Debt and Credit Facilities Available Credit Facilities and Restrictive Debt Covenants - Table Footnotes (Details) CAD in Millions, $ in Millions	Sep. 30, 2016 CAD	Sep. 30, 2016 USD ($)
Line of Credit Facility [Line Items]
Total Credit Facilities Capacity		$ 6,338
Spectra Energy Partners, LP
Line of Credit Facility [Line Items]
Total Credit Facilities Capacity		2,500	[1]
Westcoast Energy Inc.
Line of Credit Facility [Line Items]
Total Credit Facilities Capacity	CAD 400	305	[2]
Union Gas Limited
Line of Credit Facility [Line Items]
Total Credit Facilities Capacity	CAD 700	$ 533	[3]
Covenant Requirement | Spectra Energy Capital, LLC
Line of Credit Facility [Line Items]
Debt to Total Capitalization	55.80%	55.80%
Covenant Requirement | Spectra Energy Capital, LLC | Maximum
Line of Credit Facility [Line Items]
Debt to Total Capitalization	65.00%	65.00%
Covenant Requirement | Spectra Energy Partners, LP
Line of Credit Facility [Line Items]
Debt To Adjusted EBITDA Ratio Maximum	5.0	5.0
Debt To Adjusted EBITDA Ratio	3.7	3.7
Covenant Requirement | Westcoast Energy Inc.
Line of Credit Facility [Line Items]
Debt to Total Capitalization	31.10%	31.10%
Covenant Requirement | Westcoast Energy Inc. | Maximum
Line of Credit Facility [Line Items]
Debt to Total Capitalization	75.00%	75.00%
Covenant Requirement | Union Gas Limited
Line of Credit Facility [Line Items]
Debt to Total Capitalization	68.10%	68.10%
Covenant Requirement | Union Gas Limited | Maximum
Line of Credit Facility [Line Items]
Debt to Total Capitalization	75.00%	75.00%

[1] Revolving credit facility contains a covenant that requires SEP to maintain a ratio of total Consolidated Indebtedness-to-Consolidated EBITDA, as defined in the agreement, of 5.0 to 1 or less. As of September 30, 2016, this ratio was 3.7 to 1.

[2] U.S. dollar equivalent at September 30, 2016. The revolving credit facility is 400 million Canadian dollars and contains a covenant that requires the Westcoast non-consolidated debt-to-total capitalization ratio to not exceed 75%. The ratio was 31.1% at September 30, 2016.

[3] U.S. dollar equivalent at September 30, 2016. The revolving credit facility is 700 million Canadian dollars and contains a covenant that requires the Union Gas debt-to-total capitalization ratio to not exceed 75% and a provision which requires Union Gas to repay all borrowings under the facility for a period of two days during the second quarter of each year. The ratio was 68.1% at September 30, 2016.