OTHER INFORMATION (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
OTHER INFORMATION
Amount due from joint interest partners, other current assets	$ 120.0		$ 120.0
Deferred tax assets, other current assets	60.0		60.0
Greenhouse gas emission assets, other current assets	40.0		65.0
Accrued compensation-related costs, accrued liabilities	95.0		95.0
Interest payable, accrued liabilities	85.0		70.0
Greenhouse gas liabilities, accrued liabilities	70.0		65.0
Asset Retirement Obligations, other long-term liabilities	396.0		$ 397.0
Interest Paid	$ 149.0	$ 0.0