
Standby letters of credit
Guarantees
Total guarantees	1.2
Guarantees expiring in less than 1 year	1.1
Guarantees expiring within 1 to 3 years	0.1
Guarantees with expiration over 3 years	0.0
Surety bonds
Guarantees
Total guarantees	32.2
Guarantees expiring in less than 1 year	32.2
Guarantees expiring within 1 to 3 years	0.0
Guarantees with expiration over 3 years	0.0
Guarantees temporarily retained related to the sale of IES's retail energy business
Guarantees
Total guarantees	0.6
Guarantees expiring in less than 1 year	0.6
Guarantees expiring within 1 to 3 years	0.0
Guarantees with expiration over 3 years	0.0
Exposure for guarantees related to open transactions \| IES's retail energy business
Guarantees
Total guarantees	0.6
Other guarantees
Guarantees
Total guarantees	62.7
Guarantees expiring in less than 1 year	0.0
Guarantees expiring within 1 to 3 years	0.1
Guarantees with expiration over 3 years	62.6
Other guarantees \| IES's Texas retail marketing business
Guarantees
Total guarantees	10.0
Other guarantees \| PDL
Guarantees
Total guarantees	34.6
Other guarantees \| ITF
Guarantees
Total guarantees	11.2
Other indemnifications primarily for workers compensation coverage
Guarantees
Total guarantees	$ 6.9

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No definition available.

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- Definition

Represents the maximum potential payments with respect to the entity's guarantees that expire after three years.

+ References

No definition available.

+ Details

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- Definition

Represents the maximum potential payments with respect to the entity's guarantees that expire within one to three years.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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