PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Aggregate Notional Amount of Derivatives held by Pension Trusts (Details) - Pension - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Notional Amount of Derivatives	$ 4,731	$ 3,081
Equity and fixed income index derivatives, net
Defined Benefit Plan Disclosure [Line Items]
Notional Amount of Derivatives	405	449
Foreign currency derivatives, net
Defined Benefit Plan Disclosure [Line Items]
Notional Amount of Derivatives	2,811	1,023
Total return swaps, net
Defined Benefit Plan Disclosure [Line Items]
Notional Amount of Derivatives	$ 1,515	$ 1,609