DERIVATIVE FINANCIAL INSTRUMENTS (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Derivatives designated as hedging instruments
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value	$ 3	$ 9
Liability Derivatives Fair Value	172	89
Derivatives designated as hedging instruments | Interest rate contracts | Prepayments and other
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value	2	1
Derivatives designated as hedging instruments | Interest rate contracts | Other deferred debits and other assets
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value		7
Derivatives designated as hedging instruments | Interest rate contracts | Other current liabilities
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives Fair Value	55	57
Derivatives designated as hedging instruments | Interest rate contracts | Other deferred credits and other liabilities
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives Fair Value	103	25
Derivatives designated as hedging instruments | Commodity contracts | Prepayments and other
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives Fair Value	1
Derivatives designated as hedging instruments | Commodity contracts | Other current liabilities
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value	1	1
Liability Derivatives Fair Value	10	5
Derivatives designated as hedging instruments | Commodity contracts | Other deferred credits and other liabilities
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives Fair Value	3	2
Derivatives not designated as hedging instruments
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value	27	12
Liability Derivatives Fair Value	25	9
Derivatives not designated as hedging instruments | Commodity contracts | Prepayments and other
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value		3
Derivatives not designated as hedging instruments | Other energy management contracts | Prepayments and other
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value	17	7
Liability Derivatives Fair Value	3	1
Derivatives not designated as hedging instruments | Other energy management contracts | Other deferred debits and other assets
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives Fair Value	10	2
Derivatives not designated as hedging instruments | Other energy management contracts | Other current liabilities
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives Fair Value	13	6
Derivatives not designated as hedging instruments | Other energy management contracts | Other deferred credits and other liabilities
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives Fair Value	$ 9	$ 2