Consolidated Statements of Partners' Capital and Noncontrolling Interest (USD $) In Millions	Total	Common Unitholders	Class F Units [Member]	General Partner Interest	Predecessor Equity [Member]	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Balance at Dec. 31, 2011	$ 3,531	$ 3,173		$ 330		$ (5)	$ 33
Common unit offerings, net of costs	297	297
Issuance of common units under equity distribution program, net of costs	15	15
Common units issued under LTIP, net of forfeitures and tax withholding	(1)	(1)
Unit-based compensation expenses	5	5
Partner distributions	(322)	(309)		(13)
Net income (loss)	34	37		9	(14)		2
Noncontrolling interest contributions, net of distributions	42						42
Distributions to Series A Preferred Units	(8)	(8)
Accretion of Series A Preferred Units	(2)	(2)
Net cash flow hedge amounts reclassified to earnings	5					5
Contribution of net investment to unitholders	1,744				1,747	(3)
Balance at Dec. 31, 2012	5,340	3,207		326	1,733	(3)	77
Issuance of common units under equity distribution program, net of costs	149	149
Unit-based compensation expenses	7	7
Partner distributions	(386)	(371)		(15)
Contribution of net investment to the Partnership				1,925	(1,928)	3
Net income (loss)	27	40	4	11	(36)	0	8
Noncontrolling interest contributions, net of distributions	17						17
Distributions to Series A Preferred Units	(6)	(6)
Issuance of common units in connection with the SUGS Acquisition, net of costs		819		(819)
Issuance of Class F units in connection with the SUGS Acquisition, net of costs			142	(142)
Contribution of assets between entities under common control below historical cost	(273)			(504)	231
Conversion of Series A Preferred Units for common units	41	41
Balance at Dec. 31, 2013	4,916	3,886	146	782			102
Issuance of common units under equity distribution program, net of costs	428	428
Common units issued under LTIP, net of forfeitures and tax withholding	(1)	(1)
Unit-based compensation expenses	10	10
Partner distributions	(706)	(674)		(32)
Contribution of net investment to the Partnership	800	800
Issuance of common units in connection with Hoover Acquisition	109	109
Issuance of common units in connection with PVR Acquisition	3,906	3,906
Issuance of common units in connection with Eagle Rock Midstream Acquisition	266	266
Net income (loss)	(142)	(195)	7	31			15
Noncontrolling interest contributions, net of distributions	3						3
Distributions to Series A Preferred Units	(4)	(4)
Balance at Dec. 31, 2014	$ 9,585	$ 8,531	$ 153	$ 781			$ 120