PRICE RISK MANAGEMENT ASSETS AND LIABILITIES DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Balance Sheet (Details) (Interest Rate Contract [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 0	$ 0
Derivative Liability, Fair Value, Gross Liability	0	25
Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	10
Deferred Credits [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	$ 0	$ 15