PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Estimated Amortization from Cumulative Other Comprehensive Loss in 2016 (Details) $ in Millions	12 Months Ended
Dec. 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 161
Prior service cost (credit)	(4)
Net effect cost	157
Pension
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	152
Prior service cost (credit)	4
Net effect cost	156
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	9
Prior service cost (credit)	(8)
Net effect cost	$ 1

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration