MISCELLANEOUS INCOME (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Other Income and Expenses [Abstract]
Equity portion of AFUDC	$ 2.7	$ 2.1	$ 6.3	$ 3.7
Earnings from equity method investments	2.8	2.8	5.6	5.8
Key executive life insurance for retired employees	0.7	0.8	1.4	0.9
Other	0.4	0.2	0.6	0.5
Total miscellaneous income	$ 6.6	$ 5.9	$ 13.9	$ 10.9