Reportable Business Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended											12 Months Ended						8 Months Ended		0 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013		May 01, 2013	May 30, 2014	Jul. 31, 2012
Segment Reporting Information [Line Items]
Revenue from External Customers	$ 1,689		$ 964	$ 1,183	$ 2,531	$ 1,543		$ 891	$ 1,235	[1]	$ 1,853	$ 6,367		$ 5,522		$ 4,901
Depreciation and Amortization												206		230		285
Operating Income (Loss)	111		(3)	39	188	91		4	56	[1]	250	335		401		394
Assets	11,045					10,532						11,045		10,532		11,180		10,532
Capital Expenditures for Long-Lived Assets												528		478		549
Equity income												308		188		31
Investment in unconsolidated affiliate	4,521					4,518						4,521		4,518				4,518
Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												3,271		2,837		2,320
Depreciation and Amortization												201		185		173
Operating Income (Loss)												287		263		226
Capital Expenditures for Long-Lived Assets												525		430		359
Energy Services [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												3,095		2,374		1,758
Depreciation and Amortization												5		5		6
Operating Income (Loss)												52		13		(250)
Capital Expenditures for Long-Lived Assets												3		3		6
Interstate Pipelines [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers														133	[2],[3]	356	[2]
Depreciation and Amortization														20	[2],[3]	56	[2]
Operating Income (Loss)														72	[2],[3]	207	[2]
Capital Expenditures for Long-Lived Assets														29	[2],[3]	132	[2]
Field Services [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers														178	[3],[4]	467	[4]
Depreciation and Amortization														20	[3],[4]	50	[4]
Operating Income (Loss)														73	[3],[4]	214	[4]
Capital Expenditures for Long-Lived Assets														16	[3],[4]	52	[4]
Midstream Investments [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												0	[5]	0	[5]
Depreciation and Amortization												0	[5]	0	[5]
Operating Income (Loss)												0	[5]	0	[5]
Capital Expenditures for Long-Lived Assets												0	[5]	0	[5]
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												1		0		0
Depreciation and Amortization												0		0		0
Operating Income (Loss)												(4)		(20)		(3)
Capital Expenditures for Long-Lived Assets												0		0		0
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Assets	5,464					4,976						5,464		4,976		4,775		4,976
Operating Segments [Member] | Energy Services [Member]
Segment Reporting Information [Line Items]
Assets	978					895						978		895		839		895
Operating Segments [Member] | Interstate Pipelines [Member]
Segment Reporting Information [Line Items]
Assets						0	[2],[3]							0	[2],[3]	4,004	[2]	0	[2],[3]
Operating Segments [Member] | Field Services [Member]
Segment Reporting Information [Line Items]
Assets						0	[3],[4]							0	[3],[4]	2,453	[4]	0	[3],[4]
Operating Segments [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Assets	4,521	[5]				4,518	[5]					4,521	[5]	4,518	[5]			4,518	[5]
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets	1,046					1,139						1,046		1,139		637		1,139
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												(114)		(124)		(233)
Assets	(964)					(996)						(964)		(996)		(1,528)		(996)
Intersegment Eliminations [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												(30)		(26)		(22)
Intersegment Eliminations [Member] | Energy Services [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												(84)		(27)		(26)
Intersegment Eliminations [Member] | Interstate Pipelines [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers														(53)	[2],[3]	(146)	[2]
Intersegment Eliminations [Member] | Field Services [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers														(18)	[3],[4]	(39)	[4]
Intersegment Eliminations [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												0	[5]	0	[5]
Intersegment Eliminations [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers												0		0		0
Enable Midstream Partners [Member]
Segment Reporting Information [Line Items]
Equity income												303	[6]	173	[6]	0	[6]
Investment in unconsolidated affiliate	4,520					4,319						4,520		4,319				4,319		4,300
Interest in jointly-owned asset (in hundredths)	55.40%				58.30%							55.40%									54.70%
Enable Midstream Partners [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Equity income												303						173
Southeast Supply Header LLC [Member]
Segment Reporting Information [Line Items]
Equity income												5	[7]	15	[7]	26	[7]
Investment in unconsolidated affiliate	1	[8]				199	[8]					1	[8]	199	[8]			199	[8]
Interest in jointly-owned asset (in hundredths)	0.10%				25.05%							0.10%
Equity Interest Contributed, Percentage																				24.95%
Southeast Supply Header LLC [Member] | Interstate Pipelines [Member]
Segment Reporting Information [Line Items]
Equity income														7		26
Investment in unconsolidated affiliate																404
Southeast Supply Header LLC [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Equity income												5						8
Waskom Gas Processing Company [Member]
Segment Reporting Information [Line Items]
Equity income												0	[9]	0	[9]	5	[9]
Waskom Gas Processing Company [Member] | Field Services [Member]
Segment Reporting Information [Line Items]
Equity income																$ 5
Waskom Gas Processing Company [Member]
Segment Reporting Information [Line Items]
Percentage of Ownership in Affiliate 2 Acquired																						50.00%
Waskom Gas Processing Company [Member] | Enable Midstream Partners [Member]
Segment Reporting Information [Line Items]
Equity Interest Contributed, Percentage																				100.00%

[1] Effective May 1, 2013, CERC Corp. contributed CenterPoint Midstream to Enable. See Note 2(b) and Note 10 for further discussion on the formation of Enable and CERC’s investment in Enable, respectively.

[2] Interstate Pipelines recorded equity income of $7 million and $26 million in the years ended December 31, 2013 and 2012, respectively, from its interest in SESH, a jointly-owned pipeline. These amounts are included in Equity in earnings of unconsolidated affiliates under the Other Income (Expense) caption. Interstate Pipelines’ investment in SESH was $404 million as of December 31, 2012, and is included in Investment in unconsolidated affiliates. As discussed above, effective May 1, 2013, CenterPoint Energy reports equity earnings associated with its interest in Enable and equity earnings associated with its interest in SESH under its Midstream Investments segment, and no longer has an Interstate Pipelines reporting segment prospectively.

[3] Results reflected in the year ended December 31, 2013 represent only January 2013 through April 2013.

[4] Field Services recorded equity income of $5 million for the year ended December 31, 2012 from its interest in Waskom. This amount is included in Equity in earnings of unconsolidated affiliates under the Other Income (Expense) caption. Beginning on August 1, 2012, financial results for Waskom are included in operating income due to the July 31, 2012 purchase of the 50% interest in Waskom that CenterPoint Energy did not already own. CERC contributed 100% interest in Waskom to Enable on May 1, 2013. Effective May 1, 2013, CERC reports equity earnings associated with its interest in Enable under its Midstream Investments segment, and no longer has a Field Services reporting segment prospectively.

[5] Midstream Investments reported equity earnings of $303 million from Enable and $5 million of equity earnings from CERC’s interest in SESH for the year ended December 31, 2014. Midstream Investments reported equity earnings of $173 million from Enable and $8 million of equity earnings from CERC’s interest in SESH for the eight months ended December 31, 2013. Included in total assets of Midstream Investments as of December 31, 2014 and 2013 is $4,520 million and $4,319 million, respectively, related to CERC’s investment in Enable and $1 million and $199 million related to CERCs retained interest in SESH, respectively.

[6] On May 1, 2013, CERC formed Enable with OGE and ArcLight.

[7] On each of May 1, 2013 and May 30, 2014, CERC contributed a 24.95% interest in SESH to Enable, leaving CERC with a 0.1% interest in SESH as of December 31, 2014.

[8] On May 30, 2014, CERC contributed a 24.95% interest in SESH to Enable, leaving CERC with a 0.1% interest in SESH as of December 31, 2014.

[9] On July 31, 2012, Waskom became a wholly owned subsidiary of CenterPoint Energy. Beginning on August 1, 2012, Waskom’s operating results are consolidated on the Statements of Consolidated Income. On May 1, 2013, CenterPoint Energy contributed Waskom to Enable.