PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Other Postretirement Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 16	$ 15	$ 13
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligations, Beginning Balance	$ 4,345	$ 3,995
Discount rate - benefit obligations	4.26%	3.90%	4.75%
Discount rate - net periodic costs	3.90%	4.75%	3.85%
Employer Group Waiver Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	$ 10
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligations, Beginning Balance	$ 270	$ 302
Discount rate - benefit obligations	4.08%	3.75%	4.40%
Initial health care cost trend rate - benefit obligations	7.25%	7.05%	7.46%
Ultimate health care cost trend rate - benefit obligations	5.00%	5.00%	5.00%
Discount rate - net periodic costs	3.75%	4.40%	3.65%
Initial health care cost trend rate - net periodic costs	7.05%	7.46%	7.85%
Ultimate health care cost trend rate - net periodic costs	5.00%	5.00%	5.00%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2025	2020	2020
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	$ 2
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	$ 2