CONSOLIDATED STATEMENT OF INCOME (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
CONSOLIDATED STATEMENT OF INCOME
Transmission revenues	$ 341	[1]	$ 343	[1]	$ 353	[1]
Equity earnings from unconsolidated affiliates (Note 4)	67	[1]	99	[1]	135	[1]
Operation and maintenance expenses	(55)	[1]	(57)	[1]	(61)	[1]
Property taxes	(23)	[1]	(25)	[1]	(23)	[1]
General and administrative	(9)	[1]	(6)	[1]	(9)	[1]
Depreciation	(86)	[1]	(85)	[1]	(87)	[1]
Financial charges and other (Note 11)	(44)	[1]	(40)	[1]	(46)	[1]
Income taxes (Note 2(k))					(12)	[1]
Net income	191	[1]	229	[1]	250	[1]
Net income attributable to non-controlling interests	36	[1]	37	[1]	34	[1]
Net income attributable to controlling interests	155	[1]	192	[1]	216	[1]
Net income attributable to controlling interests allocation (Note 12)
Common units	126	[1]	134	[1]	154	[1]
General Partner	3	[1]	3	[1]	3	[1]
Net income attributable to controlling interests	$ 155	[1]	$ 192	[1]	$ 216	[1]
Net income per common unit (Note 12) - basic (in dollars per unit)	$ 2.13	[1]	$ 2.51	[1]	$ 3.02	[1]
Net income per common unit (Note 12) - diluted (in dollars per unit)	$ 2.13	[1]	$ 2.51	[1]	$ 3.02	[1]
Weighted average common units outstanding (millions) - basic (in units)	58.9		53.5		51.1
Weighted average common units outstanding (millions) - diluted (in units)	58.9		53.5		51.1
Common units outstanding, end of period (millions) (in units)	62.3		53.5		53.5

[1] (a) Recast as discussed in Note 2 and Note 6.