SHORT-TERM DEBT AND LINES OF CREDIT (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Short-term borrowings
Total short-term credit capacity	$ 250.0	$ 250.0
Short-term borrowings outstanding	25.6	95.4
Available capacity under existing agreements	224.4	154.6
Maximum
Short-term borrowings
Debt to capitalization ratio required to be maintained (as a percent)	65.00%
Revolving credit facility maturing on May 17, 2014
Short-term borrowings
Total short-term credit capacity	135.0	135.0
Revolving credit facility maturing on June 13, 2017
Short-term borrowings
Total short-term credit capacity	115.0	115.0
Commercial paper
Short-term borrowings
Short-term borrowings outstanding	$ 25.6	$ 95.4	$ 173.7