Segment Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues [Abstract]
Revenues	$ 1,730	$ 1,830	$ 3,384	$ 3,541
Service [Member]
Revenues [Abstract]
Revenues	1,210	1,231	2,436	2,423
Product [Member]
Revenues [Abstract]
Revenues	520	599	948	1,118
Central [Member] | Service [Member]
Revenues [Abstract]
Revenues	255	260	507	505
Central [Member] | Product [Member]
Revenues [Abstract]
Revenues	0	0	0	0
Northeast G&P [Member] | Service [Member]
Revenues [Abstract]
Revenues	199	214	407	410
Northeast G&P [Member] | Product [Member]
Revenues [Abstract]
Revenues	27	30	46	67
Atlantic-Gulf [Member] | Service [Member]
Revenues [Abstract]
Revenues	447	465	912	922
Atlantic-Gulf [Member] | Product [Member]
Revenues [Abstract]
Revenues	63	83	100	151
West [Member] | Service [Member]
Revenues [Abstract]
Revenues	255	258	518	520
West [Member] | Product [Member]
Revenues [Abstract]
Revenues	4	8	8	16
NGL & Petchem Services [Member] | Service [Member]
Revenues [Abstract]
Revenues	54	34	92	66
NGL & Petchem Services [Member] | Product [Member]
Revenues [Abstract]
Revenues	426	478	794	884
Operating Segments [Member] | Central [Member]
Revenues [Abstract]
Revenues	258	265	513	517
Operating Segments [Member] | Central [Member] | Service [Member]
Revenues [Abstract]
Revenues	258	265	513	517
Operating Segments [Member] | Central [Member] | Product [Member]
Revenues [Abstract]
Revenues	0	0	0	0
Operating Segments [Member] | Northeast G&P [Member]
Revenues [Abstract]
Revenues	241	251	476	485
Operating Segments [Member] | Northeast G&P [Member] | Service [Member]
Revenues [Abstract]
Revenues	208	216	419	412
Operating Segments [Member] | Northeast G&P [Member] | Product [Member]
Revenues [Abstract]
Revenues	33	35	57	73
Operating Segments [Member] | Atlantic-Gulf [Member]
Revenues [Abstract]
Revenues	553	591	1,088	1,170
Operating Segments [Member] | Atlantic-Gulf [Member] | Service [Member]
Revenues [Abstract]
Revenues	448	466	914	924
Operating Segments [Member] | Atlantic-Gulf [Member] | Product [Member]
Revenues [Abstract]
Revenues	105	125	174	246
Operating Segments [Member] | West [Member]
Revenues [Abstract]
Revenues	333	326	648	652
Operating Segments [Member] | West [Member] | Service [Member]
Revenues [Abstract]
Revenues	255	258	518	520
Operating Segments [Member] | West [Member] | Product [Member]
Revenues [Abstract]
Revenues	78	68	130	132
Operating Segments [Member] | NGL & Petchem Services [Member]
Revenues [Abstract]
Revenues	517	547	961	1,022
Operating Segments [Member] | NGL & Petchem Services [Member] | Service [Member]
Revenues [Abstract]
Revenues	54	34	92	66
Operating Segments [Member] | NGL & Petchem Services [Member] | Product [Member]
Revenues [Abstract]
Revenues	463	513	869	956
Intersegment Eliminations [Member]
Revenues [Abstract]
Revenues	(172)	(150)	(302)	(305)
Intersegment Eliminations [Member] | Service [Member]
Revenues [Abstract]
Revenues	(13)	(8)	(20)	(16)
Intersegment Eliminations [Member] | Product [Member]
Revenues [Abstract]
Revenues	(159)	(142)	(282)	(289)
Intersegment Eliminations [Member] | Central [Member] | Service [Member]
Revenues [Abstract]
Revenues	(3)	(5)	(6)	(12)
Intersegment Eliminations [Member] | Central [Member] | Product [Member]
Revenues [Abstract]
Revenues	0	0	0	0
Intersegment Eliminations [Member] | Northeast G&P [Member] | Service [Member]
Revenues [Abstract]
Revenues	(9)	(2)	(12)	(2)
Intersegment Eliminations [Member] | Northeast G&P [Member] | Product [Member]
Revenues [Abstract]
Revenues	(6)	(5)	(11)	(6)
Intersegment Eliminations [Member] | Atlantic-Gulf [Member] | Service [Member]
Revenues [Abstract]
Revenues	(1)	(1)	(2)	(2)
Intersegment Eliminations [Member] | Atlantic-Gulf [Member] | Product [Member]
Revenues [Abstract]
Revenues	(42)	(42)	(74)	(95)
Intersegment Eliminations [Member] | West [Member] | Service [Member]
Revenues [Abstract]
Revenues	0	0	0	0
Intersegment Eliminations [Member] | West [Member] | Product [Member]
Revenues [Abstract]
Revenues	(74)	(60)	(122)	(116)
Intersegment Eliminations [Member] | NGL & Petchem Services [Member] | Service [Member]
Revenues [Abstract]
Revenues	0	0	0	0
Intersegment Eliminations [Member] | NGL & Petchem Services [Member] | Product [Member]
Revenues [Abstract]
Revenues	$ (37)	$ (35)	$ (75)	$ (72)