PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Fair Value of Derivatives (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Derivatives, Fair Value, Net	$ 454	$ 417
Equity index instruments
Defined Benefit Plan Disclosure [Line Items]
Derivatives, Fair Value, Net	13	13
Forward contracts
Defined Benefit Plan Disclosure [Line Items]
Derivatives, Fair Value, Net	(51)	(32)
Swaps
Defined Benefit Plan Disclosure [Line Items]
Derivatives, Fair Value, Net	$ 492	$ 436