CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016
Transmission revenues	$ 100	$ 103	[1]	$ 313		$ 315	[1]
Equity earnings (Note 4)	27	22	[1]	87		75	[1]
Operation and maintenance expenses	(16)	(15)	[1]	(47)		(42)	[1]
Property taxes	(7)	(7)	[1]	(21)		(20)	[1]
General and administrative	(1)	(1)	[1]	(6)		(5)	[1]
Depreciation	(25)	(24)	[1]	(73)		(71)	[1]
Financial charges and other (Note 14)	(23)	(18)	[1]	(59)		(53)	[1]
Net income before taxes	55	60	[1]	194		199	[1]
Income taxes (Note 18)				(1)		(1)	[1]
Net income	55	60	[1]	193	[2]	198	[1]
Net income attributable to non-controlling interests	1	2	[1]	7		10	[1]
Net income attributable to controlling interests	54	58	[1]	186		188	[1]
Net income attributable to controlling interest allocation (Note 8)
General Partner	4	4	[1]	12		9	[1]
TransCanada and its subsidiaries	8	11	[1]	10		15	[1]
Net income attributable to controlling interests	54	58	[1]	186		188	[1]
Common Units
Net income attributable to controlling interest allocation (Note 8)
Limited partners	$ 42	$ 43	[1]	$ 164		$ 164	[1]
Net income per common unit (Note 8) - basic (in dollars per unit)	$ 0.61	$ 0.65	[1],[3]	$ 2.38		$ 2.51	[1],[3]
Net income per common unit (Note 8) - diluted (in dollars per unit)	$ 0.61	$ 0.65		$ 2.38		$ 2.51
Weighted average common units outstanding - basic (in units)	69.4	66.1	[1]	68.9		65.3	[1]
Weighted average common units outstanding - diluted (in units)	69.4	66.1		68.9		65.3
Common units outstanding, end of period (in units)	69.6	66.6	[1]	69.6		66.6	[1]

[1] Recast to consolidate PNGTS for all periods presented (Refer to Notes 2 and 6).

[2] Recast to consolidate PNGTS for all periods presented (Refer to Notes 2 and 6).

[3] Net income per common unit prior to recast (Refer to Note 2).