CONSOLIDATED STATEMENT OF CHANGES IN PARTNERS' EQUITY (USD $) In Millions, unless otherwise specified		Total		Common Units	General Partner	Accumulated Other Comprehensive Loss
Partners' equity at Dec. 31, 2009		$ 1,104		$ 1,107	$ 23	$ (26)
Partners' equity (in units) at Dec. 31, 2009		46.2		46.2
Increase (Decrease) in Partners' Equity
Net income		137	[1]	134	3
Distributions paid		(139)		(136)	(3)
Other comprehensive income		11				11
Partners' equity at Dec. 31, 2010		1,113		1,105	23	(15)
Partners' equity (in units) at Dec. 31, 2010		46.2		46.2
Increase (Decrease) in Partners' Equity
Net income	[1]	157		154	3
Equity issuance, net (Note 6 and 8)		338		331	7
Equity issuance, net (Note 6 and 8) (in units)		7.3		7.3
Distributions paid		(155)		(152)	(3)
Excess purchase price over net acquired assets (Note 6)		(134)		(131)	(3)
Other comprehensive income		14				14
Partners' equity at Dec. 31, 2011		1,333		1,307	27	(1)
Partners' equity (in units) at Dec. 31, 2011		53.5		53.5
Increase (Decrease) in Partners' Equity
Net income		137	[1]	134	3
Distributions paid		(169)		(166)	(3)
Partners' equity at Dec. 31, 2012		$ 1,301		$ 1,275	$ 27	$ (1)
Partners' equity (in units) at Dec. 31, 2012		53.5		53.5

[1] 25 percent interests in each of GTN and Bison were acquired in May 2011.