Entity's interest in incentive distribution rights held by the general partner.

No definition available.

Name:	cnp_IncentiveDistributionRightPercentage
Namespace Prefix:	cnp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of management rights in the general partner of Enable

+ References

No definition available.

+ Details

Name:	cnp_ManagementRightsOwnershipPercentage
Namespace Prefix:	cnp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of States in which the Entity Performs Gas Delivery Services

+ References

No definition available.

+ Details

Name:	cnp_NumberofStatesinwhichtheEntityPerformsGasDeliveryServices
Namespace Prefix:	cnp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of Series A Preferred Units held as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	cnp_PreferredUnitsHeld
Namespace Prefix:	cnp_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=cnp_VectrenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=cnp_EnableMidstreamPartnersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PreferredUnitsByNameAxis=cnp_SeriesAPreferredUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=cnp_EnableGPLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cnp_NaturalGasDistributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cnp_CercCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cnp_EnergyServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Background (Details) $ in Millions		12 Months Ended
Background (Details) $ in Millions	Feb. 01, 2019 USD ($)	Dec. 31, 2019 USD ($) state shares	Dec. 31, 2018
Vectren [Member]
Cash paid to acquire Vectren \| $	$ 6,000	$ 5,982
Enable Midstream Partners [Member]
Ownership percentage of equity method investment		53.70%	54.00%
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%
Natural Gas Distribution [Member]
Number of States in which the Entity Performs Gas Delivery Services		48
CenterPoint Energy Resources Corp. \| Natural Gas Distribution [Member]
Number of states in which entity operates		6
Number of States in which the Entity Performs Gas Delivery Services		48
CenterPoint Energy Resources Corp. \| Energy Services [Member]
Number of states in which entity operates		30