Goodwill (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Jul. 31, 2012	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Goodwill		$ 840		$ 1,468	$ 1,696
Impairment Charge		0		252	0
Acquisition	24			24
Contributed to Enable		628	[1]
Natural Gas Distribution [Member]
Goodwill [Line Items]
Goodwill		746		746	746
Impairment Charge				0
Acquisition				0
Contributed to Enable		0	[1]
Interstate Pipelines [Member]
Goodwill [Line Items]
Goodwill		0		579	579
Impairment Charge				0
Acquisition				0
Contributed to Enable		579	[1]
Energy Services [Member]
Goodwill [Line Items]
Goodwill		83		83	335
Impairment Charge				252
Acquisition				0
Contributed to Enable		0	[1]
Field Services [Member]
Goodwill [Line Items]
Goodwill		0		49	25
Impairment Charge				0
Acquisition				24
Contributed to Enable		49	[1]
Corporate and Other [Member]
Goodwill [Line Items]
Goodwill		11		11	11
Impairment Charge				0
Acquisition				0
Contributed to Enable		$ 0	[1]

[1] See Note 2(b).