Unaudited Quarterly Information (Details) - USD ($) $ in Millions	3 Months Ended										12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues	$ 1,087	[1]	$ 799	[2]	$ 824	$ 1,817	$ 1,689	$ 964	$ 1,183	$ 2,531	$ 4,527	$ 6,367	$ 5,522
Operating Income (Loss)	108	[1]	18	[2]	27	160	111	(3)	39	188	313	335	401
Net Income (Loss)	(535)	[1]	(508)	[2]	$ 22	$ 109	$ 95	$ 28	$ 48	$ 152	$ (912)	$ 323	$ 64
Enable Midstream Partners [Member]
Impairment Charges	984		862
Impairment Charge, net of tax	$ 620		$ 537

[1] CERC recognized $984 million ($620 million after tax) in impairment charges related to Enable during the three months ended December 31, 2015.

[2] CERC recognized $862 million ($537 million after tax) in impairment charges related to Enable during the three months ended September 30, 2015.