- Definition

Sets forth the anticipated percentage total fuel volume that must be purchased (at market prices prevailing on the date of the purchase) in year 2.

+ References

No definition available.

+ Details

Name:	cni_ApproximatePercentageOfAnticipatedLongTermFuelVolumePurchaseCommitmentYear2
Namespace Prefix:	cni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Sets forth the anticipated percentage total fuel volume that must be purchased (at market prices prevailing on the date of the purchase) in year 3.

+ References

No definition available.

+ Details

Name:	cni_ApproximatePercentageOfAnticipatedLongTermFuelVolumePurchaseCommitmentYear3
Namespace Prefix:	cni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Sets forth the anticipated percentage total fuel volume that must be purchased (at market prices prevailing on the date of the purchase) in year 4.

+ References

No definition available.

+ Details

Name:	cni_ApproximatePercentageOfAnticipatedLongTermFuelVolumePurchaseCommitmentYear4
Namespace Prefix:	cni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Sets forth the approximate estimated percentage total fuel volume that must be purchased (at market prices prevailing on the date of the purchase) in year 1.

+ References

No definition available.

+ Details

Name:	cni_ApproximatePercentageOfEstimatedLongTermFuelVolumePurchaseCommitmentYear1
Namespace Prefix:	cni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	cni_CommitmentsAbstract
Namespace Prefix:	cni_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The completion date of the Positive Train Control implementation.

+ References

No definition available.

+ Details

Name:	cni_PositiveTrainControlImplementationCompletionDate
Namespace Prefix:	cni_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Major commitments and contingencies (Details 1) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013 Other Commitments [Member] CAD	Dec. 31, 2012 Other Commitments [Member] CAD	Dec. 31, 2013 Business Acquisition Commitments Infrastructure Improvements And Other [Member] USD ($)	Dec. 31, 2013 Business Acquisition Commitments Infrastructure Improvements And Other [Member] CAD	Dec. 31, 2013 Positive Train Control Commitmen [Member] USD ($)	Dec. 31, 2013 Positive Train Control Commitmen [Member] CAD
B. Commitments
Aggregate commitment costs		482	735	$ 68	72	$ 273	291
Positive Train Control Implementation Completion Date						2015	2015
Approximate percentage of estimated 2014 fuel volume purchase commitment (in hundredths)	85.00%
Approximate percentage of anticipated fuel volume purchase commitment 2015 (in hundredths)	60.00%
Approximate percentage of anticipated fuel volume purchase commitment 2016 (in hundredths)	55.00%
Approximate percentage of anticipated fuel volume purchase commitment 2017 (in hundredths)	20.00%