EMPLOYEE BENEFIT PLANS - AMOUNTS IN ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Pension Benefits
EMPLOYEE BENEFIT PLANS
Unrecognized prior service credit	$ 6
Unrecognized prior service credit, net of tax	4
Unrecognized actuarial loss	190
Unrecognized actuarial gain (loss), net of tax	124
Prior service cost and unrecognized actuarial losses included in accumulated other comprehensive income that is expected to be recognized in net periodic benefit costs in 2016	10
Prior service cost and unrecognized actuarial losses included in accumulated other comprehensive income that is expected to be recognized in net periodic benefit costs in 2016, net of tax	7
Postretirement Benefits
EMPLOYEE BENEFIT PLANS
Unrecognized prior service credit	1
Unrecognized prior service credit, net of tax	1
Unrecognized actuarial loss	14
Unrecognized actuarial gain (loss), net of tax	$ 9