CASH AND CASH EQUIVALENTS (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Significant noncash transactions
Construction costs funded through accounts payable	$ 123.3	$ 81.8
Equity issued for employee stock ownership plan	1.7	6.7
Equity issued for stock-based compensation plans	0	16.0
Equity issued for reinvested dividends	0	6.1
Contingent consideration and payables related to the acquisition of Compass Energy Services	0	9.1
Noncurrent restricted cash
Rabbi trust funding related to potential change in control	$ 65.0