Background (Details) $ in Billions			12 Months Ended
		Feb. 01, 2019 USD ($)	Dec. 31, 2018 state shares	Dec. 31, 2017
Vectren [Member] | Subsequent Event [Member]
Cash paid to acquire Vectren | $		$ 6
Enable Midstream Partners [Member]
Ownership percentage of equity method investment	[1],[2]		54.00%	54.10%
Enable Midstream Partners [Member] | Series A Preferred Units [Member]
Preferred units held | shares			14,520,000
Enable GP, LLC [Member]
Management rights ownership percentage			50.00%
Incentive distribution right			40.00%
CERC Corp [Member] | Enable Midstream Partners [Member]
Ownership percentage of equity method investment	[1],[2]			54.10%
CERC Corp [Member] | Enable GP, LLC [Member]
Management rights ownership percentage	[3],[4]			50.00%
Incentive distribution right	[4],[5]			40.00%
CERC Corp [Member] | Natural Gas Distribution [Member]
Number of states in which entity operates			6
CERC Corp [Member] | Energy Services [Member]
Number of states in which entity operates			30
CenterPoint Energy [Member] | Enable GP, LLC [Member]
Management rights ownership percentage	[3],[4]		50.00%	50.00%
Incentive distribution right	[4],[5]		40.00%	40.00%

[1] Excludes the Enable Series A Preferred Units owned by CenterPoint Energy.

[2] Prior to the Internal Spin on September 4, 2018 described above, CenterPoint Energy’s investment in Enable’s common units, excluding the Enable Series A Preferred Units held directly by CenterPoint Energy, was held indirectly through CERC.

[3] As of December 31, 2018, Enable is controlled jointly by CenterPoint Energy and OGE. Sale of CenterPoint Energy’s or OGE’s ownership interests in Enable GP to a third party is subject to mutual rights of first offer and first refusal, and CenterPoint Energy is not permitted to dispose of less than all of its interest in Enable GP.

[4] CenterPoint Energy held the management rights and incentive distributions rights in Enable GP indirectly through CERC until the Internal Spin on September 4, 2018 described above.

[5] Enable is expected to pay a minimum quarterly distribution of $0.2875 per common unit on its outstanding common units to the extent it has sufficient cash from operations after establishment of cash reserves and payment of fees and expenses, including payments to Enable GP and its affiliates, within 60 days after the end of each quarter. If cash distributions to Enable’s unitholders exceed $0.330625 per common unit in any quarter, Enable GP will receive increasing percentages or incentive distributions rights, up to 50%, of the cash Enable distributes in excess of that amount. In certain circumstances Enable GP will have the right to reset the minimum quarterly distribution and the target distribution levels at which the incentive distributions receive increasing percentages to higher levels based on Enable’s cash distributions at the time of the exercise of this reset election. To date, no incentive distributions have been made.