DERIVATIVE INSTRUMENTS - Fair Value and Notional Amounts of Derivatives With Counterparty Credit Risk (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	$ 22,158	$ 22,127
Asset Derivatives Fair Value	1,144	676
Liability Derivatives Fair Value	(332)	(371)
AA
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	2,366	2,187
Asset Derivatives Fair Value	153	166
Liability Derivatives Fair Value	(58)	(35)
A
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	18,157	19,940
Asset Derivatives Fair Value	926	510
Liability Derivatives Fair Value	(199)	(336)
BBB
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	1,635	0
Asset Derivatives Fair Value	65	0
Liability Derivatives Fair Value	$ (75)	$ 0