CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL - USD ($) $ in Millions	Total	Trunkline LNG Transaction [Member]	Panhandle Merger [Member]	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Trunkline LNG Transaction [Member]	Accumulated Other Comprehensive Income (Loss) Panhandle Merger [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] Trunkline LNG Transaction [Member]	Noncontrolling Interest [Member] Panhandle Merger [Member]	Limited Partner [Member]	Limited Partner [Member] Trunkline LNG Transaction [Member]	Limited Partner [Member] Panhandle Merger [Member]
Balance at Dec. 31, 2012	$ 4,028			$ (9)			$ (13)			$ 4,050
Dividends paid to Southern Union stockholders	(313)			0			(313)			0
Other comprehensive income, net of tax	11			12			(1)			0
SUGS Contribution	(135)			0			(135)			0
Net income (loss)	(535)			0			(36)			(499)
Lake Charles LNG Transaction	12			0			12			0
Balance at Dec. 31, 2013	3,068			3			(486)			3,551
Net income (loss)	(33)
Balance at Mar. 31, 2014	2,930
Balance at Dec. 31, 2013	3,068			3			(486)			3,551
Net income (loss)	(26)
Balance at Jun. 30, 2014	2,910
Balance at Dec. 31, 2013	3,068			3			(486)			3,551
Net income (loss)	(3)
Balance at Sep. 30, 2014	2,920
Balance at Dec. 31, 2013	3,068			3			(486)			3,551
Other comprehensive income, net of tax	(2)			(2)			0			0
Net income (loss)	(39)			0			6			(45)
Distribution to partners	(102)			0			0			(102)
Unit-based compensation expense	1			0			0			1
Panhandle Merger	6	$ (43)	$ 0	0	$ 0	$ (1)	0	$ (23)	$ 503	6	$ (20)	$ (502)
Balance at Dec. 31, 2014	2,889			0			0			2,889
Balance at Mar. 31, 2014	2,930
Net income (loss)	7
Balance at Jun. 30, 2014	2,910
Net income (loss)	23
Balance at Sep. 30, 2014	2,920
Net income (loss)	(36)
Balance at Dec. 31, 2014	2,889			0			0			2,889
Net income (loss)	31
Balance at Mar. 31, 2015	2,920
Balance at Dec. 31, 2014	2,889			0			0			2,889
Net income (loss)	50
Balance at Jun. 30, 2015	2,941
Balance at Dec. 31, 2014	2,889			0			0			2,889
Net income (loss)	75
Balance at Sep. 30, 2015	2,813
Balance at Dec. 31, 2014	2,889			0			0			2,889
Other comprehensive income, net of tax	2			2			0			0
Net income (loss)	105			0			0			105
Distribution to partners	(125)			0			0			(125)
Unit-based compensation expense	2			0			0			2
Panhandle Merger	38			0			0			38
Contribution to SUG Holding	28			0			0			28
Balance at Dec. 31, 2015	2,883			2			0			2,881
Balance at Mar. 31, 2015	2,920
Net income (loss)	19
Balance at Jun. 30, 2015	2,941
Net income (loss)	25
Balance at Sep. 30, 2015	2,813
Net income (loss)	30
Balance at Dec. 31, 2015	$ 2,883			$ 2			$ 0			$ 2,881