RISK MANAGEMENT ACTIVITIES - NETTING ARRANGEMENTS AND CASH COLLATERAL (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Derivative assets subject to master netting or similar arrangements, gross amount	$ 2.3	$ 2.2
Potential effects of netting, including cash collateral	0.4	0.6
Derivative assets subject to master netting or similar arrangements, net amount	1.9	1.6
Derivative assets not subject to master netting arrangement	0	0.2
Risk Management Asset	2.3	2.4
Total Risk Management Assets, Net Amount	1.9us-gaap_DerivativeAssets	1.8us-gaap_DerivativeAssets
Liabilities
Derivative liabilities subject to master netting or similar arrangements, gross amount	3.6	0.4
Potential effects of netting, including cash collateral	3.6	0.4
Derivative liabilities subject to master netting or similar arrangements, net amount	0	0
Derivative liabilities not subject to master netting arrangement	3.4	2.7
Risk Management Liability	7.0	3.1
Total Risk Management Liabilities, Net Amount	3.4us-gaap_DerivativeLiabilities	2.7us-gaap_DerivativeLiabilities
Cash Collateral Positions
Cash collateral provided to others related to contracts under master netting or similar arrangements	6.6	3.1
Cash collateral received from others related to contracts under master netting or similar arrangements	$ 0	$ 0.2

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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