The assumed health care cost trend rate for the next year used to measure the benefit obligation. This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

No definition available.

EMPLOYEE BENEFITS - Narrative (Details) - USD ($)		1 Months Ended	12 Months Ended
EMPLOYEE BENEFITS - Narrative (Details) - USD ($)	Sep. 01, 2014	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial gain (loss) recorded in AOCI expected to be recognized during 2016			$ (16,000,000)
Postemployment Benefits [Abstract]
Postemployment benefits			$ 0	$ 1,000,000	$ 3,000,000
401(k) Plan
Employer matching contribution percentage			100.00%	100.00%
Employer matching contribution, Percent of employees' pay			4.00%	5.00%
Employer matching contribution, addition			2.00%
Employer contribution amount			$ 52,000,000	$ 60,000,000	$ 70,000,000
Non-Qualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected 2016 contribution			$ 8,000,000
Discount rate			4.54%	3.875%	4.75%
Postretirement Medical Plans with Prescription Drug Benefits [Abstract]
Liabilities transferred to Affiliate plans	$ 7,000,000
Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected 2016 contribution			$ 1,000,000
Discount rate			3.93%	3.50%
Postretirement Medical Plans with Prescription Drug Benefits [Abstract]
Assumed annual rate of increase in the per capita cost of covered health care benefits			7.00%	7.00%
Ultimate rate			5.00%	5.00%
Postretirement Benefit Plan \| 25 or more years of service
Postretirement Medical Plans with Prescription Drug Benefits [Abstract]
Cost sharing benefit (as a percentage)			70.00%
Postretirement Benefit Plan \| 15-24 years of service
Postretirement Medical Plans with Prescription Drug Benefits [Abstract]
Cost sharing benefit (as a percentage)			50.00%
Postretirement Benefit Plan \| Affiliates
Postretirement Medical Plans with Prescription Drug Benefits [Abstract]
Liabilities transferred to Affiliate plans		$ 7,000,000
Qualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected 2016 contribution			$ 0
Discount rate			4.64%	4.125%	5.00%
Postretirement Medical Plans with Prescription Drug Benefits [Abstract]
Liabilities transferred to Affiliate plans	$ 148,000,000