CONSOLIDATED STATEMENT OF CHANGES IN PARTNERS' EQUITY - 9 months ended Sep. 30, 2017 - USD ($) shares in Millions, $ in Millions		Limited Partners Common Units	Limited Partners Class B Units	General Partner	Accumulated Other Comprehensive Loss	[1]	Non-Controlling Interest		Equity of former parent of PNGTS		Total
Partners' Equity at beginning of year at Dec. 31, 2016		$ 1,002	$ 117	$ 27	$ (2)	[2]	$ 97	[2]	$ 31	[2]	$ 1,272	[2]
Partners' Equity at beginning of year (in units) at Dec. 31, 2016		67.4	1.9
Increase (Decrease) in Partners' Equity
Net income	[2]	$ 164	$ 8	12			7		2		193
Other comprehensive income	[2]				$ 2						2
ATM equity issuance, net (Note 7)		$ 124		2							126	[2]
ATM equity issuance, net (Note 7) (in units)		2.2
Reclassification of common units no longer subject to rescission (Note 7)		$ 81		2							83	[2]
Acquisition of interests in PNGTS and Iroquois (Note 6)		(383)		(8)					(32)	[2]	(423)	[2]
Distributions	[2]	(198)	(22)	(12)			(2)		$ (1)		(235)
Partners' Equity at end of year at Sep. 30, 2017		$ 790	$ 103	$ 23			$ 102	[2]			$ 1,018	[2]
Partners' Equity at end of year (in units) at Sep. 30, 2017		69.6	1.9

[1] Losses related to cash flow hedges reported in Accumulated Other Comprehensive Loss and expected to be reclassified to Net Income in the next 12 months are estimated to be $1 million. These estimates assume constant interest rates over time; however, the amounts reclassified will vary based on actual value of interest rates at the date of settlement.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).