COMMITMENTS AND CONTINGENCIES (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 31, 2014 Subsequent Event	Jan. 31, 2014 Subsequent Event 2014	Jan. 31, 2014 Subsequent Event 2015	Jan. 31, 2014 Subsequent Event 2016	Jan. 31, 2014 Subsequent Event 2017
Operating Leased Assets
Minimum initial term of operating lease to be included in commitments and contingencies table (in years)	1 year
Net gain (loss) on termination of drilling rig operating leases				$ (5.0)
Reduction in operating lease obligations					12.4	10.8	10.8	6.1
Payments made under the unconditional purchase obligations	5.8	0.4	0.4
Net rental payments under non-cancelable operating leases applicable to exploration and development activities and capitalized to oil and gas properties	10.4	15.6	21.0
Net rental payments under non-cancelable operating leases, including drilling rigs and compressor rentals, charged to expense	$ 24.5	$ 22.0	$ 16.5