DERIVATIVE INSTRUMENTS - Fair Value and Notional Amounts of Derivatives With Counterparty Credit Risk (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Fair Value of Swaps	$ (213)	$ (589)
Notional Amount of Swaps	15,085	13,370
AA
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Fair Value of Swaps	(6)	(1)
Notional Amount of Swaps	161	161
A
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Fair Value of Swaps	(207)	(588)
Notional Amount of Swaps	$ 14,924	$ 13,209