PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS Additional Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Registered Canadian Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to benefit plans during 2017	$ 19
Non Registered Canadian Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to benefit plans during 2017	3
U.S. Non-Qualified Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to benefit plans during 2017	26
U.S. and Canadian Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to benefit plans during 2017	21
U.S. Qualified Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to benefit plans during 2017	$ 0