STOCK-BASED COMPENSATION – RESTRICTED SHARE UNITS (Details) (Restricted Share Units, USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended		0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Nov. 01, 2014 Subsequent event IES retail energy business
Restricted Share Unit Awards
Outstanding at the beginning of the period (in shares)	511,301
Granted (in shares)	214,953
Dividend equivalents (in shares)	17,317
Vested and released (in shares)	(208,873)
Forfeited (in shares)	(16,730)		(94,267)
Outstanding at the end of period (in shares)	517,968
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 52.24
Granted (in dollars per share)	$ 55.23	$ 55.93
Dividend equivalents (in dollars per share)	$ 54.45
Vested and released (in dollars per share)	$ 49.76
Forfeited (in dollars per share)	$ 54.66
Outstanding at the end of the period (in dollars per share)	$ 54.48
Additional disclosures
Total intrinsic value of restricted share units vested and released	$ 11.4	$ 11.6
Tax benefit realized from the vesting and release of restricted share units	4.6	4.7
Compensation cost not yet recognized	$ 9.5
Weighted-average period over which compensation cost is to be recognized	2 years 2 months 19 days