CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Transmission revenues	$ 91	$ 83	$ 266	$ 255
Equity earnings (Note 4)	24	17	88	63
Operation and maintenance expenses	(14)	(12)	(36)	(36)
Property taxes	(4)	(5)	(14)	(16)
General and administrative	(1)	(1)	(5)	(5)
Depreciation	(21)	(21)	(64)	(63)
Financial charges and other (Note 14)	(17)	(12)	(50)	(41)
Net income	58	49	185	157
Net income attributable to non-controlling interests				7
Net income attributable to controlling interests	58	49	185	150
Net income attributable to controlling interest allocation
General Partner	4	2	9	5
Net income attributable to controlling interests	58	49	185	150
Common units
Net income attributable to controlling interest allocation
Limited partners	$ 43	$ 45	$ 164	$ 143
Net income per common unit (Note 8) - basic (in dollars per unit)	$ 0.65	$ 0.70	$ 2.51	$ 2.23
Net income per common unit (Note 8) - diluted (in dollars per unit)	$ 0.65	$ 0.70	$ 2.51	$ 2.23
Weighted average common units outstanding - basic (in units)	66.1	64.0	65.3	63.8
Weighted average common units outstanding - diluted (in units)	66.1	64.0	65.3	63.8
Common units outstanding, end of period (in units)	66.6	64.0	66.6	64.0
Class B units
Net income attributable to controlling interest allocation
Limited partners	$ 11	$ 2	$ 12	$ 2