RETIREMENT AND POSTRETIREMENT BENEFITS - PLAN CONTRIBUTIONS AND BENEFITS EXPECTED TO BE PAID (Details) - CAD CAD in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Benefits Expected to be Paid by the Company
Expected future benefit payments for 2016	CAD 104
Expected future benefit payments for 2017	110
Expected future benefit payments for 2018	117
Expected future benefit payments for 2019	124
Expected future benefit payments for 2020	132
Expected future benefit payments for 2021-2025	782
Pension Plans
Benefits Expected to be Paid by the Company
Total contributions	116	CAD 138
Contributions expected to be paid in 2016	118
Other Postretirement Plans
Benefits Expected to be Paid by the Company
Total contributions	10	CAD 11
Contributions expected to be paid in 2016	CAD 11

The increase in the fair value of plan assets from contributions made by the employer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of benefits from a defined benefit plan expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References