PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Assets Within Our U.S. and Canadian Qualified and Registered Pension Plans (Details) - Qualified and Registered Plans [Member]	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(100.00%)	(100.00%)
Cash and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(10.60%)	(13.70%)
Common and preferred stock
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(0.00%)	(0.10%)
Hedge funds and related investments
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(58.80%)	(56.60%)
Private equity and related investments
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(22.20%)	(22.70%)
Derivative instruments, net
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(8.70%)	(7.10%)
Accrued liabilities
Defined Benefit Plan Disclosure [Line Items]
Assets invested in pension plan, allocation percentage	(0.30%)	(0.20%)