Reportable Business Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended			9 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended						3 Months Ended		9 Months Ended					3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended						3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended				9 Months Ended							3 Months Ended		5 Months Ended	9 Months Ended		3 Months Ended				9 Months Ended							3 Months Ended		5 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Natural Gas Distribution	Sep. 30, 2013 Natural Gas Distribution	Sep. 30, 2014 Natural Gas Distribution	Sep. 30, 2013 Natural Gas Distribution	Dec. 31, 2013 Natural Gas Distribution	Sep. 30, 2014 Energy Services	Sep. 30, 2013 Energy Services	Sep. 30, 2014 Energy Services	Sep. 30, 2013 Energy Services	Dec. 31, 2013 Energy Services	Sep. 30, 2013 Interstate Pipelines		Dec. 31, 2013 Interstate Pipelines		Sep. 30, 2013 Field Services		Dec. 31, 2013 Field Services		Sep. 30, 2014 Midstream Investments (1)		Sep. 30, 2013 Midstream Investments (1)		Sep. 30, 2014 Midstream Investments (1)		Sep. 30, 2013 Midstream Investments (1)		Dec. 31, 2013 Midstream Investments (1)		Sep. 30, 2014 Other	Sep. 30, 2013 Other	Sep. 30, 2014 Other	Sep. 30, 2013 Other	Dec. 31, 2013 Other	Sep. 30, 2014 Consolidation, Eliminations [Member]	Dec. 31, 2013 Consolidation, Eliminations [Member]	Sep. 30, 2014 Intersegment Eliminations	Sep. 30, 2013 Intersegment Eliminations	Sep. 30, 2014 Intersegment Eliminations	Sep. 30, 2013 Intersegment Eliminations	Sep. 30, 2014 Intersegment Eliminations Natural Gas Distribution	Sep. 30, 2013 Intersegment Eliminations Natural Gas Distribution	Sep. 30, 2014 Intersegment Eliminations Natural Gas Distribution	Sep. 30, 2013 Intersegment Eliminations Natural Gas Distribution	Sep. 30, 2014 Intersegment Eliminations Energy Services	Sep. 30, 2013 Intersegment Eliminations Energy Services	Sep. 30, 2014 Intersegment Eliminations Energy Services	Sep. 30, 2013 Intersegment Eliminations Energy Services	Sep. 30, 2013 Intersegment Eliminations Interstate Pipelines		Sep. 30, 2013 Intersegment Eliminations Field Services		Sep. 30, 2014 Intersegment Eliminations Midstream Investments (1)		Sep. 30, 2013 Intersegment Eliminations Midstream Investments (1)		Sep. 30, 2014 Intersegment Eliminations Midstream Investments (1)		Sep. 30, 2013 Intersegment Eliminations Midstream Investments (1)		Sep. 30, 2014 Intersegment Eliminations Other	Sep. 30, 2013 Intersegment Eliminations Other	Sep. 30, 2014 Intersegment Eliminations Other	Sep. 30, 2013 Intersegment Eliminations Other	Sep. 30, 2014 Southeast Supply Header LLC [Member]		Sep. 30, 2013 Southeast Supply Header LLC [Member]		Sep. 30, 2014 Southeast Supply Header LLC [Member]		Sep. 30, 2013 Southeast Supply Header LLC [Member]		Mar. 31, 2014 Southeast Supply Header LLC [Member]	Dec. 31, 2013 Southeast Supply Header LLC [Member]		Sep. 30, 2014 Southeast Supply Header LLC [Member] Midstream Investments (1)	Sep. 30, 2013 Southeast Supply Header LLC [Member] Midstream Investments (1)	Sep. 30, 2013 Southeast Supply Header LLC [Member] Midstream Investments (1)	Sep. 30, 2014 Southeast Supply Header LLC [Member] Midstream Investments (1)	Dec. 31, 2013 Southeast Supply Header LLC [Member] Midstream Investments (1)	Sep. 30, 2014 Enable Midstream Partners [Member]		Sep. 30, 2013 Enable Midstream Partners [Member]		Sep. 30, 2014 Enable Midstream Partners [Member]		Sep. 30, 2013 Enable Midstream Partners [Member]		Apr. 16, 2014 Enable Midstream Partners [Member]	Mar. 31, 2014 Enable Midstream Partners [Member]	Dec. 31, 2013 Enable Midstream Partners [Member]	Sep. 30, 2014 Enable Midstream Partners [Member] Midstream Investments (1)	Sep. 30, 2013 Enable Midstream Partners [Member] Midstream Investments (1)	Sep. 30, 2013 Enable Midstream Partners [Member] Midstream Investments (1)	Sep. 30, 2014 Enable Midstream Partners [Member] Midstream Investments (1)	Dec. 31, 2013 Enable Midstream Partners [Member] Midstream Investments (1)
Segment Reporting Information [Line Items]
Equity Method Investment, Additional Contribution of Ownership Percentage																																																																					0.10%				0.10%				25.05%								55.40%				55.40%				54.70%	58.30%
Revenues	$ 964	$ 891	$ 4,678	$ 3,979		$ 375	$ 375	$ 2,379	$ 1,942		$ 589	$ 516	$ 2,298	$ 1,726		$ 133	[1]			$ 178	[1]			$ 0	[2]	$ 0	[2]	$ 0	[2]	$ 0	[2]			$ 0	$ 0	$ 1	$ 0				$ (22)	$ (10)	$ (88)	$ (109)	$ (7)	$ (6)	$ (22)	$ (19)	$ (15)	$ (4)	$ (66)	$ (19)	$ (53)	[1]	$ (18)	[1]	$ 0	[2]	$ 0	[2]	$ 0	[2]	$ 0	[2]	$ 0	$ 0	$ 0	$ 0
Operating Income (Loss)	(3)	4	224	310		(8)	5	184	169		6	2	43	12		72	[1]			73	[1]			0	[2]	0	[2]	0	[2]	0	[2]			(1)	(3)	(3)	(16)
Assets	10,545		10,545		10,542	5,059		5,059		4,976	882		882		895			0	[1]			0	[1]	4,525	[2]			4,525	[2]			4,518	[2]	769		769		1,149	(690)	(996)
Equity in earnings of unconsolidated affiliates, net	79	80	241	122																																																																	0	[3]	3	[3]	5	[3]	12	[3]				1	3	5	5		79	[4]	77	[4]	236	[4]	110	[4]				79	77	110	236
Investment in unconsolidated affiliates	$ 4,525		$ 4,525		$ 4,518																																																																$ 1	[5]			$ 1	[5]				$ 199	[5]	$ 1			$ 1	$ 199	$ 4,524				$ 4,524						$ 4,319	$ 4,524			$ 4,524	$ 4,319

[1] Results reflected in the nine months ended September 30, 2013 represent only January 2013 through April 2013.

[2] Midstream Investments reported equity earnings of $79 million from Enable and less than $1 million of equity earnings from CERC’s retained interest in SESH for the three months ended September 30, 2014. Midstream Investments reported equity earnings of $236 million from Enable and $5 million of equity earnings from CERC’s retained interest in SESH for the nine months ended September 30, 2014. Midstream Investments reported equity earnings of $77 million from Enable and $3 million of equity earnings from CERC’s interest in SESH for the three months ended September 30, 2013. Midstream Investments reported equity earnings of $110 million from Enable and $5 million of equity earnings from CERC’s interest in SESH for the five months ended September 30, 2013. Included in total assets of Midstream Investments as of September 30, 2014 and December 31, 2013 is $4,524 million and $4,319 million, respectively, related to CERC’s investment in Enable and $1 million and $199 million, respectively, related to CERC’s interest in SESH.

[3] 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 September 30, 2014.

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

[5] 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 September 30, 2014.