CenterPoint Energy (CNP) 10-K 25 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	1-31447
Entity Registrant Name	CenterPoint Energy, Inc.
Entity Tax Identification Number	74-0694415
Entity Incorporation, State or Country Code	TX
Entity Address, Address Line One	1111 Louisiana
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	(713)
Local Phone Number	207-1111
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 10,142,624,694
Entity Common Stock, Shares Outstanding		551,579,922
Entity Central Index Key	0001130310
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Stock, $0.01 par value | New York Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	CNP
Security Exchange Name	NYSE
Common Stock, $0.01 par value | Chicago Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	CNP
Security Exchange Name	CHX
Depositary shares, each representing a 1/20th interest in a share of 7.00% Series B Mandatory Convertible Preferred Stock, $0.01 par value | New York Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	Depositary shares, each representing a 1/20th interest in a share of 7.00% Series B Mandatory Convertible Preferred Stock, $0.01 par value
Trading Symbol	CNP/PB
Security Exchange Name	NYSE
CenterPoint Energy Houston Electric, LLC
Entity Information [Line Items]
Entity File Number	1-3187
Entity Registrant Name	CenterPoint Energy Houston Electric, LLC
Entity Tax Identification Number	22-3865106
Entity Incorporation, State or Country Code	TX
Entity Address, Address Line One	1111 Louisiana
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	(713)
Local Phone Number	207-1111
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			0
Entity Common Stock, Shares Outstanding		1,000
Entity Central Index Key	0000048732
CenterPoint Energy Houston Electric, LLC | 9.15% First Mortgage Bonds due 2021 | New York Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	9.15% First Mortgage Bonds due 2021
Trading Symbol	n/a
Security Exchange Name	NYSE
CenterPoint Energy Houston Electric, LLC | 6.95% General Mortgage Bonds due 2033 | New York Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	6.95% General Mortgage Bonds due 2033
Trading Symbol	n/a
Security Exchange Name	NYSE
CenterPoint Energy Resources Corp.
Entity Information [Line Items]
Entity File Number	1-13265
Entity Registrant Name	CenterPoint Energy Resources Corp.
Entity Tax Identification Number	76-0511406
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	1111 Louisiana
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	(713)
Local Phone Number	207-1111
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 0
Entity Common Stock, Shares Outstanding		1,000
Entity Central Index Key	0001042773
CenterPoint Energy Resources Corp. | 6.625% Senior Notes due 2037 | New York Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	6.625% Senior Notes due 2037
Trading Symbol	n/a
Security Exchange Name	NYSE

STATEMENTS OF CONSOLIDATED INCO

STATEMENTS OF CONSOLIDATED INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Utility revenues	$ 7,049	$ 7,202	$ 6,199
Non-utility revenues	369	362	78
Total	7,418	7,564	6,277
Expenses:
Utility natural gas, fuel and purchased power	1,488	1,762	1,464
Non-utility cost of revenues, including natural gas	257	257	40
Operation and maintenance	2,744	2,775	2,271
Depreciation and amortization	1,189	1,225	1,230
Taxes other than income taxes	516	474	404
Goodwill impairment	185	0	0
Total	6,379	6,493	5,409
Operating Income	1,039	1,071	868
Other Income (Expense):
Gain (loss) on marketable securities	49	282	(22)
Loss on indexed debt securities	(60)	(292)	(232)
Interest expense and other finance charges	(501)	(528)	(361)
Interest expense on Securitization Bonds	(28)	(39)	(59)
Equity in earnings (loss) of unconsolidated affiliates, net	(1,428)	230	307
Interest Income	3	17	24
Interest Income on Securitization Bonds	1	5	4
Other income, net	60	28	22
Total	(1,904)	(297)	(317)
Income (Loss) from Continuing Operations Before Income Taxes	(865)	774	551
Income tax expense (benefit)	(274)	92	155
Income From Continuing Operations	(591)	682	396
Income (Loss) from Discontinued Operations	(182)	109	(28)
Net Income (Loss)	(773)	791	368
Income allocated to preferred shareholders	176	117	35
Income (Loss) Available to Common Shareholders	(949)	674	333
Supplemental Income Statement Elements [Abstract]
Income tax expense (benefit) from discontinued operations	$ 21	$ 46	$ (9)
Earnings Per Share, Basic [Abstract]
Basic earnings (loss) per common share - continuing operations	$ (1.45)	$ 1.12	$ 0.80
Basic earnings (loss) per common share - discontinued operations	(0.34)	0.22	(0.06)
Earnings Per Share, Basic	(1.79)	1.34	0.74
Earnings Per Share, Diluted [Abstract]
Diluted earnings (loss) per common share - continuing operations	(1.45)	1.12	0.80
Diluted earnings (loss) per common share - discontinued operations	(0.34)	0.21	(0.06)
Diluted Earnings (Loss) Per Common Share	$ (1.79)	$ 1.33	$ 0.74
Weighted Average Common Shares Outstanding, Basic	531,031,000	502,050,000	448,829,000
Weighted Average Common Shares Outstanding, Diluted	531,031,000	505,157,000	452,465,000
Houston Electric [Member]
Revenues:
Total	$ 2,911	$ 2,990	$ 3,234
Expenses:
Operation and maintenance	1,523	1,477	1,452
Depreciation and amortization	560	648	917
Taxes other than income taxes	252	247	240
Total	2,335	2,372	2,609
Operating Income	576	618	625
Other Income (Expense):
Interest expense and other finance charges	(171)	(164)	(138)
Interest expense on Securitization Bonds	(28)	(39)	(59)
Interest Income	2	22	1
Interest Income on Securitization Bonds	1	5	4
Other income, net	7	(6)	(8)
Total	(189)	(182)	(200)
Income (Loss) from Continuing Operations Before Income Taxes	387	436	425
Income tax expense (benefit)	53	80	89
Net Income (Loss)	334	356	336
CERC Corp [Member]
Revenues:
Utility revenues	2,711	2,951	2,967
Non-utility revenues	52	67	64
Total	2,763	3,018	3,031
Expenses:
Utility natural gas, fuel and purchased power	1,100	1,391	1,464
Non-utility cost of revenues, including natural gas	17	39	40
Operation and maintenance	798	824	833
Depreciation and amortization	304	293	280
Taxes other than income taxes	182	161	155
Total	2,401	2,708	2,772
Operating Income	362	310	259
Other Income (Expense):
Interest expense and other finance charges	(111)	(116)	(122)
Equity in earnings (loss) of unconsolidated affiliates, net	0	0	184
Interest Income	0	5	1
Other income, net	(7)	(13)	(9)
Total	(118)	(124)	(130)
Income (Loss) from Continuing Operations Before Income Taxes	244	186	129
Income tax expense (benefit)	97	(3)	31
Income From Continuing Operations	147	189	98
Income (Loss) from Discontinued Operations	(66)	23	110
Net Income (Loss)	81	212	208
Supplemental Income Statement Elements [Abstract]
Income tax expense (benefit) from discontinued operations	$ (2)	$ 17	$ 37

STATEMENTS OF CONSOLIDATED COMP

STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Income (Loss)	$ (773)	$ 791	$ 368
Other comprehensive income (loss):
Adjustment to pension and other postretirement plans	(5)	12	(10)
Net deferred gain (loss) from cash flow hedges	0	(2)	(15)
Reclassification of net deferred losses from cash flow hedges	15	0	0
Other comprehensive loss from unconsolidated affiliates, net of tax	(2)	(1)	0
Total	8	10	(25)
Comprehensive income (loss)	(765)	801	343
Income allocated to preferred shareholders	176	117	35
Comprehensive income (loss) available to common shareholders	(941)	684	308
Supplemental Income Statement Elements [Abstract]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent	0	4	(2)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	0	(1)	(4)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	0	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	4	0	0
Other comprehensive loss from unconsolidated affiliates, tax	0	0	0
Houston Electric [Member]
Net Income (Loss)	334	356	336
Other comprehensive income (loss):
Net deferred gain (loss) from cash flow hedges	0	(1)	(14)
Reclassification of net deferred losses from cash flow hedges	15	0	0
Total	15	(1)	(14)
Comprehensive income (loss) available to common shareholders	349	355	322
Supplemental Income Statement Elements [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	0	0	(4)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	4	0	0
CERC Corp [Member]
Net Income (Loss)	81	212	208
Other comprehensive income (loss):
Adjustment to pension and other postretirement plans	0	5	1
Net deferred gain (loss) from cash flow hedges	0	0	(1)
Total	0	5	0
Comprehensive income (loss) available to common shareholders	81	217	208
Supplemental Income Statement Elements [Abstract]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent	1	2	1
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	$ 0	$ 0	$ 0

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 147	$ 241
Investment in marketable securities	871	822
Accounts receivable	676	702
Accrued Unbilled Revenues	505	469
Natural gas and coal inventory	203	209
Materials and supplies	297	263
Taxes receivable	82	106
Current assets held for sale	0	1,002
Prepaid expense and other current assets	139	123
Total current assets	2,920	3,937
Property, Plant and Equipment, net
Property, Plant and Equipment, Gross	32,514	30,324
Accumulated Depreciation, and Amortization	10,152	9,700
Property, Plant and Equipment, Net, Total	22,362	20,624
Other Assets:
Goodwill	4,697	4,882
Regulatory assets	2,094	2,117
Investment in unconsolidated affiliates	783	2,408
Preferred units - unconsolidated affiliate	363	363
Non-current assets held for sale	0	962
Other	252	236
Total other assets	8,189	10,968
Total Assets	33,471	35,529
Current Liabilities:
Short-term borrowings	24	0
Current portion of VIE Securitization Bonds long-term debt	211	231
Indexed debt, net	15	19
Current portion of other long-term debt	1,669	618
Indexed debt securities derivative	953	893
Accounts payable	853	884
Taxes accrued	265	239
Interest accrued	145	158
Dividends accrued	136	0
Customer deposits	119	124
Non-trading derivative liabilities	3	7
Current liabilities held for sale	0	455
Other	432	350
Total current liabilities	4,825	3,978
Other Liabilities:
Deferred income taxes, net	3,603	3,928
Non-trading derivative liabilities	27	15
Benefit obligations	680	750
Regulatory liabilities	3,448	3,474
Non-current liabilities held for sale	0	43
Other	1,019	738
Total other liabilities	8,777	8,948
Long-term Debt:
VIE Securitization Bonds, net	536	746
Other long-term debt, net	10,985	13,498
Total long-term debt, net	11,521	14,244
Commitments and Contingencies
Shareholders’ Equity:
Common stock	6	5
Additional paid-in capital	6,914	6,080
Retained earnings (accumulated deficit)	(845)	632
Accumulated other comprehensive income (loss)	(90)	(98)
Total shareholders’ equity	8,348	8,359
Total Liabilities and Shareholders’ Equity	33,471	35,529
Supplemental Income Statement Elements [Abstract]
Bad debt reserve	52	21
Accrued Unbilled Revenues, Allowance for Credit Losses, Current	5	0
Cumulative preferred stock, $0.01 par value, 20,000,000 shares authorized
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common stock, $0.01 par value	$ 0.01	$ 0.01
Common Stock, Shares, Outstanding	551,355,861	502,242,061
Variable Interest Entity, Primary Beneficiary [Member]
Current Assets:
Cash and cash equivalents	$ 139	$ 216
Accounts receivable	23	26
Prepaid expense and other current assets	15	19
Other Assets:
Regulatory assets	633	788
Houston Electric [Member]
Current Assets:
Cash and cash equivalents	139	216
Accounts and notes receivable, net	268	238
Accounts and notes receivable—affiliated companies	7	523
Accrued Unbilled Revenues	113	117
Materials and supplies	195	147
Prepaid expense and other current assets	47	49
Total current assets	769	1,290
Property, Plant and Equipment, net
Property, Plant and Equipment, Gross	13,593	12,829
Accumulated Depreciation, and Amortization	3,930	3,797
Property, Plant and Equipment, Net, Total	9,663	9,032
Other Assets:
Regulatory assets	848	915
Other	36	25
Total other assets	884	940
Total Assets	11,316	11,262
Current Liabilities:
Current portion of VIE Securitization Bonds long-term debt	211	231
Current portion of other long-term debt	402	0
Accounts payable	281	268
Accounts payable - affiliated companies	96	76
Taxes accrued	158	123
Interest accrued	71	69
Other	117	63
Total current liabilities	1,336	830
Other Liabilities:
Deferred income taxes, net	1,041	1,030
Benefit obligations	75	75
Regulatory liabilities	1,252	1,288
Other	95	69
Total other liabilities	2,463	2,462
Long-term Debt:
VIE Securitization Bonds, net	536	746
Other long-term debt, net	3,870	3,973
Total long-term debt, net	4,406	4,719
Commitments and Contingencies
Shareholders’ Equity:
Common stock	0	0
Additional paid-in capital	2,548	2,486
Retained earnings (accumulated deficit)	563	780
Accumulated other comprehensive income (loss)	0	(15)
Total shareholders’ equity	3,111	3,251
Total Liabilities and Shareholders’ Equity	11,316	11,262
Supplemental Income Statement Elements [Abstract]
Bad debt reserve	1	1
Houston Electric [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Current Assets:
Cash and cash equivalents	139	216
Accounts receivable	23	26
Prepaid expense and other current assets	15	19
Other Assets:
Regulatory assets	633	788
CERC Corp [Member]
Current Assets:
Cash and cash equivalents	1	2
Accounts receivable	233	322
Accounts and notes receivable—affiliated companies	8	10
Accrued Unbilled Revenues	260	249
Natural gas and coal inventory	121	135
Materials and supplies	58	71
Current assets held for sale	0	691
Prepaid expense and other current assets	26	9
Total current assets	707	1,489
Property, Plant and Equipment, net
Property, Plant and Equipment, Gross	8,972	8,079
Accumulated Depreciation, and Amortization	2,414	2,270
Property, Plant and Equipment, Net, Total	6,558	5,809
Other Assets:
Goodwill	757	757
Regulatory assets	220	191
Non-current assets held for sale	0	213
Other	66	53
Total other assets	1,043	1,214
Total Assets	8,308	8,512
Current Liabilities:
Short-term borrowings	24	0
Accounts payable	296	333
Accounts payable - affiliated companies	50	47
Taxes accrued	74	84
Interest accrued	28	38
Customer deposits	76	74
Current liabilities held for sale	0	368
Other	178	167
Total current liabilities	726	1,111
Other Liabilities:
Deferred income taxes, net	584	470
Benefit obligations	83	80
Regulatory liabilities	1,226	1,219
Non-current liabilities held for sale	0	27
Other	694	418
Total other liabilities	2,587	2,214
Long-term Debt:
Total long-term debt, net	2,428	2,546
Commitments and Contingencies
Shareholders’ Equity:
Common stock	0	0
Additional paid-in capital	2,046	2,116
Retained earnings (accumulated deficit)	511	515
Accumulated other comprehensive income (loss)	10	10
Total shareholders’ equity	2,567	2,641
Total Liabilities and Shareholders’ Equity	8,308	8,512
Supplemental Income Statement Elements [Abstract]
Bad debt reserve	45	15
Accrued Unbilled Revenues, Allowance for Credit Losses, Current	4	0
Series A Preferred Stock [Member]
Shareholders’ Equity:
Preferred Stock	$ 790	$ 790
Supplemental Income Statement Elements [Abstract]
Preferred Stock, $0.01 par value	$ 0.01	$ 0.01
Preferred stock aggregate liquidation preference	$ 800	$ 800
Preferred stock outstanding (in shares)	800,000	800,000
Series B Preferred Stock [Member]
Shareholders’ Equity:
Preferred Stock	$ 950	$ 950
Supplemental Income Statement Elements [Abstract]
Preferred Stock, $0.01 par value	$ 0.01	$ 0.01
Preferred stock aggregate liquidation preference	$ 977	$ 977
Preferred stock outstanding (in shares)	977,400	977,400
Series C Preferred Stock [Member]
Shareholders’ Equity:
Preferred Stock	$ 623	$ 0
Supplemental Income Statement Elements [Abstract]
Preferred Stock, $0.01 par value	$ 0.01	$ 0.01
Preferred stock aggregate liquidation preference	$ 625
Preferred stock outstanding (in shares)	625,000
Cumulative Preferred Stock [Member]
Supplemental Income Statement Elements [Abstract]
Preferred Stock, $0.01 par value	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000	20,000,000

STATEMENTS OF CONSOLIDATED CASH

STATEMENTS OF CONSOLIDATED CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net Income (Loss)	$ (773)	$ 791	$ 368
Net income (loss) from Discontinued Operations	(182)	109	(28)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,189	1,225	1,230
Depreciation and amortization on assets held for sale	0	62	13
Amortization of deferred financing costs	28	29	48
Deferred income taxes	(429)	69	48
Amortization of intangible assets in Non-utility cost of revenues	2	24	0
Goodwill impairment and loss from reclassification to held for sale	175	48	0
Goodwill impairment	185	0	0
Loss on early extinguishment of debt	2	0	0
Unrealized loss (gain) on marketable securities	(49)	(282)	22
Loss (gain) on indexed debt securities	60	292	232
Write-down of natural gas inventory	3	4	2
Equity in earnings of unconsolidated affiliates	1,428	(230)	(307)
Distributions from unconsolidated affiliates	113	261	267
Pension contributions	(86)	(109)	(69)
Changes in other assets and liabilities, excluding acquisitions:
Accounts receivable and unbilled revenues, net	90	226	(154)
Inventory	9	(52)	1
Taxes receivable	24	(106)	0
Accounts payable	2	(455)	220
Fuel cost recovery	(21)	92	33
Non-trading derivatives, net	0	(64)	103
Margin deposits, net	72	(56)	5
Interest and taxes accrued	24	54	40
Net regulatory assets and liabilities	(86)	(114)	28
Other current assets	(20)	(22)	0
Other current liabilities	28	(107)	(24)
Other assets	12	103	6
Other liabilities	13	(54)	12
Other, net	0	9	12
Net cash provided by operating activities	1,995	1,638	2,136
Cash Flows from Investing Activities:
Capital expenditures	(2,596)	(2,506)	(1,651)
Acquisitions, net of cash acquired	0	(5,991)	0
Distributions from unconsolidated affiliates in excess of cumulative earnings	80	42	30
Proceeds from sale of marketable securities	0	0	398
Proceeds from divestitures (Note 4)	1,215	0	0
Proceeds from sale of assets	0	5	0
Purchase of investments	0	(6)	0
Other, net	36	35	16
Net Cash Provided by (Used in) Investing Activities	(1,265)	(8,421)	(1,207)
Cash Flows from Financing Activities:
Decrease in short-term borrowings, net	0	0	(39)
Proceeds from Lines of Credit	1,050	135	0
Repayments of Lines of Credit	(1,050)	(135)	0
Proceeds from (payments of) commercial paper, net	(761)	1,891	(1,543)
Proceeds from long-term debt	799	2,916	2,495
Payments of long-term debt	(1,724)	(1,302)	(484)
Payment of debt issuance costs	(8)	(20)	(47)
Payment of dividends on Common Stock	(392)	(577)	(499)
Payment of dividends on preferred stock	(137)	(118)	(11)
Proceeds from issuance of Common Stock, net	672	0	1,844
Proceeds from Issuance of Preferred Stock and Preference Stock	723	0	1,740
Distribution to ZENS holders	0	0	(398)
Other, net	(6)	(14)	(5)
Net cash provided by (used in) financing activities	(834)	2,776	3,053
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	(104)	(4,007)	3,982
Cash, Cash Equivalents and Restricted Cash at Beginning of Year	271	4,278	296
Cash, Cash Equivalents and Restricted Cash at End of Year	167	271	4,278
Houston Electric [Member]
Cash Flows from Operating Activities:
Net Income (Loss)	334	356	336
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	560	648	917
Amortization of deferred financing costs	11	12	11
Deferred income taxes	(42)	(24)	(38)
Changes in other assets and liabilities, excluding acquisitions:
Accounts receivable and unbilled revenues, net	(26)	38	11
Accounts receivable/payable–affiliated companies	47	(23)	20
Inventory	(48)	(12)	(16)
Taxes receivable	0	5	(5)
Accounts payable	28	13	(1)
Non-trading derivatives, net	15	(25)	5
Interest and taxes accrued	43	13	(2)
Net regulatory assets and liabilities	(11)	(48)	(97)
Other current assets	(8)	(5)	(2)
Other current liabilities	5	(9)	(26)
Other assets	(7)	5	(3)
Other liabilities	11	(12)	17
Other, net	(13)	(14)	(12)
Net cash provided by operating activities	899	918	1,115
Cash Flows from Investing Activities:
Capital expenditures	(1,058)	(1,025)	(922)
(Increase) decrease in notes receivable–affiliated companies	481	(481)	0
Other, net	13	11	11
Net Cash Provided by (Used in) Investing Activities	(564)	(1,495)	(911)
Cash Flows from Financing Activities:
Proceeds from long-term debt	299	696	398
Payments of long-term debt	(231)	(458)	(434)
Dividend to parent	(551)	(376)	(209)
Increase (decrease) in notes payable–affiliated companies	8	(1)	(59)
Debt issuance costs	(3)	(8)	(4)
Contribution from parent	62	590	200
Other, net	0	(1)	0
Net cash provided by (used in) financing activities	(416)	442	(108)
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	(81)	(135)	96
Cash, Cash Equivalents and Restricted Cash at Beginning of Year	235	370	274
Cash, Cash Equivalents and Restricted Cash at End of Year	154	235	370
CERC Corp [Member]
Cash Flows from Operating Activities:
Net Income (Loss)	81	212	208
Net income (loss) from Discontinued Operations	(66)	23	110
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	304	293	280
Depreciation and amortization on assets held for sale	0	12	13
Amortization of deferred financing costs	8	9	9
Deferred income taxes	91	7	64
Goodwill impairment and loss from reclassification to held for sale	93	48	0
Loss on early extinguishment of debt	2	0	0
Write-down of natural gas inventory	3	4	2
Equity in earnings of unconsolidated affiliates	0	0	(184)
Distributions from unconsolidated affiliates	0	0	176
Changes in other assets and liabilities, excluding acquisitions:
Accounts receivable and unbilled revenues, net	151	252	(155)
Accounts receivable/payable–affiliated companies	4	(6)	9
Inventory	63	(12)	17
Accounts payable	(72)	(305)	163
Fuel cost recovery	(21)	86	33
Non-trading derivatives, net	(12)	(60)	98
Margin deposits, net	65	(56)	5
Interest and taxes accrued	(15)	2	13
Net regulatory assets and liabilities	(31)	(10)	50
Other current assets	(1)	1	4
Other current liabilities	10	22	(3)
Other assets	15	5	5
Other liabilities	(1)	(38)	6
Other, net	(8)	0	1
Net cash provided by operating activities	729	466	814
Cash Flows from Investing Activities:
Capital expenditures	(815)	(776)	(633)
(Increase) decrease in notes receivable–affiliated companies	(9)	114	(114)
Distributions from unconsolidated affiliates in excess of cumulative earnings	0	0	47
Proceeds from divestitures (Note 4)	365
Other, net	7	0	3
Net Cash Provided by (Used in) Investing Activities	(452)	(662)	(697)
Cash Flows from Financing Activities:
Decrease in short-term borrowings, net	0	0	(39)
Proceeds from (payments of) commercial paper, net	(30)	167	(688)
Proceeds from long-term debt	500	0	599
Payments of long-term debt	(593)	0	0
Dividend to parent	(80)	(120)	(360)
Increase (decrease) in notes payable–affiliated companies	0	0	(570)
Debt issuance costs	(4)	0	(5)
Contribution from parent	217	129	960
Capital distribution to parent associated with the sale of CES	(286)	0	0
Other, net	(2)	(3)	(1)
Net cash provided by (used in) financing activities	(278)	173	(104)
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	(1)	(23)	13
Cash, Cash Equivalents and Restricted Cash at Beginning of Year	2	25	12
Cash, Cash Equivalents and Restricted Cash at End of Year	$ 1	$ 2	$ 25

STATEMENTS OF CONSOLIDATED SHAR

STATEMENTS OF CONSOLIDATED SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Series A Preferred Stock [Member]	Series B Preferred Stock [Member]	Series C Preferred Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member]Series A Preferred Stock [Member]	Preferred Stock [Member]Series B Preferred Stock [Member]	Preferred Stock [Member]Series C Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Common Stock [Member]	Retained Earnings [Member]	Retained Earnings [Member]Series A Preferred Stock [Member]	Retained Earnings [Member]Series B Preferred Stock [Member]	Retained Earnings [Member]Series C Preferred Stock [Member]	AOCI Attributable to Parent [Member]	Houston Electric [Member]	Houston Electric [Member]Common Stock [Member]	Houston Electric [Member]Additional Paid-in Capital [Member]	Houston Electric [Member]Retained Earnings [Member]	Houston Electric [Member]AOCI Attributable to Parent [Member]	CERC Corp [Member]	CERC Corp [Member]Common Stock [Member]	CERC Corp [Member]Additional Paid-in Capital [Member]	CERC Corp [Member]Additional Paid-in Capital [Member]Discontinued Operations [Member]	CERC Corp [Member]Retained Earnings [Member]	CERC Corp [Member]AOCI Attributable to Parent [Member]
Balance, beginning of year at Dec. 31, 2017					0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of stock						1,000,000	1,000,000	0	70,000,000
Balance, end of year at Dec. 31, 2018					2,000,000
Balance, beginning of year at Dec. 31, 2017									431,000,000									1,000					1,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans									0
Balance, end of year at Dec. 31, 2018									501,000,000									1,000					1,000
Balance, beginning of year at Dec. 31, 2017					$ 0				$ 4	$ 4,209		$ 543				$ (68)		$ 0	$ 1,696	$ 673	$ 0		$ 0	$ 2,528		$ 574	$ 6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans									0	19
Issuances of stock						$ 790	$ 950	$ 0	1		$ 1,844
Number of depositary shares eligible for conversion (in shares)				0
Conversion of Stock, Amount Converted				$ 0
Conversion of Stock, Amount Issued								$ 0
Contribution From Parent																			200					960
Other																								0	$ 0
Capital distribution to parent associated with Internal Spin																								(1,473)
Net Income (Loss)	$ 368											368					$ 336			336		$ 208				208
Common Stock dividends declared (see Note 13)												(523)
Preferred stock dividends declared		$ (26)	$ (28)										$ (26)	$ (28)	$ 0
Adoption of ASU 2018-02 | Accounting Standards Update 2016-13 [Member]												0														0
Adoption of ASU 2018-02 | Accounting Standards Update 2018-02												15				(15)										1	(1)
Dividend to parent																				(209)						(360)
Other comprehensive income (loss)																(25)					(14)						0
Balance, end of year at Dec. 31, 2018	8,058				$ 1,740				$ 5	6,072		349				(108)	2,682	$ 0	1,896	800	(14)	2,443	$ 0	2,015		423	5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amortization of Beneficial Conversion Feature	0											0					0					0
Beneficial Conversion Feature	$ 0									0							0					0
Preferred Stock, $0.01 par value		$ 0.01	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000
Common stock, $0.01 par value	$ 0.01
Common Stock, Shares Authorized	1,000,000,000
Issuances of stock						0	0	0	0
Balance, end of year at Dec. 31, 2019		800,000	977,400		2,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans									1,000,000
Balance, end of year at Dec. 31, 2019	502,242,061								502,000,000									1,000					1,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans									$ 0	8
Issuances of stock						$ 0	$ 0	$ 0	0		0
Number of depositary shares eligible for conversion (in shares)				0
Conversion of Stock, Amount Converted				$ 0
Conversion of Stock, Amount Issued							$ 0	$ 0
Contribution From Parent																			590					129
Other																								0	0
Capital distribution to parent associated with Internal Spin																								(28)
Net Income (Loss)	$ 791											791					356			356		212				212
Common Stock dividends declared (see Note 13)												(433)
Preferred stock dividends declared		$ (24)	$ (51)										(24)	(51)	0
Adoption of ASU 2018-02 | Accounting Standards Update 2016-13 [Member]												0														0
Adoption of ASU 2018-02 | Accounting Standards Update 2018-02												0				0										0	0
Dividend to parent																				(376)						(120)
Other comprehensive income (loss)																10					(1)						5
Balance, end of year at Dec. 31, 2019	8,359				$ 1,740				$ 5	6,080		632				(98)	3,251	$ 0	2,486	780	(15)	2,641	$ 0	2,116		515	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amortization of Beneficial Conversion Feature	0											0					0					0
Beneficial Conversion Feature	$ 0									0							0					0
Preferred Stock, $0.01 par value		$ 0.01	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000
Common stock, $0.01 par value	$ 0.01
Common Stock, Shares Authorized	1,000,000,000
Issuances of stock						0	0	1,000,000	48,000,000
Balance, end of year at Dec. 31, 2020		800,000	977,400	625,000	3,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans									1,000,000
Balance, end of year at Dec. 31, 2020	551,355,861								551,000,000									1,000					1,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances related to benefit and investment plans									$ 0	30
Issuances of stock						$ 0	$ 0	$ 723	1		$ 672
Number of depositary shares eligible for conversion (in shares)				0
Conversion of Stock, Amount Converted				$ (100)
Conversion of Stock, Amount Issued							$ 100	$ 100
Contribution From Parent																			62					217
Other																								(1)	$ (286)
Capital distribution to parent associated with Internal Spin																								0
Net Income (Loss)	$ (773)											(773)					334			334		81				81
Common Stock dividends declared (see Note 13)												(480)
Preferred stock dividends declared		$ (73)	$ (85)	$ (27)									$ (73)	$ (85)	$ (27)
Adoption of ASU 2018-02 | Accounting Standards Update 2016-13 [Member]												7														(5)
Adoption of ASU 2018-02 | Accounting Standards Update 2018-02												0				0										0	0
Dividend to parent																				(551)						(80)
Other comprehensive income (loss)																8					15						0
Balance, end of year at Dec. 31, 2020	8,348				$ 2,363				$ 6	6,914		(845)				$ (90)	3,111	$ 0	$ 2,548	$ 563	$ 0	2,567	$ 0	$ 2,046		$ 511	$ 10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amortization of Beneficial Conversion Feature	(32)											$ (32)					0					0
Beneficial Conversion Feature	$ 32									$ 32							$ 0					$ 0
Preferred Stock, $0.01 par value		$ 0.01	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000
Common stock, $0.01 par value	$ 0.01
Common Stock, Shares Authorized	1,000,000,000

Background

Background	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background [Text Block]	Background General. This combined Form 10-K is filed separately by three registrants: CenterPoint Energy, Inc., CenterPoint Energy Houston Electric, LLC and CenterPoint Energy Resources Corp. Information contained herein relating to any individual registrant is filed by such registrant solely on its own behalf. Each registrant makes no representation as to information relating exclusively to the other Registrants or the subsidiaries of CenterPoint Energy other than itself or its subsidiaries. Except as discussed in Note 14 to the Registrants’ Consolidated Financial Statements, no registrant has an obligation in respect of any other Registrant’s debt securities, and holders of such debt securities should not consider the financial resources or results of operations of any Registrant other than the obligor in making a decision with respect to such securities. Included in this combined Form 10-K are the Financial Statements of CenterPoint Energy, Houston Electric and CERC, which are referred to collectively as the Registrants. The Combined Notes to the Consolidated Financial Statements apply to all Registrants and specific references to Houston Electric and CERC herein also pertain to CenterPoint Energy, unless otherwise indicated. Background. CenterPoint Energy, Inc. is a public utility holding company and owns interests in Enable as described below. As of December 31, 2020, CenterPoint Energy’s operating subsidiaries were as follows: • Houston Electric owns and operates electric transmission and distribution facilities in the Texas Gulf Coast area that includes the city of Houston; and • CERC Corp. (i) owns and operates natural gas distribution systems in six states, (ii) owns and operates permanent pipeline connections through interconnects with various interstate and intrastate pipeline companies through CEIP; and (iii) provides temporary delivery of LNG and CNG throughout the contiguous 48 states through MES. • Vectren holds three public utilities through its wholly-owned subsidiary, VUHI, a public utility holding company: ◦ Indiana Gas provides energy delivery services to natural gas customers located in central and southern Indiana; ◦ SIGECO provides energy delivery services to electric and natural gas customers located in and near Evansville in southwestern Indiana and owns and operates electric generation assets to serve its electric customers and optimizes those assets in the wholesale power market; and ◦ VEDO provides energy delivery services to natural gas customers located in and near Dayton in west-central Ohio. • Vectren performs non-utility activities through ESG, which provides energy performance contracting and sustainable infrastructure services, such as renewables, distributed generation and combined heat and power projects. For a description of CenterPoint Energy’s reportable segments, see Note 18. Houston Electric consists of a single reportable segment, Houston Electric T&D and CERC consists of a single reportable segment, Natural Gas. As of December 31, 2020, CenterPoint Energy, indirectly through CNP Midstream, owned approximately 53.7% of the common units representing limited partner interests in Enable, 50% of the management rights and 40% of the incentive distribution rights in Enable GP and also directly owned an aggregate of 14,520,000 Enable Series A Preferred Units. Enable owns, operates and develops natural gas and crude oil infrastructure assets. On February 16, 2021, Enable entered into the Enable Merger Agreement. At the closing of the transactions contemplated by the Enable Merger Agreement, if and when it occurs, Energy Transfer will acquire all of Enable’s outstanding equity interests, including all Enable common units and Enable Series A Preferred Units held by CenterPoint Energy, and in return CenterPoint Energy will receive Energy Transfer common units and Energy Transfer Series G Preferred Units. For further information regarding Enable and the Enable Merger, see Notes 11 and 22. Discontinued Operations. On February 3, 2020, CenterPoint Energy, through its subsidiary VUSI, entered into the Securities Purchase Agreement to sell the Infrastructure Services Disposal Group. The transaction closed on April 9, 2020 for $854 million in cash, inclusive of cash received after closing for the working capital adjustment. For further information, see Note 4.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies (a) Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. (b) Principles of Consolidation The accounts of the Registrants and their wholly-owned and majority-owned and controlled subsidiaries are included in the consolidated financial statements. All intercompany transactions and balances are eliminated in consolidation, except as described below. Businesses within the Infrastructure Services Disposal Group provided underground pipeline construction and repair services for customers that included Natural Gas utilities. In accordance with consolidation guidance in ASC 980—Regulated Operations, costs incurred by Natural Gas utilities for these pipeline construction and repair services were not eliminated in consolidation when capitalized and included in rate base by the Natural Gas utility. On February 3, 2020, CenterPoint Energy, through its subsidiary VUSI, entered into the Securities Purchase Agreement to sell the Infrastructure Services Disposal Group. The transaction closed on April 9, 2020. For further information, see Note 4. As of December 31, 2020, CenterPoint Energy and Houston Electric had VIEs consisting of the Bond Companies, which are consolidated. The consolidated VIEs are wholly-owned, bankruptcy remote special purpose entities that were formed solely for the purpose of securitizing transition and system restoration related property. Creditors of CenterPoint Energy and Houston Electric have no recourse to any assets or revenues of the Bond Companies. The bonds issued by these VIEs are payable only from and secured by transition and system restoration property and the bondholders have no recourse to the general credit of CenterPoint Energy or Houston Electric. (c) Equity Method and Investments without a Readily Determinable Fair Value (CenterPoint Energy) CenterPoint Energy uses the equity method for investments in entities when it exercises significant influence, does not have control and is not considered the primary beneficiary, if applicable. Generally, equity investments in limited partnerships with interest greater than approximately 3-5% is accounted for under the equity method. Under the equity method, CenterPoint Energy adjusts its investments each period for contributions made, distributions received, respective shares of comprehensive income and amortization of basis differences, as appropriate. CenterPoint Energy evaluates its equity method investments for impairment when events or changes in circumstances indicate there is a loss in value of the investment that is other than a temporary decline. CenterPoint Energy considers distributions received from equity method investments which do not exceed cumulative equity in earnings subsequent to the date of investment to be a return on investment and classifies these distributions as operating activities in its Statements of Consolidated Cash Flows. CenterPoint Energy considers distributions received from equity method investments in excess of cumulative equity in earnings subsequent to the date of investment to be a return of investment and classifies these distributions as investing activities in its Statements of Consolidated Cash Flows. Investments without a readily determinable fair value will be measured at cost, less impairment, plus or minus observable prices changes of an identical or similar investment of the same issuer. (d) Revenues The Registrants record revenue for electricity delivery and natural gas sales and services under the accrual method and these revenues are recognized upon delivery to customers. Electricity deliveries not billed by month-end are accrued based on actual AMS data, daily supply volumes and applicable rates. Natural gas sales not billed by month-end are accrued based upon estimated purchased gas volumes, estimated lost and unaccounted for gas and currently effective tariff rates. For further discussion, see Note 5. (e) MISO Transactions Indiana Electric is a member of the MISO. MISO-related purchase and sale transactions are recorded using settlement information provided by the MISO. These purchase and sale transactions are accounted for on at least a net hourly position, meaning net purchases within that interval are recorded on CenterPoint Energy’s Statements of Consolidated Income in Utility natural gas, fuel and purchased power, and net sales within that interval are recorded on CenterPoint Energy’s Statements of Consolidated Income in Utility revenues. On occasion, prior period transactions are resettled outside the routine process due to a change in the MISO’s tariff or a material interpretation thereof. Expenses associated with resettlements are recorded once the resettlement is probable and the resettlement amount can be estimated. Revenues associated with resettlements are recognized when the amount is determinable and collectability is reasonably assured. (f) Guarantees CenterPoint Energy recognizes guarantee obligations at fair value. CenterPoint Energy discloses parent company guarantees of a subsidiary’s obligation when that guarantee results in the exposure of a material obligation of the parent company even if the probability of fulfilling such obligation is considered remote. See Note 16(c) and (d). (g) Long-lived Assets, Goodwill and Intangibles The Registrants record property, plant and equipment at historical cost and expense repair and maintenance costs as incurred. The Registrants periodically evaluate long-lived assets, including property, plant and equipment, and specifically identifiable intangibles subject to amortization, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. For rate regulated businesses, recoverability of long-lived assets is assessed by determining if a capital disallowance from a regulator is probable through monitoring the outcome of rate cases and other proceedings. For non-rate regulated businesses, recoverability is assessed based on an estimate of undiscounted cash flows attributable to the assets compared to the carrying value of the assets. No long-lived asset or intangible asset impairments were recorded in 2020, 2019 or 2018. CenterPoint Energy and CERC perform goodwill impairment tests at least annually and evaluate goodwill when events or changes in circumstances indicate that its carrying value may not be recoverable. CenterPoint Energy and CERC recognize a goodwill impairment by the amount a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill within that reporting unit. CenterPoint Energy includes deferred tax assets and liabilities within its reporting unit’s carrying value for the purposes of annual and interim impairment tests, regardless of whether the estimated fair value reflects the disposition of such assets and liabilities. For further information about the goodwill impairment tests during 2020, see Note 6. (h) Assets Held for Sale and Discontinued Operations Generally, a long-lived asset to be sold is classified as held for sale in the period in which management, with approval from the Board of Directors, as applicable, commits to a plan to sell and a sale is expected to be completed within one year. The Registrants record assets and liabilities held for sale at the lower of their carrying value or their estimated fair value less cost to sell. If the disposal group reflects a component of a reporting unit and meets the definition of a business, the goodwill within that reporting unit is allocated to the disposal group based on the relative fair value of the components representing a business that will be retained and disposed. Goodwill is not allocated to a portion of a reporting unit that does not meet the definition of a business. A disposal group that meets the held for sale criteria and also represents a strategic shift to the Registrant, is also reflected as discontinued operations on the Statements of Consolidated Income, and prior periods are recast to reflect the earnings or losses from such businesses as income from discontinued operations, net of tax. (i) Regulatory Assets and Liabilities The Registrants apply the guidance for accounting for regulated operations within the Electric reportable segment and the Natural Gas reportable segment. The Registrants’ rate-regulated subsidiaries may collect revenues subject to refund pending final determination in rate proceedings. In connection with such revenues, estimated rate refund liabilities are recorded which reflect management’s current judgment of the ultimate outcomes of the proceedings. The Registrants’ rate-regulated businesses recognize removal costs as a component of depreciation expense in accordance with regulatory treatment. In addition, a portion of the amount of removal costs collected from customers that relate to AROs has been reflected as an asset retirement liability in accordance with accounting guidance for AROs. For further detail on the Registrants’ regulatory assets and liabilities, see Note 7. (j) Depreciation and Amortization Expense The Registrants compute depreciation and amortization using the straight-line method based on economic lives or regulatory-mandated recovery periods. Amortization expense includes amortization of certain regulatory assets and other intangibles. (k) Capitalization of Interest and AFUDC The Registrants capitalize interest and AFUDC as a component of projects under construction and amortize it over the assets’ estimated useful lives once the assets are placed in service. AFUDC represents the composite interest cost of borrowed funds and a reasonable return on the equity funds used for construction for subsidiaries that apply the guidance for accounting for regulated operations. Although AFUDC increases both utility plant and earnings, it is realized in cash when the assets are included in rates. Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Interest and AFUDC debt (1) $ 27 $ 8 $ 3 $ 36 $ 8 $ 3 $ 8 $ 6 $ 2 AFUDC equity (2) 25 14 3 22 15 3 12 10 2 (1) Included in Interest and other finance charges on the Registrants’ respective Statements of Consolidated Income. (2) Included in Other Income (Expense) on the Registrants’ respective Statements of Consolidated Income. (l) Income Taxes Houston Electric and CERC are included in CenterPoint Energy’s U.S. federal consolidated income tax return. Houston Electric and CERC report their income tax provision on a separate entity basis pursuant to a tax sharing agreement with CenterPoint Energy. Current federal and certain state income taxes are payable to or receivable from CenterPoint Energy. The Registrants use the asset and liability method of accounting for deferred income taxes. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. A valuation allowance is established against deferred tax assets for which management believes realization is not considered to be more likely than not. The Registrants recognize interest and penalties as a component of income tax expense (benefit), as applicable, in their respective Statements of Consolidated Income. CenterPoint Energy reports the income tax provision associated with its interest in Enable in income tax expense (benefit) in its Statements of Consolidated Income. To the extent certain EDIT of the Registrants’ rate-regulated subsidiaries may be recoverable or payable through future rates, regulatory assets and liabilities have been recorded, respectively. See Note 15 for further discussion of the impacts of tax reform implementation. The Registrants use the portfolio approach to recognize income tax effects on other comprehensive income from accumulated other comprehensive income. Investment tax credits are deferred and amortized to income over the approximate lives of the related property. (m) Accounts Receivable and Allowance for Credit Losses Accounts receivable are recorded at the invoiced amount and do not bear interest. Management reviews historical write-offs, current available information, and reasonable and supportable forecasts to estimate and establish allowance for credit losses. Account balances are charged off against the allowance when management determines it is probable the receivable will not be recovered. See Note 7 for further information about regulatory deferrals of bad debt expense related to COVID-19. (n) Inventory The Registrants’ inventory consists principally of materials and supplies, and for CERC, natural gas, and for CenterPoint Energy, coal inventory. Materials and supplies are valued at the lower of average cost or market. Materials and supplies are recorded to inventory when purchased and subsequently charged to expense or capitalized to plant when installed. Certain natural gas in storage at CenterPoint Energy’s and CERC’s utilities are recorded using the LIFO method. CenterPoint Energy’s and CERC’s balances in inventory that were valued using LIFO method were as follows: Year Ended December 31, 2020 (1) 2019 2020 (1) 2019 CenterPoint Energy CERC (in millions) LIFO inventory $ 92 $ 97 $ 55 $ 58 (1) Based on the average cost of gas purchased during December 2020, CenterPoint Energy’s and CERC’s cost of replacing inventories carried at LIFO cost was less than the carrying value at December 31, 2020 by $62 million and $54 million, respectively. During 2020, 2019 and 2018, CenterPoint Energy and CERC recorded write-downs of natural gas inventory to the lower of average cost or market which are disclosed on the respective Statements of Consolidated Cash Flows. (o) Derivative Instruments The Registrants are exposed to various market risks. These risks arise from transactions entered into in the normal course of business. The Registrants, from time to time, utilize derivative instruments such as physical forward contracts, swaps and options to mitigate the impact of changes in commodity prices, weather and interest rates on operating results and cash flows. Such derivatives are recognized in the Registrants’ Consolidated Balance Sheets at their fair value unless the Registrant elects the normal purchase and sales exemption for qualified physical transactions. A derivative may be designated as a normal purchase or normal sale if the intent is to physically receive or deliver the product for use or sale in the normal course of business. CenterPoint Energy elected to record changes in the fair value of amounts excluded from the assessment of effectiveness immediately in its Statements of Consolidated Income. (p) Investments in Equity Securities (CenterPoint Energy and CERC) CenterPoint Energy and CERC report equity securities at estimated fair value in their respective Consolidated Balance Sheets, and any unrealized holding gains and losses are recorded as Other Income (Expense) in their respective Statements of Consolidated Income. (q) Environmental Costs The Registrants expense or capitalize environmental expenditures, as appropriate, depending on their future economic benefit. The Registrants expense amounts that relate to an existing condition caused by past operations that do not have future economic benefit. The Registrants record undiscounted liabilities related to these future costs when environmental assessments and/or remediation activities are probable and the costs can be reasonably estimated. (r) Cash and Cash Equivalents and Restricted Cash For purposes of reporting cash flows, the Registrants consider cash equivalents to be short-term, highly-liquid investments with maturities of three months or less from the date of purchase. Cash and cash equivalents held by the Bond Companies (VIEs) solely to support servicing the Securitization Bonds as of December 31, 2020 and 2019 are reflected on CenterPoint Energy’s and Houston Electric’s Consolidated Balance Sheets. In connection with the issuance of Securitization Bonds, CenterPoint Energy and Houston Electric were required to establish restricted cash accounts to collateralize the bonds that were issued in these financing transactions. These restricted cash accounts are not available for withdrawal until the maturity of the bonds and are not included in cash and cash equivalents. For more information on restricted cash see Note 19. (s) Preferred Stock and Dividends Preferred stock is evaluated to determine balance sheet classification, and all conversion and redemption features are evaluated for bifurcation treatment. Proceeds received net of issuance costs are recognized on the settlement date. Cash dividends become a liability once declared. Income available to common stockholders is computed by deducting from net income the dividends accumulated and earned during the period on cumulative preferred stock. (t) Purchase Accounting The Registrants evaluate acquisitions to determine when a set of acquired activities and assets represent a business. When control of a business is obtained, the Registrants apply the acquisition method of accounting and record the assets acquired, liabilities assumed and any non-controlling interest obtained based on fair value at the acquisition date. The excess of the fair value of purchase consideration over the fair value of the net assets acquired is recorded as goodwill. The results of operations of the acquired business are included in the Registrants’ respective Statements of Consolidated Income beginning on the date of the acquisition. (u) New Accounting Pronouncements The following table provides an overview of certain recently adopted or issued accounting pronouncements applicable to all the Registrants, unless otherwise noted. Recently Adopted Accounting Standards ASU Number and Name Description Date of Adoption Financial Statement Impact ASU 2016-13- Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard, including standards amending this standard, requires a new model called CECL to estimate credit losses for (1) financial assets subject to credit losses and measured at amortized cost and (2) certain off-balance sheet credit exposures. Upon initial recognition of the exposure, the CECL model requires an entity to estimate the credit losses expected over the life of an exposure based on historical information, current information and reasonable and supportable forecasts, including estimates of prepayments. Transition method: modified retrospective January 1, 2020 The Registrants adopted the standard and recognized a cumulative-effect adjustment of the transition to opening retained earnings and allowance for credit losses with no impact on results of operations and cash flows. See Note 5 for more information. ASU 2019-12: Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes This standard simplifies accounting for income taxes by eliminating certain exceptions to the guidance for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also simplifies aspects of the accounting for franchise taxes that are partially based on income and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. Transition method: prospective for all amendments that apply to the Registrants January 1, 2020 Upon adoption, the Registrants are not required to apply the intraperiod tax allocation exception when there is a current-period loss from continuing operations. Accordingly, CenterPoint Energy determined the tax effect of income from continuing operations without considering the tax effects of items that are not included in continuing operations (i.e., discontinued operations). Additionally, CenterPoint Energy is no longer required to limit the year-to-date tax benefit recognized when the year-to-date benefit exceeds the anticipated full year benefit. Management believes that other recently adopted and recently issued accounting standards that are not yet effective will not have a material impact on the Registrants’ financial position, results of operations or cash flows upon adoption.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Text Block]	Property, Plant and Equipment (a) Property, Plant and Equipment Property, plant and equipment includes the following: December 31, 2020 December 31, 2019 Weighted Average Useful Lives Property, Plant and Equipment, Gross Accumulated Depreciation & Amortization Property, Plant and Equipment, Net Property, Plant and Equipment, Gross Accumulated Depreciation & Amortization Property, Plant and Equipment, Net (in years) (in millions) CenterPoint Energy Electric transmission and distribution 36 $ 15,225 $ 4,785 $ 10,440 $ 14,360 $ 4,634 $ 9,726 Electric generation (1) 27 1,922 754 1,168 1,780 698 1,082 Natural gas distribution 29 14,022 4,019 10,003 12,787 3,766 9,021 Other property 15 1,345 594 751 1,397 602 795 Total $ 32,514 $ 10,152 $ 22,362 $ 30,324 $ 9,700 $ 20,624 Houston Electric Electric transmission 46 $ 3,686 $ 700 $ 2,986 $ 3,358 $ 674 $ 2,684 Electric distribution 34 8,225 2,696 5,529 7,876 2,586 5,290 Other transmission and distribution property 22 1,682 534 1,148 1,595 537 1,058 Total $ 13,593 $ 3,930 $ 9,663 $ 12,829 $ 3,797 $ 9,032 CERC Natural gas distribution 29 $ 8,928 $ 2,392 $ 6,536 $ 8,024 $ 2,243 $ 5,781 Other property 19 44 22 22 55 27 28 Total $ 8,972 $ 2,414 $ 6,558 $ 8,079 $ 2,270 $ 5,809 (1) SIGECO and AGC own a 300 MW unit at the Warrick Power Plant (Warrick Unit 4) as tenants in common. SIGECO’s share of the cost of this unit as of December 31, 2020, is $195 million with accumulated depreciation totaling $146 million. AGC and SIGECO share equally in the cost of operation and output of the unit. SIGECO’s share of operating costs is included in Operation and maintenance expense in CenterPoint Energy’s Statements of Consolidated Income. (b) Depreciation and Amortization The following table presents depreciation and amortization expense for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Depreciation $ 961 $ 368 $ 289 $ 879 $ 339 $ 277 $ 623 $ 342 $ 261 Amortization of securitized regulatory assets 155 155 — 271 271 — 531 531 — Other amortization 73 37 15 75 38 16 76 44 19 Total $ 1,189 $ 560 $ 304 $ 1,225 $ 648 $ 293 $ 1,230 $ 917 $ 280 (c) AROs The Registrants recorded AROs associated with the removal of asbestos and asbestos-containing material in its buildings, including substation building structures. CenterPoint Energy recorded AROs relating to the closure of the ash ponds at A.B. Brown and F.B. Culley. CenterPoint Energy and Houston Electric also recorded AROs relating to treated wood poles for electric distribution, distribution transformers containing PCB (also known as Polychlorinated Biphenyl), and underground fuel storage tanks. CenterPoint Energy and CERC also recorded AROs relating to gas pipelines abandoned in place. The estimates of future liabilities were developed using historical information, and where available, quoted prices from outside contractors. A reconciliation of the changes in the ARO liability recorded in Other non-current liabilities on each of the Registrants’ respective Consolidated Balance Sheets is as follows: December 31, 2020 December 31, 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Beginning balance $ 539 $ 42 $ 325 $ 258 $ 34 $ 221 Addition from Merger with Vectren — — — 116 — — Accretion expense (1) 16 1 11 16 1 10 Revisions in estimates (2) 232 — 235 149 7 94 Ending balance $ 787 $ 43 $ 571 $ 539 $ 42 $ 325 (1) Reflected in Regulatory assets on each of the Registrants’ respective Consolidated Balance Sheets.

Divestitures (CenterPoint Energ

Divestitures (CenterPoint Energy and CERC)	12 Months Ended
	Dec. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Divestitures (CenterPoint Energy and CERC)	(4) Mergers, Acquisitions and Divestitures (CenterPoint Energy and CERC) Merger with Vectren. On the Merger Date, pursuant to the Merger Agreement, CenterPoint Energy consummated the previously announced Merger and acquired Vectren for approximately $6 billion in cash. Each share of Vectren common stock issued and outstanding immediately prior to the closing was canceled and converted into the right to receive $72.00 in cash per share, without interest. At the closing, each stock unit payable in Vectren common stock or whose value was determined with reference to the value of Vectren common stock, whether vested or unvested, was canceled with cash consideration paid in accordance with the terms of the Merger Agreement. These amounts did not include a stub period cash dividend of $0.41145 per share, which was declared, with CenterPoint Energy’s consent, by Vectren’s board of directors on January 16, 2019, and paid to Vectren stockholders as of the Merger Date. Pursuant to the Merger Agreement and immediately subsequent to the close of the Merger, CenterPoint Energy cash settled $78 million in outstanding share-based awards issued prior to the Merger Date by Vectren to its employees. As a result of the Merger, CenterPoint Energy assumed a liability for these share-based awards of $41 million and recorded an incremental cost of $37 million in Operation and maintenance expenses on its Statements of Consolidated Income during the year ended December 31, 2019 for the accelerated vesting of the awards in accordance with the Merger Agreement. Subsequent to the close of the Merger, CenterPoint Energy recognized severance totaling $61 million to employees terminated immediately subsequent to the Merger close, inclusive of change of control severance payments to executives of Vectren under existing agreements, and which is included in Operation and maintenance expenses on its Statements of Consolidated Income during the year ended December 31, 2019. Total severance cost for the year ended December 31, 2019 was $102 million. In connection with the Merger, VUHI and VCC made offers to prepay certain outstanding guaranteed senior notes as required pursuant to certain note purchase agreements previously entered into by VUHI and VCC. See Note 14 for further details. Following the closing, shares of Vectren common stock, which previously traded under the ticker symbol “VVC” on the NYSE, ceased trading on and were delisted from the NYSE. The Merger was accounted for in accordance with ASC 805, Business Combinations, with CenterPoint Energy as the accounting acquirer of Vectren. Identifiable assets acquired and liabilities assumed were recorded at their estimated fair values on the Merger Date. Vectren’s regulated operations, comprised of electric generation and electric and natural gas energy delivery services, are subject to the rate-setting authority of the FERC, the IURC and the PUCO, and were accounted for pursuant to U.S. generally accepted accounting principles for regulated operations. The rate-setting and cost-recovery provisions currently in place for Vectren’s regulated operations provide revenues derived from costs including a return on investment of assets and liabilities included in rate base. Thus, the fair value of Vectren’s tangible and intangible assets and liabilities subject to these rate-setting provisions approximated their carrying values on the Merger Date. The fair value of regulatory assets not earning a return were determined using the income approach and are considered Level 3 fair value measurements due to the use of significant judgmental and unobservable inputs. The fair value of Vectren’s assets acquired and liabilities assumed that are not subject to the rate-setting provisions, including identifiable intangibles, were determined using the income approach and the market approach. The valuation of Vectren’s long-term debt was primarily considered a Level 2 fair value measurement. All other valuations were considered Level 3 fair value measurements due to the use of significant judgmental and unobservable inputs, including projected timing and amount of future cash flows and discount rates reflecting risk inherent in the future market prices. The following table presents the purchase price allocation as of December 31, 2019, reflecting the final purchase price allocation and inclusive of assets and liabilities subsequently recast as held for sale (in millions): Cash and cash equivalents $ 16 Other current assets 577 Property, plant and equipment, net 5,147 Identifiable intangibles 297 Regulatory assets 338 Other assets 141 Total assets acquired 6,516 Current liabilities 648 Regulatory liabilities 938 Other liabilities 886 Long-term debt 2,401 Total liabilities assumed 4,873 Net assets acquired 1,643 Goodwill 4,339 Total purchase price consideration $ 5,982 CenterPoint Energy completed a final valuation analysis necessary to determine the fair market values of all of Vectren’s assets and liabilities and the allocation of its purchase price. Changes from the preliminary purchase price allocation originally reported in the first quarter of 2019 primarily included additional information obtained related to intangible assets and the allocation of the fair value between reporting units. The excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed is recognized as goodwill, which is primarily attributable to significant potential strategic benefits to CenterPoint Energy, including growth opportunities for more rate-regulated investment, more customers for existing products and services and additional products and services for existing customers. Additionally, CenterPoint Energy believes the Merger will increase geographic and business diversity as well as scale in attractive jurisdictions and economies. The value assigned to goodwill will not be deductible for tax purposes. The fair value of the identifiable intangible assets and related useful lives as included in the purchase price allocation on the Merger Date, reflecting the final purchase price allocation and inclusive of intangible assets subsequently recast as held for sale, include: Weighted Average Useful Lives Estimated Fair Value (in years) (in millions) Operation and maintenance agreements 24 $ 12 Customer relationships 18 200 Construction backlog 1 27 Trade names 10 58 Total $ 297 Amortization expense related to the operation and maintenance agreements and construction backlog was $24 million in 2019, and is included in Non-utility cost of revenues, including natural gas on CenterPoint Energy’s Statements of Consolidated Income. Amortization expense related to customer relationships and trade names was $16 million in 2019 and is included in Depreciation and amortization expense on CenterPoint Energy’s Statements of Consolidated Income. The results of operations for Vectren included in CenterPoint Energy’s Consolidated Financial Statements from the Merger Date for the year ended December 31, 2019, reflecting results included in both continuing operations and discontinued operations, are as follows: (in millions) Operating revenues $ 2,729 Net income 190 The following unaudited pro forma financial information reflects the consolidated results of operations of CenterPoint Energy, assuming the Merger had taken place on January 1, 2018 and reflecting results included in both continuing operations and discontinued operations. The unaudited pro forma financial information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved had the Merger taken place on the dates indicated or of the future consolidated results of operations of the combined company. Year Ended December 31, 2019 2018 (in millions) Operating revenues $ 12,547 $ 13,282 Net income 812 (1) 458 (2) (1) Pro forma net income was adjusted to exclude $37 million of Vectren Merger-related transaction costs incurred in 2019. (2) Pro forma net income was adjusted to include $37 million of Vectren Merger-related transaction costs incurred in 2019. CenterPoint Energy incurred integration costs in connection with the Merger of $83 million for the year ended December 31, 2019, which were included in Operation and maintenance expenses in CenterPoint Energy’s Statements of Consolidated Income. Acquisition of Utility Pipeline Construction Company. An acquisition was made during the year ended December 31, 2019 by CenterPoint Energy’s Infrastructure Services Disposal Group, resulting in goodwill and intangible assets of approximately $6 million and $8 million, respectively. The intangible assets primarily relate to backlog and customer relationships. The allocation of the $25 million purchase price has been finalized. The results of operations for the acquired company have been included in CenterPoint Energy’s consolidated financial statements from the date of acquisition, and are reflected as a discontinued operation in the Infrastructure Services Disposal Group. Pro forma results of operations have not been presented for the acquisition because the effects of the acquisition were not significant to CenterPoint Energy’s consolidated financial results for all periods presented. Divestiture of Infrastructure Services (CenterPoint Energy). On February 3, 2020, CenterPoint Energy, through its subsidiary VUSI, entered into the Securities Purchase Agreement to sell the Infrastructure Services Disposal Group to PowerTeam Services. Subject to the terms and conditions of the Securities Purchase Agreement, PowerTeam Services agreed to purchase all of the outstanding equity interests of VISCO for approximately $850 million, subject to customary adjustments set forth in the Securities Purchase Agreement, including adjustments based on VISCO’s net working capital at closing, indebtedness, cash and cash equivalents and transaction expenses. The transaction closed on April 9, 2020 for $850 million in cash, subject to the working capital adjustment. Additionally, as of December 31, 2020, CenterPoint Energy had a receivable from PowerTeam Services for working capital and other adjustments set forth in the Security Purchase Agreement. CenterPoint Energy collected a receivable of $4 million from PowerTeam Services in January 2021 for full and final settlement of the working capital adjustment under the Securities Purchase Agreement. In February 2020, certain assets and liabilities representing the Infrastructure Services Disposal Group met the held for sale criteria and represented all of the businesses within the reporting unit. In accordance with the Securities Purchase Agreement, VISCO was converted from a wholly-owned corporation to a limited liability company that was disregarded for federal income tax purposes immediately prior to the closing of the transaction resulting in the sale of membership units. The sale was considered an asset sale for tax purposes, requiring net deferred tax liabilities of approximately $129 million as of April 9, 2020, the date the transaction closed, to be recognized as a deferred income tax benefit by CenterPoint Energy. Additionally, CenterPoint Energy recognized a current tax expense of $158 million during the year ended December 31, 2020, as a result of the cash taxes payable upon sale. Upon classifying the Infrastructure Services Disposal Group as held for sale and in connection with the preparation of CenterPoint Energy’s financial statements as of March 31, 2020, CenterPoint Energy recorded a goodwill impairment of approximately $82 million, plus an additional loss of $14 million for cost to sell, during the year ended December 31, 2020. Additionally, CenterPoint Energy recognized a net pre-tax loss of $6 million in connection with the closing of the disposition of the Infrastructure Services Disposal Group during the year ended December 31, 2020, respectively. In the Securities Purchase Agreement, CenterPoint Energy agreed to a mechanism to reimburse PowerTeam Services subsequent to closing of the sale for certain amounts of specifically identified change orders that may be ultimately rejected by one of VISCO’s customers as part of on-going audits. CenterPoint Energy’s maximum contractual exposure under the Securities Purchase Agreement, in addition to the amount reflected in the working capital adjustment, for these change orders is $21 million. CenterPoint Energy does not expect the ultimate outcome of this matter to have a material adverse effect on its financial condition, results of operations or cash flows. CenterPoint Energy anticipates this matter will be resolved in the first half of 2021. Divestiture of Energy Services (CenterPoint Energy and CERC). On February 24, 2020, CenterPoint Energy, through its subsidiary CERC Corp., entered into the Equity Purchase Agreement to sell the Energy Services Disposal Group to Symmetry Energy Solutions Acquisition. This transaction did not include CEIP and its assets or MES. Symmetry Energy Solutions Acquisition agreed to purchase all of the outstanding equity interests of the Energy Services Disposal Group for approximately $400 million, subject to customary adjustments set forth in the Equity Purchase Agreement, and inclusive of an estimate of the cash adjustment for the Energy Services Disposal Group’s net working capital at closing, indebtedness and transaction expenses. The transaction closed on June 1, 2020 for approximately $286 million in cash, subject to the working capital adjustment. CenterPoint Energy collected a receivable of $79 million from Symmetry Energy Solutions Acquisition in October 2020 for full and final settlement of the working capital adjustment under the Equity Purchase Agreement. In February 2020, certain assets and liabilities representing the Energy Services Disposal Group met the criteria to be classified as held for sale and represented substantially all of the businesses within the reporting unit. In accordance with the Equity Purchase Agreement, CES was converted from a wholly-owned corporation to a limited liability company that is disregarded for federal income tax purposes immediately prior to the closing of the transaction resulting in the sale of membership units. The sale was considered an asset sale for tax purposes, requiring the net deferred tax liability of approximately $4 million as of June 1, 2020, the date the transaction closed, to be recognized as a deferred tax benefit by CenterPoint Energy and CERC upon closing. Additionally, CenterPoint Energy and CERC recognized current tax expense of $4 million during the year ended December 31, 2020, respectively, as a result of the cash taxes payable upon sale. Upon classifying the Energy Services Disposal Group as held for sale and in connection with the preparation of CenterPoint Energy’s and CERC’s respective financial statements as of March 31, 2020, CenterPoint Energy and CERC recorded a goodwill impairment of approximately $62 million during the year ended December 31, 2020. Additionally, CenterPoint Energy recognized a loss on assets held for sale of approximately $31 million, plus an additional loss $6 million for cost to sell, recorded only at CenterPoint Energy during the year ended December 31, 2020, respectively. CenterPoint Energy and CERC recognized a gain on sale of $3 million during the year ended December 31, 2020. As a result of the sale of the Energy Services and Infrastructure Services Disposal Groups, there were no assets or liabilities classified as held for sale as of December 31, 2020. The assets and liabilities of the Infrastructure Services and Energy Services Disposal Groups as of December 31, 2019 have been recast as assets and liabilities held for sale and retained their current or long-term classification applicable as of December 31, 2019. L ong-lived assets are not depreciated or amortized once they are classified as held for sale. The assets and liabilities of the Infrastructure Services and Energy Services Disposal Groups classified as held for sale in CenterPoint Energy’s and CERC’s Condensed Consolidated Balance Sheets, as applicable, as of December 31, 2019 included the following: December 31, 2019 CenterPoint Energy CERC Infrastructure Services Disposal Group Energy Services Disposal Group Total Energy Services Disposal Group (in millions) Receivables, net $ 192 $ 445 $ 637 $ 445 Accrued unbilled revenues 109 8 117 8 Natural gas inventory — 67 67 67 Materials and supplies 6 — 6 — Non-trading derivative assets — 136 136 136 Other 4 35 39 35 Total current assets held for sale 311 691 1,002 691 Property, plant and equipment, net 295 26 321 26 Goodwill 220 62 282 62 Non-trading derivative assets — 58 58 58 Other 234 67 301 67 Total non-current assets held for sale 749 213 962 213 Total assets held for sale $ 1,060 $ 904 $ 1,964 $ 904 Accounts payable $ 45 $ 299 $ 344 $ 299 Taxes accrued 2 — 2 — Non-trading derivative liabilities — 44 44 44 Other 40 25 65 25 Total current liabilities held for sale 87 368 455 368 Non-trading derivative liabilities — 14 14 14 Benefit obligations — 4 4 4 Other 16 9 25 9 Total non-current liabilities held for sale 16 27 43 27 Total liabilities held for sale $ 103 $ 395 $ 498 $ 395 Because the Infrastructure Services and Energy Services Disposal Groups met the held for sale criteria and their disposals also represent a strategic shift to CenterPoint Energy and CERC, as applicable, the earnings and expenses directly associated with these dispositions, including operating results of the businesses through the date of sale, are reflected as discontinued operations on CenterPoint Energy’s and CERC’s Statements of Consolidated Income, as applicable. As a result, prior periods have also been recast to reflect the earnings or losses from such businesses as income from discontinued operations, net of tax. A summary of the Infrastructure Services and Energy Services Disposal Groups presented as discontinued operations in CenterPoint Energy’s Statements of Consolidated Income, as applicable, is as follows: Year Ended December 31, 2020 2019 (1) 2020 2019 2018 2020 2019 2018 CenterPoint Energy Infrastructure Services Disposal Group Energy Services Disposal Group Total (in millions) Revenues $ 250 $ 1,190 $ 1,167 $ 3,767 $ 4,503 $ 1,417 $ 4,957 $ 4,503 Expenses: Non-utility cost of revenues 50 309 1,108 3,597 4,459 1,158 3,906 4,459 Operation and maintenance 184 714 34 68 66 218 782 66 Depreciation and amortization — 50 — 12 13 — 62 13 Taxes other than income taxes 1 2 3 2 2 4 4 2 Goodwill Impairment — — — 48 — — 48 — Total 235 1,075 1,145 3,727 4,540 1,380 4,802 4,540 Income (loss) from Discontinued Operations before income taxes 15 115 22 40 (37) 37 155 (37) Loss on classification to held for sale, net (2) (102) — (96) — — (198) — — Income tax expense (benefit) 24 29 (3) 17 (9) 21 46 (9) Net income (loss) from Discontinued Operations $ (111) $ 86 $ (71) $ 23 $ (28) $ (182) $ 109 $ (28) (1) Reflects February 1, 2019 to December 31, 2019 results only due to the Merger. (2) Loss from classification to held for sale is inclusive of goodwill impairment, gains and losses recognized upon sale, and for CenterPoint Energy, its costs to sell. Internal Spin (CERC). On September 4, 2018, CERC completed the Internal Spin. CERC executed the Internal Spin to, among other things, enhance the access of CERC and CenterPoint Energy to low cost debt and equity through increased transparency and understandability of the financial statements, improve CERC’s credit quality by eliminating the exposure to Enable’s midstream business and provide clarity of internal reporting and performance metrics to enhance management’s decision making for CERC and CNP Midstream. The Internal Spin represented a significant strategic shift that had a material effect on CERC’s operations and financial results and, as a result, CERC’s distribution of its equity investment in Enable met the criteria for discontinued operations classification. CERC has no continuing involvement in the equity investment of Enable. Therefore, CERC’s equity in earnings and related income taxes were classified as Income from discontinued operations, net of tax, in CERC’s Statements of Consolidated Income for the periods presented. CERC’s equity method investment and related deferred income tax liabilities were classified as Investment in unconsolidated affiliate - discontinued operations and Deferred income taxes, net - discontinued operations, respectively, in CERC’s Consolidated Balance Sheets for the periods presented. A summary of the Energy Services Disposal Group and Internal Spin presented as discontinued operations in CERC’s Statements of Consolidated Income, as applicable, is as follows: Year Ended December 31, 2020 2019 2018 CERC (in millions) Revenues $ 1,167 $ 3,767 $ 4,503 Expenses: Non-utility cost of revenues 1,108 3,597 4,459 Operation and maintenance 34 68 66 Depreciation and amortization — 12 13 Taxes other than income taxes 3 2 2 Goodwill Impairment — 48 — Total 1,145 3,727 4,540 Equity in earnings of unconsolidated affiliate, net — — 184 Income (loss) from Discontinued Operations before income taxes 22 40 147 Loss on classification to held for sale, net (1) (90) — — Income tax expense (benefit) (2) 17 37 Net income (loss) from Discontinued Operations $ (66) $ 23 $ 110 (1) Loss from classification to held for sale is inclusive of goodwill impairment, gains and losses recognized upon sale, and for CenterPoint Energy, its costs to sell. CenterPoint Energy and CERC have elected not to separately disclose discontinued operations on their respective Condensed Statements of Consolidated Cash Flows. L ong-lived assets are not depreciated or amortized once they are classified as held for sale. The following table summarizes CenterPoint Energy’s and CERC’s cash flows from discontinued operations and certain supplemental cash flow disclosures related to the Infrastructure Services and Energy Services Disposal Groups, as applicable: Year Ended December 31, 2020 2019 (1) 2020 2019 2018 CenterPoint Energy Infrastructure Services Disposal Group Energy Services Disposal Group (in millions) Depreciation and amortization $ — $ 50 $ — $ 12 $ 13 Amortization of intangible assets in Non-utility cost of revenues — 19 — — — Write-down of natural gas inventory — — 3 4 2 Capital expenditures 18 67 3 12 21 Non-cash transactions: Accounts payable related to capital expenditures — — — 2 2 (1) Reflects February 1, 2019 to December 31, 2019 results only due to the Merger. Year Ended December 31, 2020 2019 2018 CERC Energy Services Disposal Group (in millions) Depreciation and amortization $ — $ 12 $ 13 Write-down of natural gas inventory 3 4 2 Capital expenditures 3 12 21 Non-cash transactions: Accounts payable related to capital expenditures — 2 2 Other Sale Related Matters (CenterPoint Energy and CERC). CES provided natural gas supply to CenterPoint Energy’s and CERC’s Natural Gas under contracts executed in a competitive bidding process, with the duration of some contracts extending into 2021. In addition, CERC is the natural gas transportation provider for a portion of CES’s customer base and will continue to be the transportation provider for these customers as long as these customers retain a relationship with the divested CES business. Transactions between CES and CenterPoint Energy’s and CERC’s Natural Gas that were previously eliminated in consolidation have been reflected in continuing operations until the closing of the sale of the Energy Services Disposal Group. Revenues and expenses included in continuing operations were as follows: Year Ended December 31, 2020 (1) 2019 2018 2020 (1) 2019 2018 CenterPoint Energy CERC (in millions) Transportation revenue $ 34 $ 101 $ 104 $ 34 $ 101 $ 104 Natural gas expense 48 125 107 47 124 107 (1) Represents charges for the period January 1, 2020 until the closing of the sale of the Energy Services Disposal Group. Natural Gas has AMAs associated with its utility distribution service in Arkansas, Louisiana, Mississippi, Oklahoma and Texas. The AMAs are with the Energy Services Disposal Group and will expire in 2021. Pursuant to the provisions of the agreements, Natural Gas sells natural gas and agrees to repurchase an equivalent amount of natural gas during the winter heating seasons at the same cost. These transactions are accounted for as inventory financing. CenterPoint Energy and CERC had outstanding obligations related to the AMAs of $24 million and $-0- as of December 31, 2020 and December 31, 2019, respectively. The Infrastructure Services Disposal Group provided pipeline construction and repair services to CenterPoint Energy’s and CERC’s Natural Gas. In accordance with consolidation guidance in ASC 980—Regulated Operations, costs incurred by Natural Gas utilities for these pipeline construction and repair services are not eliminated in consolidation when capitalized and included in rate base by the Natural Gas utility. Amounts charged for these services that are not capitalized are included primarily in Operation and maintenance expenses. Fees incurred by CenterPoint Energy’s and CERC’s Natural Gas for pipeline construction and repair services are as follows: Year Ended December 31, 2020 (1) 2019 (2) 2020 2019 CenterPoint Energy CERC (in millions) Pipeline construction and repair services capitalized $ 34 $ 162 $ — $ 20 Pipeline construction and repair service charges in operations and maintenance expense 1 4 1 4 (1) Represents charges for the period January 1, 2020 until the closing of the sale of the Infrastructure Services Disposal Group. (2) Represents charges for the period beginning February 1, 2019 through December 31, 2019 due to the Merger.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition [Text Block]	Revenue Recognition In accordance with ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Registrants expect to be entitled to receive in exchange for these goods or services. The revenues and related balances in the following tables exclude operating revenues and balances from the Energy Services and Infrastructure Services Disposal Groups, which are reflected as discontinued operations and assets held for sale prior to the date of closing of each transaction. See Note 4 for further information. During the fourth quarter of 2020, there was a realignment of reportable segments at CenterPoint Energy and CERC. See Note 18 for further information. As a result, certain prior year amounts have been reclassified to conform to the current year presentation. The following tables disaggregate revenues by reportable segment and major source: CenterPoint Energy Year Ended December 31, 2020 Electric Natural Gas Corporate and Other Total (in millions) Revenue from contracts $ 3,451 $ 3,586 $ 313 $ 7,350 Other (1) 19 45 4 68 Total revenues $ 3,470 $ 3,631 $ 317 $ 7,418 Year Ended December 31, 2019 Electric (2) Natural Gas (2) Corporate and Other (2) Total (in millions) Revenue from contracts $ 3,507 $ 3,714 $ 290 $ 7,511 Other (1) 12 36 5 53 Total revenues $ 3,519 $ 3,750 $ 295 $ 7,564 Year Ended December 31, 2018 Electric Natural Gas Corporate and Other Total (in millions) Revenue from contracts $ 3,235 $ 3,042 $ 5 $ 6,282 Other (1) (3) (11) 9 (5) Total revenues $ 3,232 $ 3,031 $ 14 $ 6,277 (1) Primarily consists of income from ARPs and leases. ARPs are contracts between the utility and its regulators, not between the utility and a customer. The Registrants recognize ARP revenue as other revenues when the regulator-specified conditions for recognition have been met. Upon recovery of ARP revenue through incorporation in rates charged for utility service to customers, ARP revenue is reversed and recorded as revenue from contracts with customers. The recognition of ARP revenues and the reversal of ARP revenues upon recovery through rates charged for utility service may not occur in the same period. Total lease income was $6 million for each of the years ended December 31, 2020 and 2019. (2) Reflects revenues from Vectren subsidiaries for the period from February 1, 2019 to December 31, 2019. Houston Electric Year Ended December 31, 2020 2019 2018 (in millions) Revenue from contracts $ 2,896 $ 2,984 $ 3,235 Other (1) 15 6 (1) Total revenues $ 2,911 $ 2,990 $ 3,234 (1) Primarily consists of income from ARPs and leases. ARPs are contracts between the utility and its regulators, not between the utility and a customer. The Registrants recognize ARP revenue as other revenues when the regulator-specified conditions for recognition have been met. Upon recovery of ARP revenue through incorporation in rates charged for utility service to customers, ARP revenue is reversed and recorded as revenue from contracts with customers. The recognition of ARP revenues and the reversal of ARP revenues upon recovery through rates charged for utility service may not occur in the same period. Lease income was not significant for the years ended December 31, 2020 and 2019. CERC Year Ended December 31, 2020 2019 2018 (in millions) Revenue from contracts $ 2,714 $ 2,979 $ 3,042 Other (1) 49 39 (11) Total revenues $ 2,763 $ 3,018 $ 3,031 (1) Primarily consists of income from ARPs and leases. ARPs are contracts between the utility and its regulators, not between the utility and a customer. The Registrants recognize ARP revenue as other revenues when the regulator-specified conditions for recognition have been met. Upon recovery of ARP revenue through incorporation in rates charged for utility service to customers, ARP revenue is reversed and recorded as revenue from contracts with customers. The recognition of ARP revenues and the reversal of ARP revenues upon recovery through rates charged for utility service may not occur in the same period. Lease income was $2 million for the year ended December 31, 2020 and less than $1 million for the year ended December 31, 2019. Revenues from Contracts with Customers Electric (CenterPoint Energy and Houston Electric). Houston Electric distributes electricity to customers over time and customers consume the electricity when delivered. Indiana Electric generates, distributes and transmits electricity to customers over time, and customers consume the electricity when delivered. Revenue, consisting of both volumetric and fixed tariff rates set by state regulators, such as the PUCT and the IURC, is recognized as electricity is delivered and represents amounts both billed and unbilled. Discretionary services requested by customers are provided at a point in time with control transferring upon the completion of the service. Revenue for discretionary services is recognized upon completion of service based on the tariff rates set by the PUCT. Payments for electricity distribution and discretionary services are aggregated and received on a monthly basis. Houston Electric performs transmission services over time as a stand-ready obligation to provide a reliable network of transmission systems. Revenue is recognized upon time elapsed, and the monthly tariff rate set by the regulator. Payments are received on a monthly basis. Indiana Electric customers are billed monthly and payment terms, set by the regulator, require payment within a month of billing. Natural Gas (CenterPoint Energy and CERC). CenterPoint Energy and CERC distribute and transport natural gas to customers over time, and customers consume the natural gas when delivered. Revenue, consisting of both volumetric and fixed tariff rates set by the state governing agency for that service area, is recognized as natural gas is delivered and represents amounts both billed and unbilled. Discretionary services requested by the customer are satisfied at a point in time and revenue is recognized upon completion of service and the tariff rates set by the applicable state regulator. Payments of natural gas distribution, transportation and discretionary services are aggregated and received on a monthly basis. Contract Balances. When the timing of delivery of service is different from the timing of the payments made by customers and when the right to consideration is conditioned on something other than the passage of time, the Registrants recognize either a contract asset (performance precedes billing) or a contract liability (customer payment precedes performance). Those customers that prepay are represented by contract liabilities until the performance obligations are satisfied. The Registrants’ contract assets are included in Accrued unbilled revenues in their Consolidated Balance Sheets. As of December 31, 2020, CenterPoint Energy’s contract assets primarily relate to ESG contracts where revenue is recognized using the input method. The Registrants’ contract liabilities are included in Accounts payable and Other current liabilities in their Consolidated Balance Sheets. On an aggregate basis as of December 31, 2020, CenterPoint Energy’s contract liabilities primarily relate to ESG contracts where revenue is recognized using the input method. The opening and closing balances of accounts receivable, other accrued unbilled revenue, contract assets and contract liabilities from contracts with customers for the year ended December 31, 2020 are as follows: CenterPoint Energy Accounts Receivable Other Accrued Unbilled Revenues Contract Contract Liabilities (in millions) Opening balance as of December 31, 2019 $ 566 $ 469 $ 6 $ 30 Closing balance as of December 31, 2020 604 505 27 18 Increase $ 38 $ 36 $ 21 $ (12) The amount of revenue recognized in the year ended December 31, 2020 that was included in the opening contract liability was $30 million. The difference between the opening and closing balances of the contract liabilities primarily results from the timing difference between CenterPoint Energy’s performance and the customer’s payment. Houston Electric Accounts Receivable Other Accrued Unbilled Revenues Contract Liabilities (in millions) Opening balance as of December 31, 2019 $ 210 $ 117 $ 3 Closing balance as of December 31, 2020 225 113 3 Increase (decrease) $ 15 $ (4) $ — The amount of revenue recognized in the year ended December 31, 2020 that was included in the opening contract liability was $3 million. The difference between the opening and closing balances of the contract liabilities primarily results from the timing difference between Houston Electric’s performance and the customer’s payment. CERC Accounts Receivable Other Accrued (in millions) Opening balance as of December 31, 2019 $ 222 $ 249 Closing balance as of December 31, 2020 214 261 Increase (decrease) $ (8) $ 12 CERC does not have any opening or closing contract asset or contract liability balances. Remaining Performance Obligations (CenterPoint Energy). The table below discloses (1) the aggregate amount of the transaction price allocated to performance obligations that are unsatisfied (or partially unsatisfied) as of the end of the reporting period for contracts and (2) when CenterPoint Energy expects to recognize this revenue. Such contracts include energy performance and sustainable infrastructure services contracts of ESG, which are included in Corporate and Other. Rolling 12 Months Thereafter Total (in millions) Revenue expected to be recognized on contracts in place as of December 31, 2020: Corporate and Other $ 267 $ 570 $ 837 $ 267 $ 570 $ 837 Practical Expedients and Exemption. Sales taxes and other similar taxes collected from customers are excluded from the transaction price. For contracts for which revenue from the satisfaction of the performance obligations is recognized in the amount invoiced, the practical expedient was elected and revenue expected to be recognized on these contracts has not been disclosed. Allowance for Credit Losses and Bad Debt Expense The Registrants adopted ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments and all related amendments on January 1, 2020 using a modified retrospective method. ASU 2016-13 replaces the “incurred loss” model with a CECL model for financial assets measured at amortized cost and for certain off-balance sheet credit exposures. Adoption of this standard did not have a material impact on the Registrants’ respective consolidated financial statements. CenterPoint Energy and CERC applied the $5 million cumulative-effect adjustment of the transition to opening retained earnings as of the effective date, which included $2 million related to the Energy Services Disposal Group. There was no material cumulative-effect adjustment for Houston Electric. The disclosures for periods prior to adoption will be presented in accordance with accounting standards in effect for those periods. CenterPoint Energy and CERC segregate financial assets that fall under the scope of Topic 326, primarily trade receivables due in one year or less, into portfolio segments based on shared risk characteristics, such as geographical location and regulatory environment, for evaluation of expected credit losses. Historical and current information, such as average write-offs, are applied to each portfolio segment to estimate the allowance for losses on uncollectible receivables. Additionally, the allowance for losses on uncollectible receivables is adjusted for reasonable and supportable forecasts of future economic conditions, which can include changing weather, commodity prices, regulations, and macroeconomic factors, among others. Houston Electric had no material changes in its methodology to recognize losses on financial assets that fall under the scope of Topic 326, primarily due to the nature of its customers and regulatory environment. For a discussion of regulatory deferrals related to COVID-19, see Note 7. The table below summarizes the Registrants’ bad debt expense amounts for 2020, 2019 and 2018 and excludes regulatory deferrals related to COVID-19: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Bad debt expense $ 24 $ — $ 18 $ 18 $ — $ 14 $ 16 $ — $ 16

Goodwill and Other Intangibles

Goodwill and Other Intangibles (CenterPoint Energy and CERC)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangibles (CenterPoint Energy and CERC) [Text Block]	Goodwill and Other Intangibles (CenterPoint Energy and CERC) CenterPoint Energy’s goodwill by reportable segment as of December 31, 2019 and changes in the carrying amount of goodwill as of December 31, 2020 are as follows: December 31, 2019 Impairment December 31, (in millions) Electric $ 1,121 $ 185 $ 936 Natural Gas 3,323 — 3,323 Corporate and Other 438 — 438 Total $ 4,882 $ 185 $ 4,697 CenterPoint Energy and CERC perform goodwill impairment tests at least annually and evaluate goodwill when events or changes in circumstances indicate that its carrying value may not be recoverable. The impairment evaluation for goodwill is performed by comparing the fair value of each reporting unit with the carrying amount of the reporting unit, including goodwill. The estimated fair value of a reporting unit is primarily determined based on an income approach or a weighted combination of income and market approaches. If the carrying amount of the reporting unit is in excess of the estimated fair value of the reporting unit, then the excess amount is the impairment charge that should be recorded, not to exceed the carrying amount of goodwill. See Note 2(g) for further discussion. CenterPoint Energy and CERC performed the annual goodwill impairment test on July 1 of each of 2020 and 2019 and determined that no goodwill impairment charge was required for any reporting unit in its annual test. In connection with their preparation of the financial statements for the three months ended March 31, 2020, CenterPoint Energy and CERC identified triggering events to perform interim goodwill impairment tests for each of their reporting units due to the macroeconomic conditions related in part to the COVID-19 pandemic and the resulting decrease in CenterPoint Energy’s enterprise market capitalization below book value from the decline in CenterPoint Energy’s Common Stock price. CenterPoint Energy’s interim impairment test in the three months ended March 31, 2020 resulted in a non-cash goodwill impairment charge in the amount of $185 million for a reporting unit, Indiana Electric, within the Electric reportable segment. The fair value analysis resulted in an implied fair value of goodwill of $936 million for this reporting unit as of March 31, 2020, and as a result, the non-cash impairment charge was recorded in the year ended December 31, 2020. CenterPoint Energy estimated the fair value of the Indiana Electric reporting unit using primarily an income approach. Under the income approach, the fair value of the reporting unit is determined by using the present value of future expected cash flows, which include management’s projections of the amount and timing of future capital expenditures and the cash inflows from the related regulatory recovery. These estimated future cash flows are then discounted using a rate that approximates the weighted average cost of capital of a market participant. The selection of the discount rate requires significant judgment. With the exception of Indiana Electric reporting unit discussed above, the fair value of each of CenterPoint Energy’s and CERC’s reporting units exceeded their carrying value, resulting in no goodwill impairment from the March 31, 2020 interim impairment test. See Note 4 for goodwill impairments included within discontinued operations. The tables below present information on CenterPoint Energy’s other intangible assets recorded in Other in Other Assets on the Consolidated Balance Sheets and the related amortization expense included in Depreciation and amortization on CenterPoint Energy’s Statements of Consolidated Income, unless otherwise indicated in the tables below. December 31, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Balance Gross Carrying Amount Accumulated Amortization Net Balance (in millions) Customer relationships $ 33 $ (8) $ 25 $ 33 $ (4) $ 29 Trade names 16 (3) 13 16 (1) 15 Construction backlog (1) 5 (5) — 5 (4) 1 Operation and maintenance agreements (1) 12 (1) 11 12 — 12 Other 2 (1) 1 2 (1) 1 Total $ 68 $ (18) $ 50 $ 68 $ (10) $ 58 (1) Amortization expense related to the operation and maintenance agreements and construction backlog is included in Non-utility cost of revenues, including natural gas on CenterPoint Energy’s Statements of Consolidated Income. Year Ended December 31, 2020 2019 2018 (in millions) Amortization expense of intangible assets recorded in Depreciation and amortization (1) (2) $ 6 $ 5 $ — Amortization expense of intangible assets recorded in (2) 2 4 — (1) Includes $5 million for the year ended December 31, 2019 of amortization expense related to intangibles acquired in the Merger. (2) Assets held for sale are not amortized. The table reflects amortization on continuing operations. For further information on discontinued operations, see Note 4. CenterPoint Energy estimates that amortization expense of intangible assets with finite lives for the next five years will be as follows: Amortization Expense (1) (in millions) 2021 $ 6 2022 6 2023 6 2024 5 2025 5 (1) Assets held for sale are not amortized. The table reflects amortization on continuing operations. For further information on discontinued operations, see Note 4.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Regulatory Accounting [Text Block]	Regulatory Matters The following is a list of regulatory assets and liabilities reflected on the Registrants’ respective Consolidated Balance Sheets as of December 31, 2020 and 2019. The “amortization through” columns indicate the latest year when a regulatory asset or regulatory liability category will be fully amortized: December 31, 2020 CenterPoint Energy Houston Electric CERC Amortization Through (in millions) Amortization Through (in millions) Amortization Through (in millions) Regulatory Assets: Current regulatory assets (1) 2021 $ 33 n/a $ — 2021 $ 33 Non-current regulatory assets: Securitized regulatory assets 2024 633 2024 633 n/a — Unrecognized equity return Various (150) (2) 2024 (137) (2) Various (13) Unamortized loss on reacquired debt (3) 2055 57 2046 55 n/a — Pension and postretirement-related regulatory asset (3) Various (a) 591 Various (a) 31 Various (a) 21 Hurricane Harvey restoration costs (3) Various 59 2025 55 TBD (b) 4 Hurricane Laura restoration costs TBD (b) 36 TBD (b) 36 TBD (b) — Regulatory assets related to TCJA (3) (4) 2025 25 2025 20 2023 5 Relief Program Incremental Costs (COVID-19) TBD 25 TBD 5 TBD 17 Asset retirement obligation (3) Perpetual 135 Perpetual 26 Perpetual 107 Other regulatory assets-not earning a return (5) 2056 165 2049 83 2056 44 Other regulatory assets Various 518 Various 41 Various 35 Total non-current regulatory assets 2,094 848 220 Total regulatory assets 2,127 848 253 Regulatory Liabilities: Current regulatory liabilities (6) 2021 72 2021 43 2021 29 Non-current regulatory liabilities: Regulatory liabilities related to TCJA (4) Various 1,484 TBD 764 Various 421 Estimated removal costs Various 1,470 Various 231 Various 656 Other regulatory liabilities Various 494 Various 257 Various 149 Total non-current regulatory liabilities 3,448 1,252 1,226 Total regulatory liabilities 3,520 1,295 1,255 Total regulatory assets and liabilities, net $ (1,393) $ (447) $ (1,002) (a) Pension and postretirement-related regulatory assets balances are measured annually, and the ending amortization period may change based on the actuarial valuation. (b) The recovery and amortization of a portion of these amounts are expected to be determined in the next rate case. December 31, 2019 CenterPoint Energy Houston Electric CERC (in millions) Regulatory Assets: Current regulatory assets (1) $ 12 $ — $ 12 Non-current regulatory assets: Securitized regulatory assets 788 788 — Unrecognized equity return (168) (2) (168) (2) — Unamortized loss on reacquired debt (3) 62 62 — Pension and postretirement-related regulatory asset (3) 637 34 22 Hurricane Harvey restoration costs (3) 68 64 4 Regulatory assets related to TCJA (3) (4) 30 23 7 Asset retirement obligation (3) 131 26 94 Other regulatory assets-not earning a return (5) 147 57 48 Other regulatory assets 422 29 16 Total non-current regulatory assets 2,117 915 191 Total regulatory assets 2,129 915 203 Regulatory Liabilities: Current regulatory liabilities (6) 47 — 47 Non-current regulatory liabilities: Regulatory liabilities related to TCJA (4) 1,582 821 442 Estimated removal costs 1,429 244 637 Other regulatory liabilities 463 223 140 Total non-current regulatory liabilities 3,474 1,288 1,219 Total regulatory liabilities 3,521 1,288 1,266 Total regulatory assets and liabilities, net $ (1,392) $ (373) $ (1,063) (1) Current regulatory assets are included in Prepaid expenses and other current assets in the Registrants’ respective Consolidated Balance Sheets. (2) The unrecognized equity return will be recognized as it is recovered in rates through 2024. The timing of CenterPoint Energy’s and Houston Electric’s recognition of the equity return will vary each period based on amounts actually collected during the period. The actual amounts recognized are adjusted at least annually to correct any over-collections or under-collections during the preceding 12 months. CenterPoint Energy and Houston Electric Year Ended December 31, 2020 2019 2018 (in millions) Allowed equity return recognized $ 31 $ 45 $ 74 (3) Substantially all of these regulatory assets are not earning a return. (4) The EDIT and deferred revenues will be recovered or refunded to customers as required by tax and regulatory authorities. See Note 15 for additional information. The weighted average recovery periods of Regulatory assets related to TCJA for CenterPoint Energy, Houston Electric and CERC are 4 years, 5 years and 3 years, respectively. (5) Regulatory assets acquired in the Merger and not earning a return were recorded at fair value as of the Merger Date. Such fair value adjustments are recognized over time until the regulatory asset is recovered. The weighted average recovery periods of Other regulatory assets-not earning a return for CenterPoint Energy, Houston Electric and CERC are 14 years, 11 years and 27 years, respectively. (6) Current regulatory liabilities are included in Other current liabilities in each of the Registrants’ respective Consolidated Balance Sheets. Houston Electric Base Rate Case (CenterPoint Energy and Houston Electric) On April 5, 2019, and subsequently adjusted in errata filings in May and June 2019, Houston Electric filed its base rate application with the PUCT and the cities in its service area to change its rates, seeking approval for revenue increases of approximately $194 million, among other requests. On January 23, 2020, Houston Electric filed a Stipulation and Settlement Agreement with the PUCT that provided for the following, among other things: • an overall revenue requirement increase of approximately $13 million; • an ROE of 9.4%; • a capital structure of 57.5% debt/42.5% equity; • a refund of unprotected EDIT of $105 million plus carrying costs over approximately 30-36 months; and • recovery of all retail transmission related costs through the TCRF. Also, Houston Electric is not required to make a one-time refund of capital recovery from its TCOS and DCRF mechanisms. Future TCOS filings will take into account both ADFIT and EDIT until the final order from Houston Electric’s next base rate proceeding. No rate base items are required to be written off; however, approximately $12 million in rate case expenses were written off in 2019. A base rate application must be filed for Houston Electric no later than four years from the date of the PUCT’s final order in the proceeding. Additionally, Houston Electric will not file a DCRF in 2020, nor will a subsequent separate proceeding with the PUCT be instituted regarding EDIT on Houston Electric’s securitized assets. Furthermore, under the terms of the Stipulation and Settlement Agreement, Houston Electric agreed to adopt certain ring-fencing measures to increase its financial separateness from CenterPoint Energy. The PUCT approved the Stipulation and Settlement Agreement at its February 14, 2020 open meeting and issued a final order on March 9, 2020. The PUCT declined to impose a dividend restriction in the final order. The rates were implemented on April 23, 2020. CenterPoint Energy and Houston Electric record pre-tax expense for (i) probable disallowances of capital investments and (ii) customer refund obligations and costs deferred in regulatory assets when recovery of such amounts is no longer considered probable. COVID-19 Regulatory Matters Governors, public utility commissions and other authorities in the states in which the Registrants operate have issued a number of different orders related to the COVID-19 pandemic, including orders addressing customer non-payment and disconnection. Although the disconnect moratoriums have either expired or may expire during the second quarter of 2021 in certain of the Registrants’ service territories, CenterPoint Energy continues to support those customers who may need payment assistance, arrangements or extensions. On March 26, 2020, the PUCT issued two orders related to COVID-19 issues that affect Houston Electric. First, the PUCT issued an order related to accrual of regulatory assets granting authority for utilities to record as a regulatory asset expenses resulting from the effects of COVID-19. In the order, the PUCT noted that it will consider whether a utility’s request for recovery of the regulatory asset is reasonable and necessary in a future proceeding. Second, the PUCT issued an order related to the COVID-19 ERP, as modified, which, in light of the disaster declarations issued by the governor of Texas, authorized a customer assistance program for certain residential customers of electric service in areas of Texas open to customer choice, which includes Houston Electric’s service territory. The PUCT issued an order on August 27, 2020 to conclude the COVID-19 ERP. The PUCT determined that enrollment in the COVID-19 ERP would end on August 31, 2020 and benefits under the program ended on September 30, 2020. Final claims for reimbursement were required to be submitted to the transmission and distribution utilities by November 30, 2020. The transmission and distribution utilities must file a tariff rider cancellation seven days before the date on which it is estimated that revenues from the COVID-19 ERP are approximately equal to its program expenses. Final program reports were required to be submitted to the PUCT by January 15, 2021. The COVID-19 ERP allows for any over/under collection of program expenses to be recorded as a regulatory asset or liability. Houston Electric may seek recovery of such regulatory asset or liability in its next DCRF, TCRF or base rate case proceeding. CenterPoint Energy’s and Houston Electric’s COVID-19 ERP regulatory assets were $6 million as of December 31, 2020. Commissions in all of Indiana Electric’s and CenterPoint Energy’s and CERC’s Natural Gas service territories have either (1) issued orders to record a regulatory asset for incremental bad debt expenses related to COVID-19, including costs associated with the suspension of disconnections and payment plans or (2) provided authority to recover bad debt expense through an existing tracking mechanism. CenterPoint Energy and CERC have recorded estimated incremental uncollectible receivables to the associated regulatory asset of $22 million and $19 million, respectively, as of December 31, 2020. In some of the states in which the Registrants operate, public utility commissions have authorized utilities to employ deferred accounting authority for certain COVID-19 related costs which ensure the safety and health of customers, employees, and contractors, that would not have been incurred in the normal course of business. CERC’s Natural Gas service territories in Minnesota and Arkansas will include any offsetting savings in the deferral. Other jurisdictions where the Registrants operate may require them to offset the deferral with savings as well. ERCOT Loan Agreement (CenterPoint Energy and Houston Electric) On April 13, 2020, in connection with the PUCT’s COVID-19 ERP, Houston Electric entered into a no-interest loan agreement with ERCOT pursuant to which ERCOT loaned Houston Electric approximately $5 million to provide for an initial fund balance for reimbursement. The ERCOT loan was repaid on December 15, 2020.

Stock-Based Incentive Compensat

Stock-Based Incentive Compensation Plans and Employee Benefit Plans	12 Months Ended
	Dec. 31, 2020
Disclosure of Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Abstract]
Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Text Block]	Stock-Based Incentive Compensation Plans and Employee Benefit Plans (a) Stock-Based Incentive Compensation Plans (CenterPoint Energy) CenterPoint Energy has LTIPs that provide for the issuance of stock-based incentives, including stock options, performance awards, restricted stock unit awards and restricted and unrestricted stock awards to officers, employees and non-employee directors. Approximately 14 million shares of Common Stock are authorized under these plans for awards. CenterPoint Energy issues new shares of its Common Stock to satisfy stock-based payments related to LTIPs. Equity awards are granted to employees without cost to the participants. Compensation costs for the performance and stock unit awards granted under LTIPs are measured using fair value and expected achievement levels on the grant date. For performance awards with operational goals, the achievement levels are revised as goals are evaluated. The fair value of awards granted to employees is based on the closing stock price of CenterPoint Energy’s Common Stock on the grant date. The compensation expense is recorded on a straight-line basis over the vesting period. Forfeitures are estimated on the date of grant based on historical averages and estimates are updated periodically throughout the vesting period. The performance awards granted in 2020, 2019 and 2018 are distributed based upon the achievement of certain objectives over a three-year performance cycle. The stock unit awards granted in 2020, 2019 and 2018 are service based. The stock unit awards generally vest at the end of a three-year period, provided, however, that stock unit awards granted to non-employee directors vested immediately upon grant. Upon vesting, both the performance and stock unit awards are issued to the participants along with the value of dividend equivalents earned over the performance cycle or vesting period. The following table summarizes CenterPoint Energy’s expenses related to LTIPs for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 (in millions) LTIP compensation expense (1) $ 38 $ 28 $ 26 Income tax benefit recognized 9 7 6 Actual tax benefit realized for tax deductions 5 12 5 (1) Amounts presented in the table above are included in Operation and maintenance expense in CenterPoint Energy’s Statements of Consolidated Income and shown prior to any amounts capitalized. The following tables summarize CenterPoint Energy’s LTIP activity for 2020: Year Ended December 31, 2020 Shares Weighted-Average Remaining Average Aggregate Intrinsic Value (2) (Millions) Performance Awards (1) Outstanding and nonvested as of December 31, 2019 3,332 $ 28.36 Granted 2,022 23.82 Forfeited or canceled (1,128) 26.89 Vested and released to participants (326) 26.64 Outstanding and nonvested as of December 31, 2020 3,900 $ 26.58 1.2 $ 51 Stock Unit Awards Outstanding and nonvested as of December 31, 2019 966 $ 28.46 Granted 980 21.53 Forfeited or canceled (129) 27.67 Vested and released to participants (528) 22.51 Outstanding and nonvested as of December 31, 2020 1,289 $ 25.71 1.2 $ 28 (1) Reflects maximum performance achievement. (2) Reflects the impact of current expectations of achievement and stock price. The weighted average grant date fair values per unit of awards granted were as follows for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 (in millions, except for per unit amounts) Performance Awards Weighted-average grant date fair value per unit of awards granted $ 23.82 $ 31.16 $ 26.74 Total intrinsic value of awards received by participants 9 36 12 Vested grant date fair value 9 20 9 Stock Unit Awards Weighted-average grant date fair value per unit of awards granted $ 21.53 $ 31.07 $ 26.62 Total intrinsic value of awards received by participants 12 15 9 Vested grant date fair value 12 9 7 As of December 31, 2020, there was $34 million of total unrecognized compensation cost related to nonvested performance and stock unit awards which is expected to be recognized over a weighted-average period of 1.9 years. (b) Pension Benefits (CenterPoint Energy) CenterPoint Energy maintains a non-contributory qualified defined benefit pension plan covering eligible employees, with benefits determined using a cash balance formula. In addition to the non-contributory qualified defined benefit pension plan, CenterPoint Energy maintains unfunded non-qualified benefit restoration plans which allow participants to receive the benefits to which they would have been entitled under CenterPoint Energy’s non-contributory qualified pension plan except for federally mandated limits on qualified plan benefits or on the level of compensation on which qualified plan benefits may be calculated. As a result of the Merger, CenterPoint Energy now also maintains three additional qualified defined benefit pension plans, two of which are closed to new participants and one of which is completely frozen, and a non-qualified supplemental retirement plan. The defined benefit pension plans cover eligible full-time regular employees and retirees of Vectren and are primarily non-contributory. CenterPoint Energy’s net periodic cost includes the following components relating to pension, including the non-qualified benefit plans: Year Ended December 31, 2020 2019 2018 (in millions) Service cost (1) $ 43 $ 40 $ 37 Interest cost (2) 75 96 79 Expected return on plan assets (2) (112) (105) (107) Amortization of prior service cost (2) — 9 9 Amortization of net loss (2) 41 52 43 Settlement cost (2) (3) 2 2 — Curtailment gain (2) (4) — (1) — Net periodic cost $ 49 $ 93 $ 61 (1) Amounts presented in the table above are included in Operation and maintenance expense in CenterPoint Energy’s Statements of Consolidated Income, net of regulatory deferrals and amounts capitalized. (2) Amounts presented in the table above are included in Other, net in CenterPoint Energy’s Statements of Consolidated Income, net of regulatory deferrals. (3) A one-time, non-cash settlement cost is required when the total lump sum distributions or other settlements of plan benefit obligations during a plan year exceed the service cost and interest cost components of the net periodic cost for that year. In 2020 and 2019, CenterPoint Energy recognized a non-cash settlement cost due to lump sum settlement payments. (4) A curtailment gain or loss is required when the expected future services of a significant number of employees are reduced or eliminated for the accrual of benefits. In 2019, CenterPoint Energy recognized a pension curtailment gain related to employees who were terminated after the Merger Date. CenterPoint Energy used the following assumptions to determine net periodic cost relating to pension benefits: Year Ended December 31, 2020 2019 2018 Discount rate 3.20 % 4.35 % 3.65 % Expected return on plan assets 5.75 6.00 6.00 Rate of increase in compensation levels 4.95 4.60 4.45 In determining net periodic benefit cost, CenterPoint Energy uses fair value, as of the beginning of the year, as its basis for determining expected return on plan assets. The following table summarizes changes in the benefit obligation, plan assets, the amounts recognized in the Consolidated Balance Sheets as well as the key assumptions of CenterPoint Energy’s pension plans. The measurement dates for plan assets and obligations were December 31, 2020 and 2019. December 31, 2020 2019 (in millions, except for actuarial assumptions) Change in Benefit Obligation Benefit obligation, beginning of year $ 2,453 $ 2,013 Plan obligations assumed in Merger — 332 Service cost 43 40 Interest cost 75 96 Benefits paid (207) (244) Actuarial (gain) loss (1) 143 216 Plan amendment — 1 Curtailment — (1) Benefit obligation, end of year 2,507 2,453 Change in Plan Assets Fair value of plan assets, beginning of year 2,005 1,516 Plan assets assumed in Merger — 286 Employer contributions 86 109 Benefits paid (207) (244) Actual investment return 251 338 Fair value of plan assets, end of year 2,135 2,005 Funded status, end of year $ (372) $ (448) Amounts Recognized in Balance Sheets Current liabilities-other $ (8) $ (8) Other liabilities-benefit obligations (364) (440) Net liability, end of year $ (372) $ (448) Actuarial Assumptions Discount rate (2) 2.45 % 3.20 % Expected return on plan assets (3) 5.00 5.75 Rate of increase in compensation levels 5.05 4.95 Interest crediting rate 2.25 3.25 (1) Significant sources of loss for 2020 include the decrease in discount rate from 3.20% to 2.45%, partially offset by significant sources of gain that include actual return on plan assets exceeding expected return on assets during 2020. Significant sources of loss for 2019 include the decrease in discount rate from 4.35% to 3.20%. (2) The discount rate assumption was determined by matching the projected cash flows of CenterPoint Energy’s plans against a hypothetical yield curve of high-quality corporate bonds represented by a series of annualized individual discount rates from one-half to 99 years. (3) The expected rate of return assumption was developed using the targeted asset allocation of CenterPoint Energy’s plans and the expected return for each asset class. The following table displays pension benefits related to CenterPoint Energy’s pension plans that have accumulated benefit obligations in excess of plan assets: December 31, 2020 2019 Pension Pension Pension Pension (in millions) Accumulated benefit obligation $ 2,427 $ 68 $ 2,352 $ 68 Projected benefit obligation 2,440 68 2,385 68 Fair value of plan assets 2,135 — 2,005 — The accumulated benefit obligation for all defined benefit pension plans on CenterPoint Energy’s Consolidated Balance Sheets was $2,495 million and $2,420 million as of December 31, 2020 and 2019, respectively. (c) Postretirement Benefits CenterPoint Energy provides certain healthcare and life insurance benefits for eligible retired employees on both a contributory and non-contributory basis. The Registrants’ employees (other than employees of Vectren and its subsidiaries) who were hired before January 1, 2018 and who have met certain age and service requirements at retirement, as defined in the plans, are eligible to participate in these benefit plans. Employees hired on or after January 1, 2018 are not eligible for these benefits, except that such employees represented by IBEW Local Union 66 are eligible to participate in certain of the benefits, subject to the applicable age and service requirements. With respect to retiree medical and prescription drug benefits, and, effective January 1, 2021, dental and vision benefits, employees represented by the IBEW Local Union 66 who retire on or after January 1, 2017, and their dependents, receive any such benefits exclusively through the NECA/IBEW Family Medical Care Plan pursuant to the terms of the applicable collective bargaining agreement. Houston Electric and CERC are required to fund a portion of their obligations in accordance with rate orders. All other obligations are funded on a pay-as-you-go basis. CenterPoint Energy, through Vectren, also maintains a postretirement benefit plan that provides health care and life insurance benefits, which are a combination of self-insured and fully insured programs, to eligible Vectren retirees on both a contributory and non-contributory basis. Postretirement benefits are accrued over the active service period of employees. The net postretirement benefit cost includes the following components: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Service cost (1) $ 2 $ — $ 1 $ 3 $ 1 $ 1 $ 2 $ — $ 1 Interest cost (2) 11 5 3 15 7 5 13 8 4 Expected return on plan assets (2) (5) (4) (1) (5) (4) (1) (5) (4) (1) Amortization of prior service cost (credit) (2) (4) (5) 1 (5) (6) 1 (5) (5) 1 Net postretirement benefit cost (credit) $ 4 $ (4) $ 4 $ 8 $ (2) $ 6 $ 5 $ (1) $ 5 (1) Amounts presented in the table above are included in Operation and maintenance expense in each of the Registrants’ respective Statements of Consolidated Income, net of regulatory deferrals and amounts capitalized. (2) Amounts presented in the table above are included in Other, net in each of the Registrants’ respective Statements of Consolidated Income, net of regulatory deferrals. The following assumptions were used to determine net periodic cost relating to postretirement benefits: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC Discount rate 3.25 % 3.25 % 3.25 % 3.20 % 3.20 % 3.20 % 3.60 % 3.60 % 3.60 % Expected return on plan assets 3.95 4.05 3.35 4.60 4.70 4.15 4.55 4.75 3.85 The following table summarizes changes in the benefit obligation, plan assets, the amounts recognized in consolidated balance sheets and the key assumptions of the postretirement plans. The measurement dates for plan assets and benefit obligations were December 31, 2020 and 2019. December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions, except for actuarial assumptions) Change in Benefit Obligation Benefit obligation, beginning of year $ 356 $ 162 $ 102 $ 331 $ 166 $ 110 Plan obligations assumed in Merger — — — 37 — — Service cost 2 — 1 3 1 1 Interest cost 11 5 3 15 7 5 Participant contributions 6 2 2 8 2 4 Benefits paid (22) (10) (6) (26) (13) (8) Plan amendment — — — 9 3 5 Actuarial (gain) loss (1) 13 9 3 (21) (4) (15) Benefit obligation, end of year 366 168 105 356 162 102 Change in Plan Assets Fair value of plan assets, beginning of year 128 101 27 114 89 25 Employer contributions 10 3 3 17 10 3 Participant contributions 6 2 2 8 2 4 Benefits paid (22) (10) (6) (26) (13) (8) Actual investment return 12 10 2 15 13 3 Fair value of plan assets, end of year 134 106 28 128 101 27 Funded status, end of year $ (232) $ (62) $ (77) $ (228) $ (61) $ (75) Amounts Recognized in Balance Sheets Current liabilities-other $ (9) $ — $ (3) $ (8) $ — $ (3) Other liabilities-benefit obligations (223) (62) (74) (220) (61) (72) Net liability, end of year $ (232) $ (62) $ (77) $ (228) $ (61) $ (75) Actuarial Assumptions Discount rate (2) 2.50 % 2.50 % 2.50 % 3.25 % 3.25 % 3.25 % Expected return on plan assets (3) 3.20 3.30 2.85 3.95 4.05 3.35 Medical cost trend rate assumed for the next year - Pre-65 5.25 5.25 5.25 5.50 5.50 5.50 Medical/prescription drug cost trend rate assumed for the next year - Post-65 19.70 19.70 19.70 5.75 5.75 5.75 Prescription drug cost trend rate assumed for the next year - Pre-65 7.50 7.50 7.50 8.00 8.00 8.00 Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.50 4.50 4.50 4.50 4.50 4.50 Year that the cost trend rates reach the ultimate trend rate - Pre-65 2028 2028 2028 2028 2028 2028 Year that the cost trend rates reach the ultimate trend rate - Post-65 2029 2029 2029 2029 2029 2029 (1) Significant sources of loss for 2020 include the decrease in discount rate from 3.25% to 2.50%, partially offset by significant sources of gain that include the decrease in interest credit rate from 3.25% to 2.25% and change in mortality projection scale from MP2019 to MP2020. Significant sources of gain for 2019 include favorable cost trend rates and benefit claims experience in addition to the change in mortality projection scale from MP2018 to MP2019. (2) The discount rate assumption was determined by matching the projected cash flows of the plans against a hypothetical yield curve of high-quality corporate bonds represented by a series of annualized individual discount rates from one-half to 99 years. (3) The expected rate of return assumption was developed using the targeted asset allocation of the plans and the expected return for each asset class. (d) Accumulated Other Comprehensive Income (Loss) (CenterPoint Energy and CERC) CenterPoint Energy recognizes the funded status of its pension and other postretirement plans on its Consolidated Balance Sheets. To the extent this obligation exceeds amounts previously recognized in the Statements of Consolidated Income, CenterPoint Energy records a regulatory asset for that portion related to its rate regulated utilities. To the extent that excess liability does not relate to a rate regulated utility, the offset is recorded as a reduction to equity in accumulated other comprehensive income. Amounts recognized in accumulated other comprehensive loss (gain) consist of the following: December 31, 2020 2019 Pension Postretirement Pension Postretirement CenterPoint Energy CenterPoint Energy CERC CenterPoint Energy CenterPoint Energy CERC (in millions) Unrecognized actuarial loss (gain) $ 109 $ (14) $ (12) $ 105 $ (16) $ (12) Unrecognized prior service cost — 7 7 — 7 7 Net amount recognized in accumulated other comprehensive loss (gain) $ 109 $ (7) $ (5) $ 105 $ (9) $ (5) The changes in plan assets and benefit obligations recognized in other comprehensive income during 2020 are as follows: Pension Postretirement CenterPoint Energy CenterPoint Energy CERC (in millions) Net loss (gain) $ 11 $ 2 $ — Amortization of net loss (7) — — Amortization of prior service cost — — — Total recognized in comprehensive income $ 4 $ 2 $ — Total recognized in net periodic costs and Other comprehensive income $ 53 $ 6 $ 4 (e) Pension Plan Assets (CenterPoint Energy) In managing the investments associated with the benefit plans, CenterPoint Energy’s objective is to achieve and maintain a fully funded plan. This objective is expected to be achieved through an investment strategy that manages liquidity requirements while maintaining a long-term horizon in making investment decisions and efficient and effective management of plan assets. As part of the investment strategy discussed above, CenterPoint Energy maintained the following weighted average allocation targets for its pension plans as of December 31, 2020: Minimum Maximum U.S. equity 19 % 29 % International equity 8 % 18 % Real estate 3 % 9 % Fixed income 52 % 62 % Cash 0 % 2 % The following tables set forth by level, within the fair value hierarchy (see Note 10), CenterPoint Energy’s pension plan assets at fair value as of December 31, 2020 and 2019: Fair Value Measurements as of December 31, 2020 2019 (Level 1) (Level 2) (Level 3) Total (Level 1) (Level 2) (Level 3) Total (in millions) Cash $ 29 $ — $ — $ 29 $ (7) $ — $ — $ (7) Corporate bonds: Investment grade or above — 767 — 767 — 699 — 699 Equity securities: U.S. companies 76 — — 76 69 — — 69 Cash received as collateral from securities lending 81 — — 81 61 — — 61 U.S. treasuries 225 — — 225 232 — — 232 Mortgage backed securities — 5 — 5 — 8 — 8 Asset backed securities — 3 — 3 — 3 — 3 Municipal bonds — 43 — 43 — 44 — 44 Mutual funds (2) 301 — — 301 270 — — 270 International government bonds — 18 — 18 — 21 — 21 Obligation to return cash received as collateral from securities lending (81) — — (81) (61) — — (61) Total investments at fair value $ 631 $ 836 $ — $ 1,467 $ 564 $ 775 $ — $ 1,339 Investments measured by net asset value per share or its equivalent (1) (2) 668 666 Total Investments $ 2,135 $ 2,005 (1) Represents investments in common collective trust funds. (2) The amounts invested in mutual funds and common collective trust funds were allocated as follows: As of December 31, 2020 2019 Mutual Funds Common Collective Trust Funds Mutual Funds Common Collective Trust Funds International equities 14 % 37 % 31 % 29 % U.S. equities 55 % 3 % 49 % 51 % Real estate 5 % 1 % 1 % 6 % Fixed income 27 % 59 % 19 % 14 % Level 2 investments, which do not have a quoted price in active market, are valued using the market data provided by independent pricing services or major market makers, to arrive at a price a dealer would pay for the security. The pension plans utilized both exchange traded and over-the-counter financial instruments such as futures, interest rate options and swaps that were marked to market daily with the gains/losses settled in the cash accounts. The pension plans did not include any holdings of CenterPoint Energy Common Stock as of December 31, 2020 or 2019. (f) Postretirement Plan Assets In managing the investments associated with the postretirement plans, the Registrants’ primary objective is to preserve and improve the funded status of the plan, while minimizing volatility. This objective is expected to be achieved through an investment strategy that manages liquidity requirements while maintaining a long-term horizon in making investment decisions and efficient and effective management of plan assets. As part of the investment strategy discussed above, the Registrants maintained the following weighted average allocation targets for the postretirement plans as of December 31, 2020: CenterPoint Energy Houston Electric CERC Minimum Maximum Minimum Maximum Minimum Maximum U.S. equities 13 % 23 % 13 % 23 % 15 % 25 % International equities 3 % 13 % 3 % 13 % 2 % 12 % Fixed income 69 % 79 % 69 % 79 % 68 % 78 % Cash 0 % 2 % 0 % 2 % 0 % 2 % The following table presents mutual funds by level, within the fair value hierarchy, the Registrants’ postretirement plan assets at fair value as of December 31, 2020 and 2019: Fair Value Measurements as of December 31, 2020 2019 Mutual Funds Total Total (in millions) CenterPoint Energy $ 134 $ — $ — $ 134 $ 128 $ — $ — $ 128 Houston Electric 106 — — 106 101 — — 101 CERC 28 — — 28 27 — — 27 The amounts invested in mutual funds were allocated as follows: As of December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC Fixed income 74 % 74 % 72 % 71 % 71 % 69 % U.S. equities 19 % 18 % 21 % 21 % 21 % 24 % International equities 7 % 8 % 7 % 8 % 8 % 7 % (g) Benefit Plan Contributions The Registrants made the following contributions in 2020 and expect to make the following minimum contributions in 2021 to the indicated benefit plans below: Contributions in 2020 Expected Minimum Contributions in 2021 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Qualified pension plans $ 76 $ — $ — $ 53 $ — $ — Non-qualified pension plans 10 — — 8 — — Postretirement benefit plans 10 3 3 9 1 3 The following benefit payments are expected to be paid by the pension and postretirement benefit plans: Pension Postretirement Benefits CenterPoint CenterPoint Houston Electric CERC (in millions) 2021 $ 174 $ 17 $ 8 $ 4 2022 176 18 9 5 2023 176 20 9 5 2024 175 21 10 5 2025 173 21 10 6 2026-2030 775 109 53 30 (h) Savings Plan CenterPoint Energy maintains the CenterPoint Energy Savings Plan, a tax-qualified employee savings plan that includes a cash or deferred arrangement under Section 401(k) of the Code, and an employee stock ownership plan under Section 4975(e)(7) of the Code. Under the plan, participating employees may make pre-tax or Roth contributions and, if eligible, after-tax contributions up to certain federally mandated limits. Participating Registrants provide matching contributions and, as of January 1, 2020, for certain eligible employees, nonelective contributions up to certain limits. CenterPoint Energy, through the Merger, also acquired additional defined contribution retirement savings plans sponsored by Vectren and its subsidiaries that are qualified under sections 401(a) and 401(k) of the Code, one of which merged into the CenterPoint Energy Savings Plan as of January 1, 2020. The CenterPoint Energy Savings Plan has significant holdings of Common Stock. As of December 31, 2020, 10,150,958 shares of Common Stock were held by the savings plan, which represented approximately 8% of its investments. Given the concentration of the investments in Common Stock, the savings plan and its participants have market risk related to this investment. The savings plan limits the percentage of future contributions that can be invested in Common Stock to 25% and prohibits transfers of account balances where the transfer would result in more than 25% of a participant’s total account balance invested in Common Stock. CenterPoint Energy allocates the savings plan benefit expense to Houston Electric and CERC related to their respective employees. The following table summarizes the Registrants’ savings plan benefit expense for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Savings plan benefit expenses (1) $ 58 $ 18 $ 19 $ 58 $ 18 $ 18 $ 43 $ 17 $ 18 (1) Amounts presented in the table above are included in Operation and maintenance expense in the Registrants’ respective Statements of Consolidated Income and shown prior to any amounts capitalized. (i) Other Benefits Plans The Registrants participate in CenterPoint Energy’s plans that provide postemployment benefits for certain former or inactive employees, their beneficiaries and covered dependents, after employment but before retirement (primarily healthcare and life insurance benefits for participants in the long-term disability plan). CenterPoint Energy maintains non-qualified deferred compensation plans, including plans acquired in the Merger, that provide benefits payable to eligible directors, officers and select employees or their designated beneficiaries at specified future dates or upon termination, retirement or death. Benefit payments are made from the general assets of the participating Registrants or, in the case of certain plans acquired in the Merger, from a rabbi trust that is a grantor trust and remains subject to the claims of general creditors under applicable state and federal law. Expenses related to other benefit plans were recorded as follows: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Postemployment benefits $ 1 $ 1 $ — $ 2 $ 1 $ 1 $ 3 $ 4 $ 1 Deferred compensation plans 4 1 — 4 1 — 3 1 — Amounts related to other benefit plans were included in Benefit Obligations in the Registrants’ accompanying Consolidated Balance Sheets as follows: December 31, 2020 December 31, 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Postemployment benefits $ 8 $ 3 $ 5 $ 11 $ 3 $ 7 Deferred compensation plans 43 7 2 41 8 3 Split-dollar life insurance arrangements 32 1 — 32 1 — (j) Change in Control Agreements and Other Employee Matters CenterPoint Energy has a change in control plan, which was amended and restated on May 1, 2017. The plan generally provides, to the extent applicable, in the case of a change in control of CenterPoint Energy and covered termination of employment, for severance benefits of up to three times annual base salary plus bonus, and other benefits. Certain CenterPoint Energy officers, including the Executive Chairman, are participants under the plan. Certain key employees of Vectren and its subsidiaries have change in control agreements or employment agreements that provide payments and other benefits upon a covered termination of employment. As of December 31, 2020, the Registrants’ employees were covered by collective bargaining agreements as follows: Percentage of Employees Covered Agreement Expiration CenterPoint Energy Houston Electric CERC IBEW Local 66 May 2023 15 % 53 % — OPEIU Local 12 May 2021 2 % — 3 % OPEIU Mankato March 2021 — % — — % Gas Workers Union Local 340 April 2025 4 % — 12 % IBEW Locals 1393 and USW Locals 12213 & 7441 December 2023 3 % — — % IBEW Locals 949 December 2025 3 % — 7 % USW Locals 13-227 June 2022 4 % — 13 % USW Locals 13-1 July 2022 — % — 1 % IBEW Local 702 June 2022 3 % — — Teamsters Local 135 September 2021 1 % — — UWUA Local 175 October 2021 1 % — — Total 36 % 53 % 36 %

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments [Text Block]	Derivative Instruments The Registrants are exposed to various market risks. These risks arise from transactions entered into in the normal course of business. The Registrants utilize derivative instruments such as physical forward contracts, swaps and options to mitigate the impact of changes in commodity prices, weather and interest rates on operating results and cash flows. (a) Non-Trading Activities Commodity Derivative Instruments (CenterPoint Energy). CenterPoint Energy, through its Indiana utilities, enter into certain derivative instruments to mitigate the effects of commodity price movements. Outstanding derivative instruments designated as economic hedges at the Indiana Utilities hedge long-term variable rate natural gas purchases. The Indiana utilities have authority to refund and recover mark-to-market gains and losses associated with hedging natural gas purchases, and thus the gains and losses on derivatives are deferred in a regulatory liability or asset. All other financial instruments do not qualify or are not designated as cash flow or fair value hedges. On February 24, 2020, CenterPoint Energy, through its subsidiary CERC Corp., entered into the Equity Purchase Agreement to sell the Energy Services Disposal Group. The transaction closed on June 1, 2020. As a result, the following disclosures do not include the Energy Services Disposal Group. See Note 4 for further information. Interest Rate Risk Derivative Instruments. From time to time, the Registrants may enter into interest rate derivatives that are designated as economic or cash flow hedges. The objective of these hedges is to offset risk associated with interest rates borne by the Registrants in connection with an anticipated future fixed rate debt offering or other exposure to variable rate debt. The Indiana Utilities have authority to refund and recover mark-to-market gains and losses associated with hedging financing activity, and thus the gains and losses on derivatives are deferred in a regulatory liability or asset. For the impacts of cash flow hedges to Accumulated other comprehensive income, see Note 13. The table below summarizes the Registrants’ outstanding interest rate hedging activity: December 31, 2020 December 31, 2019 Hedging Classification Notional Principal (in millions) Economic hedge (1) $ 84 $ 84 (1) Relates to interest rate derivative instruments at SIGECO. Weather Hedges (CenterPoint Energy and CERC). CenterPoint Energy and CERC have weather normalization or other rate mechanisms that largely mitigate the impact of weather on Natural Gas in Arkansas, Indiana, Louisiana, Mississippi, Minnesota, Ohio and Oklahoma, as applicable. CenterPoint Energy’s and CERC’s Natural Gas in Texas and CenterPoint Energy’s electric operations in Texas and Indiana do not have such mechanisms, although fixed customer charges are historically higher in Texas for Natural Gas compared to its other jurisdictions. As a result, fluctuations from normal weather may have a positive or negative effect on CenterPoint Energy’s and CERC’s Natural Gas’ results in Texas and on CenterPoint Energy’s electric operations’ results in its Texas and Indiana service territories. CenterPoint Energy and CERC, as applicable, enter into winter season weather hedges from time to time for certain Natural Gas jurisdictions and electric operations’ service territory to mitigate the effect of fluctuations from normal weather on results of operations and cash flows. These weather hedges are based on heating degree days at 10-year normal weather. Houston Electric and Indiana Electric do not enter into weather hedges. (b) Derivative Fair Values and Income Statement Impacts The following tables present information about derivative instruments and hedging activities. The first table provides a balance sheet overview of Derivative Assets and Liabilities as of December 31, 2020 and 2019, while the last table provides a breakdown of the related income statement impacts for the years ending December 31, 2020, 2019 and 2018. Fair Value of Derivative Instruments and Hedged Items CenterPoint Energy December 31, 2020 December 31, 2019 Balance Sheet Location Derivative Derivative Derivative Derivative (in millions) Derivatives not designated as hedging instruments: Natural gas derivatives (1) Current Liabilities: Non-trading derivative liabilities $ — $ 3 $ — $ 7 Natural gas derivatives (1) Other Liabilities: Non-trading derivative liabilities — 7 — 15 Interest rate derivatives Other Liabilities — 20 — 10 Indexed debt securities derivative (2) Current Liabilities — 953 — 893 Total $ — $ 983 $ — $ 925 (1) Natural gas contracts are subject to master netting arrangements. This netting applies to all undisputed amounts due or past due. However, the mark-to-market fair value of each natural gas contract is in a liability position with no offsetting amounts (2) Derivative component of the ZENS obligation that represents the ZENS holder’s option to receive the appreciated value of the reference shares at maturity. See Note 12 for further information. Income Statement Impact of Hedge Accounting Activity (CenterPoint Energy) CenterPoint Energy Year Ended December 31, Income Statement Location 2020 2019 2018 (in millions) Effects of derivatives not designated as hedging instruments on the income statement: Indexed debt securities derivative Loss on indexed debt securities (60) (292) (232) Interest rate derivatives Gains in Other Income (Expense) — — 2 Total CenterPoint Energy $ (60) $ (292) $ (230) (c) Credit Risk Contingent Features (CenterPoint Energy) Certain of CenterPoint Energy’s derivative instruments contain provisions that require CenterPoint Energy’s debt to maintain an investment grade credit rating on its long-term unsecured unsubordinated debt from S&P and Moody’s. If CenterPoint Energy’s debt were to fall below investment grade, it would be in violation of these provisions, and the counterparties to the derivative instruments could request immediate payment. As of December 31, 2020 2019 (in millions) Aggregate fair value of derivatives with credit-risk-related contingent features in a liability position $ 20 $ 10 Fair value of collateral already posted 7 — Additional collateral required to be posted if credit risk contingent features triggered (1) 3 — (1) The maximum collateral required if further escalating collateral is triggered would equal the net liability position.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements [Text Block]	Fair Value Measurements Assets and liabilities that are recorded at fair value in the Registrants’ Consolidated Balance Sheets are categorized based upon the level of judgment associated with the inputs used to measure their value. Hierarchical levels, as defined below and directly related to the amount of subjectivity associated with the inputs to fair valuations of these assets and liabilities, are as follows: Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities at the measurement date. The types of assets carried at Level 1 fair value generally are exchange-traded derivatives and equity securities, as well as natural gas inventory that has been designated as the hedged item in a fair value hedge. Level 2: Inputs, other than quoted prices included in Level 1, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar instruments in active markets, and inputs other than quoted prices that are observable for the asset or liability. Fair value assets and liabilities that are generally included in this category are derivatives with fair values based on inputs from actively quoted markets. A market approach is utilized to value the Registrants’ Level 2 natural gas derivative assets or liabilities. CenterPoint Energy’s Level 2 indexed debt securities derivative is valued using an option model and a discounted cash flow model, which uses projected dividends on the ZENS-Related Securities and a discount rate as observable inputs. Level 3: Inputs are unobservable for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. Unobservable inputs reflect the Registrants’ judgments about the assumptions market participants would use in pricing the asset or liability since limited market data exists. The Registrants develop these inputs based on the best information available, including the Registrants’ own data. The Registrants determine the appropriate level for each financial asset and liability on a quarterly basis and recognize transfers between levels at the end of the reporting period. On February 24, 2020, CenterPoint Energy, through its subsidiary CERC Corp., entered into the Equity Purchase Agreement to sell the Energy Services Disposal Group. The transaction closed on June 1, 2020. As a result, the following disclosures do not include the Energy Services Disposal Group. See Note 4 for further information. The following tables present information about the Registrants’ assets and liabilities (including derivatives that are presented net) measured at fair value on a recurring basis as of December 31, 2020 and December 31, 2019, and indicate the fair value hierarchy of the valuation techniques utilized by the Registrants to determine such fair value. CenterPoint Energy December 31, 2020 December 31, 2019 Level 2 Level 3 Total Level 2 Level 3 Total Assets (in millions) Corporate equities $ 873 $ — $ — $ 873 $ 825 $ — $ — $ 825 Investments, including money market funds (1) 43 — — 43 49 — — 49 Total assets $ 916 $ — $ — $ 916 $ 874 $ — $ — $ 874 Liabilities Indexed debt securities derivative $ — $ 953 $ — $ 953 $ — $ 893 $ — $ 893 Interest rate derivatives — 20 — 20 — 10 — 10 Natural gas derivatives — 10 — 10 — 22 — 22 Total liabilities $ — $ 983 $ — $ 983 $ — $ 925 $ — $ 925 Houston Electric December 31, 2020 December 31, 2019 Level 2 Level 3 Total Level 2 Level 3 Total Assets (in millions) Investments, including money market funds (1) $ 26 $ — $ — $ 26 $ 32 $ — $ — $ 32 Total assets $ 26 $ — $ — $ 26 $ 32 $ — $ — $ 32 CERC December 31, 2020 December 31, 2019 Level 2 Level 3 Total Level 2 Level 3 Total Assets (in millions) Corporate equities $ 2 $ — $ — $ 2 $ 2 $ — $ — $ 2 Investments, including money market funds (1) 11 — — 11 11 — — 11 Total assets $ 13 $ — $ — $ 13 $ 13 $ — $ — $ 13 (1) Amounts are included in Prepaid and Other Current Assets in the Consolidated Balance Sheets. During 2020 and 2019, CenterPoint Energy did not have any assets or liabilities designated as Level 3. During 2018, CenterPoint Energy transferred $668 million of its indexed debt securities derivative from Level 3 to Level 2 to reflect changes in the significance of the unobservable inputs used in the valuation. Items Measured at Fair Value on a Nonrecurring Basis Based on the severity of the decline in Enable’s common unit price during the three months ended March 31, 2020 primarily due to the macroeconomic conditions related in part to the COVID-19 pandemic, combined with Enable’s announcement on April 1, 2020 to reduce its quarterly distributions per common unit by 50%, and the market outlook indicating excess supply and continued depressed crude oil and natural gas prices impacting the midstream oil and gas industry, CenterPoint Energy determined, in connection with its preparation of the financial statements, that an other than temporary decrease in the value of its investment in Enable had occurred. The impairment analysis compared the estimated fair value of CenterPoint Energy’s investment in Enable to its carrying value. The fair value of the investment was determined using multiple valuation methodologies under both the market and income approaches. Both of these approaches incorporate significant estimates and assumptions, including: Market Approach • quoted price of Enable’s common units; • recent market transactions of comparable companies; and • EBITDA to total enterprise multiples for comparable companies. Income Approach • Enable’s forecasted cash distributions; • projected cash flows of incentive distribution rights; • forecasted growth rate of Enable’s cash distributions; and • determination of the cost of equity, including market risk premiums. Weighting of the Different Approaches Significant unobservable inputs used include the growth rate applied to the projected cash distributions beyond 2020 and the discount rate used to determine the present value of the estimated future cash flows. Based on the significant unobservable estimates and assumptions required, CenterPoint Energy concluded that the fair value estimate should be classified as a Level 3 measurement within the fair value hierarchy. As a result of this analysis, CenterPoint Energy recorded an other than temporary impairment on its investment in Enable of $1,541 million during the year ended December 31, 2020, reducing the fair value of the investment to $848 million as of March 31, 2020. See Note 11 for further discussion of the impairment. During the year ended December 31, 2020, CenterPoint Energy recorded a goodwill impairment charge of $185 million in the Indiana Electric Integrated reporting unit, reducing the carrying value of the reporting unit to its fair value as of March 31, 2020. CenterPoint Energy and CERC performed their annual goodwill impairment tests in the third quarter of 2020 and determined that no goodwill impairment charge was required for any reporting unit as a result of those tests. See Note 6 for further information. As a result of classifying the Infrastructure Services and Energy Services Disposal Groups as held for sale, CenterPoint Energy and CERC recognized a goodwill impairment and loss on held for sale during the year ended December 31, 2020. CenterPoint Energy and CERC, as applicable, used the contractual sales price adjusted for estimated working capital and other contractual purchase price adjustments to determine fair value, which are Level 2 inputs. Using this market approach, the fair value of the Infrastructure Services Disposal Group as of March 31, 2020 was determined to be approximately $864 million and the fair value of the Energy Services Disposal Group as of March 31, 2020 was determined to be approximately 402000000. The same methodology was applied to estimate the fair value of the Infrastructure Services Disposal Group and Energy Services Disposal Group on the closing date and through the settlement of the net working capital adjustment, resulting in additional gains or losses upon sale during 2020 . See Note 4 for further information. Estimated Fair Value of Financial Instruments The fair values of cash and cash equivalents, investments in debt and equity securities classified as “trading” and short-term borrowings are estimated to be approximately equivalent to carrying amounts and have been excluded from the table below. The carrying amounts of non-trading derivative assets and liabilities and CenterPoint Energy’s ZENS indexed debt securities derivative are stated at fair value and are excluded from the table below. The fair value of each debt instrument is determined by multiplying the principal amount of each debt instrument by a combination of historical trading prices and comparable issue data. These liabilities, which are not measured at fair value in the Registrants’ Consolidated Balance Sheets, but for which the fair value is disclosed, would be classified as Level 2 in the fair value hierarchy. December 31, 2020 December 31, 2019 CenterPoint Energy (1) Houston Electric (1) CERC CenterPoint Energy (1) Houston Electric (1) CERC Long-term debt, including current maturities (in millions) Carrying amount $ 13,401 $ 5,019 $ 2,428 $ 15,093 $ 4,950 $ 2,546 Fair value 15,226 5,957 2,855 16,067 5,457 2,803 (1) Includes Securitization Bond debt.

Unconsolidated Affiliate (Cente

Unconsolidated Affiliate (CenterPoint Energy and CERC)	12 Months Ended
	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Unconsolidated Affiliate (CenterPoint Energy and CERC) [Text Block]	Unconsolidated Affiliates (CenterPoint Energy and CERC) CenterPoint Energy has the ability to significantly influence the operating and financial policies of Enable, a publicly traded MLP, and, accordingly, accounts for its investment in Enable’s common units using the equity method of accounting. Enable is considered to be a VIE because the power to direct the activities that most significantly impact Enable’s economic performance does not reside with the holders of equity investment at risk. However, CenterPoint Energy is not considered the primary beneficiary of Enable since it does not have the power to direct the activities of Enable that are considered most significant to the economic performance of Enable. As of December 31, 2020, CenterPoint Energy’s maximum exposure to loss related to Enable is limited to its investment in unconsolidated affiliate, its investment in Enable Series A Preferred Units and outstanding current accounts receivable from Enable. On February 16, 2021, Enable entered into the Enable Merger Agreement. For further information on the Enable Merger, see Note 22. Investment in Unconsolidated Affiliates (CenterPoint Energy): December 31, 2020 December 31, 2019 (in millions) Enable $ 782 $ 2,406 Other 1 2 Total $ 783 $ 2,408 CenterPoint Energy evaluates its equity method investments for impairment when factors indicate that a decrease in the value of its investment has occurred and the carrying amount of its investment may not be recoverable. An impairment loss, based on the excess of the carrying value over the estimated fair value of the investment, is recognized in earnings when an impairment is deemed to be other than temporary. Considerable judgment is used in determining if an impairment loss is other than temporary and the amount of any impairment. Based on the severity of the decline in Enable’s common unit price during the three months ended March 31, 2020 due to the macroeconomic conditions related in part to the COVID-19 pandemic, combined with Enable’s announcement on April 1, 2020 to reduce its quarterly distributions per common unit by 50%, and the market outlook indicating excess supply of crude oil and natural gas and continued depressed crude oil and natural gas prices impacting the midstream oil and gas industry, CenterPoint Energy determined, in connection with its preparation of the financial statements, that an other than temporary decrease in the value of its investment in Enable had occurred. CenterPoint Energy reduced the carrying value of its investment in Enable to its estimated fair value of $848 million as of March 31, 2020 and recognized an impairment charge of $1,541 million during the year ended December 31, 2020. Both the income approach and market approach were utilized to estimate the fair value of CenterPoint Energy’s equity investment in Enable, which includes common units, general partner interest and incentive distribution rights held by CenterPoint Energy through CNP Midstream. The determination of fair value considered a number of relevant factors including Enable’s common unit price and forecasted distributions, recent comparable transactions and the limited float of Enable’s publicly traded common units. As of December 31, 2020, CenterPoint Energy’s investment in Enable is $3.34 per unit and Enable’s common unit price closed at $5.26 per unit. See Note 10 for further discussion of the determination of fair value of CenterPoint Energy’s investment in Enable as of March 31, 2020. CenterPoint Energy did not identify a further decrease in value as of December 31, 2020. Equity in Earnings of Unconsolidated Affiliates, net (CenterPoint Energy): Year Ended December 31, 2020 (1) 2019 (2) 2018 (in millions) Enable (1) $ (1,428) $ 229 $ 307 Other — 1 — Total $ (1,428) $ 230 $ 307 (1) CenterPoint Energy recognized a loss of $1,428 million from its investment in Enable for the year ended December 31, 2020. This loss included an impairment charge on CenterPoint Energy’s investment in Enable of $1,541 million discussed above, and CenterPoint Energy’s interest in Enable’s $225 million impairment on an equity method investment. (2) Includes CenterPoint Energy’s share of Enable’s $86 million goodwill impairment recorded in the fourth quarter of 2019. Limited Partner Interest and Units Held in Enable (CenterPoint Energy): As of December 31, 2020 2019 Limited Partner Interest (1) Common Units Enable Series A Preferred Units (2) Limited Partner Interest (1) Common Units Enable Series A Preferred Units (2) CenterPoint Energy 53.7 % 233,856,623 14,520,000 53.7 % 233,856,623 14,520,000 OGE 25.5 % 110,982,805 — 25.5 % 110,982,805 — Public unitholders 20.8 % 90,710,464 — 20.8 % 90,361,937 — Total Units Outstanding 100.0 % 435,549,892 14,520,000 100.0 % 435,201,365 14,520,000 (1) Excludes the Enable Series A Preferred Units owned by CenterPoint Energy. (2) The carrying amount of the Enable Series A Preferred Units, reflected as Preferred units - unconsolidated affiliate on CenterPoint Energy’s Consolidated Balance Sheets, was $363 million as of both December 31, 2020 and 2019. No impairment charges or adjustment to carrying value were made as no observable price changes were identified in the current or prior reporting periods. Generally, sales to any person or entity (including a series of sales to the same person or entity) of more than 5% of the aggregate of the common units CenterPoint Energy owns in Enable or sales to any person or entity (including a series of sales to the same person or entity) by OGE of more than 5% of the aggregate of the common units it owns in Enable are subject to mutual rights of first offer and first refusal set forth in Enable’s Agreement of Limited Partnership. Interests Held in Enable GP (CenterPoint Energy): CenterPoint Energy and OGE held the following interests in Enable GP as of both December 31, 2020 and 2019: Management Rights (1) Incentive Distribution Rights (2) CenterPoint Energy (3) 50 % 40 % OGE 50 % 60 % (1) 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. (2) 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. (3) Held indirectly through CNP Midstream. Distributions Received from Enable (CenterPoint Energy and CERC): CenterPoint Energy Year Ended December 31, 2020 2019 2018 Per Unit Cash Distribution Per Unit Cash Distribution Per Unit Cash Distribution (in millions, except per unit amounts) Enable common units $ 0.8263 $ 193 $ 1.2970 $ 303 $ 1.2720 $ 297 Enable Series A Preferred Units (1) 2.5000 36 2.5000 36 2.5000 36 Total $ 229 $ 339 $ 333 (1) As of December 31, 2020, the Enable Series A Preferred Units annual distribution rate was 10%. On February 18, 2021, five years after the issue date, the Enable Series A Preferred Units annual distribution rate changed to a percentage of the Stated Series A Liquidation Preference per Series A Preferred unit equal to the sum of (a) Three-Month LIBOR, as calculated on each applicable date of determination, and (b)8.5%. Transactions with Enable (CenterPoint Energy and CERC): The transactions with Enable in the following tables exclude transactions with the Energy Services Disposal Group. See Note 4 for further information. CenterPoint Energy and CERC Year Ended December 31, 2020 2019 2018 (in millions) Natural gas expenses, including transportation and storage costs (1) $ 86 $ 86 $ 86 Reimbursement of support services (2) — — 4 (1) Included in Non-utility costs of revenues, including natural gas on CenterPoint Energy’s and CERC’s respective Statements of Consolidated Income. (2) Represents amounts billed for certain support services provided to Enable. Actual support services costs were recorded net of reimbursement. CenterPoint Energy and CERC December 31, 2020 2019 CenterPoint Energy (in millions) Accounts payable for natural gas purchases from Enable $ 9 $ 9 Accounts receivable for amounts billed for services provided to Enable 1 2 Summarized consolidated income (loss) information for Enable is as follows: Year Ended December 31, 2020 2019 2018 (in millions) Operating revenues $ 2,463 $ 2,960 $ 3,431 Cost of sales, excluding depreciation and amortization 965 1,279 1,819 Depreciation and amortization 420 433 398 Goodwill impairment 28 86 — Operating income 465 569 648 Net income attributable to Enable common units 52 360 485 Reconciliation of Equity in Earnings (Losses), net: CenterPoint Energy’s interest $ 28 $ 193 $ 262 Basis difference amortization (1) 87 47 47 Loss on dilution, net of proportional basis difference recognition (2) (11) (2) Impairment of CenterPoint Energy’s equity method investment in Enable (1,541) — — CenterPoint Energy’s equity in earnings (losses), net $ (1,428) $ 229 $ 307 (1) Equity in earnings of unconsolidated affiliate includes CenterPoint Energy’s share of Enable earnings adjusted for the amortization of the basis difference of CenterPoint Energy’s original investment in Enable and its underlying equity in net assets of Enable. The basis difference is being amortized through the year 2048. Summarized consolidated balance sheet information for Enable is as follows: December 31, 2020 2019 (in millions) Current assets $ 381 $ 389 Non-current assets 11,348 11,877 Current liabilities 582 780 Non-current liabilities 4,052 4,077 Non-controlling interest 26 37 Preferred equity 362 362 Accumulated other comprehensive loss (6) (3) Enable partners’ equity 6,713 7,013 December 31, 2020 2019 (in millions) Reconciliation of Investment in Enable: CenterPoint Energy’s ownership interest in Enable partners’ equity $ 3,601 $ 3,767 CenterPoint Energy’s basis difference (1) (2,819) (1,361) CenterPoint Energy’s equity method investment in Enable $ 782 $ 2,406 (1) Includes the impairment of CenterPoint Energy’s equity method investment in Enable of $1,541 million recorded during the year ended December 31, 2020. The basis difference is being amortized through the year 2048.

Indexed Debt Securities (ZENS)

Indexed Debt Securities (ZENS) and Securities Related to ZENS (CenterPoint Energy)	12 Months Ended
	Dec. 31, 2020
Indexed Debt Securities [Abstract]
Indexed Debt Securities (ZENS) and Securities Related to ZENS (CenterPoint Energy) [Text Block]	Indexed Debt Securities (ZENS) and Securities Related to ZENS (CenterPoint Energy) (a) Investment in Securities Related to ZENS A subsidiary of CenterPoint Energy holds shares of certain securities detailed in the table below, which are classified as trading securities and are expected to be held to facilitate CenterPoint Energy’s ability to meet its obligation under the ZENS. Unrealized gains and losses resulting from changes in the market value of the ZENS-Related Securities are recorded in CenterPoint Energy’s Statements of Consolidated Income. Shares Held at December 31, 2020 2019 AT&T Common 10,212,945 10,212,945 Charter Common 872,503 872,503 (b) ZENS In September 1999, CenterPoint Energy issued ZENS having an original principal amount of $1.0 billion of which $828 million remained outstanding as of December 31, 2020. Each ZENS is exchangeable at the holder’s option at any time for an amount of cash equal to 95% of the market value of the reference shares attributable to such note. The number and identity of the reference shares attributable to each ZENS are adjusted for certain corporate events. CenterPoint Energy’s reference shares for each ZENS consisted of the following: December 31, 2020 2019 (in shares) AT&T Common 0.7185 0.7185 Charter Common 0.061382 0.061382 CenterPoint Energy pays interest on the ZENS at an annual rate of 2% plus the amount of any quarterly cash dividends paid in respect of the reference shares attributable to the ZENS. The principal amount of the ZENS is subject to increases or decreases to the extent that the annual yield from interest and cash dividends on the reference shares is less than or more than 2.309%. The adjusted principal amount is defined in the ZENS instrument as “contingent principal.” As of December 31, 2020, the ZENS, having an original principal amount of $828 million and a contingent principal amount of $56 million, were outstanding and were exchangeable, at the option of the holders, for cash equal to 95% of the market value of the reference shares attributable to the ZENS. As of December 31, 2020, the market value of such shares was approximately $871 million, which would provide an exchange amount of $999 for each $1,000 original principal amount of ZENS. At maturity of the ZENS in 2029, CenterPoint Energy will be obligated to pay in cash the higher of the contingent principal amount of the ZENS or an amount based on the then-current market value of the reference shares, which will include any additional publicly-traded securities distributed with respect to the current reference shares prior to maturity. The ZENS obligation is bifurcated into a debt component and a derivative component (the holder’s option to receive the appreciated value of the reference shares at maturity). The bifurcated debt component accretes through interest charges annually up to the contingent principal amount of the ZENS in 2029. Such accretion will be reduced by annual cash interest payments, as described above. The derivative component is recorded at fair value and changes in the fair value of the derivative component are recorded in CenterPoint Energy’s Statements of Consolidated Income. Changes in the fair value of the ZENS-Related Securities held by CenterPoint Energy are expected to substantially offset changes in the fair value of the derivative component of the ZENS. The following table sets forth summarized financial information regarding CenterPoint Energy’s investment in ZENS-Related Securities and each component of CenterPoint Energy’s ZENS obligation. ZENS-Related Debt Derivative (in millions) Balance as of December 31, 2017 $ 960 $ 122 $ 668 Accretion of debt component of ZENS — 21 — 2% interest paid — (17) — Sale of ZENS-Related Securities (398) — — Distribution to ZENS holders — (102) (46) Gain on indexed debt securities — — (21) Loss on ZENS-Related Securities (22) — — Balance as of December 31, 2018 540 24 601 Accretion of debt component of ZENS — 17 — 2% interest paid — (17) — Distribution to ZENS holders — (5) — Loss on indexed debt securities — — 292 Gain on ZENS-Related Securities 282 — — Balance as of December 31, 2019 822 19 893 Accretion of debt component of ZENS — 17 — 2% interest paid — (16) — Distribution to ZENS holders — (5) — Loss on indexed debt securities — — 60 Gain on ZENS-Related Securities 49 — — Balance as of December 31, 2020 $ 871 $ 15 $ 953

Equity (CenterPoint Energy)

Equity (CenterPoint Energy)	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Equity (CenterPoint Energy) [Text Block]	Equity (CenterPoint Energy) Dividends Declared and Paid (CenterPoint Energy) CenterPoint Energy declared and paid dividends on its Common Stock during 2020, 2019 and 2018 as presented in the table below: Declaration Date Record Date Payment Date Per Share (1) Total December 10, 2020 February 18, 2021 March 11, 2021 $ 0.1600 $ 88 October 29, 2020 November 19, 2020 December 10, 2020 0.1500 83 July 29, 2020 August 20, 2020 September 10, 2020 0.1500 82 April 24, 2020 May 21, 2020 June 11, 2020 0.1500 82 February 3, 2020 February 20, 2020 March 12, 2020 0.2900 145 Total 2020 $ 0.9000 $ 480 October 17, 2019 November 21, 2019 December 12, 2019 $ 0.2875 $ 144 July 31, 2019 August 15, 2019 September 12, 2019 0.2875 145 April 25, 2019 May 16, 2019 June 13, 2019 0.2875 144 Total 2019 $ 0.8625 $ 433 Declaration Date Record Date Payment Date Per Share (1) Total December 12, 2018 February 21, 2019 March 14, 2019 $ 0.2875 $ 144 October 23, 2018 November 15, 2018 December 13, 2018 0.2775 139 July 26, 2018 August 16, 2018 September 13, 2018 0.2775 120 April 26, 2018 May 17, 2018 June 14, 2018 0.2775 120 Total 2018 $ 1.1200 $ 523 (1) On April 1, 2020, in response to the reduction in cash flow related to the reduction in Enable quarterly common unit distributions announced by Enable on April 1, 2020, CenterPoint Energy announced a reduction of its quarterly Common Stock dividend per share from $0.2900 to $0.1500. CenterPoint Energy declared and paid dividends on its Series A Preferred Stock during 2020, 2019 and 2018 as presented in the table below: Declaration Date Record Date Payment Date Per Share Total December 10, 2020 February 15, 2021 March 1, 2021 $ 30.6250 $ 24 July 29, 2020 August 14, 2020 September 1, 2020 30.6250 24 February 3, 2020 February 14, 2020 March 2, 2020 30.6250 25 Total 2020 $ 91.8750 $ 73 July 31, 2019 August 15, 2019 September 3, 2019 $ 30.6250 $ 24 Total 2019 $ 30.6250 $ 24 December 12, 2018 February 15, 2019 March 1, 2019 $ 32.1563 $ 26 Total 2018 $ 32.1563 $ 26 CenterPoint Energy declared dividends on its Series B Preferred Stock during 2020, 2019 and 2018 as presented in the table below: Declaration Date Record Date Payment Date Per Share Total December 10, 2020 February 15, 2021 March 1, 2021 $ 17.5000 $ 17 October 29, 2020 November 13, 2020 December 1, 2020 17.5000 17 July 29, 2020 August 14, 2020 September 1, 2020 17.5000 17 April 24, 2020 May 15, 2020 June 1, 2020 17.5000 17 February 3, 2020 February 14, 2020 March 2, 2020 17.5000 17 Total 2020 $ 87.5000 $ 85 October 17, 2019 November 15, 2019 December 2, 2019 $ 17.5000 $ 17 July 31, 2019 August 15, 2019 September 3, 2019 17.5000 17 April 25, 2019 May 15, 2019 June 3, 2019 17.5000 17 Total 2019 $ 52.5000 $ 51 December 12, 2018 February 15, 2019 March 1, 2019 $ 17.5000 $ 17 October 23, 2018 November 15, 2018 December 1, 2018 11.6667 11 Total 2018 $ 29.1667 $ 28 CenterPoint Energy declared and paid dividends on its Series C Preferred Stock during 2020 as presented in the table below: Declaration Date (1) Record Date Payment Date Per Share Total December 10, 2020 February 18, 2021 March 11, 2021 $ 0.1600 $ 7 October 29, 2020 November 19, 2020 December 10, 2020 0.1500 6 July 29, 2020 August 20, 2020 September 10, 2020 0.1500 7 April 24, 2020 May 21, 2020 June 11, 2020 0.1500 7 Total 2020 $ 0.6100 $ 27 (1) Declaration date for dividends on Common Stock. The Series C Preferred Stock is entitled to participate in any dividend or distribution (excluding those payable in Common Stock) with the Common Stock on a pari passu, pro rata, as-converted basis. The per share amount reflects the dividend per share of Common Stock as if the Series C Preferred Stock were converted into Common Stock. The Series C Preferred Stock are expected to convert to Common Stock on or around May 7, 2021. There were no Series C Preferred Stock outstanding or dividends declared in 2019 or 2018. Dividend Requirement on Preferred Stock Year Ended December 31, 2020 2019 2018 (in millions) Series A Preferred Stock $ 49 $ 49 $ 18 Series B Preferred Stock 68 68 17 Series C Preferred Stock 27 — — Preferred dividend requirement 144 117 35 Amortization of beneficial conversion feature 32 — — Total income allocated to preferred shareholders $ 176 $ 117 $ 35 Series A Preferred Stock On August 22, 2018, CenterPoint Energy completed the issuance of 800,000 shares of its Series A Preferred Stock, at a price of $1,000 per share, resulting in net proceeds of $790 million after issuance costs. The aggregate liquidation value of the Series A Preferred Stock is $800 million with a per share liquidation value of $1,000. CenterPoint Energy used the net proceeds from the Series A Preferred Stock offering to fund a portion of the Merger and to pay related fees and expenses. Dividends. The Series A Preferred Stock accrue cumulative dividends, calculated as a percentage of the stated amount per share, at a fixed annual rate of 6.125% per annum to, but excluding, September 1, 2023, and at an annual rate of three-month LIBOR plus a spread of 3.270% thereafter to be paid in cash if, when and as declared. If declared, prior to September 1, 2023, dividends are payable semi-annually in arrears on each March 1 and September 1, beginning on March 1, 2019, and, for the period commencing on September 1, 2023, dividends are payable quarterly in arrears each March 1, June 1, September 1 and December 1, beginning on December 1, 2023. Cumulative dividends earned during the applicable periods are presented on CenterPoint Energy’s Statements of Consolidated Income as Preferred stock dividend requirement. Optional Redemption. On or after September 1, 2023, CenterPoint Energy may, at its option, redeem the Series A Preferred Stock, in whole or in part, at any time or from time to time, for cash at a redemption price of $1,000 per share, plus any accumulated and unpaid dividends thereon to, but excluding, the redemption date. At any time within 120 days after the conclusion of any review or appeal process instituted by CenterPoint Energy, if any, following the occurrence of a ratings event, CenterPoint Energy may, at its option, redeem the Series A Preferred Stock in whole, but not in part, at a redemption price in cash per share equal to $1,020 (102% of the liquidation value of $1,000) plus an amount equal to all accumulated and unpaid dividends thereon to, but excluding, the redemption date, whether or not declared. Ranking. The Series A Preferred Stock, with respect to anticipated dividends and distributions upon CenterPoint Energy’s liquidation or dissolution, or winding-up of CenterPoint Energy’s affairs, ranks or will rank: • senior to Common Stock and to each other class or series of capital stock established after the initial issue date of the Series A Preferred Stock that is expressly made subordinated to the Series A Preferred Stock; • on a parity with any class or series of capital stock established after the initial issue date of the Series A Preferred Stock that is not expressly made senior or subordinated to the Series A Preferred Stock, including the Series B Preferred Stock; • junior to any class or series of capital stock established after the initial issue date of the Series A Preferred Stock that is expressly made senior to the Series A Preferred Stock; • junior to all existing and future indebtedness (including indebtedness outstanding under CenterPoint Energy’s credit facilities, senior notes and commercial paper) and other liabilities with respect to assets available to satisfy claims against CenterPoint Energy; and • structurally subordinated to any existing and future indebtedness and other liabilities of CenterPoint Energy’s subsidiaries and capital stock of CenterPoint Energy’s subsidiaries held by third parties. Voting Rights. Holders of the Series A Preferred Stock generally will not have voting rights. Whenever dividends on shares of Series A Preferred Stock have not been declared and paid for the equivalent of three or more semi-annual or six or more quarterly dividend periods (including, for the avoidance of doubt, the dividend period beginning on, and including, the original issue date and ending on, but excluding, March 1, 2019), whether or not consecutive, the holders of such shares of Series A Preferred Stock, voting together as a single class with holders of any and all other series of voting preferred stock (as defined in the Statement of Resolution for the Series A Preferred Stock) then outstanding, will be entitled at CenterPoint Energy’s next annual or special meeting of shareholders to vote for the election of a total of two additional members of CenterPoint Energy’s Board of Directors, subject to certain limitations. This right will terminate if and when all accumulated dividends have been paid in full and, upon such termination, the term of office of each director so elected will terminate at such time and the number of directors on CenterPoint Energy’s Board of Directors will automatically decrease by two, subject to the revesting of such rights in the event of each subsequent nonpayment. Series B Preferred Stock On October 1, 2018, CenterPoint Energy completed the issuance of 19,550,000 depositary shares, each representing a 1/20th interest in a share of its Series B Preferred Stock, at a price of $50 per depositary share, resulting in net proceeds of $950 million after issuance costs. The aggregate liquidation value of Series B Preferred Stock is $978 million with a per share liquidation value of $1,000. The amount issued included 2,550,000 depositary shares issued pursuant to the exercise in full of the option granted to the underwriters to purchase additional depositary shares. CenterPoint Energy used the net proceeds from the offering of depositary shares, each representing a 1/20th interest in a share of its Series B Preferred Stock, to fund a portion of the Merger and to pay related fees and expenses. Dividends. Dividends on the Series B Preferred Stock will be payable on a cumulative basis when, as and if declared at an annual rate of 7.00% on the liquidation value of $1,000 per share. CenterPoint Energy may pay declared dividends in cash or, subject to certain limitations, in shares of Common Stock, or in any combination of cash and shares of Common Stock on March 1, June 1, September 1 and December 1 of each year, commencing on December 1, 2018 and ending on, and including, September 1, 2021. Cumulative dividends earned during the applicable periods are presented on CenterPoint Energy’s Statements of Consolidated Income as Preferred stock dividend requirement. Mandatory Conversion. Unless earlier converted or redeemed, each share of the Series B Preferred Stock will automatically convert on the mandatory conversion date, which is expected to be September 1, 2021, into not less than 30.5820 and not more than 36.6980 shares of Common Stock, subject to certain anti-dilution adjustments. Correspondingly, the conversion rate per depositary share will be not less than 1.5291 and not more than 1.8349 shares of Common Stock, subject to certain anti-dilution adjustments. The conversion rate will be determined based on a preceding 20-day volume-weighted-average-price of Common Stock. The following table illustrates the conversion rate per share of the Series B Preferred Stock, subject to certain anti-dilution adjustments: Applicable Market Value of the Common Stock Conversion Rate per Share of Series B Preferred Stock Greater than $32.6990 (threshold appreciation price) 30.5820 shares of Common Stock Equal to or less than $32.6990 but greater than or equal to $27.2494 Between 30.5820 and 36.6980 shares of Common Stock, determined by dividing $1,000 by the applicable market value Less than $27.2494 (initial price) 36.6980 shares of Common Stock The following table illustrates the conversion rate per depositary share, subject to certain anti-dilution adjustments: Applicable Market Value of the Common Stock Conversion Rate per Depository Share Greater than $32.6990 (threshold appreciation price) 1.5291 shares of Common Stock Equal to or less than $32.6990 but greater than or equal to $27.2494 Between 1.5291 and 1.8349 shares of Common Stock, determined by dividing $50 by the applicable market value Less than $27.2494 (initial price) 1.8349 shares of Common Stock Optional Conversion of the Holder. Other than during a fundamental change conversion period, and unless CenterPoint Energy has redeemed the Series B Preferred Stock, a holder of the Series B Preferred Stock may, at any time prior to September 1, 2021, elect to convert such holder’s shares of the Series B Preferred Stock, in whole or in part, at the minimum conversion rate of 30.5820 shares of Common Stock per share of the Series B Preferred Stock (equivalent to 1.5291 shares of Common Stock per depositary share), subject to certain anti-dilution and other adjustments. Because each depositary share represents a 1/20th fractional interest in a share of the Series B Preferred Stock, a holder of depositary shares may convert its depositary shares only in lots of 20 depositary shares. Fundamental Change Conversion. If a fundamental change occurs on or prior to September 1, 2021, holders of the Series B Preferred Stock will have the right to convert their shares of the Series B Preferred Stock, in whole or in part, into shares of Common Stock at the fundamental change conversion rate during the period beginning on, and including, the effective date of such fundamental change and ending on, and including, the date that is 20 calendar days after such effective date (or, if later, the date that is 20 calendar days after holders receive notice of such fundamental change, but in no event later than September 1, 2021). Holders who convert shares of the Series B Preferred Stock during that period will also receive a make-whole dividend amount comprised of a fundamental change dividend make-whole amount, and to the extent there is any, the accumulated dividend amount. Because each depositary share represents a 1/20th fractional interest in a share of the Series B Preferred Stock, a holder of depositary shares may convert its depositary shares upon a fundamental change only in lots of 20 depositary shares. Ranking. The Series B Preferred Stock, with respect to anticipated dividends and distributions upon CenterPoint Energy’s liquidation or dissolution, or winding-up of CenterPoint Energy’s affairs, ranks or will rank: • senior to Common Stock and to each other class or series of capital stock established after the initial issue date of the Series B Preferred Stock that is expressly made subordinated to the Series B Preferred Stock; • on a parity with the Series A Preferred Stock and any class or series of capital stock established after the initial issue date that is not expressly made senior or subordinated to the Series B Preferred Stock; • junior to any class or series of capital stock established after the initial issue date that is expressly made senior to the Series B Preferred Stock; • junior to all existing and future indebtedness (including indebtedness outstanding under CenterPoint Energy’s credit facilities, senior notes and commercial paper) and other liabilities with respect to assets available to satisfy claims against CenterPoint Energy; and • structurally subordinated to any existing and future indebtedness and other liabilities of CenterPoint Energy’s subsidiaries and capital stock of CenterPoint Energy’s subsidiaries held by third parties. Voting Rights. Holders of the Series B Preferred Stock generally will not have voting rights. Whenever dividends on shares of the Series B Preferred Stock have not been declared and paid for six or more dividend periods (including, for the avoidance of doubt, the dividend period beginning on, and including, the initial issue date and ending on, but excluding, December 1, 2018), whether or not consecutive, the holders of such shares of Series B Preferred Stock, voting together as a single class with holders of any and all other series of voting preferred stock then outstanding (as defined in the Statement of Resolution for the Series B Preferred Stock), will be entitled at CenterPoint Energy’s next annual or special meeting of shareholders to vote for the election of a total of two additional members of CenterPoint Energy’s Board of Directors, subject to certain limitations. This right will terminate if and when all accumulated and unpaid dividends have been paid in full and, upon such termination, the term of office of each director so elected will terminate at such time and the number of directors on CenterPoint Energy’s Board of Directors will automatically decrease by two, subject to the revesting of such rights in the event of each subsequent nonpayment. On November 27, 2020, a holder of Series B Preferred Stock submitted 2,000 depository shares for conversion. The depository shares converted into an aggregate 3,064 shares of Common Stock. After the conversion, 977,400 shares of Series B Preferred Stocks remain outstanding. Series C Preferred Stock Private Placement (CenterPoint Energy) On May 6, 2020, CenterPoint Energy entered into agreements for the private placement of 725,000 shares of its Series C Preferred Stock, at a price of $1,000 share, resulting in net proceeds of $724 million after issuance costs. The Series C Preferred Stock is entitled to participate in any dividend or distribution (excluding those payable in Common Stock) with the Common Stock on a pari passu, pro rata, as-converted basis. At liquidation, the Series C Preferred Stock will rank pari passu to the existing Series A Preferred Stock and Series B Preferred Stock and senior to the Common Stock, but will participate in a liquidation only on an as-converted to Common Stock basis. Conversion of the Series C Preferred Stock is mandatory upon the occurrence of any of the following triggers: (i) the 12-month anniversary date of the preferred stock purchase agreements, (ii) a bankruptcy event, and (iii) a fundamental change in CenterPoint Energy, including, among other things certain change of control events. Upon a mandatory conversion, each share of Series C Preferred Stock will convert into the number of Common Stock equal to the quotient of $1,000 divided by the prevailing conversion price, which is initially $15.31. In a conversion at the 12-month anniversary date, in lieu of issuing Common Stock, CenterPoint Energy may, at its election, make a cash payment equal to the product of (i) the then current market price of the Common Stock multiplied by (ii) the number of shares of Common Stock that such holder would have been entitled to receive in a conversion. Following the six-month anniversary date of the issuance of the Series C Preferred Stock, holders of Series C Preferred Stock also have an optional right to convert their holdings to Common Stock at any time, subject to a limit on conversion of no more than 4.9% of the outstanding Common Stock. The conversion price is subject to adjustment for subdivisions and combinations, dividends or distributions payable in common stock. If all of the 725,000 shares of Series C Preferred Stock converted at the initial conversion price, CenterPoint Energy would issue an incremental 47,354,670 shares of Common Stock. The Series C Preferred Stock are expected to convert to Common Stock on or around May 7, 2021. CenterPoint Energy may not issue more than a specified amount of outstanding Common Stock upon conversion of Preferred Stock. Once such specified amount has been reached, each Series C Preferred Stock holder electing to convert or subject to mandatory conversion will receive a cash payment equal to the product of (i) the market price of the Common Stock multiplied by (ii) the number of shares of Common Stock that such holder would have been entitled to receive in a conversion. On June 1, 2020, CenterPoint Energy filed a shelf registration statement with the SEC registering 58,051,121 shares of Common Stock, equal to the maximum number of shares of Common Stock issuable in the aggregate upon conversion of the Series C Preferred Stock pursuant to the preferred stock purchase agreements. Series C Preferred Stock holders have no voting rights, except that the affirmative vote of a majority of outstanding Series C Preferred Stock is required for the company to (i) create any class or series of securities that is senior to the Series C Preferred Stock; (ii) reclassify or amend any authorized securities of CenterPoint Energy if reclassification would render the relevant security senior to the Series C Preferred Stock; or (iii) increase the authorized amount or issue any additional shares of Series C Preferred Stock. The vote of at least 66 2/3% of the outstanding shares of Series C Preferred Stock is needed to amend the terms of the Series C Preferred Stock in any manner that would adversely alter or change the rights of the Series C Preferred Stock, subject to certain exceptions. On November 2, 2020, CenterPoint Energy received notification of the intent for a shareholder to convert 100,000 shares of Series C Preferred Stock and establishing November 6, 2020 as the conversion date. As a result of the conversion, 6,531,677 shares of Common Stock were issued, and the outstanding number of shares of Series C Preferred Stock decreased to 625,000. Common Stock Private Placement (CenterPoint Energy) On May 6, 2020, CenterPoint Energy entered into agreements for the private placement of 41,977,612 shares of its Common Stock, at a price of $16.08 share, resulting in net proceeds of $673 million after issuance costs. On June 1, 2020, CenterPoint Energy filed a shelf registration statement with the SEC registering these 41,977,612 shares of Common Stock. Undistributed Retained Earnings As of both December 31, 2020 and 2019, CenterPoint Energy’s consolidated retained earnings balance included no undistributed earnings from Enable. Accumulated Other Comprehensive Income (Loss) Changes in accumulated comprehensive income (loss) are as follows: Year Ended December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Beginning Balance $ (98) $ (15) $ 10 $ (108) $ (14) $ 5 Other comprehensive income (loss) before reclassifications: Remeasurement of pension and other postretirement plans (12) — — 7 — 7 Deferred loss from interest rate derivatives (1) — — — (3) (1) — Reclassified to earnings — — — 1 — — Other comprehensive loss from unconsolidated affiliates (2) — — (1) — — Amounts reclassified from accumulated other comprehensive loss: Prior service cost (2) — — 1 1 — — Actuarial losses (2) 7 — — 8 — — Reclassification of deferred loss from cash flow hedges (3) 19 19 — — — — Tax benefit (expense) (4) (4) (1) (3) — (2) Net current period other comprehensive income (loss) 8 15 — 10 (1) 5 Ending Balance $ (90) $ — $ 10 $ (98) $ (15) $ 10 (1) Gains and losses are reclassified from Accumulated other comprehensive income into income when the hedged transactions affect earnings. The reclassification amounts are included in Interest and other finance charges in each of the Registrant’s respective Statements of Consolidated Income. Amounts are $-0- and $1 million for the years ended December 31, 2020 and 2019, respectively. (2) Amounts are included in the computation of net periodic cost and are reflected in Other, net in each of the Registrants’ respective Statements of Consolidated Income. (3) The cost of debt approved by the PUCT as part of Houston Electric’s Stipulation and Settlement Agreement included unrealized gains and losses on interest rate hedges. Accordingly, deferred gains and losses on interest rate hedges were reclassified to regulatory assets or liabilities, as appropriate.

Short Term Borrowings and Long

Short Term Borrowings and Long Term Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Short-term Borrowings and Long-term Debt [Text Block]	Short-term Borrowings and Long-term Debt December 31, December 31, Long-Term Current (1) Long-Term Current (1) (in millions) CenterPoint Energy: ZENS due 2029 (2) $ — $ 15 $ — $ 19 CenterPoint Energy senior notes 2.50% to 4.25% due 2021 to 2049 (3) 2,700 500 3,200 — CenterPoint Energy variable rate term loan 0.865% due 2021 — 700 1,000 — CenterPoint Energy pollution control bonds 5.125% due 2028 (5) 68 — 68 — CenterPoint Energy commercial paper (6) (7) 1,078 — 1,633 — VUHI senior notes 3.72% to 6.10% due 2021 to 2045 377 55 432 100 VUHI commercial paper (6) (7) 92 — 268 — VUHI variable rate term loan — — — 300 VCC variable rate term loan — — — 200 IGC senior notes 6.34% to 7.08% due 2025 to 2029 96 — 96 — SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055 (4) 293 — 293 — Other debt 6 12 18 18 Unamortized debt issuance costs (17) — (22) — Unamortized discount and premium, net (6) — (7) — Houston Electric debt (see details below) 4,406 613 4,719 231 CERC debt (see details below) 2,428 24 2,546 — Total CenterPoint Energy debt $ 11,521 $ 1,919 $ 14,244 $ 868 Houston Electric: First mortgage bonds 9.15% due 2021 (8) $ — $ 102 $ 102 $ — General mortgage bonds 1.85% to 6.95% due 2021 to 2050 3,912 300 3,912 — Restoration Bond Company: System restoration bonds 4.243% due 2022 69 66 134 62 Bond Company III: Transition bonds 5.234% due 2020 — — — 29 Bond Company IV: Transition bonds 3.028% due 2024 467 145 613 140 Unamortized debt issuance costs (28) — (27) — Unamortized discount and premium, net (14) — (15) — Total Houston Electric debt $ 4,406 $ 613 $ 4,719 $ 231 CERC (9) : Short-term borrowings: Inventory financing $ — $ 24 $ — $ — Total CERC short-term borrowings — 24 — — Long-term debt: Senior notes 1.75% to 6.625% due 2023 to 2047 $ 2,100 $ — $ 2,193 $ — Commercial paper (6) (7) 347 — 377 — Unamortized debt issuance costs (15) — (13) — Unamortized discount and premium, net (4) — (11) — Total CERC long-term debt 2,428 — 2,546 — Total CERC debt $ 2,428 $ 24 $ 2,546 $ — (1) Includes amounts due or exchangeable within one year of the date noted. (2) CenterPoint Energy’s ZENS obligation is bifurcated into a debt component and an embedded derivative component. For additional information regarding ZENS, see Note 12(b). As ZENS are exchangeable for cash at any time at the option of the holders, these notes are classified as a current portion of long-term debt. (3) The senior notes issued by VUHI are guaranteed by SIGECO, Indiana Gas and VEDO. (4) The first mortgage bonds issued by SIGECO subject SIGECO’s properties to a lien under the related mortgage indenture as further discussed below. (5) These pollution control bonds were secured by general mortgage bonds of Houston Electric as of December 31, 2020 and 2019 and are not reflected in Houston Electric’s consolidated financial statements because of the contingent nature of the obligations. (6) Classified as long-term debt because the termination date of the facility that backstops the commercial paper is more than one year from the date noted. (7) Commercial paper issued by CenterPoint Energy, CERC Corp. and VUHI has maturities up to 60 days, 30 days, and 30 days, respectively, and are backstopped by the respective issuer’s long-term revolving credit facility. (8) The first mortgage bonds issued by Houston Electric subject Houston Electric’s properties to a lien under the related mortgage indenture as further discussed below. (9) Issued by CERC Corp. Long-term Debt Debt Repayments. In April 2020, VCC repaid the aggregate principal amount of its $200 million variable term loan, and VUHI refinanced a $100 million 6.28% guaranteed senior note that matured in April 2020. In June 2020, VUHI repaid the aggregate principal amount of its $300 million variable term loan. In addition, in June 2020, CenterPoint Energy repaid $300 million of principal on its outstanding $1.0 billion variable rate term loan. Debt Redemption. In September 2020, CERC Corp. provided notice of redemption relating to $593 million aggregate principal amount of CERC Corp.’s outstanding 4.50% Senior Notes due 2021, Series A and B. All of the outstanding senior notes were redeemed in full in October 2020 at a redemption price equal to 100% of the principal amount thereof, plus accrued and unpaid interest to, but excluding, the redemption date. In December 2020, CenterPoint Energy provided notice of redemption relating to $250 million aggregate principal amount of its outstanding $500 million aggregate principal amount 3.85% senior notes, which were redeemed in January 2021 at a redemption price equal to 100% of the principal amount redeemed, plus accrued and unpaid interest to, but excluding, the redemption date, plus the applicable make-whole premium of $26 million. Debt Transactions. In June 2020, Houston Electric issued $300 million aggregate principal amount of 2.90% general mortgage bonds maturing in 2050. Total proceeds, net of issuance expenses and fees, of approximately $296 million were used for general limited liability company purposes, including capital expenditures and the repayment of a portion of borrowings under the CenterPoint Energy money pool. In September 2020, SIGECO completed the remarketing of two series of tax-exempt debt of approximately $38 million, comprised of: (i) $23 million aggregate principal amount of Environmental Improvement Revenue Bonds, Series 2015, issued by the City of Mount Vernon, Indiana, and (ii) $15 million aggregate principal amount of Environmental Improvement Revenue Bonds, Series 2015, issued by Warrick County, Indiana, that, in each case, were originally issued on September 9, 2015. Both series of revenue bonds originally had an initial term interest rate of 2.375%. After the remarketing, each series of revenue bonds have a new term interest rate of 0.875% that is fixed through August 31, 2023. Each series of revenue bonds have a final maturity date of September 1, 2055, subject to prior redemption. In October 2020, CERC Corp. issued $500 million aggregate principal amount of 1.75% senior notes due 2030. Total proceeds, net of issuance expenses and fees, of approximately $495 million were used for general corporate purposes, including the payment of a portion of the redemption amount of CERC Corp.’s 4.50% senior notes due 2021 redeemed in full on October 15, 2020. Securitization Bonds. As of December 31, 2020, CenterPoint Energy and Houston Electric had special purpose subsidiaries consisting of the Bond Companies, which they consolidate. The consolidated special purpose subsidiaries are wholly-owned, bankruptcy remote entities that were formed solely for the purpose of purchasing and owning transition or system restoration property through the issuance of transition bonds or system restoration bonds and activities incidental thereto. These Securitization Bonds are payable only through the imposition and collection of “transition” or “system restoration” charges, as defined in the Texas Public Utility Regulatory Act, which are irrevocable, non-bypassable charges to provide recovery of authorized qualified costs. CenterPoint Energy and Houston Electric have no payment obligations in respect of the Securitization Bonds other than to remit the applicable transition or system restoration charges they collect as set forth in servicing agreements among Houston Electric, the Bond Companies and other parties. Each special purpose entity is the sole owner of the right to impose, collect and receive the applicable transition or system restoration charges securing the bonds issued by that entity. Creditors of CenterPoint Energy or Houston Electric have no recourse to any assets or revenues of the Bond Companies (including the transition and system restoration charges), and the holders of Securitization Bonds have no recourse to the assets or revenues of CenterPoint Energy or Houston Electric. Credit Facilities. The Registrants had the following revolving credit facilities as of December 31, 2020: Execution Registrant Size of Draw Rate of LIBOR plus (1) Financial Covenant Limit on Debt for Borrowed Money to Capital Ratio Debt for Borrowed Money to Capital Ratio as of December 31, 2020 (2) Termination (in millions) March 3, 2016 CenterPoint Energy $ 3,300 1.500% 65% (3) 53.9% March 3, 2022 July 14, 2017 CenterPoint Energy (4) 400 1.125% 65% 49.7% July 14, 2022 March 3, 2016 Houston Electric 300 1.250% 65% (3) 53.1% March 3, 2022 March 3, 2016 CERC 900 1.125% 65% 48.9% March 3, 2022 Total $ 4,900 (1) Based on credit ratings as of December 31, 2020. (2) As defined in the revolving credit facility agreement, excluding Securitization Bonds. (3) For CenterPoint Energy and Houston Electric, the financial covenant limit will temporarily increase from 65% to 70% if Houston Electric experiences damage from a natural disaster in its service territory and CenterPoint Energy certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive 12-month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Such temporary increase in the financial covenant would be in effect from the date CenterPoint Energy delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of CenterPoint Energy’s certification or (iii) the revocation of such certification. (4) This credit facility was issued by VUHI, is guaranteed by SIGECO, Indiana Gas and VEDO and included a $10 million swing line sublimit and a $20 million letter of credit sublimit. This credit facility backstops VUHI’s commercial paper program. On September 30, 2020, VCC terminated its $200 million credit agreement dated as of July 14, 2017 after determining that it was no longer necessary for financing purposes. VCC did not incur any penalties in connection with the early termination. The Registrants, as well as the subsidiaries of CenterPoint Energy discussed above, were in compliance with all financial debt covenants as of December 31, 2020. As of December 31, 2020 and 2019, the Registrants had the following revolving credit facilities and utilization of such facilities: December 31, 2020 December 31, 2019 Registrant Loans Letters Commercial Weighted Average Interest Rate Loans Letters Commercial Weighted Average Interest Rate (in millions, except weighted average interest rate) CenterPoint Energy (1) $ — $ 11 $ 1,078 0.23 % $ — $ 6 $ 1,633 1.95 % CenterPoint Energy (2) — — 92 0.22 % — — 268 2.08 % Houston Electric — — — — % — — — — % CERC — — 347 0.23 % — 1 377 1.94 % Total $ — $ 11 $ 1,517 $ — $ 7 $ 2,278 (1) CenterPoint Energy’s outstanding commercial paper generally has maturities of 60 days or less. (2) This credit facility was issued by VUHI and is guaranteed by SIGECO, Indiana Gas and VEDO. On February 4, 2021, each of CenterPoint Energy, Houston Electric, CERC Corp. and VUHI replaced their existing revolving credit facilities with new amended and restated credit facilities. The size of the CenterPoint Energy facility decreased from $3.3 billion to $2.4 billion, while the sizes of the Houston Electric, CERC Corp. and VUHI facilities remained unchanged. The VUHI facility remains guaranteed by SIGECO, Indiana Gas and VEDO. Based on the credit ratings as of February 4, 2021, the draw rate would have been LIBOR plus 1.625% under the CenterPoint Energy facility, LIBOR plus 1.375% under the Houston Electric facility, LIBOR plus 1.250% under the CERC Corp. facility, and LIBOR plus 1.250% under the VUHI facility. Each credit facility contains provisions relating to the replacement of LIBOR. The financial covenant limit on debt for borrowed money to capital ratio remained at 65.0% for each of the CenterPoint Energy, CERC Corp. and VUHI facilities and increased to 67.5% for the Houston Electric facility. As with the facilities that were replaced, the CenterPoint Energy and Houston Electric facilities’ financial covenant limit on debt for borrowed money to capital ratio can temporarily increase to 70.0% if Houston Electric experiences certain damages from a natural disaster in its service territory and CenterPoint Energy certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive 12-month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Each of the amended and restated facilities have a maturity date of February 4, 2024. Maturities. As of December 31, 2020, maturities of long-term debt, capital leases and sinking fund requirements, excluding the ZENS obligation and unamortized discounts, premiums and issuance costs, are as follows: CenterPoint Energy (1) Houston Electric (1) CERC Securitization Bonds (in millions) 2021 $ 1,868 $ 613 $ — $ 211 2022 2,542 519 347 219 2023 713 356 300 156 2024 1,184 162 — 162 2025 51 — — — (1) These maturities include Securitization Bonds principal repayments on scheduled payment dates. Liens. As of December 31, 2020, Houston Electric’s assets were subject to liens securing approximately $102 million of first mortgage bonds. Sinking or improvement fund and replacement fund requirements on the first mortgage bonds may be satisfied by certification of property additions. Sinking fund and replacement fund requirements for 2020, 2019 and 2018 have been satisfied by certification of property additions. The replacement fund requirement to be satisfied in 2021 is approximately $317 million, and the sinking fund requirement to be satisfied in 2021 is approximately $1.6 million. CenterPoint Energy expects Houston Electric to meet these 2021 obligations by certification of property additions. As of December 31, 2020, Houston Electric’s assets were also subject to liens securing approximately $4.0 billion of general mortgage bonds, including approximately $68 million held in trust to secure pollution control bonds for which CenterPoint Energy is obligated. The lien of the general mortgage indenture is junior to that of the mortgage pursuant to which the first mortgage bonds are issued. Houston Electric may issue additional general mortgage bonds on the basis of retired bonds, 70% of property additions or cash deposited with the trustee. Approximately $4.3 billion of additional first mortgage bonds and general mortgage bonds could be issued on the basis of retired bonds and 70% of property additions as of December 31, 2020. Houston Electric has contractually agreed that it will not issue additional first mortgage bonds, subject to certain exceptions. As of December 31, 2020, SIGECO had approximately $293 million aggregate principal amount of first mortgage bonds outstanding. Generally, of SIGECO’s real and tangible property is subject to the lien of SIGECO’s mortgage indenture. SIGECO may issue additional bonds under its mortgage indenture up to 60% of currently unfunded property additions. As of December 31, 2020, approximately $1.3 billion of additional first mortgage bonds could be issued on this basis. However, SIGECO is also limited in its ability to issue additional bonds under its mortgage indenture due to certain provisions in its parent’s, VUHI, debt agreements.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes [Text Block]	Income Taxes The components of the Registrant’ income tax expense (benefit) were as follows: Year Ended December 31, 2020 2019 2018 (in millions) CenterPoint Energy - Continuing Operations Current income tax expense (benefit): Federal $ (1) $ 30 $ 77 State 32 15 6 Total current expense 31 45 83 Deferred income tax expense (benefit): Federal (257) 55 (6) State (48) (8) 78 Total deferred expense (benefit) (305) 47 72 Total income tax expense (benefit) $ (274) $ 92 $ 155 CenterPoint Energy - Discontinued Operations Current income tax expense: Federal $ 117 $ 18 $ 12 State 28 6 3 Total current expense 145 24 15 Deferred income tax expense (benefit): Federal (102) 19 (19) State (22) 3 (5) Total deferred expense (benefit) (124) 22 (24) Total income tax expense (benefit) $ 21 $ 46 $ (9) Houston Electric Current income tax expense: Federal $ 76 $ 84 $ 109 State 19 20 18 Total current expense 95 104 127 Deferred income tax benefit: Federal (42) (24) (38) Total deferred benefit (42) (24) (38) Total income tax expense $ 53 $ 80 $ 89 Year Ended December 31, 2020 2019 2018 (in millions) CERC - Continuing Operations Current income tax expense (benefit): State $ 4 $ 5 $ (3) Total current expense (benefit) 4 5 (3) Deferred income tax expense (benefit): Federal 26 26 9 State 67 (34) 25 Total deferred expense (benefit) 93 (8) 34 Total income tax expense (benefit) $ 97 $ (3) $ 31 CERC - Discontinued Operations Current income tax expense: State — 2 7 Total current expense — 2 7 Deferred income tax expense (benefit): Federal — 13 30 State (2) 2 — Total deferred expense (benefit) (2) 15 30 Total income tax expense (benefit) $ (2) $ 17 $ 37 A reconciliation of income tax expense (benefit) using the federal statutory income tax rate to the actual income tax expense and resulting effective income tax rate is as follows: Year Ended December 31, 2020 2019 2018 (in millions) CenterPoint Energy - Continuing Operations (1) (2) (3) Income (loss) before income taxes $ (865) $ 774 $ 551 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense (benefit) (182) 163 116 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax (15) 30 23 State valuation allowance, net of federal income tax 1 (4) 11 State law change, net of federal income tax — (21) 32 Excess deferred income tax amortization (76) (55) (24) Goodwill impairment 39 — — Net operating loss carryback (37) — — Other, net (4) (21) (3) Total (92) (71) 39 Total income tax expense (benefit) $ (274) $ 92 $ 155 Effective tax rate 32 % 12 % 28 % CenterPoint Energy - Discontinued Operations (4)(5) Income (loss) before income taxes $ (161) $ 155 $ (37) Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense (benefit) (34) 32 (8) Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax (5) 6 (1) Goodwill impairment 25 8 — Tax impact of sale of Energy Services and Infrastructure Services Disposal Groups 30 — — Other, net 5 — — Total 55 14 (1) Total income tax expense (benefit) $ 21 $ 46 $ (9) Effective tax rate (13) % 30 % 24 % Year Ended December 31, 2020 2019 2018 (in millions) Houston Electric (6) (7) (8) Income before income taxes $ 387 $ 436 $ 425 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense 81 92 89 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax 15 16 14 Excess deferred income tax amortization (42) (21) (9) Other, net (1) (7) (5) Total (28) (12) — Total income tax expense $ 53 $ 80 $ 89 Effective tax rate 14 % 18 % 21 % CERC - Continuing Operations (9) (10) (11) Income before income taxes $ 244 $ 186 $ 129 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense 51 39 27 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax 55 (15) 5 State law change, net of federal income tax — (4) — State valuation allowance, net of federal income tax 1 (4) 11 Excess deferred income tax amortization (16) (18) (15) Other, net 6 (1) 3 Total 46 (42) 4 Total income tax expense (benefit) $ 97 $ (3) $ 31 Effective tax rate 40 % (2) % 24 % CERC - Discontinued Operations (12) (13) Income (loss) before income taxes $ (68) $ 40 $ 147 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense (benefit) (14) 8 31 Increase in tax expense resulting from: State income tax expense, net of federal income tax (2) 3 7 Goodwill impairment 10 8 — Other, net 4 (2) (1) Total 12 9 6 Total income tax expense (benefit) $ (2) $ 17 $ 37 Effective tax rate 3 % 43 % 25 % (1) Recognized a $76 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions, a $39 million deferred tax expense for the non-deductible portion of the goodwill impairment on SIGECO, and a $37 million benefit for the NOL carryback claim allowed by the CARES Act. (2) Recognized a $55 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions, a $21 million net benefit for the impact of state law changes that resulted in the remeasurement of state deferred taxes in those jurisdictions, and a $4 million net benefit for the reduction in valuation allowances on certain state NOLs that are now expected to be realized. (3) Recognized a $32 million deferred tax expense due to state law changes that resulted in remeasurement of state deferred taxes in those jurisdictions. Also, recorded an additional $11 million valuation allowance on certain state net operating loss deferred tax assets that are no longer expected to be utilized prior to expiration after the Internal Spin. These items are partially offset by $24 million of amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions beginning in 2018. (4) Recognized a $25 million deferred tax expense for the non-deductible portion of the goodwill impairment on both the Energy Services and Infrastructure Services Disposal Groups. Also, recognized a $30 million net tax expense on both the sale of the Energy Services and Infrastructure Services Disposal Groups. (5) Recognized an $8 million deferred tax expense for the non-deductible portion of the goodwill impairment on the Energy Services Disposal Group. (6) Recognized a $42 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions. (7) Recognized a $21 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions. (8) Recognized a $9 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions beginning in 2018. (9) Recognized a $16 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulatory in certain jurisdictions. (10) Recognized an $18 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions, a $4 million net benefit for the impact of state law changes that resulted in the remeasurement of state deferred taxes in those jurisdictions and a $4 million net benefit for the reduction in valuation allowances on certain state NOLs that are now expected to be realized. (11) Recorded an additional $11 million valuation allowance on certain state net operating loss deferred tax assets that are no longer expected to be utilized prior to expiration after the Internal Spin. This item was offset by $15 million of amortization of the net regulatory EDIT liability in certain jurisdictions as decreed by regulators beginning in 2018. (12) Recognized a $10 million deferred tax expense for the non-deductible portion of the goodwill impairment on the Energy Services Disposal Group. (13) Recognized an $8 million deferred tax expense for the non-deductible portion of the goodwill impairment on the Energy Services Disposal Group. The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities were as follows: December 31, 2020 2019 (in millions) CenterPoint Energy Deferred tax assets: Benefits and compensation $ 141 $ 152 Regulatory liabilities 435 447 Loss and credit carryforwards 103 111 Asset retirement obligations 152 89 Indexed debt securities derivative 47 34 Other 52 40 Valuation allowance (26) (25) Total deferred tax assets 904 848 Deferred tax liabilities: Property, plant and equipment 2,790 2,656 Investment in unconsolidated affiliates 624 1,010 Regulatory assets 325 344 Investment in marketable securities and indexed debt 649 586 Other 119 180 Total deferred tax liabilities 4,507 4,776 Net deferred tax liabilities $ 3,603 $ 3,928 Houston Electric Deferred tax assets: Regulatory liabilities $ 201 $ 195 Benefits and compensation 17 14 Asset retirement obligations 9 9 Other 9 7 Total deferred tax assets 236 225 Deferred tax liabilities: Property, plant and equipment 1,159 1,129 Regulatory assets 118 126 Total deferred tax liabilities 1,277 1,255 Net deferred tax liabilities $ 1,041 $ 1,030 CERC Deferred tax assets: Benefits and compensation $ 28 $ 24 Regulatory liabilities 147 144 Loss and credit carryforwards 143 183 Asset retirement obligations 140 80 Other 26 23 Valuation allowance (15) (15) Total deferred tax assets 469 439 Deferred tax liabilities: Property, plant and equipment 916 821 Regulatory assets 53 45 Other 84 43 Total deferred tax liabilities 1,053 909 Net deferred tax liabilities $ 584 $ 470 Merger with Vectren . On Merger Date, pursuant to the Merger Agreement, CenterPoint Energy consummated the Merger and acquired Vectren for approximately $6 billion in cash. On the Merger Date, Vectren became a wholly-owned subsidiary of CenterPoint Energy which triggered an ownership change under Section 382 of the Code. Under this Code section, future utilization of acquired NOL carry forwards and other tax attributes can be limited. On the Merger Date, Vectren estimated $177 million and $60 million of federal NOL and of charitable contribution carryforwards, respectively, the utilization of which is not expected to be limited under Section 382. Tax Attribute Carryforwards and Valuation Allowance . CenterPoint Energy has no federal NOL carryforwards and no federal charitable contribution carryforwards as of December 31, 2020. As of December 31, 2020, CenterPoint Energy had $979 million of state NOL carryforwards that expire between 2021 and 2040 and $22 million of state tax credits that do not expire. CenterPoint Energy reported a valuation allowance of $26 million because it is more likely than not that the benefit from certain state NOL carryforwards will not be realized. CERC has $425 million of federal NOL carryforwards which have an indefinite carryforward period. CERC has $592 million of gross state NOL carryforwards which expire between 2021 and 2040 and $17 million of state tax credits which do not expire. CERC reported a valuation allowance of $15 million since it is more likely than not that the benefit from certain state NOL carryforwards will not be realized. A reconciliation of CenterPoint Energy’s beginning and ending balance of unrecognized tax benefits, excluding interest and penalties, for 2020 and 2019 are as follows: Year Ended December 31, 2020 2019 (in millions) Balance, beginning of year $ 8 $ — Unrecognized tax benefits assumed through the Merger — 9 Increases related to tax positions of prior years 3 — Decreases related to tax positions of prior years (4) (1) Balance, end of year $ 7 $ 8 CenterPoint Energy had no unrecognized tax benefits for 2018 and acquired $9 million of unrecognized tax benefits in connection with the Merger during 2019. Included in the balance of uncertain tax positions as of December 31, 2020 are $3 million of tax benefits that, if recognized, would affect the effective tax rate. The above table does not include $2 million of accrued penalties and interest as of December 31, 2020. The Registrants recognize interest accrued related to unrecognized tax benefits and penalties as income tax expense. The Registrants believe that it is reasonably possible that a decrease of up to $6 million including interest and penalties, in unrecognized tax benefits may occur by the end of 2021 as a result of a lapse of statutes on older exposures and/or the acceptance of an application for an accounting method change. CenterPoint Energy’s net unrecognized tax benefits, including penalties and interest, were $9 million as of December 31, 2020 and are included in other non-current liabilities in the Consolidated Financial Statements. Tax Audits and Settlements . Tax years through 2018 have been audited and settled with the IRS for CenterPoint Energy. For the 2019 and 2020 tax years, the Registrants are participants in the IRS’s Compliance Assurance Process. Legacy Vectren is not currently under audit with the IRS, and the 2017-2019 tax years are still open.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies (a) Purchase Obligations (CenterPoint Energy and CERC) Commitments include minimum purchase obligations related to CenterPoint Energy’s and CERC’s Natural Gas reportable segment and CenterPoint Energy’s Electric reportable segment. A purchase obligation is defined as an agreement to purchase goods or services that is enforceable and legally binding on the registrant and that specifies all significant terms, including: fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. Contracts with minimum payment provisions have various quantity requirements and durations and are not classified as non-trading derivative assets and liabilities in CenterPoint Energy’s and CERC’s Consolidated Balance Sheets as of December 31, 2020 and 2019. These contracts meet an exception as “normal purchases contracts” or do not meet the definition of a derivative. Natural gas and coal supply commitments also include transportation contracts that do not meet the definition of a derivative. CenterPoint Energy, through Indiana Electric, has purchased power agreements that do not have minimum thresholds but do require payment when energy is generated by the provider. Costs arising from certain of these commitments are pass-through costs, generally collected dollar-for-dollar from retail customers through regulator-approved cost recovery mechanisms. As of December 31, 2020, minimum purchase obligations are approximately: Natural Gas and Coal Supply Other (1) CenterPoint Energy CERC CenterPoint Energy (in millions) 2021 $ 708 $ 491 $ 17 2022 542 328 12 2023 465 275 10 2024 387 254 190 2025 370 227 — 2026 and beyond 1,930 1,547 — (1) Primarily relates to technology hardware and software (b) AMAs (CenterPoint Energy and CERC) CenterPoint Energy’s and CERC’s Natural Gas have AMAs associated with their utility distribution service in Arkansas, Louisiana and Oklahoma with the Energy Services Disposal Group and in Arkansas, Indiana, Louisiana, Mississippi and Texas with other third parties. The AMAs have varying terms, the longest of which expires in 2025. Pursuant to the provisions of the agreements, CenterPoint Energy’s and CERC’s Natural Gas either sells natural gas to the asset manager and agrees to repurchase an equivalent amount of natural gas throughout the year at the same cost, or simply purchases its full natural gas requirements at each delivery point from the asset manager. Generally, AMAs are contracts between CenterPoint Energy’s and CERC’s Natural Gas and an asset manager that are intended to transfer the working capital obligation and maximize the utilization of the assets. In these agreements, CenterPoint Energy’s and CERC’s Natural Gas agrees to release transportation and storage capacity to other parties to manage natural gas storage, supply and delivery arrangements for CenterPoint Energy’s and CERC’s Natural Gas and to use the released capacity for other purposes when it is not needed for CenterPoint Energy’s and CERC’s Natural Gas. CenterPoint Energy’s and CERC’s Natural Gas may receive compensation from the asset manager through payments made over the life of the AMAs. CenterPoint Energy’s and CERC’s Natural Gas has an obligation to purchase their winter storage requirements that have been released to the asset manager under these AMAs. For further information regarding the AMAs with the Energy Services Disposal Group, see Note 4. (c) Guarantees and Product Warranties (CenterPoint Energy) In the normal course of business, ESG enters into contracts requiring it to timely install infrastructure, operate facilities, pay vendors and subcontractors and support warranty obligations and, at times, issue payment and performance bonds and other forms of assurance in connection with these contracts. Specific to ESG’s role as a general contractor in the performance contracting industry, as of December 31, 2020, there were 61 open surety bonds supporting future performance with an aggregate face amount of approximately $610 million. ESG’s exposure is less than the face amount of the surety bonds and is limited to the level of uncompleted work under the contracts. As of December 31, 2020, approximately 33% of the work was yet to be completed on projects with open surety bonds. Further, various subcontractors issue surety bonds to ESG. In addition to these performance obligations, ESG also warrants the functionality of certain installed infrastructure generally for one year and the associated energy savings over a specified number of years. As of December 31, 2020, there were 31 warranties totaling $558 million and an additional $1.2 billion in energy savings commitments not guaranteed by Vectren Corp. Since ESG’s inception in 1994, CenterPoint Energy believes ESG has had a history of generally meeting its performance obligations and energy savings guarantees and its installed products operating effectively. CenterPoint Energy assessed the fair value of its obligation for such guarantees as of December 31, 2020 and no amounts were recorded on CenterPoint Energy’s Consolidated Balance Sheets. CenterPoint Energy issues parent company level guarantees to certain vendors, customers and other commercial counterparties of ESG. These guarantees do not represent incremental consolidated obligations, but rather, represent guarantees of subsidiary obligations to allow those subsidiaries to conduct business without posting other forms of assurance. As of December 31, 2020, CenterPoint Energy, primarily through Vectren, has issued parent company level guarantees supporting ESG’s obligations. For those obligations where potential exposure can be estimated, management estimates the maximum exposure under these guarantees to be approximately $518 million as of December 31, 2020. This exposure primarily relates to energy savings guarantees on federal energy savings performance contracts. Other parent company level guarantees, certain of which do not contain a cap on potential liability, have been issued in support of federal operations and maintenance projects for which a maximum exposure cannot be estimated based on the nature of the projects. While there can be no assurance that performance under any of these parent company guarantees will not be required in the future, CenterPoint Energy considers the likelihood of a material amount being incurred as remote. (d) Guarantees and Product Warranties (CenterPoint Energy and CERC) On February 24, 2020, CenterPoint Energy, through its subsidiary CERC Corp., entered into the Equity Purchase Agreement to sell the Energy Services Disposal Group. The transaction closed on June 1, 2020. In the normal course of business prior to June 1, 2020, the Energy Services Disposal Group through CES, traded natural gas under supply contracts and entered into natural gas related transactions under transportation, storage and other contracts. In connection with the Energy Services Disposal Group’s business activities prior to the closing of the sale of the Energy Services Disposal Group on June 1, 2020, CERC Corp. issued guarantees to CES’s counterparties to guarantee the payment of CES’s obligations. When CES remained wholly owned by CERC Corp., these guarantees did not represent incremental consolidated obligations, but rather, these guarantees represented guarantees of CES’s obligations to allow it to conduct business without posting other forms of assurance. See Note 4 for further information. A CERC Corp. guarantee primarily had a one- or two-year term, although CERC Corp. would generally not be released from obligations incurred by CES prior to the termination of such guarantee unless the beneficiary of the guarantee affirmatively released CERC Corp. from its obligations under the guarantee. Throughout CERC Corp.’s ownership of CES and subsequent to the sale of the Energy Services Disposal Group through December 31, 2020, CERC Corp. did not pay any amounts under guarantees of CES’s obligations. Under the terms of the Equity Purchase Agreement, Symmetry Energy Solutions Acquisition must generally use reasonable best efforts to replace existing CERC Corp. guarantees with credit support provided by a party other than CERC Corp. as of and after the closing of the transaction. Additionally, to the extent that CERC Corp. retains any exposure relating to certain guarantees of CES’s obligations 90 days after closing of the transaction, Symmetry Energy Solutions Acquisition will pay a 3% annualized fee on such exposure, increasing by 1% on an annualized basis every three months. As of December 31, 2020, CES had provided replacement credit support to counterparties to whom CERC Corp. had issued guarantees prior to June 1, 2020, representing all $61 million of the remaining exposure under the previously issued guarantees. CERC believes that counterparties to whom replacement credit support has been provided would seek payment if needed under such replacement credit support instead of a CERC Corp. guarantee. No additional guarantees were provided by CERC Corp. to CES subsequent to the closing of the transaction on June 1, 2020. While there can be no assurance that payment under any of these guarantees will not be required in the future, CenterPoint Energy and CERC consider the likelihood of a material amount being incurred as remote. CenterPoint Energy and CERC recorded no amounts on their respective Consolidated Balance Sheets as of December 31, 2020 and December 31, 2019 related to the performance of these guarantees. (e) Legal, Environmental and Other Matters Legal Matters Minnehaha Academy (CenterPoint Energy and CERC). On August 2, 2017, a natural gas explosion occurred at the Minnehaha Academy in Minneapolis, Minnesota, resulting in the deaths of two school employees, serious injuries to others and significant property damage to the school. CenterPoint Energy, certain of its subsidiaries, including CERC, and the contractor company working in the school have been named in litigation arising out of this incident. CenterPoint Energy and CERC have reached confidential settlement agreements on all wrongful death and property damage claims and with some personal injury claimants. Additionally, CenterPoint Energy and CERC cooperated with the investigation conducted by the National Transportation Safety Board, which concluded its investigation in December 2019 and issued a report without making any recommendations. Further, CenterPoint Energy and CERC contested and reached a settlement regarding approximately $200,000 in fines imposed by the Minnesota Office of Pipeline Safety. In early 2018, the Minnesota Occupational Safety and Health Administration concluded its investigation without any adverse findings against CenterPoint Energy or CERC. CenterPoint Energy’s and CERC’s general and excess liability insurance policies provide coverage for third party bodily injury and property damage claims. Litigation Related to the Merger (CenterPoint Energy). With respect to the Merger, in July 2018, seven separate lawsuits were filed against Vectren and the individual directors of Vectren’s Board of Directors in the U.S. District Court for the Southern District of Indiana. These lawsuits alleged violations of Sections 14(a) of the Exchange Act and SEC Rule 14a-9 on the grounds that the Vectren Proxy Statement filed on June 18, 2018 was materially incomplete because it omitted material information concerning the Merger. In August 2018, the seven lawsuits were consolidated, and the Court denied the plaintiffs’ request for a preliminary injunction. In October 2018, the plaintiffs filed their Consolidated Amended Class Action Complaint. In December 2018, two plaintiffs voluntarily dismissed their lawsuits. In September 2019, the court granted the defendants’ motion to dismiss and dismissed the remaining plaintiffs’ claims with prejudice, which the plaintiffs appealed in October 2019. The U.S. Court of Appeals for the Seventh Circuit heard oral arguments in September 2020, and a ruling is expected in early 2021. The defendants believe that the allegations asserted are without merit and intend to vigorously defend themselves against the claims raised. CenterPoint Energy does not expect the ultimate outcome of this matter to have a material adverse effect on its financial condition, results of operations or cash flows. Litigation Related to the February 2021 Winter Storm Event. With respect to the February 2021 Winter Storm Event, CenterPoint Energy and Houston Electric, along with ERCOT, have received claims and lawsuits filed by plaintiffs alleging personal injury, property damage and other injuries and damages. Additionally, various regulatory and governmental entities have announced that they intend to conduct or are conducting inquiries, investigations and other reviews of the February 2021 Winter Storm Event and the efforts made by various entities to prepare for, and respond to, this event, including the electric generation shortfall issues. Entities that have already announced that they plan to conduct or are conducting such inquiries, investigations and other reviews include the United States Congress, FERC, NERC, Texas RE, ERCOT, Texas government entities and officials such as the Texas Governor’s office, the Texas Legislature, the Texas Attorney General, the PUCT, the City of Houston and other municipal and county entities in Houston Electric’s service territory, among others entities. In addition to the litigation filed thus far, like other Texas TDUs, Houston Electric may become involved in such various investigations, litigation or other regulatory and legal proceedings regarding their efforts to restore power and their compliance with NERC, ERCOT and PUCT rules and directives. CenterPoint Energy, Houston Electric and CERC may also be subject to additional litigation, and potential claims could include personal injury and property damage claims, lawsuits for impacts on businesses and other organizations and entities and shareholder claims, among other claims or litigation matters. CenterPoint Energy, Houston Electric and CERC are unable to predict the consequences of any such matters or to estimate a range of potential losses. See Note 22 for further information on the February 2021 Winter Storm Event. Environmental Matters MGP Sites. CenterPoint Energy, CERC and their predecessors operated MGPs in the past. In addition, certain of CenterPoint Energy’s subsidiaries acquired through the Merger operated MGPs in the past. The costs CenterPoint Energy or CERC, as applicable, expect to incur to fulfill their respective obligations are estimated by management using assumptions based on actual costs incurred, the timing of expected future payments and inflation factors, among others. While CenterPoint Energy and CERC have recorded all costs which they presently are obligated to incur in connection with activities at these sites, it is possible that future events may require remedial activities which are not presently foreseen, and those costs may not be subject to PRP or insurance recovery. (i) Minnesota MGPs (CenterPoint Energy and CERC) . With respect to certain Minnesota MGP sites, CenterPoint Energy and CERC have completed state-ordered remediation and continue state-ordered monitoring and water treatment. CenterPoint Energy and CERC recorded a liability as reflected in the table below for continued monitoring and any future remediation required by regulators in Minnesota. (ii) Indiana MGPs (CenterPoint Energy) . In the Indiana Gas service territory, the existence, location and certain general characteristics of 26 gas manufacturing and storage sites have been identified for which CenterPoint Energy may have some remedial responsibility. A remedial investigation/feasibility study was completed at one of the sites under an agreed upon order between Indiana Gas and the IDEM, and a Record of Decision was issued by the IDEM in January 2000. The remaining sites have been submitted to the IDEM’s VRP. CenterPoint Energy has also identified its involvement in five manufactured gas plant sites in SIGECO’s service territory, all of which are currently enrolled in the IDEM’s VRP. CenterPoint Energy is currently conducting some level of remedial activities, including groundwater monitoring at certain sites. (iii) Other MGPs (CenterPoint Energy and CERC). In addition to the Minnesota and Indiana sites, the EPA and other regulators have investigated MGP sites that were owned or operated by CenterPoint Energy or CERC or may have been owned by one of their former affiliates. Total costs that may be incurred in connection with addressing these sites cannot be determined at this time. The estimated accrued costs are limited to CenterPoint Energy’s and CERC’s share of the remediation efforts and are therefore net of exposures of other PRPs. The estimated range of possible remediation costs for the sites for which CenterPoint Energy and CERC believe they may have responsibility was based on remediation continuing for the minimum time frame given in the table below. December 31, 2020 CenterPoint Energy CERC (in millions, except years) Amount accrued for remediation $ 12 $ 7 Minimum estimated remediation costs 7 4 Maximum estimated remediation costs 54 32 Minimum years of remediation 5 30 Maximum years of remediation 50 50 The cost estimates are based on studies of a site or industry average costs for remediation of sites of similar size. The actual remediation costs will depend on the number of sites to be remediated, the participation of other PRPs, if any, and the remediation methods used. CenterPoint Energy and CERC do not expect the ultimate outcome of these matters to have a material adverse effect on the financial condition, results of operations or cash flows of either CenterPoint Energy or CERC. Asbestos. Some facilities owned by the Registrants or their predecessors contain or have contained asbestos insulation and other asbestos-containing materials. The Registrants are from time to time named, along with numerous others, as defendants in lawsuits filed by a number of individuals who claim injury due to exposure to asbestos, and the Registrants anticipate that additional claims may be asserted in the future. Although their ultimate outcome cannot be predicted at this time, the Registrants do not expect these matters, either individually or in the aggregate, to have a material adverse effect on their financial condition, results of operations or cash flows. CCR Rule (CenterPoint Energy). In April 2015, the EPA finalized its CCR Rule, which regulates ash as non-hazardous material under the RCRA. The final rule allows beneficial reuse of ash, and the majority of the ash generated by Indiana Electric’s generating plants will continue to be reused. In July 2018, the EPA released its final CCR Rule Phase I Reconsideration which extended the deadline to October 31, 2020 for ceasing placement of ash in ponds that exceed groundwater protections standards or that fail to meet location restrictions. In August 2019, the EPA proposed additional “Part A” amendments to its CCR Rule with respect to beneficial reuse of ash and other materials. Further “Part B” amendments, which related to alternate liners for CCR surface impoundments and the surface impoundment closure process, were published in March 2020. The Part A amendments were finalized in August 2020 and extended the deadline to cease placement of ash in ponds to April 11, 2021. The EPA published the final Part B amendments in November 2020. The Part A amendments do not restrict Indiana Electric’s current beneficial reuse of its fly ash. CenterPoint Energy continues to evaluate the Part B amendments to determine potential impacts. Indiana Electric has three ash ponds, two at the F.B. Culley facility (Culley East and Culley West) and one at the A.B. Brown facility. Under the existing CCR Rule, Indiana Electric is required to perform integrity assessments, including ground water monitoring, at its F.B. Culley and A.B. Brown generating stations. The ground water studies are necessary to determine the remaining service life of the ponds and whether a pond must be retrofitted with liners or closed in place. Indiana Electric’s Warrick generating unit is not included in the scope of the CCR Rule as this unit has historically been part of a larger generating station that predominantly serves an adjacent industrial facility. Preliminary groundwater monitoring indicates potential groundwater impacts very close to Indiana Electric’s ash impoundments, and further analysis is ongoing. The CCR Rule required companies to complete location restriction determinations by October 18, 2018. Indiana Electric completed its evaluation and determined that one F.B. Culley pond (Culley East) and the A.B. Brown pond fail the aquifer placement location restriction. As a result of this failure, Indiana Electric is required to cease disposal of new ash in the ponds and commence closure of the ponds by April 11, 2021. CenterPoint Energy has applied for the extensions available under the CCR Rule that would allow Indiana Electric to continue to use the ponds through October 15, 2023. The inability to take these extensions may result in increased and potentially significant operational costs in connection with the accelerated implementation of an alternative ash disposal system or adversely impact Indiana Electric’s future operations. Failure to comply with these requirements could also result in an enforcement proceeding including the imposition of fines and penalties. On April 24, 2019, Indiana Electric received an order from the IURC approving recovery in rates of costs associated with the closure of the Culley West pond, which has already completed closure activities. On August 14, 2019, Indiana Electric filed its petition with the IURC for recovery of costs associated with the closure of the A.B. Brown ash pond, which would include costs associated with the excavation and recycling of ponded ash. This petition was subsequently approved by the IURC on May 13, 2020. On October 28, 2020, the IURC approved Indiana Electric’s ECA proceeding, which included the initiation of recovery of the federally mandated project costs. Indiana Electric continues to refine site specific estimates of closure costs for its ten-acre Culley East pond. In July 2018, Indiana Electric filed a Complaint for Damages and Declaratory Relief against its insurers seeking reimbursement of defense, investigation and pond closure costs incurred to comply with the CCR Rule, and has since reached confidential settlement agreements with its insurers. The proceeds of these settlements will offset costs that have been and will be incurred to close the ponds. As of December 31, 2020, CenterPoint Energy has recorded an approximate $74 million ARO, which represents the discounted value of future cash flow estimates to close the ponds at A.B. Brown and F.B. Culley. This estimate is subject to change due to the contractual arrangements; continued assessments of the ash, closure methods, and the timing of closure; implications of Indiana Electric’s generation transition plan; changing environmental regulations; and proceeds received from the settlements in the aforementioned insurance proceeding. In addition to these removal costs, Indiana Electric also anticipates equipment purchases of between $60 million and $80 million to complete the A.B. Brown closure project. Other Environmental. From time to time, the Registrants identify the presence of environmental contaminants during operations or on property where predecessors have conducted operations. Other such sites involving contaminants may be identified in the future. The Registrants have and expect to continue to remediate any identified sites consistent with state and federal legal obligations. From time to time, the Registrants have received notices, and may receive notices in the future, from regulatory authorities or others regarding status as a PRP in connection with sites found to require remediation due to the presence of environmental contaminants. In addition, the Registrants have been, or may be, named from time to time as defendants in litigation related to such sites. Although the ultimate outcome of such matters cannot be predicted at this time, the Registrants do not expect these matters, either individually or in the aggregate, to have a material adverse effect on their financial condition, results of operations or cash flows. Other Proceedings The Registrants are involved in other legal, environmental, tax and regulatory proceedings before various courts, regulatory commissions and governmental agencies regarding matters arising in the ordinary course of business. From time to time, the Registrants are also defendants in legal proceedings with respect to claims brought by various plaintiffs against broad groups of participants in the energy industry. Some of these proceedings involve substantial amounts. The Registrants regularly analyze current information and, as necessary, provide accruals for probable and reasonably estimable liabilities on the eventual disposition of these matters. The Registrants do not expect the disposition of these matters to have a material adverse effect on the Registrants’ financial condition, results of operations or cash flows.

Earnings Per Share (CenterPoint

Earnings Per Share (CenterPoint Energy)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share (CenterPoint Energy) [Text Block]	Earnings Per Share (CenterPoint Energy) The Series C Preferred Stock issued in May 2020 are considered participating securities since these shares participate in dividends on Common Stock on a pari passu, pro rata, as-converted basis. See Note 13 for further information on the issuance of Series C Preferred Stock. As a result, beginning June 30, 2020, earnings per share on Common Stock is computed using the two-class method required for participating securities. The two-class method uses an earnings allocation formula that treats participating securities as having rights to earnings that otherwise would have been available only to common shareholders. Under the two-class method, income (loss) available to common shareholders from continuing operations is derived by subtracting the following from income (loss) from continuing operations: • preferred share dividend requirement; • deemed dividends for the amortization of the beneficial conversion feature recognized at issuance of the Series C Preferred Stock; and • an allocation of undistributed earnings to preferred shareholders of participating securities (Series C Preferred Stock) based on the securities’ right to receive dividends. Undistributed earnings are calculated by subtracting dividends declared on Common Stock, the preferred share dividend requirement and deemed dividends for the amortization of the beneficial conversion feature from net income. Net losses are not allocated to the Series C Preferred Stock as it does not have a contractual obligation to share in the losses of CenterPoint Energy. The Series C Preferred Stock includes conversion features at a price that is below the fair value of the Common Stock on the commitment date. This beneficial conversion feature, which was approximately $32 million, represents the difference between the fair value per share of the Common Stock as of the commitment date and the conversion price, multiplied by the number of common shares issuable upon conversion. The beneficial conversion feature was recognized as a discount to Series C Preferred Stock and was amortized as a deemed dividend over the period from the issue date to the first allowable conversion date, which was November 6, 2020. See Note 13 for further information. Basic earnings per common share is computed by dividing income available to common shareholders from continuing operations by the basic weighted average number of common shares outstanding during the period. Participating securities are excluded from basic weighted average number of common shares outstanding. Diluted earnings per common share is computed by dividing income available to common shareholders from continuing operations by the weighted average number of common shares outstanding, including all potentially dilutive common shares, if the effect of such common shares is dilutive. Diluted earnings per share reflects the dilutive effect of potential common shares from share-based awards and convertible preferred shares. The dilutive effect of the restricted stock, Series B Preferred Stock and Series C Preferred Stock is computed using the if-converted method, which assumes conversion of the restricted stock, Series B Preferred Stock and Series C Preferred Stock at the beginning of the period, giving income recognition for the add-back of the preferred share dividends, amortization of beneficial conversion feature, and undistributed earnings allocated to preferred shareholders. The following table reconciles numerators and denominators of CenterPoint Energy’s basic and diluted earnings per common share. Basic earnings per common share is determined by dividing Income available to common shareholders - basic by the Weighted average common shares outstanding - basic for the applicable period. Diluted earnings per common share is determined by the inclusion of potentially dilutive common stock equivalent shares that may occur if securities to issue Common Stock were exercised or converted into Common Stock. For the Year Ended December 31, 2020 2019 2018 (in millions, except per share and share amounts) Numerator: Income (loss) from continuing operations $ (591) $ 682 $ 396 Less: Preferred stock dividend requirement (Note 13) 144 117 35 Less: Amortization of beneficial conversion feature (Note 13) 32 — — Less: Undistributed earnings allocated to preferred shareholders (1) — — — Income (loss) available to common shareholders from continuing operations - basic and diluted (767) 565 361 Income (loss) available to common shareholders from discontinued operations - basic and diluted (182) 109 (28) Income (loss) available to common shareholders - basic and diluted $ (949) $ 674 $ 333 Denominator: Weighted average common shares outstanding - basic 531,031,000 502,050,000 448,829,000 Plus: Incremental shares from assumed conversions: Restricted stock (2) — 3,107,000 3,636,000 Series B Preferred Stock (3) — — — Series C Preferred Stock (4) — — — Weighted average common shares outstanding - diluted 531,031,000 505,157,000 452,465,000 Earnings (loss) per common share: Basic earnings (loss) per common share - continuing operations $ (1.45) $ 1.12 $ 0.80 Basic earnings (loss) per common share - discontinued operations (0.34) 0.22 (0.06) Basic Earnings (Loss) Per Common Share $ (1.79) $ 1.34 $ 0.74 Diluted earnings (loss) per common share - continuing operations $ (1.45) $ 1.12 $ 0.80 Diluted earnings (loss) per common share - discontinued operations (0.34) 0.21 (0.06) Diluted Earnings (Loss) Per Common Share $ (1.79) $ 1.33 $ 0.74 (1) There were no undistributed earnings to be allocated to participating securities for the year ended December 31, 2020. (2) The computation of diluted earnings (loss) per common share outstanding for the year ended December 31, 2020 excludes 3,690,000 incremental common shares from assumed conversions of restricted stock from the denominator because the shares would be anti-dilutive. (3) The computation of diluted earnings (loss) per common share outstanding for the years ended December 31, 2020, 2019 and 2018 excludes 35,922,000, 34,354,000, and 8,885,000 of incremental common shares from assumed conversion of Series B Preferred Stock from the denominator, respectively, because the shares would be anti-dilutive. (4) The computation of diluted earnings (loss) per common share outstanding for the year ended December 31, 2020 excludes 23,807,000 of incremental common shares from assumed conversion of Series C Preferred Stock from the denominator because the shares would be anti-dilutive.

Reportable Segments

Reportable Segments	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Reportable Segments [Text Block]	(18) Reportable Segments The Registrants’ determination of reportable segments considers the strategic operating units under which the Registrants’ CODM manages sales, allocates resources and assesses performance of various products and services to wholesale or retail customers in differing regulatory environments. As of January 1, 2020, each Registrant’s CODM viewed net income as the measure of profit or loss for the reportable segments rather than the previous measure of operating income. During the fourth quarter of 2020, CenterPoint Energy’s CODM requested that the financial information for the electric businesses be presented on an aggregated basis for review, resulting in one Electric reportable segment, inclusive of Houston Electric and Indiana Electric. Also, the Natural Gas Distribution reportable segment was renamed Natural Gas. Additionally during the fourth quarter of 2020, CenterPoint Energy’s and CERC’s CODM requested that the CERC corporate functions be included within the financial results of CenterPoint Energy’s Natural Gas reportable segment for review purposes. Certain prior year amounts have been reclassified to conform to the current year presentation. As of December 31, 2020, reportable segments by Registrant are as follows: CenterPoint Energy • CenterPoint Energy’s Electric reportable segment consists of electric transmission and distribution services in the Texas Gulf Coast area and electric transmission and distribution services primarily to southwestern Indiana and includes power generation and wholesale power operations. • CenterPoint Energy’s Natural Gas reportable segment consists of (i) intrastate natural gas sales to, and natural gas transportation and distribution for residential, commercial, industrial and institutional customers in Arkansas, Indiana, Louisiana, Minnesota, Mississippi, Ohio, Oklahoma and Texas; (ii) permanent pipeline connections through interconnects with various interstate and intrastate pipeline companies through CEIP, formerly included in the Energy Services reportable segment; and (iii) temporary delivery of LNG and CNG throughout the contiguous 48 states through MES, formerly included in the Energy Services reportable segment. • CenterPoint Energy’s Midstream Investments reportable segment consists of the equity investment in Enable (excluding the Enable Series A Preferred Units). For further information, see Notes 11 and 22. CenterPoint Energy’s Corporate and Other consists of energy performance contracting and sustainable infrastructure services through ESG and other corporate operations which support all of the business operations of CenterPoint Energy. Houston Electric • Houston Electric’s Houston Electric T&D reportable segment consists of electric transmission and distribution services in the Texas Gulf Coast area. CERC • During the fourth quarter of 2020, CERC’s CODM requested that the CERC corporate functions be included within the financial results of CERC’s Natural Gas reportable segment for review purposes. As a result of this change and following the divestiture of the Energy Services Disposal Group, CERC now consists of a single reportable segment. CERC’s Natural Gas reportable segment consists of (i) intrastate natural gas sales to, and natural gas transportation and distribution for residential, commercial, industrial and institutional customers in Arkansas, Louisiana, Minnesota, Mississippi, Oklahoma and Texas; (ii) permanent pipeline connections through interconnects with various interstate and intrastate pipeline companies through CEIP, formerly included in the Energy Services reportable segment; and (iii) temporary delivery of LNG and CNG throughout the contiguous 48 states through MES, formerly included in the Energy Services reportable segment. Discontinued Operations (CenterPoint Energy and CERC) On February 3, 2020, CenterPoint Energy, through its subsidiary VUSI, entered into the Securities Purchase Agreement to sell the Infrastructure Services Disposal Group, which consisted of underground pipeline construction and repair services. Accordingly, the previously reported Infrastructure Services reportable segment has been eliminated. The transaction closed on April 9, 2020. See Note 4 for further information. Additionally, on February 24, 2020, CenterPoint Energy, through its subsidiary CERC Corp., entered into the Equity Purchase Agreement to sell the Energy Services Disposal Group, which consisted of non-rate regulated natural gas sales and service operations. Accordingly, the previously reported Energy Services reportable segment has been eliminated. The transaction closed on June 1, 2020. See Note 4 for further information. Expenditures for long-lived assets include property, plant and equipment. Intersegment sales are eliminated in consolidation, except as described in Note 2(b). Financial data for reportable segments and products and services are as follows: CenterPoint Energy Revenues Equity in Earnings of Unconsolidated Affiliates Depreciation Interest Income Interest Expense Income Tax Expense Net Income (Loss) (in millions) For the year ended December 31, 2020: Electric $ 3,470 $ — $ 663 $ 3 $ (220) $ 72 $ 230 Natural Gas 3,631 — 454 8 (153) 125 278 Midstream Investments — (1,428) — 1 (54) (364) (1,116) Corporate and Other 317 — 72 103 (213) (107) 17 Eliminations — — — (111) 111 — — Continuing Operations $ 7,418 $ (1,428) $ 1,189 $ 4 $ (529) $ (274) (591) Discontinued Operations, net (182) Consolidated $ (773) For the year ended December 31, 2019: Electric $ 3,519 $ — $ 739 $ 27 $ (225) $ 96 $ 419 Natural Gas 3,750 — 420 6 (144) 2 251 Midstream Investments — 229 — 8 (53) 53 131 Corporate and Other 295 1 66 126 (290) (59) (119) Eliminations — — — (145) 145 — — Continuing Operations $ 7,564 $ 230 $ 1,225 $ 22 $ (567) $ 92 682 Discontinued Operations, net 109 Consolidated $ 791 For the year ended December 31, 2018: Electric $ 3,232 $ — $ 917 $ 5 $ (197) $ 89 $ 334 Natural Gas 3,031 — 280 1 (122) 31 98 Midstream Investments — 307 — — (10) 73 224 Corporate and Other 14 — 33 66 (135) (38) (260) Eliminations — — — (44) 44 — — Continuing Operations $ 6,277 $ 307 $ 1,230 $ 28 $ (420) $ 155 396 Discontinued Operations, net (28) Consolidated $ 368 (1) Houston Electric’s revenues from major external customers are as follows (CenterPoint Energy and Houston Electric): Year Ended December 31, 2020 2019 2018 (in millions) Affiliates of NRG $ 749 $ 727 $ 705 Affiliates of Vistra Energy Corp. 404 263 251 Total Assets Expenditures for Long-lived Assets December 31, December 31, 2020 2019 2018 2020 2019 2018 (in millions) Electric $ 14,493 $ 14,432 $ 10,509 $ 1,281 $ 1,216 $ 952 Natural Gas 14,976 14,002 7,188 1,139 1,098 638 Midstream Investments 913 2,473 2,482 — — — Corporate and Other, net of eliminations (1) 3,089 2,658 5,805 95 194 110 Continuing Operations 33,471 33,565 25,984 2,515 2,508 1,700 Assets Held for Sale/Discontinued Operations — 1,964 1,109 21 79 20 Consolidated $ 33,471 $ 35,529 $ 27,093 $ 2,536 $ 2,587 $ 1,720 (1) Total assets included pension and other postemployment-related regulatory assets of $540 million, $584 million and $665 million as of December 31, 2020, 2019 and 2018, respectively. Additionally, total assets as of December 31, 2018 included $3.9 billion of temporary investments included in Cash and cash equivalents on CenterPoint Energy’s Consolidated Balance Sheets. Houston Electric Houston Electric consists of a single reportable segment; therefore, a tabular reportable segment presentation has not been included. CERC CERC consists of a single reportable segment; therefore, a tabular reportable segment presentation has not been included. Revenues by Products and Services: Year Ended December 31, 2020 2019 2018 Revenues by Products and Services: CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Electric delivery $ 2,941 $ 2,911 $ — $ 3,019 $ 2,990 $ — $ 3,232 $ 3,234 $ — Retail electric sales 515 — — 486 — — — — — Wholesale electric sales 14 — — 14 — — — — — Retail gas sales 3,462 — 2,594 3,563 — 2,831 2,857 — 2,857 Gas transportation and processing 15 — 15 33 — 33 32 — 32 Energy products and services 471 — 154 449 — 154 156 — 142 Total $ 7,418 $ 2,911 $ 2,763 $ 7,564 $ 2,990 $ 3,018 $ 6,277 $ 3,234 $ 3,031

Supplemental Disclosure of Cash

Supplemental Disclosure of Cash Flow Information	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosure of Cash Flow Information [Text Block]	(19) Supplemental Disclosure of Cash Flow Information The tables below provide supplemental disclosure of cash flow information: 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Cash Payments/Receipts: Interest, net of capitalized interest $ 471 $ 201 $ 114 $ 436 $ 229 $ 109 $ 363 $ 200 $ 105 Income tax payments, net 143 65 4 155 87 7 89 154 3 Non-cash transactions: Accounts payable related to capital expenditures 153 102 69 236 117 86 201 124 80 Capital distribution associated with the Internal Spin (1) — — — — — 28 — — 1,473 ROU assets obtained in exchange for lease liabilities (2) 15 1 5 44 1 29 — — — Beneficial conversion feature 32 — — — — — — — — Amortization of beneficial conversion feature (32) — — — — — — — — (1) The capital distribution in 2019 associated with the Internal Spin is a result of the return to accrual for the periods of CERC’s ownership during 2018. (2) Includes the transition impact of adoption of ASU 2016-02 Leases as of January 1, 2019. The Registrants elected not to recast comparative periods in the year of adoption as permitted by the standard. The table below provides a reconciliation of cash, cash equivalents and restricted cash reported in the Consolidated Balance Sheets to the amount reported in the Statements of Consolidated Cash Flows and has not been recast to exclude the Infrastructure Services and Energy Services Disposal Groups as of December 31, 2019: December 31, 2020 December 31, 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Cash and cash equivalents (1) $ 147 $ 139 $ 1 $ 241 $ 216 $ 2 Restricted cash included in Prepaid expenses and other current assets 20 15 — 30 19 — Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows $ 167 $ 154 $ 1 $ 271 $ 235 $ 2

Related Party Transactions (Hou

Related Party Transactions (Houston Electric and CERC)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions (Houston Electric and CERC) [Text Block]	Related Party Transactions (Houston Electric and CERC) Houston Electric and CERC participate in a money pool through which they can borrow or invest on a short-term basis. Funding needs are aggregated and external borrowing or investing is based on the net cash position. The net funding requirements of the money pool are expected to be met with borrowings under CenterPoint Energy’s revolving credit facility or the sale of CenterPoint Energy’s commercial paper. The table below summarizes money pool activity: December 31, 2020 December 31, 2019 Houston Electric CERC Houston Electric CERC (in millions, except interest rates) Money pool investments (borrowings) (1) $ (8) $ — $ 481 $ — Weighted average interest rate 0.24 % 0.24 % 1.98 % 1.98 % (1) Included in Accounts and notes receivable (payable)–affiliated companies in Houston Electric’s and CERC’s Consolidated Balance Sheets. Houston Electric and CERC affiliate-related net interest income (expense) were as follows: Year Ended December 31, 2020 2019 2018 Houston Electric CERC Houston Electric CERC Houston Electric CERC (in millions) Interest income (expense), net (1) $ — $ — $ 18 $ 4 $ 1 $ — (1) Interest income is included in Other, net and interest expense is included in Interest and other finance charges on Houston Electric’s and CERC’s respective Statements of Consolidated Income. CenterPoint Energy provides some corporate services to Houston Electric and CERC. The costs of services have been charged directly to Houston Electric and CERC using methods that management believes are reasonable. These methods include negotiated usage rates, dedicated asset assignment and proportionate corporate formulas based on operating expenses, assets, gross margin, employees and a composite of assets, gross margin and employees. Houston Electric provides certain services to CERC. These services are billed at actual cost, either directly or as an allocation and include fleet services, shop services, geographic services, surveying and right-of-way services, radio communications, data circuit management and field operations. Additionally, CERC provides certain services to Houston Electric. These services are billed at actual cost, either directly or as an allocation and include line locating and other miscellaneous services. These charges are not necessarily indicative of what would have been incurred had Houston Electric and CERC not been affiliates. The Infrastructure Services Disposal Group provided pipeline construction and repair services to CERC’s Natural Gas. Additionally, CERC, through the Energy Services Disposal Group, sold natural gas to Indiana Electric for use in electric generation activities. These transactions are now included in discontinued operations and are excluded from the disclosures below. See Note 4 for further information. Amounts charged for these services are included primarily in Operation and maintenance expenses: Year Ended December 31, 2020 2019 2018 Houston Electric CERC Houston Electric CERC Houston Electric CERC (in millions) Corporate service charges $ 197 $ 212 $ 177 $ 141 $ 190 $ 147 Net affiliate service charges (billings) (16) 16 (8) 8 (17) 17 The table below presents transactions among Houston Electric, CERC and their parent, Utility Holding. Year Ended December 31, 2020 2019 2018 Houston Electric CERC Houston Electric CERC Houston Electric CERC (in millions) Cash dividends paid to parent $ 551 $ 80 $ 376 $ 120 $ 209 $ 360 Cash contribution from parent 62 217 590 129 200 960 Capital distribution to parent associated with the sale of CES — 286 — — — — Capital distribution to parent associated with the Internal Spin (1) — — — 28 — 1,473 Property, plant and equipment from parent (2) 36 23 — — — — (1) The capital distribution in 2019 associated with the Internal Spin is a result of the return to accrual for the periods of CERC’s ownership during 2018. (2) Property, plant and equipment purchased from CenterPoint Energy at its net carrying value on the date of purchase.

Leases (Notes)

Leases (Notes)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases [Text Block]	Leases The Registrants adopted ASC 842, Leases, and all related amendments on January 1, 2019 using the modified retrospective transition method and elected not to recast comparative periods in the year of adoption as permitted by the standard. There was no adjustment to retained earnings as a result of transition. As a result, disclosures for periods prior to adoption will be presented in accordance with accounting standards in effect for those periods. The Registrants also elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed them to carry forward the historical lease classification. Additionally, the Registrants elected the practical expedient related to land easements, which allows the carry forward of the accounting treatment for land easements on existing agreements. The total ROU assets obtained in exchange for new operating lease liabilities upon adoption were $22 million, $1 million and $19 million for CenterPoint Energy, Houston Electric and CERC, respectively. The Merger was completed on February 1, 2019, and as such the amounts recorded upon adoption are exclusive of Vectren’s leases. An arrangement is determined to be a lease at inception based on whether the Registrant has the right to control the use of an identified asset. ROU assets represent the Registrants’ right to use the underlying asset for the lease term and lease liabilities represent the Registrants’ obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term, including payments at commencement that depend on an index or rate. Most leases in which the Registrants are the lessee do not have a readily determinable implicit rate, so an incremental borrowing rate, based on the information available at the lease commencement date, is utilized to determine the present value of lease payments. When a secured borrowing rate is not readily available, unsecured borrowing rates are adjusted for the effects of collateral to determine the incremental borrowing rate. Each Registrant uses the implicit rate for agreements in which it is a lessor. Lease expense and lease income are recognized on a straight-line basis over the lease term for operating leases. The Registrants have lease agreements with lease and non-lease components and have elected the practical expedient to combine lease and non-lease components for certain classes of leases, such as office buildings. For classes of leases in which lease and non-lease components are not combined, consideration is allocated between components based on the stand-alone prices. Sublease income is not significant to the Registrants. The Registrants’ lease agreements do not contain any material residual value guarantees, material restrictions or material covenants. There are no material lease transactions with related parties. Agreements in which the Registrants are lessors do not include provisions for the lessee to purchase the assets. Because risk is minimal, the Registrants do not take any significant actions to manage risk associated with the residual value of their leased assets. The Registrants’ lease agreements are primarily equipment and real property leases, including land and office facility leases. The Registrants’ lease terms may include options to extend or terminate a lease when it is reasonably certain that those options will be exercised. CenterPoint Energy’s operating lease payments exclude approximately $847 million of legally- binding undiscounted minimum lease payments for leases signed but not yet commenced. The Registrants have elected an accounting policy that exempts leases with terms of one year or less from the recognition requirements of ASC 842. The components of lease cost, included in Operation and maintenance expense on the Registrants’ respective Statements of Consolidated Income, are as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 CenterPoint Energy Houston CERC CenterPoint Energy Houston CERC (in millions) Operating lease cost $ 9 $ — $ 5 $ 7 $ — $ 4 Short-term lease cost 14 12 — 25 23 — Total lease cost $ 23 $ 12 $ 5 $ 32 $ 23 $ 4 The components of lease income were as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 CenterPoint Energy Houston CERC CenterPoint Energy Houston CERC (in millions) Operating lease income $ 5 $ — $ 2 $ 4 $ 2 $ 1 Variable lease income 1 — — 2 — — Total lease income $ 6 $ — $ 2 $ 6 $ 2 $ 1 Supplemental balance sheet information related to leases was as follows: December 31, 2020 December 31, 2019 CenterPoint Energy Houston CERC CenterPoint Energy Houston CERC (in millions, except lease term and discount rate) Assets: Operating ROU assets (1) $ 31 $ 1 $ 19 $ 31 $ 1 $ 18 Total leased assets $ 31 $ 1 $ 19 $ 31 $ 1 $ 18 Liabilities: Current operating lease liability (2) $ 6 $ — $ 3 $ 7 $ — $ 3 Non-current operating lease liability (3) 26 1 18 24 1 15 Total leased liabilities $ 32 $ 1 $ 21 $ 31 $ 1 $ 18 Weighted-average remaining lease term (in years) - operating leases 6.0 4.0 7.5 6.5 5.2 7.1 Weighted-average discount rate - operating leases 3.14 % 2.59 % 3.36 % 3.57 % 3.52 % 3.61 % (1) Reported within Other assets in the Registrants’ respective Consolidated Balance Sheets. (2) Reported within Current other liabilities in the Registrants’ respective Consolidated Balance Sheets. (3) Reported within Other liabilities in the Registrants’ respective Consolidated Balance Sheets. As of December 31, 2020, maturities of operating lease liabilities were as follows: CenterPoint Houston CERC (in millions) 2021 $ 8 $ 1 $ 4 2022 6 — 4 2023 6 — 4 2024 4 — 3 2025 3 — 2 2026 and beyond 10 — 7 Total lease payments 37 1 24 Less: Interest 5 — 3 Present value of lease liabilities $ 32 $ 1 $ 21 As of December 31, 2020, maturities of undiscounted operating lease payments to be received are as follows: CenterPoint Houston CERC (in millions) 2021 $ 4 $ — $ 1 2022 2 — — 2023 2 — — 2024 2 — — 2025 2 — — 2026 and beyond 8 — — Total lease payments to be received $ 20 $ — $ 1 Other information related to leases is as follows. See Note 19 for information on ROU assets obtained in exchange for operating lease liabilities: Year Ended December 31, 2020 CenterPoint Houston CERC (in millions) Operating cash flows from operating leases included in the measurement of lease liabilities $ 8 $ 1 $ 4

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Enable Distributions Declarations (CenterPoint Energy) Equity Instrument Declaration Date Record Date Payment Date Per Unit Distribution Expected Cash Distribution (in millions) Enable common units February 12, 2021 February 22, 2021 March 1, 2021 $ 0.16525 $ 39 Enable Series A Preferred Units February 12, 2021 February 12, 2021 February 12, 2021 0.62500 9 February 2021 Winter Storm Event In February 2021, certain of our jurisdictions experienced an extreme and unprecedented winter weather event that resulted in prolonged freezing temperatures, which impacted, and may continue to impact, our businesses. In Texas, the February 2021 Winter Storm Event caused an electricity generation shortage that was severely disruptive to Houston Electric’s service territory and the wholesale generation market. While demand for electricity reached extraordinary levels due to the extreme cold, the supply of electricity significantly decreased in part because of the inability of certain power generation facilities to supply electric power to the grid. Houston Electric does not own or operate any electric generation facilities. It transmits and distributes to customers of REPs electric power that the REPs obtain from power generation facilities owned by third parties. ERCOT serves as the independent system operator and regional reliability coordinator for member electric power systems in most of Texas. To comply with ERCOT’s orders, Houston Electric implemented controlled outages across its service territory, resulting in a substantial number of businesses and residents being without power, many for extended periods of time, in compliance with ERCOT’s directives as an emergency procedure to avoid prolonged large-scale state-wide blackouts and long-term damage to the electric system in Texas. In anticipation of this weather event, Houston Electric implemented its emergency operations plan’s processes and procedures necessary to respond to such events, including establishing an incident command center and calling for mutual assistance from other utilities where needed, among other measures. Throughout the February 2021 Winter Storm Event, Houston Electric remained in contact with its regulators and stakeholders, including federal, state and local officials, as well as the PUCT and ERCOT. On February 21, 2021, in response to the 2021 February Winter Storm Event, the PUCT issued an order prohibiting REPs from sending a request to TDUs to disconnect such REPs’ customers for non-payment, effective February 21, 2021. As a result of this order, in event a request for disconnect is received from a REP, Houston Electric will not execute any such disconnect request until the PUCT issues orders for disconnects to resume. The February 2021 Winter Storm Event also impacted wholesale prices CenterPoint Energy and CERC paid for their natural gas and their ability to service customers in their Natural Gas service territories, including due to the reduction in available natural gas capacity and impacts to CenterPoint Energy’s and CERC’s natural gas supply portfolio activities, and the effects of weather on their systems and their ability to transport natural gas, among other things. The overall natural gas market, including the markets from which CenterPoint Energy and CERC sourced a significant portion of their natural gas for their operations, experienced significant impacts caused by the February 2021 Winter Storm Event, resulting in extraordinary increases in the price of natural gas purchased by CenterPoint Energy and CERC. On February 13, 2021, the Railroad Commission authorized each Texas natural gas distribution utility to record in a regulatory asset the extraordinary expenses associated with the February 2021 Winter Storm Event, including, but not limited to, natural gas cost and other costs related to the procurement and transportation of natural gas supply, subject to recovery in future regulatory proceedings. CenterPoint Energy’s and CERC’s Natural Gas utilities in their jurisdictions outside of Texas have natural gas cost recovery mechanisms to recover the increased cost of natural gas. Various regulatory and governmental entities have announced that they intend to conduct inquiries, investigations and other reviews of the February 2021 Winter Storm Event and the efforts made by various entities to prepare for, and respond to, this event, including the electric generation shortfall issues. Entities that have already announced that they plan to conduct or are conducting such inquiries, investigations and other reviews include the United States Congress, FERC, NERC, Texas RE, ERCOT, Texas government entities and officials such as the Texas Governor’s office, the Texas Legislature, the Texas Attorney General, the PUCT, the City of Houston and other municipal and county entities in Houston Electric’s service territory, among others entities. Like other Texas TDUs, Houston Electric may become involved in certain of these investigations, litigation or other regulatory and legal proceedings regarding their efforts to restore power and their compliance with NERC, ERCOT and PUCT rules and directives. CenterPoint Energy and CERC may also be subject to litigation, and potential claims could include personal injury and property damage claims, lawsuits for impacts on businesses and other organizations and entities and shareholder claims, among other claims or litigation matters. CenterPoint Energy, Houston Electric and CERC are unable to predict the consequences of any such matters or to estimate a range of potential losses. On February 24, 2021, CERC received financing commitments totaling $1.7 billion on a 364-day term loan facility to bridge any working capital needs related to the February 2021 Winter Storm Event. Enable Merger (CenterPoint Energy) On February 16, 2021, Enable entered into the Enable Merger Agreement. At the closing of the transactions contemplated by the Enable Merger Agreement, if and when it occurs, Energy Transfer will acquire all of Enable’s outstanding equity interests, resulting in the exchange of Enable common units owned by CenterPoint Energy at the transaction exchange ratio of 0.8595x Energy Transfer common units for each Enable common unit. CenterPoint Energy will also receive $5 million in cash in exchange for its interest in Enable GP and approximately $385 million of Energy Transfer Series G Preferred Units in exchange for all of its Enable Series A Preferred Units. The transactions contemplated under the Enable Merger Agreement are expected to be completed in the second half of 2021, subject to customary closing conditions, including Hart-Scott-Rodino antitrust clearance.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Use of Estimates	Use of EstimatesThe preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The accounts of the Registrants and their wholly-owned and majority-owned and controlled subsidiaries are included in the consolidated financial statements. All intercompany transactions and balances are eliminated in consolidation, except as described below. Businesses within the Infrastructure Services Disposal Group provided underground pipeline construction and repair services for customers that included Natural Gas utilities. In accordance with consolidation guidance in ASC 980—Regulated Operations, costs incurred by Natural Gas utilities for these pipeline construction and repair services were not eliminated in consolidation when capitalized and included in rate base by the Natural Gas utility. On February 3, 2020, CenterPoint Energy, through its subsidiary VUSI, entered into the Securities Purchase Agreement to sell the Infrastructure Services Disposal Group. The transaction closed on April 9, 2020. For further information, see Note 4.
Equity Method and Investments Without a Readily Determinable Fair Value (CenterPoint Energy)	Equity Method and Investments without a Readily Determinable Fair Value (CenterPoint Energy) CenterPoint Energy uses the equity method for investments in entities when it exercises significant influence, does not have control and is not considered the primary beneficiary, if applicable. Generally, equity investments in limited partnerships with interest greater than approximately 3-5% is accounted for under the equity method. Under the equity method, CenterPoint Energy adjusts its investments each period for contributions made, distributions received, respective shares of comprehensive income and amortization of basis differences, as appropriate. CenterPoint Energy evaluates its equity method investments for impairment when events or changes in circumstances indicate there is a loss in value of the investment that is other than a temporary decline. CenterPoint Energy considers distributions received from equity method investments which do not exceed cumulative equity in earnings subsequent to the date of investment to be a return on investment and classifies these distributions as operating activities in its Statements of Consolidated Cash Flows. CenterPoint Energy considers distributions received from equity method investments in excess of cumulative equity in earnings subsequent to the date of investment to be a return of investment and classifies these distributions as investing activities in its Statements of Consolidated Cash Flows. Investments without a readily determinable fair value will be measured at cost, less impairment, plus or minus observable prices changes of an identical or similar investment of the same issuer.
Revenues	RevenuesThe Registrants record revenue for electricity delivery and natural gas sales and services under the accrual method and these revenues are recognized upon delivery to customers. Electricity deliveries not billed by month-end are accrued based on actual AMS data, daily supply volumes and applicable rates. Natural gas sales not billed by month-end are accrued based upon estimated purchased gas volumes, estimated lost and unaccounted for gas and currently effective tariff rates. For further discussion, see Note 5.
MISO Transactions	MISO TransactionsIndiana Electric is a member of the MISO. MISO-related purchase and sale transactions are recorded using settlement information provided by the MISO. These purchase and sale transactions are accounted for on at least a net hourly position, meaning net purchases within that interval are recorded on CenterPoint Energy’s Statements of Consolidated Income in Utility natural gas, fuel and purchased power, and net sales within that interval are recorded on CenterPoint Energy’s Statements of Consolidated Income in Utility revenues. On occasion, prior period transactions are resettled outside the routine process due to a change in the MISO’s tariff or a material interpretation thereof. Expenses associated with resettlements are recorded once the resettlement is probable and the resettlement amount can be estimated. Revenues associated with resettlements are recognized when the amount is determinable and collectability is reasonably assured.
Guarantees	GuaranteesCenterPoint Energy recognizes guarantee obligations at fair value. CenterPoint Energy discloses parent company guarantees of a subsidiary’s obligation when that guarantee results in the exposure of a material obligation of the parent company even if the probability of fulfilling such obligation is considered remote. See Note 16(c) and (d).
Long-lived Assets, Goodwill and Intangibles	Long-lived Assets, Goodwill and Intangibles The Registrants record property, plant and equipment at historical cost and expense repair and maintenance costs as incurred. The Registrants periodically evaluate long-lived assets, including property, plant and equipment, and specifically identifiable intangibles subject to amortization, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. For rate regulated businesses, recoverability of long-lived assets is assessed by determining if a capital disallowance from a regulator is probable through monitoring the outcome of rate cases and other proceedings. For non-rate regulated businesses, recoverability is assessed based on an estimate of undiscounted cash flows attributable to the assets compared to the carrying value of the assets. No long-lived asset or intangible asset impairments were recorded in 2020, 2019 or 2018. CenterPoint Energy and CERC perform goodwill impairment tests at least annually and evaluate goodwill when events or changes in circumstances indicate that its carrying value may not be recoverable. CenterPoint Energy and CERC recognize a goodwill impairment by the amount a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill within that reporting unit. CenterPoint Energy includes deferred tax assets and liabilities within its reporting unit’s carrying value for the purposes of annual and interim impairment tests, regardless of whether the estimated fair value reflects the disposition of such assets and liabilities. For further information about the goodwill impairment tests during 2020, see Note 6.
Assets Held for Sale and Discontinued Operations	Assets Held for Sale and Discontinued OperationsGenerally, a long-lived asset to be sold is classified as held for sale in the period in which management, with approval from the Board of Directors, as applicable, commits to a plan to sell and a sale is expected to be completed within one year. The Registrants record assets and liabilities held for sale at the lower of their carrying value or their estimated fair value less cost to sell. If the disposal group reflects a component of a reporting unit and meets the definition of a business, the goodwill within that reporting unit is allocated to the disposal group based on the relative fair value of the components representing a business that will be retained and disposed. Goodwill is not allocated to a portion of a reporting unit that does not meet the definition of a business. A disposal group that meets the held for sale criteria and also represents a strategic shift to the Registrant, is also reflected as discontinued operations on the Statements of Consolidated Income, and prior periods are recast to reflect the earnings or losses from such businesses as income from discontinued operations, net of tax.
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities The Registrants apply the guidance for accounting for regulated operations within the Electric reportable segment and the Natural Gas reportable segment. The Registrants’ rate-regulated subsidiaries may collect revenues subject to refund pending final determination in rate proceedings. In connection with such revenues, estimated rate refund liabilities are recorded which reflect management’s current judgment of the ultimate outcomes of the proceedings. The Registrants’ rate-regulated businesses recognize removal costs as a component of depreciation expense in accordance with regulatory treatment. In addition, a portion of the amount of removal costs collected from customers that relate to AROs has been reflected as an asset retirement liability in accordance with accounting guidance for AROs. For further detail on the Registrants’ regulatory assets and liabilities, see Note 7.
Depreciation and Amortization Expense	Depreciation and Amortization ExpenseThe Registrants compute depreciation and amortization using the straight-line method based on economic lives or regulatory-mandated recovery periods. Amortization expense includes amortization of certain regulatory assets and other intangibles.
Capitalization of Interest and AFUDC	Capitalization of Interest and AFUDC The Registrants capitalize interest and AFUDC as a component of projects under construction and amortize it over the assets’ estimated useful lives once the assets are placed in service. AFUDC represents the composite interest cost of borrowed funds and a reasonable return on the equity funds used for construction for subsidiaries that apply the guidance for accounting for regulated operations. Although AFUDC increases both utility plant and earnings, it is realized in cash when the assets are included in rates. Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Interest and AFUDC debt (1) $ 27 $ 8 $ 3 $ 36 $ 8 $ 3 $ 8 $ 6 $ 2 AFUDC equity (2) 25 14 3 22 15 3 12 10 2 (1) Included in Interest and other finance charges on the Registrants’ respective Statements of Consolidated Income. (2) Included in Other Income (Expense) on the Registrants’ respective Statements of Consolidated Income.
Income Taxes	Income Taxes Houston Electric and CERC are included in CenterPoint Energy’s U.S. federal consolidated income tax return. Houston Electric and CERC report their income tax provision on a separate entity basis pursuant to a tax sharing agreement with CenterPoint Energy. Current federal and certain state income taxes are payable to or receivable from CenterPoint Energy. The Registrants use the asset and liability method of accounting for deferred income taxes. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. A valuation allowance is established against deferred tax assets for which management believes realization is not considered to be more likely than not. The Registrants recognize interest and penalties as a component of income tax expense (benefit), as applicable, in their respective Statements of Consolidated Income. CenterPoint Energy reports the income tax provision associated with its interest in Enable in income tax expense (benefit) in its Statements of Consolidated Income. To the extent certain EDIT of the Registrants’ rate-regulated subsidiaries may be recoverable or payable through future rates, regulatory assets and liabilities have been recorded, respectively. See Note 15 for further discussion of the impacts of tax reform implementation. The Registrants use the portfolio approach to recognize income tax effects on other comprehensive income from accumulated other comprehensive income.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Credit LossesAccounts receivable are recorded at the invoiced amount and do not bear interest. Management reviews historical write-offs, current available information, and reasonable and supportable forecasts to estimate and establish allowance for credit losses. Account balances are charged off against the allowance when management determines it is probable the receivable will not be recovered. See Note 7 for further information about regulatory deferrals of bad debt expense related to COVID-19.
Inventory	Inventory The Registrants’ inventory consists principally of materials and supplies, and for CERC, natural gas, and for CenterPoint Energy, coal inventory. Materials and supplies are valued at the lower of average cost or market. Materials and supplies are recorded to inventory when purchased and subsequently charged to expense or capitalized to plant when installed. Certain natural gas in storage at CenterPoint Energy’s and CERC’s utilities are recorded using the LIFO method. CenterPoint Energy’s and CERC’s balances in inventory that were valued using LIFO method were as follows: Year Ended December 31, 2020 (1) 2019 2020 (1) 2019 CenterPoint Energy CERC (in millions) LIFO inventory $ 92 $ 97 $ 55 $ 58 (1) Based on the average cost of gas purchased during December 2020, CenterPoint Energy’s and CERC’s cost of replacing inventories carried at LIFO cost was less than the carrying value at December 31, 2020 by $62 million and $54 million, respectively. During 2020, 2019 and 2018, CenterPoint Energy and CERC recorded write-downs of natural gas inventory to the lower of average cost or market which are disclosed on the respective Statements of Consolidated Cash Flows.
Derivative Instruments	Derivative InstrumentsThe Registrants are exposed to various market risks. These risks arise from transactions entered into in the normal course of business. The Registrants, from time to time, utilize derivative instruments such as physical forward contracts, swaps and options to mitigate the impact of changes in commodity prices, weather and interest rates on operating results and cash flows. Such derivatives are recognized in the Registrants’ Consolidated Balance Sheets at their fair value unless the Registrant elects the normal purchase and sales exemption for qualified physical transactions. A derivative may be designated as a normal purchase or normal sale if the intent is to physically receive or deliver the product for use or sale in the normal course of business. CenterPoint Energy elected to record changes in the fair value of amounts excluded from the assessment of effectiveness immediately in its Statements of Consolidated Income.
Investments in Equity Securities (CenterPoint Energy and CERC)	Investments in Equity Securities (CenterPoint Energy and CERC)CenterPoint Energy and CERC report equity securities at estimated fair value in their respective Consolidated Balance Sheets, and any unrealized holding gains and losses are recorded as Other Income (Expense) in their respective Statements of Consolidated Income.
Environmental Costs	Environmental CostsThe Registrants expense or capitalize environmental expenditures, as appropriate, depending on their future economic benefit. The Registrants expense amounts that relate to an existing condition caused by past operations that do not have future economic benefit. The Registrants record undiscounted liabilities related to these future costs when environmental assessments and/or remediation activities are probable and the costs can be reasonably estimated.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted CashFor purposes of reporting cash flows, the Registrants consider cash equivalents to be short-term, highly-liquid investments with maturities of three months or less from the date of purchase. Cash and cash equivalents held by the Bond Companies (VIEs) solely to support servicing the Securitization Bonds as of December 31, 2020 and 2019 are reflected on CenterPoint Energy’s and Houston Electric’s Consolidated Balance Sheets.In connection with the issuance of Securitization Bonds, CenterPoint Energy and Houston Electric were required to establish restricted cash accounts to collateralize the bonds that were issued in these financing transactions. These restricted cash accounts are not available for withdrawal until the maturity of the bonds and are not included in cash and cash equivalents. For more information on restricted cash see Note 19
Preferred Stock Dividends	Preferred Stock and Dividends Preferred stock is evaluated to determine balance sheet classification, and all conversion and redemption features are evaluated for bifurcation treatment. Proceeds received net of issuance costs are recognized on the settlement date. Cash dividends become a liability once declared. Income available to common stockholders is computed by deducting from net income the dividends accumulated and earned during the period on cumulative preferred stock.
Purchase Accounting	Purchase AccountingThe Registrants evaluate acquisitions to determine when a set of acquired activities and assets represent a business. When control of a business is obtained, the Registrants apply the acquisition method of accounting and record the assets acquired, liabilities assumed and any non-controlling interest obtained based on fair value at the acquisition date. The excess of the fair value of purchase consideration over the fair value of the net assets acquired is recorded as goodwill. The results of operations of the acquired business are included in the Registrants’ respective Statements of Consolidated Income beginning on the date of the acquisition.
New Accounting Pronouncements	New Accounting Pronouncements The following table provides an overview of certain recently adopted or issued accounting pronouncements applicable to all the Registrants, unless otherwise noted. Recently Adopted Accounting Standards ASU Number and Name Description Date of Adoption Financial Statement Impact ASU 2016-13- Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard, including standards amending this standard, requires a new model called CECL to estimate credit losses for (1) financial assets subject to credit losses and measured at amortized cost and (2) certain off-balance sheet credit exposures. Upon initial recognition of the exposure, the CECL model requires an entity to estimate the credit losses expected over the life of an exposure based on historical information, current information and reasonable and supportable forecasts, including estimates of prepayments. Transition method: modified retrospective January 1, 2020 The Registrants adopted the standard and recognized a cumulative-effect adjustment of the transition to opening retained earnings and allowance for credit losses with no impact on results of operations and cash flows. See Note 5 for more information. ASU 2019-12: Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes This standard simplifies accounting for income taxes by eliminating certain exceptions to the guidance for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also simplifies aspects of the accounting for franchise taxes that are partially based on income and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. Transition method: prospective for all amendments that apply to the Registrants January 1, 2020 Upon adoption, the Registrants are not required to apply the intraperiod tax allocation exception when there is a current-period loss from continuing operations. Accordingly, CenterPoint Energy determined the tax effect of income from continuing operations without considering the tax effects of items that are not included in continuing operations (i.e., discontinued operations). Additionally, CenterPoint Energy is no longer required to limit the year-to-date tax benefit recognized when the year-to-date benefit exceeds the anticipated full year benefit. Management believes that other recently adopted and recently issued accounting standards that are not yet effective will not have a material impact on the Registrants’ financial position, results of operations or cash flows upon adoption.

Leases (Policies)

Leases (Policies)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lessee, Leases [Policy Text Block]	The Registrants adopted ASC 842, Leases, and all related amendments on January 1, 2019 using the modified retrospective transition method and elected not to recast comparative periods in the year of adoption as permitted by the standard. There was no adjustment to retained earnings as a result of transition. As a result, disclosures for periods prior to adoption will be presented in accordance with accounting standards in effect for those periods. The Registrants also elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed them to carry forward the historical lease classification. Additionally, the Registrants elected the practical expedient related to land easements, which allows the carry forward of the accounting treatment for land easements on existing agreements. The total ROU assets obtained in exchange for new operating lease liabilities upon adoption were $22 million, $1 million and $19 million for CenterPoint Energy, Houston Electric and CERC, respectively. The Merger was completed on February 1, 2019, and as such the amounts recorded upon adoption are exclusive of Vectren’s leases. An arrangement is determined to be a lease at inception based on whether the Registrant has the right to control the use of an identified asset. ROU assets represent the Registrants’ right to use the underlying asset for the lease term and lease liabilities represent the Registrants’ obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term, including payments at commencement that depend on an index or rate. Most leases in which the Registrants are the lessee do not have a readily determinable implicit rate, so an incremental borrowing rate, based on the information available at the lease commencement date, is utilized to determine the present value of lease payments. When a secured borrowing rate is not readily available, unsecured borrowing rates are adjusted for the effects of collateral to determine the incremental borrowing rate. Each Registrant uses the implicit rate for agreements in which it is a lessor. Lease expense and lease income are recognized on a straight-line basis over the lease term for operating leases. The Registrants have lease agreements with lease and non-lease components and have elected the practical expedient to combine lease and non-lease components for certain classes of leases, such as office buildings. For classes of leases in which lease and non-lease components are not combined, consideration is allocated between components based on the stand-alone prices. Sublease income is not significant to the Registrants. The Registrants’ lease agreements do not contain any material residual value guarantees, material restrictions or material covenants. There are no material lease transactions with related parties. Agreements in which the Registrants are lessors do not include provisions for the lessee to purchase the assets. Because risk is minimal, the Registrants do not take any significant actions to manage risk associated with the residual value of their leased assets. The Registrants’ lease agreements are primarily equipment and real property leases, including land and office facility leases. The Registrants’ lease terms may include options to extend or terminate a lease when it is reasonably certain that those options will be exercised. CenterPoint Energy’s operating lease payments exclude approximately $847 million of legally-

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Public Utilities General Disclosures [Table Text Block]	The Registrants capitalize interest and AFUDC as a component of projects under construction and amortize it over the assets’ estimated useful lives once the assets are placed in service. AFUDC represents the composite interest cost of borrowed funds and a reasonable return on the equity funds used for construction for subsidiaries that apply the guidance for accounting for regulated operations. Although AFUDC increases both utility plant and earnings, it is realized in cash when the assets are included in rates. Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Interest and AFUDC debt (1) $ 27 $ 8 $ 3 $ 36 $ 8 $ 3 $ 8 $ 6 $ 2 AFUDC equity (2) 25 14 3 22 15 3 12 10 2 (1) Included in Interest and other finance charges on the Registrants’ respective Statements of Consolidated Income. (2) Included in Other Income (Expense) on the Registrants’ respective Statements of Consolidated Income.
LIFO Inventory	The Registrants’ inventory consists principally of materials and supplies, and for CERC, natural gas, and for CenterPoint Energy, coal inventory. Materials and supplies are valued at the lower of average cost or market. Materials and supplies are recorded to inventory when purchased and subsequently charged to expense or capitalized to plant when installed. Certain natural gas in storage at CenterPoint Energy’s and CERC’s utilities are recorded using the LIFO method. CenterPoint Energy’s and CERC’s balances in inventory that were valued using LIFO method were as follows: Year Ended December 31, 2020 (1) 2019 2020 (1) 2019 CenterPoint Energy CERC (in millions) LIFO inventory $ 92 $ 97 $ 55 $ 58 (1) Based on the average cost of gas purchased during December 2020, CenterPoint Energy’s and CERC’s cost of replacing inventories carried at LIFO cost was less than the carrying value at December 31, 2020 by $62 million and $54 million, respectively.
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	The following table provides an overview of certain recently adopted or issued accounting pronouncements applicable to all the Registrants, unless otherwise noted. Recently Adopted Accounting Standards ASU Number and Name Description Date of Adoption Financial Statement Impact ASU 2016-13- Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard, including standards amending this standard, requires a new model called CECL to estimate credit losses for (1) financial assets subject to credit losses and measured at amortized cost and (2) certain off-balance sheet credit exposures. Upon initial recognition of the exposure, the CECL model requires an entity to estimate the credit losses expected over the life of an exposure based on historical information, current information and reasonable and supportable forecasts, including estimates of prepayments. Transition method: modified retrospective January 1, 2020 The Registrants adopted the standard and recognized a cumulative-effect adjustment of the transition to opening retained earnings and allowance for credit losses with no impact on results of operations and cash flows. See Note 5 for more information. ASU 2019-12: Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes This standard simplifies accounting for income taxes by eliminating certain exceptions to the guidance for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also simplifies aspects of the accounting for franchise taxes that are partially based on income and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. Transition method: prospective for all amendments that apply to the Registrants January 1, 2020 Upon adoption, the Registrants are not required to apply the intraperiod tax allocation exception when there is a current-period loss from continuing operations. Accordingly, CenterPoint Energy determined the tax effect of income from continuing operations without considering the tax effects of items that are not included in continuing operations (i.e., discontinued operations). Additionally, CenterPoint Energy is no longer required to limit the year-to-date tax benefit recognized when the year-to-date benefit exceeds the anticipated full year benefit.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment [Table Text Block]	Property, plant and equipment includes the following: December 31, 2020 December 31, 2019 Weighted Average Useful Lives Property, Plant and Equipment, Gross Accumulated Depreciation & Amortization Property, Plant and Equipment, Net Property, Plant and Equipment, Gross Accumulated Depreciation & Amortization Property, Plant and Equipment, Net (in years) (in millions) CenterPoint Energy Electric transmission and distribution 36 $ 15,225 $ 4,785 $ 10,440 $ 14,360 $ 4,634 $ 9,726 Electric generation (1) 27 1,922 754 1,168 1,780 698 1,082 Natural gas distribution 29 14,022 4,019 10,003 12,787 3,766 9,021 Other property 15 1,345 594 751 1,397 602 795 Total $ 32,514 $ 10,152 $ 22,362 $ 30,324 $ 9,700 $ 20,624 Houston Electric Electric transmission 46 $ 3,686 $ 700 $ 2,986 $ 3,358 $ 674 $ 2,684 Electric distribution 34 8,225 2,696 5,529 7,876 2,586 5,290 Other transmission and distribution property 22 1,682 534 1,148 1,595 537 1,058 Total $ 13,593 $ 3,930 $ 9,663 $ 12,829 $ 3,797 $ 9,032 CERC Natural gas distribution 29 $ 8,928 $ 2,392 $ 6,536 $ 8,024 $ 2,243 $ 5,781 Other property 19 44 22 22 55 27 28 Total $ 8,972 $ 2,414 $ 6,558 $ 8,079 $ 2,270 $ 5,809 (1) SIGECO and AGC own a 300 MW unit at the Warrick Power Plant (Warrick Unit 4) as tenants in common. SIGECO’s share of the cost of this unit as of December 31, 2020, is $195 million with accumulated depreciation totaling $146 million. AGC and SIGECO share equally in the cost of operation and output of the unit. SIGECO’s share of operating costs is included in Operation and maintenance expense in CenterPoint Energy’s Statements of Consolidated Income.
Depreciation and Amortization [Table Text Block]	The following table presents depreciation and amortization expense for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Depreciation $ 961 $ 368 $ 289 $ 879 $ 339 $ 277 $ 623 $ 342 $ 261 Amortization of securitized regulatory assets 155 155 — 271 271 — 531 531 — Other amortization 73 37 15 75 38 16 76 44 19 Total $ 1,189 $ 560 $ 304 $ 1,225 $ 648 $ 293 $ 1,230 $ 917 $ 280
Asset Retirement Obligation [Table Text Block]	A reconciliation of the changes in the ARO liability recorded in Other non-current liabilities on each of the Registrants’ respective Consolidated Balance Sheets is as follows: December 31, 2020 December 31, 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Beginning balance $ 539 $ 42 $ 325 $ 258 $ 34 $ 221 Addition from Merger with Vectren — — — 116 — — Accretion expense (1) 16 1 11 16 1 10 Revisions in estimates (2) 232 — 235 149 7 94 Ending balance $ 787 $ 43 $ 571 $ 539 $ 42 $ 325 (1) Reflected in Regulatory assets on each of the Registrants’ respective Consolidated Balance Sheets.

Divestitures (CenterPoint Ene_2

Divestitures (CenterPoint Energy and CERC) (Tables)	12 Months Ended
	Dec. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations Balance Sheet	The assets and liabilities of the Infrastructure Services and Energy Services Disposal Groups classified as held for sale in CenterPoint Energy’s and CERC’s Condensed Consolidated Balance Sheets, as applicable, as of December 31, 2019 included the following: December 31, 2019 CenterPoint Energy CERC Infrastructure Services Disposal Group Energy Services Disposal Group Total Energy Services Disposal Group (in millions) Receivables, net $ 192 $ 445 $ 637 $ 445 Accrued unbilled revenues 109 8 117 8 Natural gas inventory — 67 67 67 Materials and supplies 6 — 6 — Non-trading derivative assets — 136 136 136 Other 4 35 39 35 Total current assets held for sale 311 691 1,002 691 Property, plant and equipment, net 295 26 321 26 Goodwill 220 62 282 62 Non-trading derivative assets — 58 58 58 Other 234 67 301 67 Total non-current assets held for sale 749 213 962 213 Total assets held for sale $ 1,060 $ 904 $ 1,964 $ 904 Accounts payable $ 45 $ 299 $ 344 $ 299 Taxes accrued 2 — 2 — Non-trading derivative liabilities — 44 44 44 Other 40 25 65 25 Total current liabilities held for sale 87 368 455 368 Non-trading derivative liabilities — 14 14 14 Benefit obligations — 4 4 4 Other 16 9 25 9 Total non-current liabilities held for sale 16 27 43 27 Total liabilities held for sale $ 103 $ 395 $ 498 $ 395
Disposal Groups, Including Discontinued Operations [Table Text Block]	A summary of the Infrastructure Services and Energy Services Disposal Groups presented as discontinued operations in CenterPoint Energy’s Statements of Consolidated Income, as applicable, is as follows: Year Ended December 31, 2020 2019 (1) 2020 2019 2018 2020 2019 2018 CenterPoint Energy Infrastructure Services Disposal Group Energy Services Disposal Group Total (in millions) Revenues $ 250 $ 1,190 $ 1,167 $ 3,767 $ 4,503 $ 1,417 $ 4,957 $ 4,503 Expenses: Non-utility cost of revenues 50 309 1,108 3,597 4,459 1,158 3,906 4,459 Operation and maintenance 184 714 34 68 66 218 782 66 Depreciation and amortization — 50 — 12 13 — 62 13 Taxes other than income taxes 1 2 3 2 2 4 4 2 Goodwill Impairment — — — 48 — — 48 — Total 235 1,075 1,145 3,727 4,540 1,380 4,802 4,540 Income (loss) from Discontinued Operations before income taxes 15 115 22 40 (37) 37 155 (37) Loss on classification to held for sale, net (2) (102) — (96) — — (198) — — Income tax expense (benefit) 24 29 (3) 17 (9) 21 46 (9) Net income (loss) from Discontinued Operations $ (111) $ 86 $ (71) $ 23 $ (28) $ (182) $ 109 $ (28) (1) Reflects February 1, 2019 to December 31, 2019 results only due to the Merger. (2) Loss from classification to held for sale is inclusive of goodwill impairment, gains and losses recognized upon sale, and for CenterPoint Energy, its costs to sell. Internal Spin (CERC). On September 4, 2018, CERC completed the Internal Spin. CERC executed the Internal Spin to, among other things, enhance the access of CERC and CenterPoint Energy to low cost debt and equity through increased transparency and understandability of the financial statements, improve CERC’s credit quality by eliminating the exposure to Enable’s midstream business and provide clarity of internal reporting and performance metrics to enhance management’s decision making for CERC and CNP Midstream. The Internal Spin represented a significant strategic shift that had a material effect on CERC’s operations and financial results and, as a result, CERC’s distribution of its equity investment in Enable met the criteria for discontinued operations classification. CERC has no continuing involvement in the equity investment of Enable. Therefore, CERC’s equity in earnings and related income taxes were classified as Income from discontinued operations, net of tax, in CERC’s Statements of Consolidated Income for the periods presented. CERC’s equity method investment and related deferred income tax liabilities were classified as Investment in unconsolidated affiliate - discontinued operations and Deferred income taxes, net - discontinued operations, respectively, in CERC’s Consolidated Balance Sheets for the periods presented. A summary of the Energy Services Disposal Group and Internal Spin presented as discontinued operations in CERC’s Statements of Consolidated Income, as applicable, is as follows: Year Ended December 31, 2020 2019 2018 CERC (in millions) Revenues $ 1,167 $ 3,767 $ 4,503 Expenses: Non-utility cost of revenues 1,108 3,597 4,459 Operation and maintenance 34 68 66 Depreciation and amortization — 12 13 Taxes other than income taxes 3 2 2 Goodwill Impairment — 48 — Total 1,145 3,727 4,540 Equity in earnings of unconsolidated affiliate, net — — 184 Income (loss) from Discontinued Operations before income taxes 22 40 147 Loss on classification to held for sale, net (1) (90) — — Income tax expense (benefit) (2) 17 37 Net income (loss) from Discontinued Operations $ (66) $ 23 $ 110 (1) Loss from classification to held for sale is inclusive of goodwill impairment, gains and losses recognized upon sale, and for CenterPoint Energy, its costs to sell. Transactions between CES and CenterPoint Energy’s and CERC’s Natural Gas that were previously eliminated in consolidation have been reflected in continuing operations until the closing of the sale of the Energy Services Disposal Group. Revenues and expenses included in continuing operations were as follows: Year Ended December 31, 2020 (1) 2019 2018 2020 (1) 2019 2018 CenterPoint Energy CERC (in millions) Transportation revenue $ 34 $ 101 $ 104 $ 34 $ 101 $ 104 Natural gas expense 48 125 107 47 124 107 (1) Represents charges for the period January 1, 2020 until the closing of the sale of the Energy Services Disposal Group. Natural Gas has AMAs associated with its utility distribution service in Arkansas, Louisiana, Mississippi, Oklahoma and Texas. The AMAs are with the Energy Services Disposal Group and will expire in 2021. Pursuant to the provisions of the agreements, Natural Gas sells natural gas and agrees to repurchase an equivalent amount of natural gas during the winter heating seasons at the same cost. These transactions are accounted for as inventory financing. CenterPoint Energy and CERC had outstanding obligations related to the AMAs of $24 million and $-0- as of December 31, 2020 and December 31, 2019, respectively. The Infrastructure Services Disposal Group provided pipeline construction and repair services to CenterPoint Energy’s and CERC’s Natural Gas. In accordance with consolidation guidance in ASC 980—Regulated Operations, costs incurred by Natural Gas utilities for these pipeline construction and repair services are not eliminated in consolidation when capitalized and included in rate base by the Natural Gas utility. Amounts charged for these services that are not capitalized are included primarily in Operation and maintenance expenses. Fees incurred by CenterPoint Energy’s and CERC’s Natural Gas for pipeline construction and repair services are as follows: Year Ended December 31, 2020 (1) 2019 (2) 2020 2019 CenterPoint Energy CERC (in millions) Pipeline construction and repair services capitalized $ 34 $ 162 $ — $ 20 Pipeline construction and repair service charges in operations and maintenance expense 1 4 1 4 (1) Represents charges for the period January 1, 2020 until the closing of the sale of the Infrastructure Services Disposal Group. (2) Represents charges for the period beginning February 1, 2019 through December 31, 2019 due to the Merger.
Disposal Groups, Including Discontinued Operations Cash Flow	The following table summarizes CenterPoint Energy’s and CERC’s cash flows from discontinued operations and certain supplemental cash flow disclosures related to the Infrastructure Services and Energy Services Disposal Groups, as applicable: Year Ended December 31, 2020 2019 (1) 2020 2019 2018 CenterPoint Energy Infrastructure Services Disposal Group Energy Services Disposal Group (in millions) Depreciation and amortization $ — $ 50 $ — $ 12 $ 13 Amortization of intangible assets in Non-utility cost of revenues — 19 — — — Write-down of natural gas inventory — — 3 4 2 Capital expenditures 18 67 3 12 21 Non-cash transactions: Accounts payable related to capital expenditures — — — 2 2 (1) Reflects February 1, 2019 to December 31, 2019 results only due to the Merger. Year Ended December 31, 2020 2019 2018 CERC Energy Services Disposal Group (in millions) Depreciation and amortization $ — $ 12 $ 13 Write-down of natural gas inventory 3 4 2 Capital expenditures 3 12 21 Non-cash transactions: Accounts payable related to capital expenditures — 2 2
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table presents the purchase price allocation as of December 31, 2019, reflecting the final purchase price allocation and inclusive of assets and liabilities subsequently recast as held for sale (in millions): Cash and cash equivalents $ 16 Other current assets 577 Property, plant and equipment, net 5,147 Identifiable intangibles 297 Regulatory assets 338 Other assets 141 Total assets acquired 6,516 Current liabilities 648 Regulatory liabilities 938 Other liabilities 886 Long-term debt 2,401 Total liabilities assumed 4,873 Net assets acquired 1,643 Goodwill 4,339 Total purchase price consideration $ 5,982
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	The fair value of the identifiable intangible assets and related useful lives as included in the purchase price allocation on the Merger Date, reflecting the final purchase price allocation and inclusive of intangible assets subsequently recast as held for sale, include: Weighted Average Useful Lives Estimated Fair Value (in years) (in millions) Operation and maintenance agreements 24 $ 12 Customer relationships 18 200 Construction backlog 1 27 Trade names 10 58 Total $ 297
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited pro forma financial information reflects the consolidated results of operations of CenterPoint Energy, assuming the Merger had taken place on January 1, 2018 and reflecting results included in both continuing operations and discontinued operations. The unaudited pro forma financial information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved had the Merger taken place on the dates indicated or of the future consolidated results of operations of the combined company. Year Ended December 31, 2019 2018 (in millions) Operating revenues $ 12,547 $ 13,282 Net income 812 (1) 458 (2) (1) Pro forma net income was adjusted to exclude $37 million of Vectren Merger-related transaction costs incurred in 2019. (2) Pro forma net income was adjusted to include $37 million of Vectren Merger-related transaction costs incurred in 2019.
Business Combination, Separately Recognized Transactions [Table Text Block]	The results of operations for Vectren included in CenterPoint Energy’s Consolidated Financial Statements from the Merger Date for the year ended December 31, 2019, reflecting results included in both continuing operations and discontinued operations, are as follows: (in millions) Operating revenues $ 2,729 Net income 190

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following tables disaggregate revenues by reportable segment and major source: CenterPoint Energy Year Ended December 31, 2020 Electric Natural Gas Corporate and Other Total (in millions) Revenue from contracts $ 3,451 $ 3,586 $ 313 $ 7,350 Other (1) 19 45 4 68 Total revenues $ 3,470 $ 3,631 $ 317 $ 7,418 Year Ended December 31, 2019 Electric (2) Natural Gas (2) Corporate and Other (2) Total (in millions) Revenue from contracts $ 3,507 $ 3,714 $ 290 $ 7,511 Other (1) 12 36 5 53 Total revenues $ 3,519 $ 3,750 $ 295 $ 7,564 Year Ended December 31, 2018 Electric Natural Gas Corporate and Other Total (in millions) Revenue from contracts $ 3,235 $ 3,042 $ 5 $ 6,282 Other (1) (3) (11) 9 (5) Total revenues $ 3,232 $ 3,031 $ 14 $ 6,277 (1) Primarily consists of income from ARPs and leases. ARPs are contracts between the utility and its regulators, not between the utility and a customer. The Registrants recognize ARP revenue as other revenues when the regulator-specified conditions for recognition have been met. Upon recovery of ARP revenue through incorporation in rates charged for utility service to customers, ARP revenue is reversed and recorded as revenue from contracts with customers. The recognition of ARP revenues and the reversal of ARP revenues upon recovery through rates charged for utility service may not occur in the same period. Total lease income was $6 million for each of the years ended December 31, 2020 and 2019. (2) Reflects revenues from Vectren subsidiaries for the period from February 1, 2019 to December 31, 2019. Houston Electric Year Ended December 31, 2020 2019 2018 (in millions) Revenue from contracts $ 2,896 $ 2,984 $ 3,235 Other (1) 15 6 (1) Total revenues $ 2,911 $ 2,990 $ 3,234 (1) Primarily consists of income from ARPs and leases. ARPs are contracts between the utility and its regulators, not between the utility and a customer. The Registrants recognize ARP revenue as other revenues when the regulator-specified conditions for recognition have been met. Upon recovery of ARP revenue through incorporation in rates charged for utility service to customers, ARP revenue is reversed and recorded as revenue from contracts with customers. The recognition of ARP revenues and the reversal of ARP revenues upon recovery through rates charged for utility service may not occur in the same period. Lease income was not significant for the years ended December 31, 2020 and 2019. CERC Year Ended December 31, 2020 2019 2018 (in millions) Revenue from contracts $ 2,714 $ 2,979 $ 3,042 Other (1) 49 39 (11) Total revenues $ 2,763 $ 3,018 $ 3,031 (1) Primarily consists of income from ARPs and leases. ARPs are contracts between the utility and its regulators, not between the utility and a customer. The Registrants recognize ARP revenue as other revenues when the regulator-specified conditions for recognition have been met. Upon recovery of ARP revenue through incorporation in rates charged for utility service to customers, ARP revenue is reversed and recorded as revenue from contracts with customers. The recognition of ARP revenues and the reversal of ARP revenues upon recovery through rates charged for utility service may not occur in the same period. Lease income was $2 million for the year ended December 31, 2020 and less than $1 million for the year ended December 31, 2019.
Contract with Customer, Asset and Liability [Table Text Block]	The opening and closing balances of accounts receivable, other accrued unbilled revenue, contract assets and contract liabilities from contracts with customers for the year ended December 31, 2020 are as follows: CenterPoint Energy Accounts Receivable Other Accrued Unbilled Revenues Contract Contract Liabilities (in millions) Opening balance as of December 31, 2019 $ 566 $ 469 $ 6 $ 30 Closing balance as of December 31, 2020 604 505 27 18 Increase $ 38 $ 36 $ 21 $ (12) The amount of revenue recognized in the year ended December 31, 2020 that was included in the opening contract liability was $30 million. The difference between the opening and closing balances of the contract liabilities primarily results from the timing difference between CenterPoint Energy’s performance and the customer’s payment. Houston Electric Accounts Receivable Other Accrued Unbilled Revenues Contract Liabilities (in millions) Opening balance as of December 31, 2019 $ 210 $ 117 $ 3 Closing balance as of December 31, 2020 225 113 3 Increase (decrease) $ 15 $ (4) $ — The amount of revenue recognized in the year ended December 31, 2020 that was included in the opening contract liability was $3 million. The difference between the opening and closing balances of the contract liabilities primarily results from the timing difference between Houston Electric’s performance and the customer’s payment. CERC Accounts Receivable Other Accrued (in millions) Opening balance as of December 31, 2019 $ 222 $ 249 Closing balance as of December 31, 2020 214 261 Increase (decrease) $ (8) $ 12 CERC does not have any opening or closing contract asset or contract liability balances.
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	Remaining Performance Obligations (CenterPoint Energy). The table below discloses (1) the aggregate amount of the transaction price allocated to performance obligations that are unsatisfied (or partially unsatisfied) as of the end of the reporting period for contracts and (2) when CenterPoint Energy expects to recognize this revenue. Such contracts include energy performance and sustainable infrastructure services contracts of ESG, which are included in Corporate and Other. Rolling 12 Months Thereafter Total (in millions) Revenue expected to be recognized on contracts in place as of December 31, 2020: Corporate and Other $ 267 $ 570 $ 837 $ 267 $ 570 $ 837
Provision for doubtful accounts [Table Text Block]	The table below summarizes the Registrants’ bad debt expense amounts for 2020, 2019 and 2018 and excludes regulatory deferrals related to COVID-19: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Bad debt expense $ 24 $ — $ 18 $ 18 $ — $ 14 $ 16 $ — $ 16

Goodwill and Other Intangible_2

Goodwill and Other Intangibles (CenterPoint Energy and CERC) (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill by Reportable Segments [Table Text Block]	CenterPoint Energy’s goodwill by reportable segment as of December 31, 2019 and changes in the carrying amount of goodwill as of December 31, 2020 are as follows: December 31, 2019 Impairment December 31, (in millions) Electric $ 1,121 $ 185 $ 936 Natural Gas 3,323 — 3,323 Corporate and Other 438 — 438 Total $ 4,882 $ 185 $ 4,697
Schedule of Finite-Lived Intangible Assets [Table Text Block]	The tables below present information on CenterPoint Energy’s other intangible assets recorded in Other in Other Assets on the Consolidated Balance Sheets and the related amortization expense included in Depreciation and amortization on CenterPoint Energy’s Statements of Consolidated Income, unless otherwise indicated in the tables below. December 31, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Balance Gross Carrying Amount Accumulated Amortization Net Balance (in millions) Customer relationships $ 33 $ (8) $ 25 $ 33 $ (4) $ 29 Trade names 16 (3) 13 16 (1) 15 Construction backlog (1) 5 (5) — 5 (4) 1 Operation and maintenance agreements (1) 12 (1) 11 12 — 12 Other 2 (1) 1 2 (1) 1 Total $ 68 $ (18) $ 50 $ 68 $ (10) $ 58 (1) Amortization expense related to the operation and maintenance agreements and construction backlog is included in Non-utility cost of revenues, including natural gas on CenterPoint Energy’s Statements of Consolidated Income.
Finite-lived Intangible Assets Amortization Expense [Table Text Block]	Year Ended December 31, 2020 2019 2018 (in millions) Amortization expense of intangible assets recorded in Depreciation and amortization (1) (2) $ 6 $ 5 $ — Amortization expense of intangible assets recorded in (2) 2 4 — (1) Includes $5 million for the year ended December 31, 2019 of amortization expense related to intangibles acquired in the Merger. (2) Assets held for sale are not amortized. The table reflects amortization on continuing operations. For further information on discontinued operations, see Note 4.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	CenterPoint Energy estimates that amortization expense of intangible assets with finite lives for the next five years will be as follows: Amortization Expense (1) (in millions) 2021 $ 6 2022 6 2023 6 2024 5 2025 5 (1) Assets held for sale are not amortized. The table reflects amortization on continuing operations. For further information on discontinued operations, see Note 4.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Schedule of Regulatory Assets and Liabilities [Table Text Block]	The following is a list of regulatory assets and liabilities reflected on the Registrants’ respective Consolidated Balance Sheets as of December 31, 2020 and 2019. The “amortization through” columns indicate the latest year when a regulatory asset or regulatory liability category will be fully amortized: December 31, 2020 CenterPoint Energy Houston Electric CERC Amortization Through (in millions) Amortization Through (in millions) Amortization Through (in millions) Regulatory Assets: Current regulatory assets (1) 2021 $ 33 n/a $ — 2021 $ 33 Non-current regulatory assets: Securitized regulatory assets 2024 633 2024 633 n/a — Unrecognized equity return Various (150) (2) 2024 (137) (2) Various (13) Unamortized loss on reacquired debt (3) 2055 57 2046 55 n/a — Pension and postretirement-related regulatory asset (3) Various (a) 591 Various (a) 31 Various (a) 21 Hurricane Harvey restoration costs (3) Various 59 2025 55 TBD (b) 4 Hurricane Laura restoration costs TBD (b) 36 TBD (b) 36 TBD (b) — Regulatory assets related to TCJA (3) (4) 2025 25 2025 20 2023 5 Relief Program Incremental Costs (COVID-19) TBD 25 TBD 5 TBD 17 Asset retirement obligation (3) Perpetual 135 Perpetual 26 Perpetual 107 Other regulatory assets-not earning a return (5) 2056 165 2049 83 2056 44 Other regulatory assets Various 518 Various 41 Various 35 Total non-current regulatory assets 2,094 848 220 Total regulatory assets 2,127 848 253 Regulatory Liabilities: Current regulatory liabilities (6) 2021 72 2021 43 2021 29 Non-current regulatory liabilities: Regulatory liabilities related to TCJA (4) Various 1,484 TBD 764 Various 421 Estimated removal costs Various 1,470 Various 231 Various 656 Other regulatory liabilities Various 494 Various 257 Various 149 Total non-current regulatory liabilities 3,448 1,252 1,226 Total regulatory liabilities 3,520 1,295 1,255 Total regulatory assets and liabilities, net $ (1,393) $ (447) $ (1,002) (a) Pension and postretirement-related regulatory assets balances are measured annually, and the ending amortization period may change based on the actuarial valuation. (b) The recovery and amortization of a portion of these amounts are expected to be determined in the next rate case. December 31, 2019 CenterPoint Energy Houston Electric CERC (in millions) Regulatory Assets: Current regulatory assets (1) $ 12 $ — $ 12 Non-current regulatory assets: Securitized regulatory assets 788 788 — Unrecognized equity return (168) (2) (168) (2) — Unamortized loss on reacquired debt (3) 62 62 — Pension and postretirement-related regulatory asset (3) 637 34 22 Hurricane Harvey restoration costs (3) 68 64 4 Regulatory assets related to TCJA (3) (4) 30 23 7 Asset retirement obligation (3) 131 26 94 Other regulatory assets-not earning a return (5) 147 57 48 Other regulatory assets 422 29 16 Total non-current regulatory assets 2,117 915 191 Total regulatory assets 2,129 915 203 Regulatory Liabilities: Current regulatory liabilities (6) 47 — 47 Non-current regulatory liabilities: Regulatory liabilities related to TCJA (4) 1,582 821 442 Estimated removal costs 1,429 244 637 Other regulatory liabilities 463 223 140 Total non-current regulatory liabilities 3,474 1,288 1,219 Total regulatory liabilities 3,521 1,288 1,266 Total regulatory assets and liabilities, net $ (1,392) $ (373) $ (1,063) (1) Current regulatory assets are included in Prepaid expenses and other current assets in the Registrants’ respective Consolidated Balance Sheets. (2) The unrecognized equity return will be recognized as it is recovered in rates through 2024. The timing of CenterPoint Energy’s and Houston Electric’s recognition of the equity return will vary each period based on amounts actually collected during the period. The actual amounts recognized are adjusted at least annually to correct any over-collections or under-collections during the preceding 12 months. CenterPoint Energy and Houston Electric Year Ended December 31, 2020 2019 2018 (in millions) Allowed equity return recognized $ 31 $ 45 $ 74 (3) Substantially all of these regulatory assets are not earning a return. (4) The EDIT and deferred revenues will be recovered or refunded to customers as required by tax and regulatory authorities. See Note 15 for additional information. The weighted average recovery periods of Regulatory assets related to TCJA for CenterPoint Energy, Houston Electric and CERC are 4 years, 5 years and 3 years, respectively. (5) Regulatory assets acquired in the Merger and not earning a return were recorded at fair value as of the Merger Date. Such fair value adjustments are recognized over time until the regulatory asset is recovered. The weighted average recovery periods of Other regulatory assets-not earning a return for CenterPoint Energy, Houston Electric and CERC are 14 years, 11 years and 27 years, respectively. (6) Current regulatory liabilities are included in Other current liabilities in each of the Registrants’ respective Consolidated Balance Sheets.

Stock-Based Incentive Compens_2

Stock-Based Incentive Compensation Plans and Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	The following table summarizes CenterPoint Energy’s expenses related to LTIPs for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 (in millions) LTIP compensation expense (1) $ 38 $ 28 $ 26 Income tax benefit recognized 9 7 6 Actual tax benefit realized for tax deductions 5 12 5 (1) Amounts presented in the table above are included in Operation and maintenance expense in CenterPoint Energy’s Statements of Consolidated Income and shown prior to any amounts capitalized.
Share-Based Compensation, Activity [Table Text Block]	The following tables summarize CenterPoint Energy’s LTIP activity for 2020: Year Ended December 31, 2020 Shares Weighted-Average Remaining Average Aggregate Intrinsic Value (2) (Millions) Performance Awards (1) Outstanding and nonvested as of December 31, 2019 3,332 $ 28.36 Granted 2,022 23.82 Forfeited or canceled (1,128) 26.89 Vested and released to participants (326) 26.64 Outstanding and nonvested as of December 31, 2020 3,900 $ 26.58 1.2 $ 51 Stock Unit Awards Outstanding and nonvested as of December 31, 2019 966 $ 28.46 Granted 980 21.53 Forfeited or canceled (129) 27.67 Vested and released to participants (528) 22.51 Outstanding and nonvested as of December 31, 2020 1,289 $ 25.71 1.2 $ 28 (1) Reflects maximum performance achievement. (2) Reflects the impact of current expectations of achievement and stock price.
Share-Based Compensation Arrangement By Award, Weighted Average Grant Date Fair Value, Grant Date Intrinsic Value, and Vested Grant Date Fair Value [Table Text Block]	The weighted average grant date fair values per unit of awards granted were as follows for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 (in millions, except for per unit amounts) Performance Awards Weighted-average grant date fair value per unit of awards granted $ 23.82 $ 31.16 $ 26.74 Total intrinsic value of awards received by participants 9 36 12 Vested grant date fair value 9 20 9 Stock Unit Awards Weighted-average grant date fair value per unit of awards granted $ 21.53 $ 31.07 $ 26.62 Total intrinsic value of awards received by participants 12 15 9 Vested grant date fair value 12 9 7
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Amounts recognized in accumulated other comprehensive loss (gain) consist of the following: December 31, 2020 2019 Pension Postretirement Pension Postretirement CenterPoint Energy CenterPoint Energy CERC CenterPoint Energy CenterPoint Energy CERC (in millions) Unrecognized actuarial loss (gain) $ 109 $ (14) $ (12) $ 105 $ (16) $ (12) Unrecognized prior service cost — 7 7 — 7 7 Net amount recognized in accumulated other comprehensive loss (gain) $ 109 $ (7) $ (5) $ 105 $ (9) $ (5) Changes in accumulated comprehensive income (loss) are as follows: Year Ended December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Beginning Balance $ (98) $ (15) $ 10 $ (108) $ (14) $ 5 Other comprehensive income (loss) before reclassifications: Remeasurement of pension and other postretirement plans (12) — — 7 — 7 Deferred loss from interest rate derivatives (1) — — — (3) (1) — Reclassified to earnings — — — 1 — — Other comprehensive loss from unconsolidated affiliates (2) — — (1) — — Amounts reclassified from accumulated other comprehensive loss: Prior service cost (2) — — 1 1 — — Actuarial losses (2) 7 — — 8 — — Reclassification of deferred loss from cash flow hedges (3) 19 19 — — — — Tax benefit (expense) (4) (4) (1) (3) — (2) Net current period other comprehensive income (loss) 8 15 — 10 (1) 5 Ending Balance $ (90) $ — $ 10 $ (98) $ (15) $ 10 (1) Gains and losses are reclassified from Accumulated other comprehensive income into income when the hedged transactions affect earnings. The reclassification amounts are included in Interest and other finance charges in each of the Registrant’s respective Statements of Consolidated Income. Amounts are $-0- and $1 million for the years ended December 31, 2020 and 2019, respectively. (2) Amounts are included in the computation of net periodic cost and are reflected in Other, net in each of the Registrants’ respective Statements of Consolidated Income. (3) The cost of debt approved by the PUCT as part of Houston Electric’s Stipulation and Settlement Agreement included unrealized gains and losses on interest rate hedges. Accordingly, deferred gains and losses on interest rate hedges were reclassified to regulatory assets or liabilities, as appropriate.
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	The changes in plan assets and benefit obligations recognized in other comprehensive income during 2020 are as follows: Pension Postretirement CenterPoint Energy CenterPoint Energy CERC (in millions) Net loss (gain) $ 11 $ 2 $ — Amortization of net loss (7) — — Amortization of prior service cost — — — Total recognized in comprehensive income $ 4 $ 2 $ — Total recognized in net periodic costs and Other comprehensive income $ 53 $ 6 $ 4
Benefit Plan Contributions [Table Text Block]	The Registrants made the following contributions in 2020 and expect to make the following minimum contributions in 2021 to the indicated benefit plans below: Contributions in 2020 Expected Minimum Contributions in 2021 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Qualified pension plans $ 76 $ — $ — $ 53 $ — $ — Non-qualified pension plans 10 — — 8 — — Postretirement benefit plans 10 3 3 9 1 3
Schedule of Expected Benefit Payments [Table Text Block]	The following benefit payments are expected to be paid by the pension and postretirement benefit plans: Pension Postretirement Benefits CenterPoint CenterPoint Houston Electric CERC (in millions) 2021 $ 174 $ 17 $ 8 $ 4 2022 176 18 9 5 2023 176 20 9 5 2024 175 21 10 5 2025 173 21 10 6 2026-2030 775 109 53 30
Defined Contribution Plan Disclosures [Table Text Block]	CenterPoint Energy allocates the savings plan benefit expense to Houston Electric and CERC related to their respective employees. The following table summarizes the Registrants’ savings plan benefit expense for 2020, 2019 and 2018: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Savings plan benefit expenses (1) $ 58 $ 18 $ 19 $ 58 $ 18 $ 18 $ 43 $ 17 $ 18
Other Benefit Plans [Table Text Block]	Expenses related to other benefit plans were recorded as follows: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Postemployment benefits $ 1 $ 1 $ — $ 2 $ 1 $ 1 $ 3 $ 4 $ 1 Deferred compensation plans 4 1 — 4 1 — 3 1 — Amounts related to other benefit plans were included in Benefit Obligations in the Registrants’ accompanying Consolidated Balance Sheets as follows: December 31, 2020 December 31, 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Postemployment benefits $ 8 $ 3 $ 5 $ 11 $ 3 $ 7 Deferred compensation plans 43 7 2 41 8 3 Split-dollar life insurance arrangements 32 1 — 32 1 —
Other Employee Matters [Table Text Block]	As of December 31, 2020, the Registrants’ employees were covered by collective bargaining agreements as follows: Percentage of Employees Covered Agreement Expiration CenterPoint Energy Houston Electric CERC IBEW Local 66 May 2023 15 % 53 % — OPEIU Local 12 May 2021 2 % — 3 % OPEIU Mankato March 2021 — % — — % Gas Workers Union Local 340 April 2025 4 % — 12 % IBEW Locals 1393 and USW Locals 12213 & 7441 December 2023 3 % — — % IBEW Locals 949 December 2025 3 % — 7 % USW Locals 13-227 June 2022 4 % — 13 % USW Locals 13-1 July 2022 — % — 1 % IBEW Local 702 June 2022 3 % — — Teamsters Local 135 September 2021 1 % — — UWUA Local 175 October 2021 1 % — — Total 36 % 53 % 36 %
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Benefit Costs [Table Text Block]	CenterPoint Energy’s net periodic cost includes the following components relating to pension, including the non-qualified benefit plans: Year Ended December 31, 2020 2019 2018 (in millions) Service cost (1) $ 43 $ 40 $ 37 Interest cost (2) 75 96 79 Expected return on plan assets (2) (112) (105) (107) Amortization of prior service cost (2) — 9 9 Amortization of net loss (2) 41 52 43 Settlement cost (2) (3) 2 2 — Curtailment gain (2) (4) — (1) — Net periodic cost $ 49 $ 93 $ 61 (1) Amounts presented in the table above are included in Operation and maintenance expense in CenterPoint Energy’s Statements of Consolidated Income, net of regulatory deferrals and amounts capitalized. (2) Amounts presented in the table above are included in Other, net in CenterPoint Energy’s Statements of Consolidated Income, net of regulatory deferrals. (3) A one-time, non-cash settlement cost is required when the total lump sum distributions or other settlements of plan benefit obligations during a plan year exceed the service cost and interest cost components of the net periodic cost for that year. In 2020 and 2019, CenterPoint Energy recognized a non-cash settlement cost due to lump sum settlement payments.
Schedule of Assumptions Used [Table Text Block]	CenterPoint Energy used the following assumptions to determine net periodic cost relating to pension benefits: Year Ended December 31, 2020 2019 2018 Discount rate 3.20 % 4.35 % 3.65 % Expected return on plan assets 5.75 6.00 6.00 Rate of increase in compensation levels 4.95 4.60 4.45
Schedule of Net Pension and Post-retirement Benefit Costs [Table Text Block]	The following table summarizes changes in the benefit obligation, plan assets, the amounts recognized in the Consolidated Balance Sheets as well as the key assumptions of CenterPoint Energy’s pension plans. The measurement dates for plan assets and obligations were December 31, 2020 and 2019. December 31, 2020 2019 (in millions, except for actuarial assumptions) Change in Benefit Obligation Benefit obligation, beginning of year $ 2,453 $ 2,013 Plan obligations assumed in Merger — 332 Service cost 43 40 Interest cost 75 96 Benefits paid (207) (244) Actuarial (gain) loss (1) 143 216 Plan amendment — 1 Curtailment — (1) Benefit obligation, end of year 2,507 2,453 Change in Plan Assets Fair value of plan assets, beginning of year 2,005 1,516 Plan assets assumed in Merger — 286 Employer contributions 86 109 Benefits paid (207) (244) Actual investment return 251 338 Fair value of plan assets, end of year 2,135 2,005 Funded status, end of year $ (372) $ (448) Amounts Recognized in Balance Sheets Current liabilities-other $ (8) $ (8) Other liabilities-benefit obligations (364) (440) Net liability, end of year $ (372) $ (448) Actuarial Assumptions Discount rate (2) 2.45 % 3.20 % Expected return on plan assets (3) 5.00 5.75 Rate of increase in compensation levels 5.05 4.95 Interest crediting rate 2.25 3.25 (1) Significant sources of loss for 2020 include the decrease in discount rate from 3.20% to 2.45%, partially offset by significant sources of gain that include actual return on plan assets exceeding expected return on assets during 2020. Significant sources of loss for 2019 include the decrease in discount rate from 4.35% to 3.20%. (2) The discount rate assumption was determined by matching the projected cash flows of CenterPoint Energy’s plans against a hypothetical yield curve of high-quality corporate bonds represented by a series of annualized individual discount rates from one-half to 99 years.
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block]	The following table displays pension benefits related to CenterPoint Energy’s pension plans that have accumulated benefit obligations in excess of plan assets: December 31, 2020 2019 Pension Pension Pension Pension (in millions) Accumulated benefit obligation $ 2,427 $ 68 $ 2,352 $ 68 Projected benefit obligation 2,440 68 2,385 68 Fair value of plan assets 2,135 — 2,005 —
Target Allocation of Plan Assets [Table Text Block]	As part of the investment strategy discussed above, CenterPoint Energy maintained the following weighted average allocation targets for its pension plans as of December 31, 2020: Minimum Maximum U.S. equity 19 % 29 % International equity 8 % 18 % Real estate 3 % 9 % Fixed income 52 % 62 % Cash 0 % 2 %
Schedule of Allocation of Plan Assets [Table Text Block]	The following tables set forth by level, within the fair value hierarchy (see Note 10), CenterPoint Energy’s pension plan assets at fair value as of December 31, 2020 and 2019: Fair Value Measurements as of December 31, 2020 2019 (Level 1) (Level 2) (Level 3) Total (Level 1) (Level 2) (Level 3) Total (in millions) Cash $ 29 $ — $ — $ 29 $ (7) $ — $ — $ (7) Corporate bonds: Investment grade or above — 767 — 767 — 699 — 699 Equity securities: U.S. companies 76 — — 76 69 — — 69 Cash received as collateral from securities lending 81 — — 81 61 — — 61 U.S. treasuries 225 — — 225 232 — — 232 Mortgage backed securities — 5 — 5 — 8 — 8 Asset backed securities — 3 — 3 — 3 — 3 Municipal bonds — 43 — 43 — 44 — 44 Mutual funds (2) 301 — — 301 270 — — 270 International government bonds — 18 — 18 — 21 — 21 Obligation to return cash received as collateral from securities lending (81) — — (81) (61) — — (61) Total investments at fair value $ 631 $ 836 $ — $ 1,467 $ 564 $ 775 $ — $ 1,339 Investments measured by net asset value per share or its equivalent (1) (2) 668 666 Total Investments $ 2,135 $ 2,005 (1) Represents investments in common collective trust funds. (2) The amounts invested in mutual funds and common collective trust funds were allocated as follows: As of December 31, 2020 2019 Mutual Funds Common Collective Trust Funds Mutual Funds Common Collective Trust Funds International equities 14 % 37 % 31 % 29 % U.S. equities 55 % 3 % 49 % 51 % Real estate 5 % 1 % 1 % 6 % Fixed income 27 % 59 % 19 % 14 % Level 2 investments, which do not have a quoted price in active market, are valued using the market data provided by independent pricing services or major market makers, to arrive at a price a dealer would pay for the
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Benefit Costs [Table Text Block]	Postretirement benefits are accrued over the active service period of employees. The net postretirement benefit cost includes the following components: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Service cost (1) $ 2 $ — $ 1 $ 3 $ 1 $ 1 $ 2 $ — $ 1 Interest cost (2) 11 5 3 15 7 5 13 8 4 Expected return on plan assets (2) (5) (4) (1) (5) (4) (1) (5) (4) (1) Amortization of prior service cost (credit) (2) (4) (5) 1 (5) (6) 1 (5) (5) 1 Net postretirement benefit cost (credit) $ 4 $ (4) $ 4 $ 8 $ (2) $ 6 $ 5 $ (1) $ 5 (1) Amounts presented in the table above are included in Operation and maintenance expense in each of the Registrants’ respective Statements of Consolidated Income, net of regulatory deferrals and amounts capitalized. (2) Amounts presented in the table above are included in Other, net in each of the Registrants’ respective Statements of Consolidated Income, net of regulatory deferrals.
Schedule of Assumptions Used [Table Text Block]	The following assumptions were used to determine net periodic cost relating to postretirement benefits: Year Ended December 31, 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC Discount rate 3.25 % 3.25 % 3.25 % 3.20 % 3.20 % 3.20 % 3.60 % 3.60 % 3.60 % Expected return on plan assets 3.95 4.05 3.35 4.60 4.70 4.15 4.55 4.75 3.85
Schedule of Net Pension and Post-retirement Benefit Costs [Table Text Block]	The following table summarizes changes in the benefit obligation, plan assets, the amounts recognized in consolidated balance sheets and the key assumptions of the postretirement plans. The measurement dates for plan assets and benefit obligations were December 31, 2020 and 2019. December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions, except for actuarial assumptions) Change in Benefit Obligation Benefit obligation, beginning of year $ 356 $ 162 $ 102 $ 331 $ 166 $ 110 Plan obligations assumed in Merger — — — 37 — — Service cost 2 — 1 3 1 1 Interest cost 11 5 3 15 7 5 Participant contributions 6 2 2 8 2 4 Benefits paid (22) (10) (6) (26) (13) (8) Plan amendment — — — 9 3 5 Actuarial (gain) loss (1) 13 9 3 (21) (4) (15) Benefit obligation, end of year 366 168 105 356 162 102 Change in Plan Assets Fair value of plan assets, beginning of year 128 101 27 114 89 25 Employer contributions 10 3 3 17 10 3 Participant contributions 6 2 2 8 2 4 Benefits paid (22) (10) (6) (26) (13) (8) Actual investment return 12 10 2 15 13 3 Fair value of plan assets, end of year 134 106 28 128 101 27 Funded status, end of year $ (232) $ (62) $ (77) $ (228) $ (61) $ (75) Amounts Recognized in Balance Sheets Current liabilities-other $ (9) $ — $ (3) $ (8) $ — $ (3) Other liabilities-benefit obligations (223) (62) (74) (220) (61) (72) Net liability, end of year $ (232) $ (62) $ (77) $ (228) $ (61) $ (75) Actuarial Assumptions Discount rate (2) 2.50 % 2.50 % 2.50 % 3.25 % 3.25 % 3.25 % Expected return on plan assets (3) 3.20 3.30 2.85 3.95 4.05 3.35 Medical cost trend rate assumed for the next year - Pre-65 5.25 5.25 5.25 5.50 5.50 5.50 Medical/prescription drug cost trend rate assumed for the next year - Post-65 19.70 19.70 19.70 5.75 5.75 5.75 Prescription drug cost trend rate assumed for the next year - Pre-65 7.50 7.50 7.50 8.00 8.00 8.00 Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.50 4.50 4.50 4.50 4.50 4.50 Year that the cost trend rates reach the ultimate trend rate - Pre-65 2028 2028 2028 2028 2028 2028 Year that the cost trend rates reach the ultimate trend rate - Post-65 2029 2029 2029 2029 2029 2029 (1) Significant sources of loss for 2020 include the decrease in discount rate from 3.25% to 2.50%, partially offset by significant sources of gain that include the decrease in interest credit rate from 3.25% to 2.25% and change in mortality projection scale from MP2019 to MP2020. Significant sources of gain for 2019 include favorable cost trend rates and benefit claims experience in addition to the change in mortality projection scale from MP2018 to MP2019. (2) The discount rate assumption was determined by matching the projected cash flows of the plans against a hypothetical yield curve of high-quality corporate bonds represented by a series of annualized individual discount rates from one-half to 99 years.
Target Allocation of Plan Assets [Table Text Block]	As part of the investment strategy discussed above, the Registrants maintained the following weighted average allocation targets for the postretirement plans as of December 31, 2020: CenterPoint Energy Houston Electric CERC Minimum Maximum Minimum Maximum Minimum Maximum U.S. equities 13 % 23 % 13 % 23 % 15 % 25 % International equities 3 % 13 % 3 % 13 % 2 % 12 % Fixed income 69 % 79 % 69 % 79 % 68 % 78 % Cash 0 % 2 % 0 % 2 % 0 % 2 %
Schedule of Allocation of Plan Assets [Table Text Block]	The following table presents mutual funds by level, within the fair value hierarchy, the Registrants’ postretirement plan assets at fair value as of December 31, 2020 and 2019: Fair Value Measurements as of December 31, 2020 2019 Mutual Funds Total Total (in millions) CenterPoint Energy $ 134 $ — $ — $ 134 $ 128 $ — $ — $ 128 Houston Electric 106 — — 106 101 — — 101 CERC 28 — — 28 27 — — 27 The amounts invested in mutual funds were allocated as follows: As of December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC Fixed income 74 % 74 % 72 % 71 % 71 % 69 % U.S. equities 19 % 18 % 21 % 21 % 21 % 24 % International equities 7 % 8 % 7 % 8 % 8 % 7 %

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	The table below summarizes the Registrants’ outstanding interest rate hedging activity: December 31, 2020 December 31, 2019 Hedging Classification Notional Principal (in millions) Economic hedge (1) $ 84 $ 84 (1) Relates to interest rate derivative instruments at SIGECO.
Fair Value of Derivative Instruments [Table Text Block]	The following tables present information about derivative instruments and hedging activities. The first table provides a balance sheet overview of Derivative Assets and Liabilities as of December 31, 2020 and 2019, while the last table provides a breakdown of the related income statement impacts for the years ending December 31, 2020, 2019 and 2018. Fair Value of Derivative Instruments and Hedged Items CenterPoint Energy December 31, 2020 December 31, 2019 Balance Sheet Location Derivative Derivative Derivative Derivative (in millions) Derivatives not designated as hedging instruments: Natural gas derivatives (1) Current Liabilities: Non-trading derivative liabilities $ — $ 3 $ — $ 7 Natural gas derivatives (1) Other Liabilities: Non-trading derivative liabilities — 7 — 15 Interest rate derivatives Other Liabilities — 20 — 10 Indexed debt securities derivative (2) Current Liabilities — 953 — 893 Total $ — $ 983 $ — $ 925 (1) Natural gas contracts are subject to master netting arrangements. This netting applies to all undisputed amounts due or past due. However, the mark-to-market fair value of each natural gas contract is in a liability position with no offsetting amounts (2) Derivative component of the ZENS obligation that represents the ZENS holder’s option to receive the appreciated value of the reference shares at maturity. See Note 12 for further information.
Income Statement Impact of Derivative Activity [Table Text Block]	Income Statement Impact of Hedge Accounting Activity (CenterPoint Energy) CenterPoint Energy Year Ended December 31, Income Statement Location 2020 2019 2018 (in millions) Effects of derivatives not designated as hedging instruments on the income statement: Indexed debt securities derivative Loss on indexed debt securities (60) (292) (232) Interest rate derivatives Gains in Other Income (Expense) — — 2 Total CenterPoint Energy $ (60) $ (292) $ (230) (c) Credit Risk Contingent Features (CenterPoint Energy) Certain of CenterPoint Energy’s derivative instruments contain provisions that require CenterPoint Energy’s debt to maintain an investment grade credit rating on its long-term unsecured unsubordinated debt from S&P and Moody’s. If CenterPoint Energy’s debt were to fall below investment grade, it would be in violation of these provisions, and the counterparties to the derivative instruments could request immediate payment. As of December 31, 2020 2019 (in millions) Aggregate fair value of derivatives with credit-risk-related contingent features in a liability position $ 20 $ 10 Fair value of collateral already posted 7 — Additional collateral required to be posted if credit risk contingent features triggered (1) 3 — (1) The maximum collateral required if further escalating collateral is triggered would equal the net liability position.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on a Recurring Basis [Table Text Block]	The following tables present information about the Registrants’ assets and liabilities (including derivatives that are presented net) measured at fair value on a recurring basis as of December 31, 2020 and December 31, 2019, and indicate the fair value hierarchy of the valuation techniques utilized by the Registrants to determine such fair value. CenterPoint Energy December 31, 2020 December 31, 2019 Level 2 Level 3 Total Level 2 Level 3 Total Assets (in millions) Corporate equities $ 873 $ — $ — $ 873 $ 825 $ — $ — $ 825 Investments, including money market funds (1) 43 — — 43 49 — — 49 Total assets $ 916 $ — $ — $ 916 $ 874 $ — $ — $ 874 Liabilities Indexed debt securities derivative $ — $ 953 $ — $ 953 $ — $ 893 $ — $ 893 Interest rate derivatives — 20 — 20 — 10 — 10 Natural gas derivatives — 10 — 10 — 22 — 22 Total liabilities $ — $ 983 $ — $ 983 $ — $ 925 $ — $ 925 Houston Electric December 31, 2020 December 31, 2019 Level 2 Level 3 Total Level 2 Level 3 Total Assets (in millions) Investments, including money market funds (1) $ 26 $ — $ — $ 26 $ 32 $ — $ — $ 32 Total assets $ 26 $ — $ — $ 26 $ 32 $ — $ — $ 32 CERC December 31, 2020 December 31, 2019 Level 2 Level 3 Total Level 2 Level 3 Total Assets (in millions) Corporate equities $ 2 $ — $ — $ 2 $ 2 $ — $ — $ 2 Investments, including money market funds (1) 11 — — 11 11 — — 11 Total assets $ 13 $ — $ — $ 13 $ 13 $ — $ — $ 13 (1) Amounts are included in Prepaid and Other Current Assets in the Consolidated Balance Sheets.
Estimated Fair Value of Financial Instruments, Debt Instruments [Table Text Block]	The fair values of cash and cash equivalents, investments in debt and equity securities classified as “trading” and short-term borrowings are estimated to be approximately equivalent to carrying amounts and have been excluded from the table below. The carrying amounts of non-trading derivative assets and liabilities and CenterPoint Energy’s ZENS indexed debt securities derivative are stated at fair value and are excluded from the table below. The fair value of each debt instrument is determined by multiplying the principal amount of each debt instrument by a combination of historical trading prices and comparable issue data. These liabilities, which are not measured at fair value in the Registrants’ Consolidated Balance Sheets, but for which the fair value is disclosed, would be classified as Level 2 in the fair value hierarchy. December 31, 2020 December 31, 2019 CenterPoint Energy (1) Houston Electric (1) CERC CenterPoint Energy (1) Houston Electric (1) CERC Long-term debt, including current maturities (in millions) Carrying amount $ 13,401 $ 5,019 $ 2,428 $ 15,093 $ 4,950 $ 2,546 Fair value 15,226 5,957 2,855 16,067 5,457 2,803 (1) Includes Securitization Bond debt.

Unconsolidated Affiliate (Cen_2

Unconsolidated Affiliate (CenterPoint Energy and CERC) (Tables)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments [Table Text Block]	Limited Partner Interest and Units Held in Enable (CenterPoint Energy): As of December 31, 2020 2019 Limited Partner Interest (1) Common Units Enable Series A Preferred Units (2) Limited Partner Interest (1) Common Units Enable Series A Preferred Units (2) CenterPoint Energy 53.7 % 233,856,623 14,520,000 53.7 % 233,856,623 14,520,000 OGE 25.5 % 110,982,805 — 25.5 % 110,982,805 — Public unitholders 20.8 % 90,710,464 — 20.8 % 90,361,937 — Total Units Outstanding 100.0 % 435,549,892 14,520,000 100.0 % 435,201,365 14,520,000 (1) Excludes the Enable Series A Preferred Units owned by CenterPoint Energy. (2) The carrying amount of the Enable Series A Preferred Units, reflected as Preferred units - unconsolidated affiliate on CenterPoint Energy’s Consolidated Balance Sheets, was $363 million as of both December 31, 2020 and 2019. No impairment charges or adjustment to carrying value were made as no observable price changes were identified in the current or prior reporting periods. Interests Held in Enable GP (CenterPoint Energy): CenterPoint Energy and OGE held the following interests in Enable GP as of both December 31, 2020 and 2019: Management Rights (1) Incentive Distribution Rights (2) CenterPoint Energy (3) 50 % 40 % OGE 50 % 60 % (1) 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. (2) 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. (3) Held indirectly through CNP Midstream. Distributions Received from Enable (CenterPoint Energy and CERC): CenterPoint Energy Year Ended December 31, 2020 2019 2018 Per Unit Cash Distribution Per Unit Cash Distribution Per Unit Cash Distribution (in millions, except per unit amounts) Enable common units $ 0.8263 $ 193 $ 1.2970 $ 303 $ 1.2720 $ 297 Enable Series A Preferred Units (1) 2.5000 36 2.5000 36 2.5000 36 Total $ 229 $ 339 $ 333 (1) As of December 31, 2020, the Enable Series A Preferred Units annual distribution rate was 10%. On February 18, 2021, five years after the issue date, the Enable Series A Preferred Units annual distribution rate changed to a percentage of the Stated Series A Liquidation Preference per Series A Preferred unit equal to the sum of (a) Three-Month LIBOR, as calculated on each applicable date of determination, and (b)8.5%. Transactions with Enable (CenterPoint Energy and CERC): The transactions with Enable in the following tables exclude transactions with the Energy Services Disposal Group. See Note 4 for further information. CenterPoint Energy and CERC Year Ended December 31, 2020 2019 2018 (in millions) Natural gas expenses, including transportation and storage costs (1) $ 86 $ 86 $ 86 Reimbursement of support services (2) — — 4 (1) Included in Non-utility costs of revenues, including natural gas on CenterPoint Energy’s and CERC’s respective Statements of Consolidated Income. (2) Represents amounts billed for certain support services provided to Enable. Actual support services costs were recorded net of reimbursement. CenterPoint Energy and CERC December 31, 2020 2019 CenterPoint Energy (in millions) Accounts payable for natural gas purchases from Enable $ 9 $ 9 Accounts receivable for amounts billed for services provided to Enable 1 2 Summarized consolidated income (loss) information for Enable is as follows: Year Ended December 31, 2020 2019 2018 (in millions) Operating revenues $ 2,463 $ 2,960 $ 3,431 Cost of sales, excluding depreciation and amortization 965 1,279 1,819 Depreciation and amortization 420 433 398 Goodwill impairment 28 86 — Operating income 465 569 648 Net income attributable to Enable common units 52 360 485 Reconciliation of Equity in Earnings (Losses), net: CenterPoint Energy’s interest $ 28 $ 193 $ 262 Basis difference amortization (1) 87 47 47 Loss on dilution, net of proportional basis difference recognition (2) (11) (2) Impairment of CenterPoint Energy’s equity method investment in Enable (1,541) — — CenterPoint Energy’s equity in earnings (losses), net $ (1,428) $ 229 $ 307 (1) Equity in earnings of unconsolidated affiliate includes CenterPoint Energy’s share of Enable earnings adjusted for the amortization of the basis difference of CenterPoint Energy’s original investment in Enable and its underlying equity in net assets of Enable. The basis difference is being amortized through the year 2048. Summarized consolidated balance sheet information for Enable is as follows: December 31, 2020 2019 (in millions) Current assets $ 381 $ 389 Non-current assets 11,348 11,877 Current liabilities 582 780 Non-current liabilities 4,052 4,077 Non-controlling interest 26 37 Preferred equity 362 362 Accumulated other comprehensive loss (6) (3) Enable partners’ equity 6,713 7,013 December 31, 2020 2019 (in millions) Reconciliation of Investment in Enable: CenterPoint Energy’s ownership interest in Enable partners’ equity $ 3,601 $ 3,767 CenterPoint Energy’s basis difference (1) (2,819) (1,361) CenterPoint Energy’s equity method investment in Enable $ 782 $ 2,406 (1) Includes the impairment of CenterPoint Energy’s equity method investment in Enable of $1,541 million recorded during the year ended December 31, 2020. The basis difference is being amortized through the year 2048.	Investment in Unconsolidated Affiliates (CenterPoint Energy): December 31, 2020 December 31, 2019 (in millions) Enable $ 782 $ 2,406 Other 1 2 Total $ 783 $ 2,408 CenterPoint Energy evaluates its equity method investments for impairment when factors indicate that a decrease in the value of its investment has occurred and the carrying amount of its investment may not be recoverable. An impairment loss, based on the excess of the carrying value over the estimated fair value of the investment, is recognized in earnings when an impairment is deemed to be other than temporary. Considerable judgment is used in determining if an impairment loss is other than temporary and the amount of any impairment. Based on the severity of the decline in Enable’s common unit price during the three months ended March 31, 2020 due to the macroeconomic conditions related in part to the COVID-19 pandemic, combined with Enable’s announcement on April 1, 2020 to reduce its quarterly distributions per common unit by 50%, and the market outlook indicating excess supply of crude oil and natural gas and continued depressed crude oil and natural gas prices impacting the midstream oil and gas industry, CenterPoint Energy determined, in connection with its preparation of the financial statements, that an other than temporary decrease in the value of its investment in Enable had occurred. CenterPoint Energy reduced the carrying value of its investment in Enable to its estimated fair value of $848 million as of March 31, 2020 and recognized an impairment charge of $1,541 million during the year ended December 31, 2020. Both the income approach and market approach were utilized to estimate the fair value of CenterPoint Energy’s equity investment in Enable, which includes common units, general partner interest and incentive distribution rights held by CenterPoint Energy through CNP Midstream. The determination of fair value considered a number of relevant factors including Enable’s common unit price and forecasted distributions, recent comparable transactions and the limited float of Enable’s publicly traded common units. As of December 31, 2020, CenterPoint Energy’s investment in Enable is $3.34 per unit and Enable’s common unit price closed at $5.26 per unit. See Note 10 for further discussion of the determination of fair value of CenterPoint Energy’s investment in Enable as of March 31, 2020. CenterPoint Energy did not identify a further decrease in value as of December 31, 2020. Equity in Earnings of Unconsolidated Affiliates, net (CenterPoint Energy): Year Ended December 31, 2020 (1) 2019 (2) 2018 (in millions) Enable (1) $ (1,428) $ 229 $ 307 Other — 1 — Total $ (1,428) $ 230 $ 307 (1) CenterPoint Energy recognized a loss of $1,428 million from its investment in Enable for the year ended December 31, 2020. This loss included an impairment charge on CenterPoint Energy’s investment in Enable of $1,541 million discussed above, and CenterPoint Energy’s interest in Enable’s $225 million impairment on an equity method investment. (2) Includes CenterPoint Energy’s share of Enable’s $86 million goodwill impairment recorded in the fourth quarter of 2019.

Indexed Debt Securities (ZENS_2

Indexed Debt Securities (ZENS) and Securities Related to ZENS (CenterPoint Energy) (Tables)	12 Months Ended
	Dec. 31, 2020
Indexed Debt Securities [Abstract]
Summarized Financial Information on Investment in Time Warner Securities and Indexed Debt Security Obligation [Table Text Block]	A subsidiary of CenterPoint Energy holds shares of certain securities detailed in the table below, which are classified as trading securities and are expected to be held to facilitate CenterPoint Energy’s ability to meet its obligation under the ZENS. Unrealized gains and losses resulting from changes in the market value of the ZENS-Related Securities are recorded in CenterPoint Energy’s Statements of Consolidated Income. Shares Held at December 31, 2020 2019 AT&T Common 10,212,945 10,212,945 Charter Common 872,503 872,503 CenterPoint Energy’s reference shares for each ZENS consisted of the following: December 31, 2020 2019 (in shares) AT&T Common 0.7185 0.7185 Charter Common 0.061382 0.061382 The following table sets forth summarized financial information regarding CenterPoint Energy’s investment in ZENS-Related Securities and each component of CenterPoint Energy’s ZENS obligation. ZENS-Related Debt Derivative (in millions) Balance as of December 31, 2017 $ 960 $ 122 $ 668 Accretion of debt component of ZENS — 21 — 2% interest paid — (17) — Sale of ZENS-Related Securities (398) — — Distribution to ZENS holders — (102) (46) Gain on indexed debt securities — — (21) Loss on ZENS-Related Securities (22) — — Balance as of December 31, 2018 540 24 601 Accretion of debt component of ZENS — 17 — 2% interest paid — (17) — Distribution to ZENS holders — (5) — Loss on indexed debt securities — — 292 Gain on ZENS-Related Securities 282 — — Balance as of December 31, 2019 822 19 893 Accretion of debt component of ZENS — 17 — 2% interest paid — (16) — Distribution to ZENS holders — (5) — Loss on indexed debt securities — — 60 Gain on ZENS-Related Securities 49 — — Balance as of December 31, 2020 $ 871 $ 15 $ 953

Equity (CenterPoint Energy) (Ta

Equity (CenterPoint Energy) (Tables)	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Dividends Declared [Table Text Block]	CenterPoint Energy declared and paid dividends on its Common Stock during 2020, 2019 and 2018 as presented in the table below: Declaration Date Record Date Payment Date Per Share (1) Total December 10, 2020 February 18, 2021 March 11, 2021 $ 0.1600 $ 88 October 29, 2020 November 19, 2020 December 10, 2020 0.1500 83 July 29, 2020 August 20, 2020 September 10, 2020 0.1500 82 April 24, 2020 May 21, 2020 June 11, 2020 0.1500 82 February 3, 2020 February 20, 2020 March 12, 2020 0.2900 145 Total 2020 $ 0.9000 $ 480 October 17, 2019 November 21, 2019 December 12, 2019 $ 0.2875 $ 144 July 31, 2019 August 15, 2019 September 12, 2019 0.2875 145 April 25, 2019 May 16, 2019 June 13, 2019 0.2875 144 Total 2019 $ 0.8625 $ 433 Declaration Date Record Date Payment Date Per Share (1) Total December 12, 2018 February 21, 2019 March 14, 2019 $ 0.2875 $ 144 October 23, 2018 November 15, 2018 December 13, 2018 0.2775 139 July 26, 2018 August 16, 2018 September 13, 2018 0.2775 120 April 26, 2018 May 17, 2018 June 14, 2018 0.2775 120 Total 2018 $ 1.1200 $ 523 (1) On April 1, 2020, in response to the reduction in cash flow related to the reduction in Enable quarterly common unit distributions announced by Enable on April 1, 2020, CenterPoint Energy announced a reduction of its quarterly Common Stock dividend per share from $0.2900 to $0.1500. CenterPoint Energy declared and paid dividends on its Series A Preferred Stock during 2020, 2019 and 2018 as presented in the table below: Declaration Date Record Date Payment Date Per Share Total December 10, 2020 February 15, 2021 March 1, 2021 $ 30.6250 $ 24 July 29, 2020 August 14, 2020 September 1, 2020 30.6250 24 February 3, 2020 February 14, 2020 March 2, 2020 30.6250 25 Total 2020 $ 91.8750 $ 73 July 31, 2019 August 15, 2019 September 3, 2019 $ 30.6250 $ 24 Total 2019 $ 30.6250 $ 24 December 12, 2018 February 15, 2019 March 1, 2019 $ 32.1563 $ 26 Total 2018 $ 32.1563 $ 26 CenterPoint Energy declared dividends on its Series B Preferred Stock during 2020, 2019 and 2018 as presented in the table below: Declaration Date Record Date Payment Date Per Share Total December 10, 2020 February 15, 2021 March 1, 2021 $ 17.5000 $ 17 October 29, 2020 November 13, 2020 December 1, 2020 17.5000 17 July 29, 2020 August 14, 2020 September 1, 2020 17.5000 17 April 24, 2020 May 15, 2020 June 1, 2020 17.5000 17 February 3, 2020 February 14, 2020 March 2, 2020 17.5000 17 Total 2020 $ 87.5000 $ 85 October 17, 2019 November 15, 2019 December 2, 2019 $ 17.5000 $ 17 July 31, 2019 August 15, 2019 September 3, 2019 17.5000 17 April 25, 2019 May 15, 2019 June 3, 2019 17.5000 17 Total 2019 $ 52.5000 $ 51 December 12, 2018 February 15, 2019 March 1, 2019 $ 17.5000 $ 17 October 23, 2018 November 15, 2018 December 1, 2018 11.6667 11 Total 2018 $ 29.1667 $ 28 CenterPoint Energy declared and paid dividends on its Series C Preferred Stock during 2020 as presented in the table below: Declaration Date (1) Record Date Payment Date Per Share Total December 10, 2020 February 18, 2021 March 11, 2021 $ 0.1600 $ 7 October 29, 2020 November 19, 2020 December 10, 2020 0.1500 6 July 29, 2020 August 20, 2020 September 10, 2020 0.1500 7 April 24, 2020 May 21, 2020 June 11, 2020 0.1500 7 Total 2020 $ 0.6100 $ 27 (1) Declaration date for dividends on Common Stock. The Series C Preferred Stock is entitled to participate in any dividend or distribution (excluding those payable in Common Stock) with the Common Stock on a pari passu, pro rata, as-converted basis. The per share amount reflects the dividend per share of Common Stock as if the Series C Preferred Stock were converted into Common Stock. The Series C Preferred Stock are expected to convert to Common Stock on or around May 7, 2021. There were no Series C Preferred Stock outstanding or dividends declared in 2019 or 2018. Dividend Requirement on Preferred Stock Year Ended December 31, 2020 2019 2018 (in millions) Series A Preferred Stock $ 49 $ 49 $ 18 Series B Preferred Stock 68 68 17 Series C Preferred Stock 27 — — Preferred dividend requirement 144 117 35 Amortization of beneficial conversion feature 32 — — Total income allocated to preferred shareholders $ 176 $ 117 $ 35
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Amounts recognized in accumulated other comprehensive loss (gain) consist of the following: December 31, 2020 2019 Pension Postretirement Pension Postretirement CenterPoint Energy CenterPoint Energy CERC CenterPoint Energy CenterPoint Energy CERC (in millions) Unrecognized actuarial loss (gain) $ 109 $ (14) $ (12) $ 105 $ (16) $ (12) Unrecognized prior service cost — 7 7 — 7 7 Net amount recognized in accumulated other comprehensive loss (gain) $ 109 $ (7) $ (5) $ 105 $ (9) $ (5) Changes in accumulated comprehensive income (loss) are as follows: Year Ended December 31, 2020 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Beginning Balance $ (98) $ (15) $ 10 $ (108) $ (14) $ 5 Other comprehensive income (loss) before reclassifications: Remeasurement of pension and other postretirement plans (12) — — 7 — 7 Deferred loss from interest rate derivatives (1) — — — (3) (1) — Reclassified to earnings — — — 1 — — Other comprehensive loss from unconsolidated affiliates (2) — — (1) — — Amounts reclassified from accumulated other comprehensive loss: Prior service cost (2) — — 1 1 — — Actuarial losses (2) 7 — — 8 — — Reclassification of deferred loss from cash flow hedges (3) 19 19 — — — — Tax benefit (expense) (4) (4) (1) (3) — (2) Net current period other comprehensive income (loss) 8 15 — 10 (1) 5 Ending Balance $ (90) $ — $ 10 $ (98) $ (15) $ 10 (1) Gains and losses are reclassified from Accumulated other comprehensive income into income when the hedged transactions affect earnings. The reclassification amounts are included in Interest and other finance charges in each of the Registrant’s respective Statements of Consolidated Income. Amounts are $-0- and $1 million for the years ended December 31, 2020 and 2019, respectively. (2) Amounts are included in the computation of net periodic cost and are reflected in Other, net in each of the Registrants’ respective Statements of Consolidated Income. (3) The cost of debt approved by the PUCT as part of Houston Electric’s Stipulation and Settlement Agreement included unrealized gains and losses on interest rate hedges. Accordingly, deferred gains and losses on interest rate hedges were reclassified to regulatory assets or liabilities, as appropriate.
Convertible Debt [Table Text Block]	The following table illustrates the conversion rate per share of the Series B Preferred Stock, subject to certain anti-dilution adjustments: Applicable Market Value of the Common Stock Conversion Rate per Share of Series B Preferred Stock Greater than $32.6990 (threshold appreciation price) 30.5820 shares of Common Stock Equal to or less than $32.6990 but greater than or equal to $27.2494 Between 30.5820 and 36.6980 shares of Common Stock, determined by dividing $1,000 by the applicable market value Less than $27.2494 (initial price) 36.6980 shares of Common Stock The following table illustrates the conversion rate per depositary share, subject to certain anti-dilution adjustments: Applicable Market Value of the Common Stock Conversion Rate per Depository Share Greater than $32.6990 (threshold appreciation price) 1.5291 shares of Common Stock Equal to or less than $32.6990 but greater than or equal to $27.2494 Between 1.5291 and 1.8349 shares of Common Stock, determined by dividing $50 by the applicable market value Less than $27.2494 (initial price) 1.8349 shares of Common Stock

Short Term Borrowings and Lon_2

Short Term Borrowings and Long Term Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Revolving Credit Facilities and Utilization of Such Facilities [Table Text Block]	The Registrants had the following revolving credit facilities as of December 31, 2020: Execution Registrant Size of Draw Rate of LIBOR plus (1) Financial Covenant Limit on Debt for Borrowed Money to Capital Ratio Debt for Borrowed Money to Capital Ratio as of December 31, 2020 (2) Termination (in millions) March 3, 2016 CenterPoint Energy $ 3,300 1.500% 65% (3) 53.9% March 3, 2022 July 14, 2017 CenterPoint Energy (4) 400 1.125% 65% 49.7% July 14, 2022 March 3, 2016 Houston Electric 300 1.250% 65% (3) 53.1% March 3, 2022 March 3, 2016 CERC 900 1.125% 65% 48.9% March 3, 2022 Total $ 4,900 (1) Based on credit ratings as of December 31, 2020. (2) As defined in the revolving credit facility agreement, excluding Securitization Bonds. (3) For CenterPoint Energy and Houston Electric, the financial covenant limit will temporarily increase from 65% to 70% if Houston Electric experiences damage from a natural disaster in its service territory and CenterPoint Energy certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive 12-month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Such temporary increase in the financial covenant would be in effect from the date CenterPoint Energy delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of CenterPoint Energy’s certification or (iii) the revocation of such certification. (4) This credit facility was issued by VUHI, is guaranteed by SIGECO, Indiana Gas and VEDO and included a $10 million swing line sublimit and a $20 million letter of credit sublimit. This credit facility backstops VUHI’s commercial paper program. On September 30, 2020, VCC terminated its $200 million credit agreement dated as of July 14, 2017 after determining that it was no longer necessary for financing purposes. VCC did not incur any penalties in connection with the early termination. The Registrants, as well as the subsidiaries of CenterPoint Energy discussed above, were in compliance with all financial debt covenants as of December 31, 2020. As of December 31, 2020 and 2019, the Registrants had the following revolving credit facilities and utilization of such facilities: December 31, 2020 December 31, 2019 Registrant Loans Letters Commercial Weighted Average Interest Rate Loans Letters Commercial Weighted Average Interest Rate (in millions, except weighted average interest rate) CenterPoint Energy (1) $ — $ 11 $ 1,078 0.23 % $ — $ 6 $ 1,633 1.95 % CenterPoint Energy (2) — — 92 0.22 % — — 268 2.08 % Houston Electric — — — — % — — — — % CERC — — 347 0.23 % — 1 377 1.94 % Total $ — $ 11 $ 1,517 $ — $ 7 $ 2,278 (1) CenterPoint Energy’s outstanding commercial paper generally has maturities of 60 days or less. (2) This credit facility was issued by VUHI and is guaranteed by SIGECO, Indiana Gas and VEDO. On February 4, 2021, each of CenterPoint Energy, Houston Electric, CERC Corp. and VUHI replaced their existing revolving credit facilities with new amended and restated credit facilities. The size of the CenterPoint Energy facility decreased from $3.3 billion to $2.4 billion, while the sizes of the Houston Electric, CERC Corp. and VUHI facilities remained unchanged. The VUHI facility remains guaranteed by SIGECO, Indiana Gas and VEDO. Based on the credit ratings as of February 4, 2021, the draw rate would have been LIBOR plus 1.625% under the CenterPoint Energy facility, LIBOR plus 1.375% under the Houston Electric facility, LIBOR plus 1.250% under the CERC Corp. facility, and LIBOR plus 1.250% under the VUHI facility. Each credit facility contains provisions relating to the replacement of LIBOR. The financial covenant limit on debt for borrowed money to capital ratio remained at 65.0% for each of the CenterPoint Energy, CERC Corp. and VUHI facilities and increased to 67.5% for the Houston Electric facility. As with the facilities that were replaced, the CenterPoint Energy and Houston Electric facilities’ financial covenant limit on debt for borrowed money to capital ratio can temporarily increase to 70.0% if Houston Electric experiences certain damages from a natural disaster in its service territory and CenterPoint Energy certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive 12-month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Each of the amended and restated facilities have a maturity date of February 4, 2024.
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturities. As of December 31, 2020, maturities of long-term debt, capital leases and sinking fund requirements, excluding the ZENS obligation and unamortized discounts, premiums and issuance costs, are as follows: CenterPoint Energy (1) Houston Electric (1) CERC Securitization Bonds (in millions) 2021 $ 1,868 $ 613 $ — $ 211 2022 2,542 519 347 219 2023 713 356 300 156 2024 1,184 162 — 162 2025 51 — — — (1) These maturities include Securitization Bonds principal repayments on scheduled payment dates.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Income Tax Contingencies [Table Text Block]	A reconciliation of CenterPoint Energy’s beginning and ending balance of unrecognized tax benefits, excluding interest and penalties, for 2020 and 2019 are as follows: Year Ended December 31, 2020 2019 (in millions) Balance, beginning of year $ 8 $ — Unrecognized tax benefits assumed through the Merger — 9 Increases related to tax positions of prior years 3 — Decreases related to tax positions of prior years (4) (1) Balance, end of year $ 7 $ 8
Income Tax Expense [Table Text Block]	The components of the Registrant’ income tax expense (benefit) were as follows: Year Ended December 31, 2020 2019 2018 (in millions) CenterPoint Energy - Continuing Operations Current income tax expense (benefit): Federal $ (1) $ 30 $ 77 State 32 15 6 Total current expense 31 45 83 Deferred income tax expense (benefit): Federal (257) 55 (6) State (48) (8) 78 Total deferred expense (benefit) (305) 47 72 Total income tax expense (benefit) $ (274) $ 92 $ 155 CenterPoint Energy - Discontinued Operations Current income tax expense: Federal $ 117 $ 18 $ 12 State 28 6 3 Total current expense 145 24 15 Deferred income tax expense (benefit): Federal (102) 19 (19) State (22) 3 (5) Total deferred expense (benefit) (124) 22 (24) Total income tax expense (benefit) $ 21 $ 46 $ (9) Houston Electric Current income tax expense: Federal $ 76 $ 84 $ 109 State 19 20 18 Total current expense 95 104 127 Deferred income tax benefit: Federal (42) (24) (38) Total deferred benefit (42) (24) (38) Total income tax expense $ 53 $ 80 $ 89 Year Ended December 31, 2020 2019 2018 (in millions) CERC - Continuing Operations Current income tax expense (benefit): State $ 4 $ 5 $ (3) Total current expense (benefit) 4 5 (3) Deferred income tax expense (benefit): Federal 26 26 9 State 67 (34) 25 Total deferred expense (benefit) 93 (8) 34 Total income tax expense (benefit) $ 97 $ (3) $ 31 CERC - Discontinued Operations Current income tax expense: State — 2 7 Total current expense — 2 7 Deferred income tax expense (benefit): Federal — 13 30 State (2) 2 — Total deferred expense (benefit) (2) 15 30 Total income tax expense (benefit) $ (2) $ 17 $ 37
Reconciliation of Expected Federal Income Tax Expense to Actual [Table Text Block]	A reconciliation of income tax expense (benefit) using the federal statutory income tax rate to the actual income tax expense and resulting effective income tax rate is as follows: Year Ended December 31, 2020 2019 2018 (in millions) CenterPoint Energy - Continuing Operations (1) (2) (3) Income (loss) before income taxes $ (865) $ 774 $ 551 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense (benefit) (182) 163 116 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax (15) 30 23 State valuation allowance, net of federal income tax 1 (4) 11 State law change, net of federal income tax — (21) 32 Excess deferred income tax amortization (76) (55) (24) Goodwill impairment 39 — — Net operating loss carryback (37) — — Other, net (4) (21) (3) Total (92) (71) 39 Total income tax expense (benefit) $ (274) $ 92 $ 155 Effective tax rate 32 % 12 % 28 % CenterPoint Energy - Discontinued Operations (4)(5) Income (loss) before income taxes $ (161) $ 155 $ (37) Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense (benefit) (34) 32 (8) Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax (5) 6 (1) Goodwill impairment 25 8 — Tax impact of sale of Energy Services and Infrastructure Services Disposal Groups 30 — — Other, net 5 — — Total 55 14 (1) Total income tax expense (benefit) $ 21 $ 46 $ (9) Effective tax rate (13) % 30 % 24 % Year Ended December 31, 2020 2019 2018 (in millions) Houston Electric (6) (7) (8) Income before income taxes $ 387 $ 436 $ 425 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense 81 92 89 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax 15 16 14 Excess deferred income tax amortization (42) (21) (9) Other, net (1) (7) (5) Total (28) (12) — Total income tax expense $ 53 $ 80 $ 89 Effective tax rate 14 % 18 % 21 % CERC - Continuing Operations (9) (10) (11) Income before income taxes $ 244 $ 186 $ 129 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense 51 39 27 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax 55 (15) 5 State law change, net of federal income tax — (4) — State valuation allowance, net of federal income tax 1 (4) 11 Excess deferred income tax amortization (16) (18) (15) Other, net 6 (1) 3 Total 46 (42) 4 Total income tax expense (benefit) $ 97 $ (3) $ 31 Effective tax rate 40 % (2) % 24 % CERC - Discontinued Operations (12) (13) Income (loss) before income taxes $ (68) $ 40 $ 147 Federal statutory income tax rate 21 % 21 % 21 % Expected federal income tax expense (benefit) (14) 8 31 Increase in tax expense resulting from: State income tax expense, net of federal income tax (2) 3 7 Goodwill impairment 10 8 — Other, net 4 (2) (1) Total 12 9 6 Total income tax expense (benefit) $ (2) $ 17 $ 37 Effective tax rate 3 % 43 % 25 % (1) Recognized a $76 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions, a $39 million deferred tax expense for the non-deductible portion of the goodwill impairment on SIGECO, and a $37 million benefit for the NOL carryback claim allowed by the CARES Act. (2) Recognized a $55 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions, a $21 million net benefit for the impact of state law changes that resulted in the remeasurement of state deferred taxes in those jurisdictions, and a $4 million net benefit for the reduction in valuation allowances on certain state NOLs that are now expected to be realized. (3) Recognized a $32 million deferred tax expense due to state law changes that resulted in remeasurement of state deferred taxes in those jurisdictions. Also, recorded an additional $11 million valuation allowance on certain state net operating loss deferred tax assets that are no longer expected to be utilized prior to expiration after the Internal Spin. These items are partially offset by $24 million of amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions beginning in 2018. (4) Recognized a $25 million deferred tax expense for the non-deductible portion of the goodwill impairment on both the Energy Services and Infrastructure Services Disposal Groups. Also, recognized a $30 million net tax expense on both the sale of the Energy Services and Infrastructure Services Disposal Groups. (5) Recognized an $8 million deferred tax expense for the non-deductible portion of the goodwill impairment on the Energy Services Disposal Group. (6) Recognized a $42 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions. (7) Recognized a $21 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions. (8) Recognized a $9 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions beginning in 2018. (9) Recognized a $16 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulatory in certain jurisdictions. (10) Recognized an $18 million benefit for the amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions, a $4 million net benefit for the impact of state law changes that resulted in the remeasurement of state deferred taxes in those jurisdictions and a $4 million net benefit for the reduction in valuation allowances on certain state NOLs that are now expected to be realized. (11) Recorded an additional $11 million valuation allowance on certain state net operating loss deferred tax assets that are no longer expected to be utilized prior to expiration after the Internal Spin. This item was offset by $15 million of amortization of the net regulatory EDIT liability in certain jurisdictions as decreed by regulators beginning in 2018. (12) Recognized a $10 million deferred tax expense for the non-deductible portion of the goodwill impairment on the Energy Services Disposal Group. (13) Recognized an $8 million deferred tax expense for the non-deductible portion of the goodwill impairment on the Energy Services Disposal Group.
Tax Assets and Liabilities [Table Text Block]	The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities were as follows: December 31, 2020 2019 (in millions) CenterPoint Energy Deferred tax assets: Benefits and compensation $ 141 $ 152 Regulatory liabilities 435 447 Loss and credit carryforwards 103 111 Asset retirement obligations 152 89 Indexed debt securities derivative 47 34 Other 52 40 Valuation allowance (26) (25) Total deferred tax assets 904 848 Deferred tax liabilities: Property, plant and equipment 2,790 2,656 Investment in unconsolidated affiliates 624 1,010 Regulatory assets 325 344 Investment in marketable securities and indexed debt 649 586 Other 119 180 Total deferred tax liabilities 4,507 4,776 Net deferred tax liabilities $ 3,603 $ 3,928 Houston Electric Deferred tax assets: Regulatory liabilities $ 201 $ 195 Benefits and compensation 17 14 Asset retirement obligations 9 9 Other 9 7 Total deferred tax assets 236 225 Deferred tax liabilities: Property, plant and equipment 1,159 1,129 Regulatory assets 118 126 Total deferred tax liabilities 1,277 1,255 Net deferred tax liabilities $ 1,041 $ 1,030 CERC Deferred tax assets: Benefits and compensation $ 28 $ 24 Regulatory liabilities 147 144 Loss and credit carryforwards 143 183 Asset retirement obligations 140 80 Other 26 23 Valuation allowance (15) (15) Total deferred tax assets 469 439 Deferred tax liabilities: Property, plant and equipment 916 821 Regulatory assets 53 45 Other 84 43 Total deferred tax liabilities 1,053 909 Net deferred tax liabilities $ 584 $ 470

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Long-term Purchase Commitment [Table Text Block]	As of December 31, 2020, minimum purchase obligations are approximately: Natural Gas and Coal Supply Other (1) CenterPoint Energy CERC CenterPoint Energy (in millions) 2021 $ 708 $ 491 $ 17 2022 542 328 12 2023 465 275 10 2024 387 254 190 2025 370 227 — 2026 and beyond 1,930 1,547 — (1) Primarily relates to technology hardware and software
Schedule of Environmental Loss Contingencies by Site [Table Text Block]	Total costs that may be incurred in connection with addressing these sites cannot be determined at this time. The estimated accrued costs are limited to CenterPoint Energy’s and CERC’s share of the remediation efforts and are therefore net of exposures of other PRPs. The estimated range of possible remediation costs for the sites for which CenterPoint Energy and CERC believe they may have responsibility was based on remediation continuing for the minimum time frame given in the table below. December 31, 2020 CenterPoint Energy CERC (in millions, except years) Amount accrued for remediation $ 12 $ 7 Minimum estimated remediation costs 7 4 Maximum estimated remediation costs 54 32 Minimum years of remediation 5 30 Maximum years of remediation 50 50

Earnings Per Share (CenterPoi_2

Earnings Per Share (CenterPoint Energy) (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Share [Table Text Block]	The following table reconciles numerators and denominators of CenterPoint Energy’s basic and diluted earnings per common share. Basic earnings per common share is determined by dividing Income available to common shareholders - basic by the Weighted average common shares outstanding - basic for the applicable period. Diluted earnings per common share is determined by the inclusion of potentially dilutive common stock equivalent shares that may occur if securities to issue Common Stock were exercised or converted into Common Stock. For the Year Ended December 31, 2020 2019 2018 (in millions, except per share and share amounts) Numerator: Income (loss) from continuing operations $ (591) $ 682 $ 396 Less: Preferred stock dividend requirement (Note 13) 144 117 35 Less: Amortization of beneficial conversion feature (Note 13) 32 — — Less: Undistributed earnings allocated to preferred shareholders (1) — — — Income (loss) available to common shareholders from continuing operations - basic and diluted (767) 565 361 Income (loss) available to common shareholders from discontinued operations - basic and diluted (182) 109 (28) Income (loss) available to common shareholders - basic and diluted $ (949) $ 674 $ 333 Denominator: Weighted average common shares outstanding - basic 531,031,000 502,050,000 448,829,000 Plus: Incremental shares from assumed conversions: Restricted stock (2) — 3,107,000 3,636,000 Series B Preferred Stock (3) — — — Series C Preferred Stock (4) — — — Weighted average common shares outstanding - diluted 531,031,000 505,157,000 452,465,000 Earnings (loss) per common share: Basic earnings (loss) per common share - continuing operations $ (1.45) $ 1.12 $ 0.80 Basic earnings (loss) per common share - discontinued operations (0.34) 0.22 (0.06) Basic Earnings (Loss) Per Common Share $ (1.79) $ 1.34 $ 0.74 Diluted earnings (loss) per common share - continuing operations $ (1.45) $ 1.12 $ 0.80 Diluted earnings (loss) per common share - discontinued operations (0.34) 0.21 (0.06) Diluted Earnings (Loss) Per Common Share $ (1.79) $ 1.33 $ 0.74 (1) There were no undistributed earnings to be allocated to participating securities for the year ended December 31, 2020. (2) The computation of diluted earnings (loss) per common share outstanding for the year ended December 31, 2020 excludes 3,690,000 incremental common shares from assumed conversions of restricted stock from the denominator because the shares would be anti-dilutive. (3) The computation of diluted earnings (loss) per common share outstanding for the years ended December 31, 2020, 2019 and 2018 excludes 35,922,000, 34,354,000, and 8,885,000 of incremental common shares from assumed conversion of Series B Preferred Stock from the denominator, respectively, because the shares would be anti-dilutive. (4) The computation of diluted earnings (loss) per common share outstanding for the year ended December 31, 2020 excludes 23,807,000 of incremental common shares from assumed conversion of Series C Preferred Stock from the denominator because the shares would be anti-dilutive.

Reportable Segments (Tables)

Reportable Segments (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Financial Data for Business Segments [Table Text Block]	Financial data for reportable segments and products and services are as follows: CenterPoint Energy Revenues Equity in Earnings of Unconsolidated Affiliates Depreciation Interest Income Interest Expense Income Tax Expense Net Income (Loss) (in millions) For the year ended December 31, 2020: Electric $ 3,470 $ — $ 663 $ 3 $ (220) $ 72 $ 230 Natural Gas 3,631 — 454 8 (153) 125 278 Midstream Investments — (1,428) — 1 (54) (364) (1,116) Corporate and Other 317 — 72 103 (213) (107) 17 Eliminations — — — (111) 111 — — Continuing Operations $ 7,418 $ (1,428) $ 1,189 $ 4 $ (529) $ (274) (591) Discontinued Operations, net (182) Consolidated $ (773) For the year ended December 31, 2019: Electric $ 3,519 $ — $ 739 $ 27 $ (225) $ 96 $ 419 Natural Gas 3,750 — 420 6 (144) 2 251 Midstream Investments — 229 — 8 (53) 53 131 Corporate and Other 295 1 66 126 (290) (59) (119) Eliminations — — — (145) 145 — — Continuing Operations $ 7,564 $ 230 $ 1,225 $ 22 $ (567) $ 92 682 Discontinued Operations, net 109 Consolidated $ 791 For the year ended December 31, 2018: Electric $ 3,232 $ — $ 917 $ 5 $ (197) $ 89 $ 334 Natural Gas 3,031 — 280 1 (122) 31 98 Midstream Investments — 307 — — (10) 73 224 Corporate and Other 14 — 33 66 (135) (38) (260) Eliminations — — — (44) 44 — — Continuing Operations $ 6,277 $ 307 $ 1,230 $ 28 $ (420) $ 155 396 Discontinued Operations, net (28) Consolidated $ 368 Total Assets Expenditures for Long-lived Assets December 31, December 31, 2020 2019 2018 2020 2019 2018 (in millions) Electric $ 14,493 $ 14,432 $ 10,509 $ 1,281 $ 1,216 $ 952 Natural Gas 14,976 14,002 7,188 1,139 1,098 638 Midstream Investments 913 2,473 2,482 — — — Corporate and Other, net of eliminations (1) 3,089 2,658 5,805 95 194 110 Continuing Operations 33,471 33,565 25,984 2,515 2,508 1,700 Assets Held for Sale/Discontinued Operations — 1,964 1,109 21 79 20 Consolidated $ 33,471 $ 35,529 $ 27,093 $ 2,536 $ 2,587 $ 1,720 (1) Total assets included pension and other postemployment-related regulatory assets of $540 million, $584 million and $665 million as of December 31, 2020, 2019 and 2018, respectively. Additionally, total assets as of December 31, 2018 included $3.9 billion of temporary investments included in Cash and cash equivalents on CenterPoint Energy’s Consolidated Balance Sheets.
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]	Houston Electric’s revenues from major external customers are as follows (CenterPoint Energy and Houston Electric): Year Ended December 31, 2020 2019 2018 (in millions) Affiliates of NRG $ 749 $ 727 $ 705 Affiliates of Vistra Energy Corp. 404 263 251
Revenues by Products and Services [Table Text Block]	Revenues by Products and Services: Year Ended December 31, 2020 2019 2018 Revenues by Products and Services: CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Electric delivery $ 2,941 $ 2,911 $ — $ 3,019 $ 2,990 $ — $ 3,232 $ 3,234 $ — Retail electric sales 515 — — 486 — — — — — Wholesale electric sales 14 — — 14 — — — — — Retail gas sales 3,462 — 2,594 3,563 — 2,831 2,857 — 2,857 Gas transportation and processing 15 — 15 33 — 33 32 — 32 Energy products and services 471 — 154 449 — 154 156 — 142 Total $ 7,418 $ 2,911 $ 2,763 $ 7,564 $ 2,990 $ 3,018 $ 6,277 $ 3,234 $ 3,031

Supplemental Disclosure of Ca_2

Supplemental Disclosure of Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	The tables below provide supplemental disclosure of cash flow information: 2020 2019 2018 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Cash Payments/Receipts: Interest, net of capitalized interest $ 471 $ 201 $ 114 $ 436 $ 229 $ 109 $ 363 $ 200 $ 105 Income tax payments, net 143 65 4 155 87 7 89 154 3 Non-cash transactions: Accounts payable related to capital expenditures 153 102 69 236 117 86 201 124 80 Capital distribution associated with the Internal Spin (1) — — — — — 28 — — 1,473 ROU assets obtained in exchange for lease liabilities (2) 15 1 5 44 1 29 — — — Beneficial conversion feature 32 — — — — — — — — Amortization of beneficial conversion feature (32) — — — — — — — — (1) The capital distribution in 2019 associated with the Internal Spin is a result of the return to accrual for the periods of CERC’s ownership during 2018. (2) Includes the transition impact of adoption of ASU 2016-02 Leases as of January 1, 2019. The Registrants elected not to recast comparative periods in the year of adoption as permitted by the standard. The table below provides a reconciliation of cash, cash equivalents and restricted cash reported in the Consolidated Balance Sheets to the amount reported in the Statements of Consolidated Cash Flows and has not been recast to exclude the Infrastructure Services and Energy Services Disposal Groups as of December 31, 2019: December 31, 2020 December 31, 2019 CenterPoint Energy Houston Electric CERC CenterPoint Energy Houston Electric CERC (in millions) Cash and cash equivalents (1) $ 147 $ 139 $ 1 $ 241 $ 216 $ 2 Restricted cash included in Prepaid expenses and other current assets 20 15 — 30 19 — Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows $ 167 $ 154 $ 1 $ 271 $ 235 $ 2

Related Party Transactions (H_2

Related Party Transactions (Houston Electric and CERC) (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Schedule of Money Pool Investment and Borrowing [Table Text Block]	Houston Electric and CERC participate in a money pool through which they can borrow or invest on a short-term basis. Funding needs are aggregated and external borrowing or investing is based on the net cash position. The net funding requirements of the money pool are expected to be met with borrowings under CenterPoint Energy’s revolving credit facility or the sale of CenterPoint Energy’s commercial paper. The table below summarizes money pool activity: December 31, 2020 December 31, 2019 Houston Electric CERC Houston Electric CERC (in millions, except interest rates) Money pool investments (borrowings) (1) $ (8) $ — $ 481 $ — Weighted average interest rate 0.24 % 0.24 % 1.98 % 1.98 % (1) Included in Accounts and notes receivable (payable)–affiliated companies in Houston Electric’s and CERC’s Consolidated Balance Sheets.
Schedule of Related Party Transactions [Table Text Block]	Houston Electric and CERC affiliate-related net interest income (expense) were as follows: Year Ended December 31, 2020 2019 2018 Houston Electric CERC Houston Electric CERC Houston Electric CERC (in millions) Interest income (expense), net (1) $ — $ — $ 18 $ 4 $ 1 $ — (1) Interest income is included in Other, net and interest expense is included in Interest and other finance charges on Houston Electric’s and CERC’s respective Statements of Consolidated Income. Amounts charged for these services are included primarily in Operation and maintenance expenses: Year Ended December 31, 2020 2019 2018 Houston Electric CERC Houston Electric CERC Houston Electric CERC (in millions) Corporate service charges $ 197 $ 212 $ 177 $ 141 $ 190 $ 147 Net affiliate service charges (billings) (16) 16 (8) 8 (17) 17 The table below presents transactions among Houston Electric, CERC and their parent, Utility Holding. Year Ended December 31, 2020 2019 2018 Houston Electric CERC Houston Electric CERC Houston Electric CERC (in millions) Cash dividends paid to parent $ 551 $ 80 $ 376 $ 120 $ 209 $ 360 Cash contribution from parent 62 217 590 129 200 960 Capital distribution to parent associated with the sale of CES — 286 — — — — Capital distribution to parent associated with the Internal Spin (1) — — — 28 — 1,473 Property, plant and equipment from parent (2) 36 23 — — — — (1) The capital distribution in 2019 associated with the Internal Spin is a result of the return to accrual for the periods of CERC’s ownership during 2018. (2) Property, plant and equipment purchased from CenterPoint Energy at its net carrying value on the date of purchase.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease, Cost [Table Text Block]	The components of lease cost, included in Operation and maintenance expense on the Registrants’ respective Statements of Consolidated Income, are as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 CenterPoint Energy Houston CERC CenterPoint Energy Houston CERC (in millions) Operating lease cost $ 9 $ — $ 5 $ 7 $ — $ 4 Short-term lease cost 14 12 — 25 23 — Total lease cost $ 23 $ 12 $ 5 $ 32 $ 23 $ 4
Operating Lease, Lease Income [Table Text Block]	The components of lease income were as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 CenterPoint Energy Houston CERC CenterPoint Energy Houston CERC (in millions) Operating lease income $ 5 $ — $ 2 $ 4 $ 2 $ 1 Variable lease income 1 — — 2 — — Total lease income $ 6 $ — $ 2 $ 6 $ 2 $ 1
Supplemental Balance Sheet Information Related To Leases [Table Text Block]	Supplemental balance sheet information related to leases was as follows: December 31, 2020 December 31, 2019 CenterPoint Energy Houston CERC CenterPoint Energy Houston CERC (in millions, except lease term and discount rate) Assets: Operating ROU assets (1) $ 31 $ 1 $ 19 $ 31 $ 1 $ 18 Total leased assets $ 31 $ 1 $ 19 $ 31 $ 1 $ 18 Liabilities: Current operating lease liability (2) $ 6 $ — $ 3 $ 7 $ — $ 3 Non-current operating lease liability (3) 26 1 18 24 1 15 Total leased liabilities $ 32 $ 1 $ 21 $ 31 $ 1 $ 18 Weighted-average remaining lease term (in years) - operating leases 6.0 4.0 7.5 6.5 5.2 7.1 Weighted-average discount rate - operating leases 3.14 % 2.59 % 3.36 % 3.57 % 3.52 % 3.61 % (1) Reported within Other assets in the Registrants’ respective Consolidated Balance Sheets. (2) Reported within Current other liabilities in the Registrants’ respective Consolidated Balance Sheets. (3) Reported within Other liabilities in the Registrants’ respective Consolidated Balance Sheets.
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	As of December 31, 2020, maturities of operating lease liabilities were as follows: CenterPoint Houston CERC (in millions) 2021 $ 8 $ 1 $ 4 2022 6 — 4 2023 6 — 4 2024 4 — 3 2025 3 — 2 2026 and beyond 10 — 7 Total lease payments 37 1 24 Less: Interest 5 — 3 Present value of lease liabilities $ 32 $ 1 $ 21
Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block]	As of December 31, 2020, maturities of undiscounted operating lease payments to be received are as follows: CenterPoint Houston CERC (in millions) 2021 $ 4 $ — $ 1 2022 2 — — 2023 2 — — 2024 2 — — 2025 2 — — 2026 and beyond 8 — — Total lease payments to be received $ 20 $ — $ 1
Other Information Related To Leases [Table Text Block]	Other information related to leases is as follows. See Note 19 for information on ROU assets obtained in exchange for operating lease liabilities: Year Ended December 31, 2020 CenterPoint Houston CERC (in millions) Operating cash flows from operating leases included in the measurement of lease liabilities $ 8 $ 1 $ 4

Subsequent Events (Tables)

Subsequent Events (Tables)	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Schedule of Subsequent Events [Table Text Block]	Enable Distributions Declarations (CenterPoint Energy) Equity Instrument Declaration Date Record Date Payment Date Per Unit Distribution Expected Cash Distribution (in millions) Enable common units February 12, 2021 February 22, 2021 March 1, 2021 $ 0.16525 $ 39 Enable Series A Preferred Units February 12, 2021 February 12, 2021 February 12, 2021 0.62500 9 February 2021 Winter Storm Event In February 2021, certain of our jurisdictions experienced an extreme and unprecedented winter weather event that resulted in prolonged freezing temperatures, which impacted, and may continue to impact, our businesses. In Texas, the February 2021 Winter Storm Event caused an electricity generation shortage that was severely disruptive to Houston Electric’s service territory and the wholesale generation market. While demand for electricity reached extraordinary levels due to the extreme cold, the supply of electricity significantly decreased in part because of the inability of certain power generation facilities to supply electric power to the grid. Houston Electric does not own or operate any electric generation facilities. It transmits and distributes to customers of REPs electric power that the REPs obtain from power generation facilities owned by third parties. ERCOT serves as the independent system operator and regional reliability coordinator for member electric power systems in most of Texas. To comply with ERCOT’s orders, Houston Electric implemented controlled outages across its service territory, resulting in a substantial number of businesses and residents being without power, many for extended periods of time, in compliance with ERCOT’s directives as an emergency procedure to avoid prolonged large-scale state-wide blackouts and long-term damage to the electric system in Texas. In anticipation of this weather event, Houston Electric implemented its emergency operations plan’s processes and procedures necessary to respond to such events, including establishing an incident command center and calling for mutual assistance from other utilities where needed, among other measures. Throughout the February 2021 Winter Storm Event, Houston Electric remained in contact with its regulators and stakeholders, including federal, state and local officials, as well as the PUCT and ERCOT. On February 21, 2021, in response to the 2021 February Winter Storm Event, the PUCT issued an order prohibiting REPs from sending a request to TDUs to disconnect such REPs’ customers for non-payment, effective February 21, 2021. As a result of this order, in event a request for disconnect is received from a REP, Houston Electric will not execute any such disconnect request until the PUCT issues orders for disconnects to resume. The February 2021 Winter Storm Event also impacted wholesale prices CenterPoint Energy and CERC paid for their natural gas and their ability to service customers in their Natural Gas service territories, including due to the reduction in available natural gas capacity and impacts to CenterPoint Energy’s and CERC’s natural gas supply portfolio activities, and the effects of weather on their systems and their ability to transport natural gas, among other things. The overall natural gas market, including the markets from which CenterPoint Energy and CERC sourced a significant portion of their natural gas for their operations, experienced significant impacts caused by the February 2021 Winter Storm Event, resulting in extraordinary increases in the price of natural gas purchased by CenterPoint Energy and CERC. On February 13, 2021, the Railroad Commission authorized each Texas natural gas distribution utility to record in a regulatory asset the extraordinary expenses associated with the February 2021 Winter Storm Event, including, but not limited to, natural gas cost and other costs related to the procurement and transportation of natural gas supply, subject to recovery in future regulatory proceedings. CenterPoint Energy’s and CERC’s Natural Gas utilities in their jurisdictions outside of Texas have natural gas cost recovery mechanisms to recover the increased cost of natural gas. Various regulatory and governmental entities have announced that they intend to conduct inquiries, investigations and other reviews of the February 2021 Winter Storm Event and the efforts made by various entities to prepare for, and respond to, this event, including the electric generation shortfall issues. Entities that have already announced that they plan to conduct or are conducting such inquiries, investigations and other reviews include the United States Congress, FERC, NERC, Texas RE, ERCOT, Texas government entities and officials such as the Texas Governor’s office, the Texas Legislature, the Texas Attorney General, the PUCT, the City of Houston and other municipal and county entities in Houston Electric’s service territory, among others entities. Like other Texas TDUs, Houston Electric may become involved in certain of these investigations, litigation or other regulatory and legal proceedings regarding their efforts to restore power and their compliance with NERC, ERCOT and PUCT rules and directives. CenterPoint Energy and CERC may also be subject to litigation, and potential claims could include personal injury and property damage claims, lawsuits for impacts on businesses and other organizations and entities and shareholder claims, among other claims or litigation matters. CenterPoint Energy, Houston Electric and CERC are unable to predict the consequences of any such matters or to estimate a range of potential losses. On February 24, 2021, CERC received financing commitments totaling $1.7 billion on a 364-day term loan facility to bridge any working capital needs related to the February 2021 Winter Storm Event. Enable Merger (CenterPoint Energy) On February 16, 2021, Enable entered into the Enable Merger Agreement. At the closing of the transactions contemplated by the Enable Merger Agreement, if and when it occurs, Energy Transfer will acquire all of Enable’s outstanding equity interests, resulting in the exchange of Enable common units owned by CenterPoint Energy at the transaction exchange ratio of 0.8595x Energy Transfer common units for each Enable common unit. CenterPoint Energy will also receive $5 million in cash in exchange for its interest in Enable GP and approximately $385 million of Energy Transfer Series G Preferred Units in exchange for all of its Enable Series A Preferred Units. The transactions contemplated under the Enable Merger Agreement are expected to be completed in the second half of 2021, subject to customary closing conditions, including Hart-Scott-Rodino antitrust clearance.

Background (Details)

Background (Details) $ in Millions	Apr. 09, 2020USD ($)	Feb. 01, 2019USD ($)	Dec. 31, 2020USD ($)stateshares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Cash proceeds from sale			$ 1,215	$ 0	$ 0
Infrastructure Services Disposal Group [Member]
Sales price of outstanding equity interests			850
Cash proceeds from sale	$ 850		854
Energy Services [Member]
Cash proceeds from sale			$ 365
Vectren [Member]
Cash paid to acquire Vectren		$ 6,000		$ 5,982
Enable Midstream Partners [Member]
Ownership percentage of equity method investment			53.70%	53.70%
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]
Cash proceeds from sale			$ 365
CERC Corp [Member] | Natural Gas [Member]
Number of states in which entity operates | state			6
CERC Corp [Member] | Natural Gas Distribution
Number of States in which the Entity Performs Gas Delivery Services | state			48
CenterPoint Energy [Member] | Enable GP, LLC [Member]
Management rights ownership percentage			50.00%
Incentive distribution right			40.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
LIFO Inventory Amount	$ 92	$ 97
Excess of Replacement or Current Costs over Stated LIFO Value	62
Interest Expense [Member]
Significant Accounting Policies [Line Items]
Interest and AFUDC debt (1)	27	36	$ 8
Other Income (Expense) [Member]
Significant Accounting Policies [Line Items]
AFUDC equity (2)	25	22	12
Houston Electric [Member] | Interest Expense [Member]
Significant Accounting Policies [Line Items]
Interest and AFUDC debt (1)	8	8	6
Houston Electric [Member] | Other Income (Expense) [Member]
Significant Accounting Policies [Line Items]
AFUDC equity (2)	14	15	10
CERC Corp [Member]
Significant Accounting Policies [Line Items]
LIFO Inventory Amount	55	58
Excess of Replacement or Current Costs over Stated LIFO Value		54
CERC Corp [Member] | Interest Expense [Member]
Significant Accounting Policies [Line Items]
Interest and AFUDC debt (1)	3	3	2
CERC Corp [Member] | Other Income (Expense) [Member]
Significant Accounting Policies [Line Items]
AFUDC equity (2)	$ 3	$ 3	$ 2

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 32,514	$ 30,324
Accumulated Depreciation, and Amortization	10,152	9,700
Property, Plant and Equipment, Net	22,362	20,624
Depreciation and Amortization [Abstract]
Depreciation	961	879	$ 623
Amortization of securitized regulatory assets	155	271	531
Other amortization	73	75	76
Total	1,189	1,225	1,230
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	539	258
Asset Retirement Obligation Addition from Merger with Vectren	0	116
Accretion expense (1)	16	16
Revisions in estimates (2)	232	149
Ending balance	787	539	258
Houston Electric [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	13,593	12,829
Accumulated Depreciation, and Amortization	3,930	3,797
Property, Plant and Equipment, Net	9,663	9,032
Depreciation and Amortization [Abstract]
Depreciation	368	339	342
Amortization of securitized regulatory assets	155	271	531
Other amortization	37	38	44
Total	560	648	917
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	42	34
Asset Retirement Obligation Addition from Merger with Vectren	0	0
Accretion expense (1)	1	1
Revisions in estimates (2)	0	7
Ending balance	43	42	34
CERC Corp [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	8,972	8,079
Accumulated Depreciation, and Amortization	2,414	2,270
Property, Plant and Equipment, Net	6,558	5,809
Depreciation and Amortization [Abstract]
Depreciation	289	277	261
Amortization of securitized regulatory assets	0	0	0
Other amortization	15	16	19
Total	304	293	280
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	325	221
Asset Retirement Obligation Addition from Merger with Vectren	0	0
Accretion expense (1)	11	10
Revisions in estimates (2)	235	94
Ending balance	571	325	$ 221
Electric Transmission and Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	15,225	14,360
Accumulated Depreciation, and Amortization	4,785	4,634
Property, Plant and Equipment, Net	10,440	9,726
Electric Generation Equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	1,922	1,780
Accumulated Depreciation, and Amortization	754	698
Property, Plant and Equipment, Net	$ 1,168	1,082
Electric Generation Equipment [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	27 years
Electric Transmission [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	36 years
Electric Transmission [Member] | Houston Electric [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 3,686	3,358
Accumulated Depreciation, and Amortization	700	674
Property, Plant and Equipment, Net	$ 2,986	2,684
Electric Transmission [Member] | Houston Electric [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	46 years
Electric Distribution [Member] | Houston Electric [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 8,225	7,876
Accumulated Depreciation, and Amortization	2,696	2,586
Property, Plant and Equipment, Net	$ 5,529	5,290
Electric Distribution [Member] | Houston Electric [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	34 years
Natural Gas Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 14,022	12,787
Accumulated Depreciation, and Amortization	4,019	3,766
Property, Plant and Equipment, Net	$ 10,003	9,021
Natural Gas Distribution [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	29 years
Natural Gas Distribution [Member] | CERC Corp [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 8,928	8,024
Accumulated Depreciation, and Amortization	2,392	2,243
Property, Plant and Equipment, Net	$ 6,536	5,781
Natural Gas Distribution [Member] | CERC Corp [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	29 years
Other property [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 1,345	1,397
Accumulated Depreciation, and Amortization	594	602
Property, Plant and Equipment, Net	$ 751	795
Other property [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	15 years
Other property [Member] | Houston Electric [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 1,682	1,595
Accumulated Depreciation, and Amortization	534	537
Property, Plant and Equipment, Net	$ 1,148	1,058
Other property [Member] | Houston Electric [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	22 years
Other property [Member] | CERC Corp [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 44	55
Accumulated Depreciation, and Amortization	22	27
Property, Plant and Equipment, Net	$ 22	$ 28
Other property [Member] | CERC Corp [Member] | Weighted Average [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	19 years
SIGECO [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
SIGECO's share of cost of Warrick Unit 4	$ 195
SIGECO's share of accumulated depreciation of Warrick Unit 4	$ 146

Divestitures (CenterPoint Ene_3

Divestitures (CenterPoint Energy and CERC) (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 01, 2020	Apr. 09, 2020	Feb. 01, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2021
Discontinued Operation, Additional Disclosures [Abstract]
Cash proceeds from sale					$ 1,215	$ 0	$ 0
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, net						637
Accrued unbilled revenues						117
Natural gas inventory						67
Materials and supplies						6
Non-trading derivative assets						136
Other						39
Total current assets held for sale					0	1,002
Property, plant and equipment, net						321
Goodwill						282
Non-trading derivative assets						58
Other						301
Total non-current assets held for sale					0	962
Total assets held for sale						1,964
Accounts payable						344
Taxes accrued						2
Non-trading derivative liabilities						44
Other						65
Total current liabilities held for sale					0	455
Non-trading derivative liabilities						14
Benefit obligations						4
Other						25
Total non-current liabilities held for sale					0	43
Total liabilities held for sale						498
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues					1,417	4,957	4,503
Non-utility cost of revenues					1,158	3,906	4,459
Operation and maintenance					218	782	66
Depreciation and amortization					0	62	13
Taxes other than income taxes					4	4	2
Goodwill, Impairment Loss					185	0	0
Goodwill impairment					0	48	0
Total					1,380	4,802	4,540
Income (loss) from Discontinued Operations before income taxes					37	155	(37)
Loss on classification to held for sale, net (2)					(198)	0	0
Income tax expense (benefit)					21	46	(9)
Net income (loss) from Discontinued Operations					(182)	109	(28)
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and amortization on assets held for sale					0	62	13
Discontinued Operation, Continuing Involvement [Abstract]
Amortization of intangible assets in Non-utility cost of revenues					2	24	0
Goodwill					4,697	4,882
Cost of Sales [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Amortization of intangible assets in Non-utility cost of revenues					2	4	0
Depreciation and amortization expense [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Amortization of intangible assets in Non-utility cost of revenues					6	5	0
Vectren [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Cash paid to acquire Vectren			$ 6,000			$ 5,982
Cash paid per share of Vectren common stock at closing of the Merger						$ 72
Goodwill						$ 4,339
Identifiable intangibles						297
Vectren [Member] | Operation And Maintenance Expense [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Severance expense related to the Merger				$ 61		102
Integration costs					83
Vectren [Member] | Cost of Sales [Member] | Operation and maintenance agreements and construction backlog [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Amortization of intangible assets in Non-utility cost of revenues						24
Vectren [Member] | Depreciation and amortization expense [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Amortization of intangible assets in Non-utility cost of revenues					5
Vectren [Member] | Depreciation and amortization expense [Member] | Customer relationships and trade names [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Amortization of intangible assets in Non-utility cost of revenues						$ 16
Vectren [Member] | Stub period [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Common Stock, Dividends, Per Share, Declared						$ 0.41145
Vectren acquisition [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Cash payments towards outstanding share-based awards						$ 78
Other non-qualified plans benefit obligations deferred compensation						41
Incremental share-based awards expense recorded						37
Utility pipeline construction company [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Cash paid to acquire Vectren					25
Goodwill					6
Identifiable intangibles					8
CERC Corp [Member]
Discontinued Operation, Additional Disclosures [Abstract]
Cash proceeds from sale					365
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total current assets held for sale					0	691
Total non-current assets held for sale					0	213
Total current liabilities held for sale					0	368
Total non-current liabilities held for sale					0	27
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income tax expense (benefit)					(2)	17	37
Net income (loss) from Discontinued Operations					(66)	23	110
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and amortization on assets held for sale					0	12	13
Discontinued Operation, Continuing Involvement [Abstract]
Goodwill					757	757
CERC Corp [Member] | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Equity in earnings of unconsolidated affiliate, net							184
Infrastructure Services Disposal Group [Member]
Discontinued Operation, Additional Disclosures [Abstract]
Sales price of outstanding equity interests					850
Cash proceeds from sale		$ 850			854
Net deferred tax liabilities on sale recognized as deferred income tax benefit by CenterPoint Energy					129
Cost to sell					14
Pre-tax gain on sale					6
Maximum contractual exposure under Securities Purchase Agreement					21
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, net						192
Accrued unbilled revenues						109
Natural gas inventory						0
Materials and supplies						6
Non-trading derivative assets						0
Other						4
Total current assets held for sale						311
Property, plant and equipment, net						295
Goodwill						220
Non-trading derivative assets						0
Other						234
Total non-current assets held for sale						749
Total assets held for sale						1,060
Accounts payable						45
Taxes accrued						2
Non-trading derivative liabilities						0
Other						40
Total current liabilities held for sale						87
Non-trading derivative liabilities						0
Benefit obligations						0
Other						16
Total non-current liabilities held for sale						16
Total liabilities held for sale						103
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues					250	1,190
Non-utility cost of revenues					50	309
Operation and maintenance					184	714
Depreciation and amortization					0	50
Taxes other than income taxes					1	2
Goodwill, Impairment Loss					82
Goodwill impairment					0	0
Total					235	1,075
Income (loss) from Discontinued Operations before income taxes					15	115
Loss on classification to held for sale, net (2)					(102)	0
Income tax expense (benefit)					24	29
Net income (loss) from Discontinued Operations					(111)	86
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and amortization on assets held for sale					0	50
Amortization of intangible assets in Non-utility cost of revenues					0	19
Write-down of natural gas inventory					0	0
Capital expenditures					18	67
Accounts payable related to capital expenditures					0	0
Discontinued Operation, Continuing Involvement [Abstract]
Pipeline construction and repair services capitalized					34	162
Pipeline construction and repair service charges in operations and maintenance expense					1	4
Current tax expense (benefit) of cash taxes payable upon sale					158
Infrastructure Services Disposal Group [Member] | Subsequent Event [Member]
Discontinued Operation, Additional Disclosures [Abstract]
Receivable from sale of disposal group								$ 4
Infrastructure Services Disposal Group [Member] | CERC Corp [Member]
Discontinued Operation, Continuing Involvement [Abstract]
Pipeline construction and repair services capitalized					0	20
Pipeline construction and repair service charges in operations and maintenance expense					1	4
Energy Services Disposal Group [Member]
Discontinued Operation, Additional Disclosures [Abstract]
Sales price of outstanding equity interests					400
Cash proceeds from sale	$ 286
Net deferred tax liabilities on sale recognized as deferred income tax benefit by CenterPoint Energy					4
Current tax expense (benefit) of cash taxes payable upon sale					(4)
Cost to sell					6
Receivable from sale of disposal group					79
Loss from reclassification to held for sale					31
Outstanding obligation related to AMAs					24	0
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, net						445
Accrued unbilled revenues						8
Natural gas inventory						67
Materials and supplies						0
Non-trading derivative assets						136
Other						35
Total current assets held for sale						691
Property, plant and equipment, net						26
Goodwill						62
Non-trading derivative assets						58
Other						67
Total non-current assets held for sale						213
Total assets held for sale						904
Accounts payable						299
Taxes accrued						0
Non-trading derivative liabilities						44
Other						25
Total current liabilities held for sale						368
Non-trading derivative liabilities						14
Benefit obligations						4
Other						9
Total non-current liabilities held for sale						27
Total liabilities held for sale						395
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues					1,167	3,767	4,503
Non-utility cost of revenues					1,108	3,597	4,459
Operation and maintenance					34	68	66
Depreciation and amortization					0	12	13
Taxes other than income taxes					3	2	2
Goodwill, Impairment Loss					62
Goodwill impairment					0	48	0
Total					1,145	3,727	4,540
Income (loss) from Discontinued Operations before income taxes					22	40	(37)
Loss on classification to held for sale, net (2)					(96)	0	0
Income tax expense (benefit)					(3)	17	(9)
Net income (loss) from Discontinued Operations					(71)	23	(28)
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and amortization on assets held for sale					0	12	13
Amortization of intangible assets in Non-utility cost of revenues					0	0	0
Write-down of natural gas inventory					3	4	2
Capital expenditures					3	12	21
Accounts payable related to capital expenditures					0	2	2
Discontinued Operation, Continuing Involvement [Abstract]
Transportation revenue					34	101	104
Natural gas expense					48	125	107
Energy Services Disposal Group [Member] | CERC Corp [Member]
Discontinued Operation, Additional Disclosures [Abstract]
Net deferred tax liabilities on sale recognized as deferred income tax benefit by CenterPoint Energy					4
Current tax expense (benefit) of cash taxes payable upon sale					(4)
Pre-tax gain on sale					(3)
Outstanding obligation related to AMAs					24	0
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, net						445
Accrued unbilled revenues						8
Natural gas inventory						67
Materials and supplies						0
Non-trading derivative assets						136
Other						35
Total current assets held for sale						691
Property, plant and equipment, net						26
Goodwill						62
Non-trading derivative assets						58
Other						67
Total non-current assets held for sale						213
Total assets held for sale						904
Accounts payable						299
Taxes accrued						0
Non-trading derivative liabilities						44
Other						25
Total current liabilities held for sale						368
Non-trading derivative liabilities						14
Benefit obligations						4
Other						9
Total non-current liabilities held for sale						27
Total liabilities held for sale						395
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues					1,167	3,767	4,503
Non-utility cost of revenues					1,108	3,597	4,459
Operation and maintenance					34	68	66
Depreciation and amortization					0	12	13
Taxes other than income taxes					3	2	2
Goodwill, Impairment Loss					62
Goodwill impairment					0	48	0
Total					1,145	3,727	4,540
Equity in earnings of unconsolidated affiliate, net					0	0
Income (loss) from Discontinued Operations before income taxes					22	40	147
Loss on classification to held for sale, net (2)					(90)	0	0
Income tax expense (benefit)					(2)	17	37
Net income (loss) from Discontinued Operations					(66)	23	110
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and amortization on assets held for sale					0	12	13
Write-down of natural gas inventory					3	4	2
Capital expenditures					3	12	21
Accounts payable related to capital expenditures					0	2	2
Discontinued Operation, Continuing Involvement [Abstract]
Transportation revenue					34	101	104
Natural gas expense					47	$ 124	$ 107
Energy Services [Member]
Discontinued Operation, Additional Disclosures [Abstract]
Cash proceeds from sale					$ 365

Divestitures (CenterPoint Ene_4

Divestitures (CenterPoint Energy and CERC) - Purchase Price Allocation (Details) - USD ($) $ in Millions	Feb. 01, 2019	Dec. 31, 2019	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill		$ 4,882	$ 4,697
Vectren [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents		16
Other current assets		577
Property, plant and equipment, net		5,147
Identifiable intangibles		297
Regulatory assets		338
Other assets		141
Total assets acquired		6,516
Current liabilities		648
Regulatory liabilities		938
Other liabilities		886
Long-term debt		2,401
Total liabilities assumed		4,873
Net assets acquired		1,643
Goodwill		4,339
Cash paid to acquire Vectren	$ 6,000	$ 5,982

Divestitures (CenterPoint Ene_5

Divestitures (CenterPoint Energy and CERC) - Identifiable Intangible Assets (Details) - Vectren [Member] $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated Fair Value	$ 297
Operation and maintenance agreements [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	24 years
Estimated Fair Value	$ 12
Customer Relationships [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	18 years
Estimated Fair Value	$ 200
Construction backlog [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	1 year
Estimated Fair Value	$ 27
Trade Names [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	10 years
Estimated Fair Value	$ 58

Divestitures (CenterPoint Ene_6

Divestitures (CenterPoint Energy and CERC) - Financial Information and Pro Forma (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	$ 7,418	$ 7,564	$ 6,277
Net income (loss)	$ (773)	791	368
Vectren [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues		2,729
Net income (loss)		190
Operating Revenue		12,547	13,282
Net Income (1)		812	458
Vectren acquisition [Member] | Pro Forma [Member] | Vectren [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction costs associated with the Merger		$ 37	$ 37

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts	$ 7,350	$ 7,511	$ 6,282
Other (1)	68	53	(5)
Total revenues	7,418	7,564	6,277
Lease Income	6	6
Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Reportable Subsegments [Member] | Electric
Disaggregation of Revenue [Line Items]
Revenue from contracts	3,451	3,507	3,235
Other (1)	19	12	(3)
Total revenues	3,470	3,519	3,232
Reportable Subsegments [Member] | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts	3,586	3,714	3,042
Other (1)	45	36	(11)
Total revenues	3,631	3,750	3,031
Reportable Subsegments [Member] | Corporate and Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts	313	290	5
Other (1)	4	5	9
Total revenues	317	295	14
Houston Electric [Member]
Disaggregation of Revenue [Line Items]
Total revenues	2,911	2,990	3,234
Houston Electric [Member] | Reportable Subsegments [Member] | Electric Transmission & Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts	2,896	2,984	3,235
Other (1)	15	6	(1)
Total revenues	2,911	2,990	3,234
CERC Corp [Member]
Disaggregation of Revenue [Line Items]
Total revenues	2,763	3,018	3,031
Lease Income	2
CERC Corp [Member] | Reportable Subsegments [Member] | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts	2,714	2,979	3,042
Other (1)	49	39	(11)
Total revenues	$ 2,763	$ 3,018	$ 3,031

Revenue Recognition Summary of

Revenue Recognition Summary of Contract Assets and Liabilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Change in Accounts Receivable [Roll Forward]
Opening balance as of December 31, 2019	$ 566
Closing balance as of December 31, 2020	604
Increase (Decrease) in Accounts Receivable	38
Change in Other Accrued Unbilled Revenues [Roll Forward]
Opening balance as of December 31, 2019	469
Closing balance as of December 31, 2020	505
Increase (Decrease) in Other Accrued Unbilled Revenues	36
Change in Contract Asset [Roll Forward]
Opening balance as of December 31, 2019	6
Closing balance as of December 31, 2020	27
Increase (Decrease) in Contract with Customer, Asset	21
Change in Contract Liability [Roll Forward]
Opening balance as of December 31, 2019	30
Closing balance as of December 31, 2020	18
Increase (Decrease) in Contract with Customer, Liability	(12)
Contract with Customer, Liability, Revenue Recognized	30
Houston Electric [Member]
Change in Accounts Receivable [Roll Forward]
Opening balance as of December 31, 2019	210
Closing balance as of December 31, 2020	225
Increase (Decrease) in Accounts Receivable	15
Change in Other Accrued Unbilled Revenues [Roll Forward]
Opening balance as of December 31, 2019	117
Closing balance as of December 31, 2020	113
Increase (Decrease) in Other Accrued Unbilled Revenues	(4)
Change in Contract Liability [Roll Forward]
Opening balance as of December 31, 2019	3
Closing balance as of December 31, 2020	3
Increase (Decrease) in Contract with Customer, Liability	0
Contract with Customer, Liability, Revenue Recognized	3
CERC Corp [Member]
Change in Accounts Receivable [Roll Forward]
Opening balance as of December 31, 2019	222
Closing balance as of December 31, 2020	214
Increase (Decrease) in Accounts Receivable	(8)
Change in Other Accrued Unbilled Revenues [Roll Forward]
Opening balance as of December 31, 2019	249
Closing balance as of December 31, 2020	261
Increase (Decrease) in Other Accrued Unbilled Revenues	$ 12

Revenue Recognition Remaining P

Revenue Recognition Remaining Performance Obligations (Details) $ in Millions	Dec. 31, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized	$ 837
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized	837
Corporate and Other [Member]
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized	837
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized	837
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized	$ 267
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period	1 year
Revenue expected to be recognized	$ 267
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Corporate and Other [Member]
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized	267
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized	267
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized	$ 570
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period
Revenue expected to be recognized	$ 570
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Corporate and Other [Member]
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized	570
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized	$ 570

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Bad debt expense	$ 24	$ 18	$ 16
Accounting Standards Update 2016-13 [Member]
Cumulative Effect on Retained Earnings	5
Accounting Standards Update 2016-13 [Member] | Energy Services [Member]
Cumulative Effect on Retained Earnings	2
Houston Electric [Member]
Bad debt expense	0	0	0
CERC Corp [Member]
Bad debt expense	18	$ 14	$ 16
CERC Corp [Member] | Accounting Standards Update 2016-13 [Member]
Cumulative Effect on Retained Earnings	$ 5

Goodwill and Other Intangible_3

Goodwill and Other Intangibles (CenterPoint Energy and CERC) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2020
Goodwill [Line Items]
Goodwill	$ 4,697	$ 4,882
Goodwill impairment	185	0	$ 0
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	68	68
Accumulated Amortization	(18)	(10)
Net Balance	50	58
Amortization of intangible assets in Non-utility cost of revenues	2	24	0
2021	6
2022	6
2023	6
2024	5
2025	5
Continuing Operations [Member]
Goodwill [Line Items]
Goodwill impairment	185
Indiana Electric Integrated [Member]
Goodwill [Line Items]
Goodwill impairment	185
Fair value of goodwill				$ 936
Customer Relationships [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	33	33
Accumulated Amortization	(8)	(4)
Net Balance	25	29
Trade Names [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	16	16
Accumulated Amortization	(3)	(1)
Net Balance	13	15
Construction backlog [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	5	5
Accumulated Amortization	(5)	(4)
Net Balance	0	1
Operation and maintenance agreements [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	12	12
Accumulated Amortization	(1)	0
Net Balance	11	12
Other [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	2	2
Accumulated Amortization	(1)	(1)
Net Balance	1	1
Electric
Goodwill [Line Items]
Goodwill	936	1,121
Goodwill impairment	185
Natural Gas [Member]
Goodwill [Line Items]
Goodwill	3,323	3,323
Goodwill impairment	0
Corporate and Other [Member]
Goodwill [Line Items]
Goodwill	438	438
Goodwill impairment	0
CERC Corp [Member]
Goodwill [Line Items]
Goodwill	757	757
Depreciation and amortization expense [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of intangible assets in Non-utility cost of revenues	6	5	0
Non-utility cost of revenues [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of intangible assets in Non-utility cost of revenues	2	4	$ 0
Vectren [Member]
Goodwill [Line Items]
Goodwill		$ 4,339
Vectren [Member] | Depreciation and amortization expense [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of intangible assets in Non-utility cost of revenues	$ 5

Regulatory Matters Regulatory A

Regulatory Matters Regulatory Assets and Regulatory Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Regulatory Assets and Liabilities [Line Items]
Securitized regulatory assets	$ 633	$ 788
Unrecognized equity return (2)	(150)	(168)
Unamortized loss on reacquired debt (3)	57	62
Non-current regulatory assets	2,094	2,117
Total regulatory assets	2,127	2,129
Non-current regulatory liabilities	3,448	3,474
Total regulatory liabilities	3,520	3,521
Total regulatory assets and liabilities, net	(1,393)	(1,392)
Amount of allowed equity return on the true-up balance that was recognized in the period	31	45	$ 74
Prepaid Expenses and Other Current Assets [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Current regulatory assets (1)	33	12
Other Current Liabilities [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Current regulatory liabilities (6)	72	47
Amounts related to TCJA [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	1,484	1,582
Removal Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	1,470	1,429
Other Regulatory Assets (Liabilities) [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	494	463
Pension and Other Postretirement Plans Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	591	637
Hurricane Harvey
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	59
Hurricane Laura
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	36
Amounts related to TCJA [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	$ 25	30
Weighted average recovery period	4 years
Relief Program Incremental Costs (COVID-19)
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	$ 25
Asset Retirement Obligation Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	135	131
Other Regulatory Assets (Liabilities) [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	518	422
Remaining amounts of regulatory assets for which no return on investment during recovery period is provided	$ 165	147
Remaining weighted average period for which no return on investment during recovery period is provided	14 years
Hurricane Harvey [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets		68
Houston Electric [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Securitized regulatory assets	$ 633	788
Unrecognized equity return (2)	(137)	(168)
Unamortized loss on reacquired debt (3)	55	62
Non-current regulatory assets	848	915
Total regulatory assets	848	915
Non-current regulatory liabilities	1,252	1,288
Total regulatory liabilities	1,295	1,288
Total regulatory assets and liabilities, net	(447)	(373)
Amount of allowed equity return on the true-up balance that was recognized in the period	31	45	$ 74
Houston Electric [Member] | Prepaid Expenses and Other Current Assets [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Current regulatory assets (1)	0	0
Houston Electric [Member] | Other Current Liabilities [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Current regulatory liabilities (6)	43	0
Houston Electric [Member] | Amounts related to TCJA [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	764	821
Houston Electric [Member] | Removal Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	231	244
Houston Electric [Member] | Other Regulatory Assets (Liabilities) [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	257	223
Houston Electric [Member] | Pension and Other Postretirement Plans Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	31	34
Houston Electric [Member] | Hurricane Harvey
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	55
Houston Electric [Member] | Hurricane Laura
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	36
Houston Electric [Member] | Amounts related to TCJA [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	$ 20	23
Weighted average recovery period	5 years
Houston Electric [Member] | Relief Program Incremental Costs (COVID-19)
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	$ 5
Houston Electric [Member] | Asset Retirement Obligation Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	26	26
Houston Electric [Member] | Other Regulatory Assets (Liabilities) [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	41	29
Remaining amounts of regulatory assets for which no return on investment during recovery period is provided	$ 83	57
Remaining weighted average period for which no return on investment during recovery period is provided	11 years
Houston Electric [Member] | Hurricane Harvey [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets		64
CERC Corp [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Securitized regulatory assets	$ 0	0
Unrecognized equity return (2)	(13)	0
Unamortized loss on reacquired debt (3)	0	0
Non-current regulatory assets	220	191
Total regulatory assets	253	203
Non-current regulatory liabilities	1,226	1,219
Total regulatory liabilities	1,255	1,266
Total regulatory assets and liabilities, net	(1,002)	(1,063)
CERC Corp [Member] | Prepaid Expenses and Other Current Assets [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Current regulatory assets (1)	33	12
CERC Corp [Member] | Other Current Liabilities [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Current regulatory liabilities (6)	29	47
CERC Corp [Member] | Amounts related to TCJA [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	421	442
CERC Corp [Member] | Removal Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	656	637
CERC Corp [Member] | Other Regulatory Assets (Liabilities) [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory liabilities	149	140
CERC Corp [Member] | Pension and Other Postretirement Plans Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	21	22
CERC Corp [Member] | Hurricane Harvey
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	4
CERC Corp [Member] | Hurricane Laura
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	0
CERC Corp [Member] | Amounts related to TCJA [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	$ 5	7
Weighted average recovery period	3 years
CERC Corp [Member] | Relief Program Incremental Costs (COVID-19)
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	$ 17
CERC Corp [Member] | Asset Retirement Obligation Costs [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	107	94
CERC Corp [Member] | Other Regulatory Assets (Liabilities) [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets	35	16
Remaining amounts of regulatory assets for which no return on investment during recovery period is provided	$ 44	48
Remaining weighted average period for which no return on investment during recovery period is provided	27 years
CERC Corp [Member] | Hurricane Harvey [Member]
Schedule of Regulatory Assets and Liabilities [Line Items]
Non-current regulatory assets		$ 4

Regulatory Matters Houston Elec

Regulatory Matters Houston Electric Base Rate Case (Details) - USD ($) $ in Millions	Jan. 23, 2020	Apr. 05, 2019	Dec. 31, 2020	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Non-current regulatory assets			$ 2,094	$ 2,117
Houston Electric [Member]
Public Utilities, General Disclosures [Line Items]
Non-current regulatory assets			$ 848	915
CenterPoint Energy Houston Electric 2019 Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
Revenue increase		$ 194
Houston electric stipulation and settlement agreement [Member]
Public Utilities, General Disclosures [Line Items]
Revenue increase	$ 13
Return on equity	9.40%
Debt capital structure	57.50%
Equity capital structure	42.50%
Unprotected excess deferred income tax	$ 105
Houston electric stipulation and settlement agreement [Member] | Houston Electric [Member]
Public Utilities, General Disclosures [Line Items]
Revenue increase	$ 13
Rate case expense [Member] | Houston electric stipulation and settlement agreement [Member]
Public Utilities, General Disclosures [Line Items]
Non-current regulatory assets				$ 12

Regulatory Matters (Details)

Regulatory Matters (Details) - USD ($) $ in Millions	Dec. 31, 2020	Apr. 13, 2020
Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Incremental Uncollectible Receivables, Regulatory Asset	$ 22
CERC Corp [Member]
Public Utilities, General Disclosures [Line Items]
Incremental Uncollectible Receivables, Regulatory Asset	19
Public Utility Commission of Texas [Member]
Public Utilities, General Disclosures [Line Items]
COVID-19 ERP Regulatory Liability	6
ERCOT Loan, COVID-19 ERP		$ 5
Public Utility Commission of Texas [Member] | Houston Electric [Member]
Public Utilities, General Disclosures [Line Items]
COVID-19 ERP Regulatory Liability	$ 6
ERCOT Loan, COVID-19 ERP		$ 5

Stock-Based Incentive Compens_3

Stock-Based Incentive Compensation Plans and Employee Benefit Plans Stock Based Incentive Compensation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance under long-term incentive plans (in shares)	14,000
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Income tax benefit recognized related to LTIPs	$ 9	$ 7	$ 6
Actual tax benefit realized for tax deductions	$ 5	$ 12	$ 5
CenterPoint Energy [Member] | Common Stock [Member]
Summary of nonvested shares [Roll Forward]
Percentage of investment in common stocks (in hundredths)	8.00%
Performance Awards [Member]
Summary of nonvested shares [Roll Forward]
Nonvested, beginning of period (in shares)	3,332
Granted (in shares)	2,022
Forfeited or cancelled (in shares)	(1,128)
Vested and released to participants (in shares)	(326)
Nonvested, end of period (in shares)	3,900	3,332
Weighted average grant date fair value, nonvested, beginning of period (in dollars per share)	$ 28.36
Weighted average grant date fair values of awards granted (in dollars per share)	23.82	$ 31.16	$ 26.74
Weighted average grant date fair value, forfeited or cancelled (in dollars per share)	26.89
Weighted average grant date fair value, vested and released to participants (in dollars per share)	26.64
Weighted average grant date fair value, nonvested, end of period (in dollars per share)	$ 26.58	$ 28.36
Remaining average contractual life of nonvested shares outstanding (in years)	1 year 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested	$ 51
Total intrinsic value of awards received by participants	9	$ 36	$ 12
Total grant date fair values of performance and stock awards which vested during the period	$ 9	$ 20	$ 9
Stock Awards [Member]
Summary of nonvested shares [Roll Forward]
Nonvested, beginning of period (in shares)	966
Granted (in shares)	980
Forfeited or cancelled (in shares)	(129)
Vested and released to participants (in shares)	(528)
Nonvested, end of period (in shares)	1,289	966
Weighted average grant date fair value, nonvested, beginning of period (in dollars per share)	$ 28.46
Weighted average grant date fair values of awards granted (in dollars per share)	21.53	$ 31.07	$ 26.62
Weighted average grant date fair value, forfeited or cancelled (in dollars per share)	27.67
Weighted average grant date fair value, vested and released to participants (in dollars per share)	22.51
Weighted average grant date fair value, nonvested, end of period (in dollars per share)	$ 25.71	$ 28.46
Remaining average contractual life of nonvested shares outstanding (in years)	1 year 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested	$ 28
Total intrinsic value of awards received by participants	12	$ 15	$ 9
Total grant date fair values of performance and stock awards which vested during the period	12	9	7
Performance and Stock Awards [Member]
Summary of nonvested shares [Roll Forward]
Unrecognized compensation cost related to non-vested performance and stock awards	$ 34
Weighted average period of recognition (in years)	1 year 10 months 24 days
Operation And Maintenance Expense [Member]
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
LTIP compensation expense	$ 38	$ 28	$ 26

Stock-Based Incentive Compens_4

Stock-Based Incentive Compensation Plans and Employee Benefit Plans Pension and Postretirement Benefits (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amounts recognized in balance sheets
Other liabilities-benefit obligations	$ (750)		$ (680)	$ (750)
Interest crediting rate	3.25%		2.25%	3.25%
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net loss			$ (7)	$ (8)
Prior service cost (2)			0	(1)
Other Postretirement Benefits Plan [Member]
Components of net periodic costs [Abstract]
Service cost (1)			2	3	$ 2
Interest cost (2)			11	15	13
Expected return on plan assets (2)			(5)	(5)	(5)
Amortization of prior service cost (2)			(4)	(5)	(5)
Net periodic cost (credit)			$ 4	$ 8	$ 5
Assumptions used to determine net periodic benefit (income) cost
Discount rate			3.25%	3.20%	3.60%
Expected return on plan assets	3.20%	3.95%	3.95%	4.60%	4.55%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year			$ 356	$ 331
Plan obligations assumed in Merger			0	37
Service cost (1)			2	3	$ 2
Interest cost (2)			11	15	13
Participant contributions			6	8
Benefits paid			(22)	(26)
Plan amendment			0	9
Actuarial (gain) loss (1)			13	(21)
Benefit obligation, end of year	$ 356	$ 331	366	356	331
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year			128	114
Employer contributions			10	17
Participant contributions			6	8
Benefits paid			(22)	(26)
Actual investment return			12	15
Fair value of plan assets, end of year	128	$ 114	134	128	$ 114
Funded status of plan
Funded status, end of year	(228)		(232)	(228)
Amounts recognized in balance sheets
Current liabilities-other	(8)		(9)	(8)
Other liabilities-benefit obligations	(220)		(223)	(220)
Net liability, end of year	$ (228)		$ (232)	$ (228)
Discount rate (2)	3.25%		2.50%	3.25%
Expected return on plan assets (3)	3.20%	3.95%	3.95%	4.60%	4.55%
Prescription drug cost trend rate assumed for the next year - Pre-65			7.50%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%		4.50%	4.50%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)	$ (16)		$ (14)	$ (16)
Unrecognized prior service cost	7		7	7
Net amount recognized in accumulated other comprehensive loss (gain)	$ (9)		(7)	(9)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss (gain)			2
Amortization of net loss			0
Prior service cost (2)			0
Total recognized in comprehensive income			2
Total expense recognized in net periodic cost and other comprehensive income			6
Pension Plan [Member]
Components of net periodic costs [Abstract]
Service cost (1)			43	40
Interest cost (2)			75	96
Net periodic cost (credit)			$ 49	$ 93	$ 61
Assumptions used to determine net periodic benefit (income) cost
Discount rate			3.20%	4.35%	3.65%
Expected return on plan assets	5.00%	5.75%	5.75%	6.00%	6.00%
Rate of increase in compensation levels			4.95%	4.60%	4.45%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year			$ 2,453	$ 2,013
Plan obligations assumed in Merger			0	332
Service cost (1)			43	40
Interest cost (2)			75	96
Benefits paid			(207)	(244)
Plan amendment			0	1
Actuarial (gain) loss (1)			143	216
Curtailment			0	(1)
Benefit obligation, end of year	$ 2,453	$ 2,013	2,507	2,453	$ 2,013
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year			2,005	1,516
Plan assets assumed in Merger			0	286
Employer contributions			86	109
Benefits paid			(207)	(244)
Actual investment return			251	338
Fair value of plan assets, end of year	2,005	$ 1,516	2,135	2,005	$ 1,516
Funded status of plan
Funded status, end of year	(448)		(372)	(448)
Amounts recognized in balance sheets
Current liabilities-other	(8)		(8)	(8)
Other liabilities-benefit obligations	(440)		(364)	(440)
Net liability, end of year	$ (448)		$ (372)	$ (448)
Discount rate (2)	3.20%	4.35%	2.45%	3.20%	4.35%
Expected return on plan assets (3)	5.00%	5.75%	5.75%	6.00%	6.00%
Rate of increase in compensation levels	4.95%		5.05%	4.95%
Interest crediting rate	3.25%		2.25%	3.25%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)	$ 105		$ 109	$ 105
Unrecognized prior service cost	0		0	0
Net amount recognized in accumulated other comprehensive loss (gain)	105		109	105
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss (gain)			11
Amortization of net loss			(7)
Prior service cost (2)			0
Total recognized in comprehensive income			4
Total expense recognized in net periodic cost and other comprehensive income			53
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation	2,352		2,427	2,352
Projected benefit obligation	2,385		2,440	2,385
Fair value of plan assets	2,005		2,135	2,005
Accumulated benefit obligation for all defined benefit pension plans	2,420		2,495	2,420
Non-qualified Pension Plan [Member]
Change in plan assets [Rollforward]
Employer contributions			10
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation	68		68	68
Projected benefit obligation	68		68	68
Fair value of plan assets	$ 0		$ 0	$ 0
Minimum [Member] | Other Postretirement Benefits Plan [Member]
Amounts recognized in balance sheets
Health care cost trend rate assumed for the next year	5.50%		5.25%	5.50%
Year that the cost trend rates reach the ultimate trend rate			2028	2028
Maximum [Member] | Other Postretirement Benefits Plan [Member]
Amounts recognized in balance sheets
Health care cost trend rate assumed for the next year	5.75%		19.70%	5.75%
Year that the cost trend rates reach the ultimate trend rate			2029	2029
Common Stock [Member] | CenterPoint Energy [Member]
Pension benefits that have accumulated benefit obligations in excess of plan assets
Number of Common stock held by the savings plan (in shares)			10,150,958
CERC Corp [Member]
Amounts recognized in balance sheets
Other liabilities-benefit obligations	$ (80)		$ (83)	$ (80)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net loss			0	0
Prior service cost (2)			(1)	0
CERC Corp [Member] | Other Postretirement Benefits Plan [Member]
Components of net periodic costs [Abstract]
Service cost (1)			1	1	$ 1
Interest cost (2)			3	5	4
Expected return on plan assets (2)			(1)	(1)	(1)
Amortization of prior service cost (2)			1	1	1
Net periodic cost (credit)			$ 4	$ 6	$ 5
Assumptions used to determine net periodic benefit (income) cost
Discount rate			3.25%	3.20%	3.60%
Expected return on plan assets	2.85%	3.35%	3.35%	4.15%	3.85%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year			$ 102	$ 110
Plan obligations assumed in Merger			0	0
Service cost (1)			1	1	$ 1
Interest cost (2)			3	5	4
Participant contributions			2	4
Benefits paid			(6)	(8)
Plan amendment			0	5
Actuarial (gain) loss (1)			3	15
Benefit obligation, end of year	$ 102	$ 110	105	102	110
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year			27	25
Employer contributions			3	3
Participant contributions			2	4
Benefits paid			(6)	(8)
Actual investment return			2	3
Fair value of plan assets, end of year	27	$ 25	28	27	$ 25
Funded status of plan
Funded status, end of year	(75)		(77)	(75)
Amounts recognized in balance sheets
Current liabilities-other	(3)		(3)	(3)
Other liabilities-benefit obligations	(72)		(74)	(72)
Net liability, end of year	$ (75)		$ (77)	$ (75)
Discount rate (2)	3.25%		2.50%	3.25%
Expected return on plan assets (3)	2.85%	3.35%	3.35%	4.15%	3.85%
Prescription drug cost trend rate assumed for the next year - Pre-65			7.50%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%		4.50%	4.50%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)	$ (12)		$ (12)	$ (12)
Unrecognized prior service cost	7		7	7
Net amount recognized in accumulated other comprehensive loss (gain)	$ (5)		(5)	$ (5)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss (gain)			0
Amortization of net loss			0
Prior service cost (2)			0
Total recognized in comprehensive income			0
Total expense recognized in net periodic cost and other comprehensive income			4
CERC Corp [Member] | Non-qualified Pension Plan [Member]
Change in plan assets [Rollforward]
Employer contributions			$ 0
CERC Corp [Member] | Minimum [Member] | Other Postretirement Benefits Plan [Member]
Amounts recognized in balance sheets
Health care cost trend rate assumed for the next year	5.50%		5.25%	5.50%
Year that the cost trend rates reach the ultimate trend rate			2028	2028
CERC Corp [Member] | Maximum [Member] | Other Postretirement Benefits Plan [Member]
Amounts recognized in balance sheets
Health care cost trend rate assumed for the next year	5.75%		19.70%	5.75%
Year that the cost trend rates reach the ultimate trend rate			2029	2029
Houston Electric [Member]
Amounts recognized in balance sheets
Other liabilities-benefit obligations	$ (75)		$ (75)	$ (75)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net loss			0	0
Prior service cost (2)			0	0
Houston Electric [Member] | Other Postretirement Benefits Plan [Member]
Components of net periodic costs [Abstract]
Service cost (1)			0	1	$ 0
Interest cost (2)			5	7	8
Expected return on plan assets (2)			(4)	(4)	(4)
Amortization of prior service cost (2)			(5)	(6)	(5)
Net periodic cost (credit)			$ (4)	$ (2)	$ (1)
Assumptions used to determine net periodic benefit (income) cost
Discount rate			3.25%	3.20%	3.60%
Expected return on plan assets	3.30%	4.05%	4.05%	4.70%	4.75%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year			$ 162	$ 166
Plan obligations assumed in Merger			0	0
Service cost (1)			0	1	$ 0
Interest cost (2)			5	7	8
Participant contributions			2	2
Benefits paid			(10)	(13)
Plan amendment			0	3
Actuarial (gain) loss (1)			9	(4)
Benefit obligation, end of year	$ 162	$ 166	168	162	166
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year			101	89
Employer contributions			3	10
Participant contributions			2	2
Benefits paid			(10)	(13)
Actual investment return			10	13
Fair value of plan assets, end of year	101	$ 89	106	101	$ 89
Funded status of plan
Funded status, end of year	(61)		(62)	(61)
Amounts recognized in balance sheets
Current liabilities-other	0		0	0
Other liabilities-benefit obligations	(61)		(62)	(61)
Net liability, end of year	$ (61)		$ (62)	$ (61)
Discount rate (2)	3.25%		2.50%	3.25%
Expected return on plan assets (3)	3.30%	4.05%	4.05%	4.70%	4.75%
Prescription drug cost trend rate assumed for the next year - Pre-65			7.50%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%		4.50%	4.50%
Houston Electric [Member] | Non-qualified Pension Plan [Member]
Change in plan assets [Rollforward]
Employer contributions			$ 0
Houston Electric [Member] | Minimum [Member] | Other Postretirement Benefits Plan [Member]
Amounts recognized in balance sheets
Health care cost trend rate assumed for the next year	5.50%		5.25%	5.50%
Year that the cost trend rates reach the ultimate trend rate			2028	2028
Houston Electric [Member] | Maximum [Member] | Other Postretirement Benefits Plan [Member]
Amounts recognized in balance sheets
Health care cost trend rate assumed for the next year	5.75%		19.70%	5.75%
Year that the cost trend rates reach the ultimate trend rate			2029	2029
Operation And Maintenance Expense [Member] | Pension Plan [Member]
Components of net periodic costs [Abstract]
Service cost (1)			$ 43	$ 40	$ 37
Change in benefit obligation [Roll Forward]
Service cost (1)			43	40	37
Other Nonoperating Income (Expense) [Member] | Pension Plan [Member]
Components of net periodic costs [Abstract]
Interest cost (2)			75	96	79
Expected return on plan assets (2)			(112)	(105)	(107)
Amortization of prior service cost (2)			0	9	9
Amortization of net loss (2)			41	52	43
Settlement cost (2) (3)			2	2	0
Curtailment gain (2) (4)			0	(1)	0
Change in benefit obligation [Roll Forward]
Interest cost (2)			$ 75	$ 96	$ 79

Stock-Based Incentive Compens_5

Stock-Based Incentive Compensation Plans and Employee Benefit Plans Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Savings Plan [Abstract]
Defined Contribution Plan, Cost	$ 58	$ 58	$ 43
Postemployment Benefits [Abstract]
Postemployment Benefits, Period Expense	1	2	3
Other Non-Qualified Plans [Abstract]
Benefit expense related to deferred compensation plans	4	$ 4	$ 3
Non-qualified Pension Plan [Member]
Total contributions to the plans during the period	10
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 8
Pension Plan [Member]
Discount Rate	2.45%	3.20%	4.35%
Plan assets, fair value	$ 2,135	$ 2,005	$ 1,516
Obligation To Return Cash Received As Collateral From Securities Lending,	(81)	(61)
Defined Benefits Plan, Fair Value Of Plan Assets, Excluding Investments Measured at Net Asset Value	1,467	1,339
Defined Benefit Plan, Contribution by Employer, Qualified Plan	76
Total contributions to the plans during the period	86	$ 109
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	53
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Pension benefit payments 2020	174
Pension benefit payments 2021	176
Pension benefit payments 2022	176
Pension benefit payments 2023	175
Pension benefit payments 2024	173
Pension benefit payments 2025 - 2029	$ 775
Postretirement Benefits [Member]
Discount Rate	2.50%	3.25%
Plan assets, fair value	$ 134	$ 128	114
Total contributions to the plans during the period	10	17
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	9
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Pension benefit payments 2020	17
Pension benefit payments 2021	18
Pension benefit payments 2022	20
Pension benefit payments 2023	21
Pension benefit payments 2024	21
Pension benefit payments 2025 - 2029	109
Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	631	564
Obligation To Return Cash Received As Collateral From Securities Lending,	(81)	(61)
Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	836	775
Obligation To Return Cash Received As Collateral From Securities Lending,	0	0
Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Obligation To Return Cash Received As Collateral From Securities Lending,	0	0
U.S. Equity [Member] | Pension Plan [Member]
Plan assets, fair value	76	69
U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	76	69
U.S. Equity [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
U.S. Equity [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Cash and Cash Equivalents [Member] | Pension Plan [Member]
Plan assets, fair value	29	(7)
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	29	(7)
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Investment grade or above [Member] | Pension Plan [Member]
Plan assets, fair value	767	699
Investment grade or above [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Investment grade or above [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	767	699
Investment grade or above [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Cash received as collateral from securities [Member] | Pension Plan [Member]
Plan assets, fair value	81	61
Cash received as collateral from securities [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	81	61
Cash received as collateral from securities [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Cash received as collateral from securities [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
U.S. treasuries [Member] | Pension Plan [Member]
Plan assets, fair value	225	232
U.S. treasuries [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	225	232
U.S. treasuries [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
U.S. treasuries [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Mortgage backed securities [Member] | Pension Plan [Member]
Plan assets, fair value	5	8
Mortgage backed securities [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Mortgage backed securities [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	5	8
Mortgage backed securities [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Asset backed securities [Member] | Pension Plan [Member]
Plan assets, fair value	3	3
Asset backed securities [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Asset backed securities [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	3	3
Asset backed securities [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Municipal bonds [Member] | Pension Plan [Member]
Plan assets, fair value	43	44
Municipal bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Municipal bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	43	44
Municipal bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Mutual funds [Member] | Pension Plan [Member]
Plan assets, fair value	301	270
Mutual funds [Member] | Postretirement Benefits [Member]
Plan assets, fair value	$ 134	$ 128
Mutual funds [Member] | International Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	14.00%	31.00%
Mutual funds [Member] | International Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	7.00%	8.00%
Mutual funds [Member] | U.S. Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	55.00%	49.00%
Mutual funds [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	19.00%	21.00%
Mutual funds [Member] | Real Estate Funds [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	5.00%	1.00%
Mutual funds [Member] | Fixed Income Funds [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	27.00%	19.00%
Mutual funds [Member] | Fixed Income Funds [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	74.00%	71.00%
Mutual funds [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	$ 301	$ 270
Mutual funds [Member] | Fair Value, Inputs, Level 1 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	134	128
Mutual funds [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Mutual funds [Member] | Fair Value, Inputs, Level 2 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	0	0
Mutual funds [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Mutual funds [Member] | Fair Value, Inputs, Level 3 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	0	0
International government bonds [Member] | Pension Plan [Member]
Plan assets, fair value	18	21
International government bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
International government bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Plan assets, fair value	18	21
International government bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Plan assets, fair value	0	0
Common Collective Trust Funds [Member] | Pension Plan [Member]
Plan assets, fair value	$ 668	$ 666
Common Collective Trust Funds [Member] | International Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	37.00%	29.00%
Common Collective Trust Funds [Member] | U.S. Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	3.00%	51.00%
Common Collective Trust Funds [Member] | Real Estate Funds [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	1.00%	6.00%
Common Collective Trust Funds [Member] | Fixed Income Funds [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	59.00%	14.00%
Benefit Obligation [Member]
Postemployment Benefits [Abstract]
Postemployment benefit obligations	$ 8	$ 11
Other Non-Qualified Plans [Abstract]
Other non-qualified plans benefit obligations deferred compensation	43	41
Benefit obligations related to split-dollar life insurance arrangements	$ 32	32
Minimum [Member] | U.S. Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	19.00%
Minimum [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	13.00%
Minimum [Member] | International Developed Market Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	8.00%
Minimum [Member] | International Developed Market Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	3.00%
Minimum [Member] | Real Estate Funds [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	3.00%
Minimum [Member] | Fixed Income [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	52.00%
Minimum [Member] | Fixed Income [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	69.00%
Minimum [Member] | Cash and Cash Equivalents [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Minimum [Member] | Cash and Cash Equivalents [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Maximum [Member] | U.S. Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	29.00%
Maximum [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	23.00%
Maximum [Member] | International Developed Market Equity [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	18.00%
Maximum [Member] | International Developed Market Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	13.00%
Maximum [Member] | Real Estate Funds [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	9.00%
Maximum [Member] | Fixed Income [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	62.00%
Maximum [Member] | Fixed Income [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	79.00%
Maximum [Member] | Cash and Cash Equivalents [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	2.00%
Maximum [Member] | Cash and Cash Equivalents [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	2.00%
Common Stock [Member] | CenterPoint Energy [Member]
Savings Plan [Abstract]
Defined Contribution Plan, Maximum Limit Of Account Balance In Company Stock, Percentage	25.00%
Houston Electric [Member]
Savings Plan [Abstract]
Defined Contribution Plan, Cost	$ 18	18	17
Postemployment Benefits [Abstract]
Postemployment Benefits, Period Expense	1	1	4
Other Non-Qualified Plans [Abstract]
Benefit expense related to deferred compensation plans	1	$ 1	1
Houston Electric [Member] | Non-qualified Pension Plan [Member]
Total contributions to the plans during the period	0
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	0
Houston Electric [Member] | Pension Plan [Member]
Defined Benefit Plan, Contribution by Employer, Qualified Plan	0
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 0
Houston Electric [Member] | Postretirement Benefits [Member]
Discount Rate	2.50%	3.25%
Plan assets, fair value	$ 106	$ 101	89
Total contributions to the plans during the period	3	10
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	1
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Pension benefit payments 2020	8
Pension benefit payments 2021	9
Pension benefit payments 2022	9
Pension benefit payments 2023	10
Pension benefit payments 2024	10
Pension benefit payments 2025 - 2029	53
Houston Electric [Member] | Mutual funds [Member] | Postretirement Benefits [Member]
Plan assets, fair value	$ 106	$ 101
Houston Electric [Member] | Mutual funds [Member] | International Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	8.00%	8.00%
Houston Electric [Member] | Mutual funds [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	18.00%	21.00%
Houston Electric [Member] | Mutual funds [Member] | Fixed Income Funds [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	74.00%	71.00%
Houston Electric [Member] | Mutual funds [Member] | Fair Value, Inputs, Level 1 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	$ 106	$ 101
Houston Electric [Member] | Mutual funds [Member] | Fair Value, Inputs, Level 2 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	0	0
Houston Electric [Member] | Mutual funds [Member] | Fair Value, Inputs, Level 3 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	0	0
Houston Electric [Member] | Benefit Obligation [Member]
Postemployment Benefits [Abstract]
Postemployment benefit obligations	3	3
Other Non-Qualified Plans [Abstract]
Other non-qualified plans benefit obligations deferred compensation	7	8
Benefit obligations related to split-dollar life insurance arrangements	$ 1	1
Houston Electric [Member] | Minimum [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	13.00%
Houston Electric [Member] | Minimum [Member] | International Developed Market Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	3.00%
Houston Electric [Member] | Minimum [Member] | Fixed Income [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	69.00%
Houston Electric [Member] | Minimum [Member] | Cash and Cash Equivalents [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Houston Electric [Member] | Maximum [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	23.00%
Houston Electric [Member] | Maximum [Member] | International Developed Market Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	13.00%
Houston Electric [Member] | Maximum [Member] | Fixed Income [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	79.00%
Houston Electric [Member] | Maximum [Member] | Cash and Cash Equivalents [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	2.00%
CERC Corp [Member]
Savings Plan [Abstract]
Defined Contribution Plan, Cost	$ 19	18	18
Postemployment Benefits [Abstract]
Postemployment Benefits, Period Expense	0	1	1
Other Non-Qualified Plans [Abstract]
Benefit expense related to deferred compensation plans	0	$ 0	0
CERC Corp [Member] | Non-qualified Pension Plan [Member]
Total contributions to the plans during the period	0
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	0
CERC Corp [Member] | Pension Plan [Member]
Defined Benefit Plan, Contribution by Employer, Qualified Plan	0
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 0
CERC Corp [Member] | Postretirement Benefits [Member]
Discount Rate	2.50%	3.25%
Plan assets, fair value	$ 28	$ 27	$ 25
Total contributions to the plans during the period	3	3
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	3
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Pension benefit payments 2020	4
Pension benefit payments 2021	5
Pension benefit payments 2022	5
Pension benefit payments 2023	5
Pension benefit payments 2024	6
Pension benefit payments 2025 - 2029	30
CERC Corp [Member] | Mutual funds [Member] | Postretirement Benefits [Member]
Plan assets, fair value	$ 28	$ 27
CERC Corp [Member] | Mutual funds [Member] | International Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	7.00%	7.00%
CERC Corp [Member] | Mutual funds [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	21.00%	24.00%
CERC Corp [Member] | Mutual funds [Member] | Fixed Income Funds [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	72.00%	69.00%
CERC Corp [Member] | Mutual funds [Member] | Fair Value, Inputs, Level 1 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	$ 28	$ 27
CERC Corp [Member] | Mutual funds [Member] | Fair Value, Inputs, Level 2 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	0	0
CERC Corp [Member] | Mutual funds [Member] | Fair Value, Inputs, Level 3 [Member] | Postretirement Benefits [Member]
Plan assets, fair value	0	0
CERC Corp [Member] | Benefit Obligation [Member]
Postemployment Benefits [Abstract]
Postemployment benefit obligations	5	7
Other Non-Qualified Plans [Abstract]
Other non-qualified plans benefit obligations deferred compensation	2	3
Benefit obligations related to split-dollar life insurance arrangements	$ 0	$ 0
CERC Corp [Member] | Minimum [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	15.00%
CERC Corp [Member] | Minimum [Member] | International Developed Market Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	2.00%
CERC Corp [Member] | Minimum [Member] | Fixed Income [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	68.00%
CERC Corp [Member] | Minimum [Member] | Cash and Cash Equivalents [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
CERC Corp [Member] | Maximum [Member] | U.S. Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	25.00%
CERC Corp [Member] | Maximum [Member] | International Developed Market Equity [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	12.00%
CERC Corp [Member] | Maximum [Member] | Fixed Income [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	78.00%
CERC Corp [Member] | Maximum [Member] | Cash and Cash Equivalents [Member] | Postretirement Benefits [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	2.00%

Stock-Based Incentive Compens_6

Stock-Based Incentive Compensation Plans and Employee Benefit Plans Change in Control Agreements and Other Employee Matters (Details)	12 Months Ended
	Dec. 31, 2020salary_severance_benefits
Concentration Risk [Line Items]
Maximum Number Of Times Annual Salary Included In Severance Benefits	3
Workforce Subject to Collective Bargaining Arrangements Expiring in May 2023 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	15.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in May 2021 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	2.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in March 2021 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in April 2025 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	4.00%
Workforce Subject to Collective Bargaining Arrangements Expiring December 2023 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	3.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in December 2025 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	3.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in June 2022 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	4.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in July 2022 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Workforce Subject to Collective Bargaining Arrangements Expiring June 2022, Additional | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	3.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in September 2021 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%
Workforce Subject to Collective Bargaining Arrangements Expiring in October 2021 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%
Workforce Subject to Collective Bargaining Arrangements [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	36.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in May 2023 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	53.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in May 2021 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in March 2021 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in April 2025 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring December 2023 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in December 2025 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in June 2022 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in July 2022 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring June 2022, Additional | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in September 2021 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in October 2021 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
Houston Electric [Member] | Workforce Subject to Collective Bargaining Arrangements [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	53.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in May 2023 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in May 2021 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	3.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in March 2021 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in April 2025 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	12.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring December 2023 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in December 2025 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	7.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in June 2022 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	13.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in July 2022 | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring June 2022, Additional | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in September 2021 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring in October 2021 [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%
CERC Corp [Member] | Workforce Subject to Collective Bargaining Arrangements [Member] | Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	36.00%

Derivative Instruments Derivati

Derivative Instruments Derivatives and Hedging (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Weather Hedge Term	10
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Contract [Member]
Derivative Liability, Notional Amount	$ 84	$ 84

Derivative Instruments Summary

Derivative Instruments Summary of Derivative Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Assets Fair Value	$ 0	$ 0
Derivative Liabilities Fair Value	983	925
Income Statement Impact of Derivative Activity [Abstract]
Gain (loss) on derivative instruments not designated as hedging instruments	(60)	(292)	$ (230)
Derivative, Credit Risk Related Contingent Features [Abstract]
Aggregate fair value of derivatives with credit-risk-related contingent features in a liability position	20	10
Fair value of collateral already posted	7	0
Additional collateral required to be posted if credit risk contingent features triggered (1)	3	0
Not Designated as Hedging Instrument [Member] | Current Liabilities [Member] | Energy Related Derivative [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Assets Fair Value	0	0
Derivative Liabilities Fair Value	3	7
Not Designated as Hedging Instrument [Member] | Current Liabilities [Member] | IDS Derivative [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Assets Fair Value	0	0
Derivative Liabilities Fair Value	953	893
Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member] | Interest Rate Contract [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Assets Fair Value	0	0
Derivative Liabilities Fair Value	20	10
Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member] | Energy Related Derivative [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Assets Fair Value	0	0
Derivative Liabilities Fair Value	7	15
Gains (Losses) in Other Income (Expense) [Member] | Interest Rate Contract [Member]
Income Statement Impact of Derivative Activity [Abstract]
Gain (loss) on derivative instruments not designated as hedging instruments	0	0	2
Gains (Losses) in Other Income (Expense) [Member] | IDS Derivative [Member]
Income Statement Impact of Derivative Activity [Abstract]
Gain (loss) on derivative instruments not designated as hedging instruments	$ (60)	$ (292)	$ (232)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	Apr. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2020
Assets
Total assets		$ 916	$ 874
Liabilities
Total liabilities		983	925
Indexed debt securities derivatives transferred out of level 3				$ 668
Estimated Fair Value of Financial Instruments
Goodwill impairment		185	0	0
Indiana Electric Integrated [Member]
Estimated Fair Value of Financial Instruments
Goodwill impairment		185
Carrying amount [Member]
Estimated Fair Value of Financial Instruments
Long-term Debt, Fair Value		13,401	15,093
Fair value [Member]
Estimated Fair Value of Financial Instruments
Long-term Debt, Fair Value		15,226	16,067
Fair Value, Inputs, Level 1 [Member]
Assets
Total assets		916	874
Liabilities
Total liabilities		0	0
Fair Value, Inputs, Level 2 [Member]
Assets
Total assets		0	0
Liabilities
Total liabilities		983	925
Fair Value, Inputs, Level 3 [Member]
Assets
Total assets		0	0
Liabilities
Total liabilities		0	0
Fair Value, Measurements, Recurring [Member]
Assets
Corporate equities		873	825
Investments, including money market funds (1)		43	49
Fair Value, Measurements, Recurring [Member] | IDS Derivative [Member]
Liabilities
Derivative Liability		953	893
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Liabilities
Derivative Liability		20	10
Fair Value, Measurements, Recurring [Member] | Energy Related Derivative [Member]
Liabilities
Derivative Liability		10	22
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Corporate equities		873	825
Investments, including money market funds (1)		43	49
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | IDS Derivative [Member]
Liabilities
Gross Amounts Recognized		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Contract [Member]
Liabilities
Gross Amounts Recognized		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Energy Related Derivative [Member]
Liabilities
Gross Amounts Recognized		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Corporate equities		0	0
Investments, including money market funds (1)		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | IDS Derivative [Member]
Liabilities
Gross Amounts Recognized		(953)	(893)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Contract [Member]
Liabilities
Gross Amounts Recognized		(20)	(10)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Energy Related Derivative [Member]
Liabilities
Gross Amounts Recognized		(10)	(22)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Corporate equities		0	0
Investments, including money market funds (1)		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | IDS Derivative [Member]
Liabilities
Gross Amounts Recognized		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Contract [Member]
Liabilities
Gross Amounts Recognized		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Energy Related Derivative [Member]
Liabilities
Gross Amounts Recognized		0	0
Houston Electric [Member]
Assets
Total assets		26	32
Houston Electric [Member] | Carrying amount [Member]
Estimated Fair Value of Financial Instruments
Long-term Debt, Fair Value		5,019	4,950
Houston Electric [Member] | Fair value [Member]
Estimated Fair Value of Financial Instruments
Long-term Debt, Fair Value		5,957	5,457
Houston Electric [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Total assets		26	32
Houston Electric [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Total assets		0	0
Houston Electric [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Total assets		0	0
Houston Electric [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Investments, including money market funds (1)		26	32
Houston Electric [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Investments, including money market funds (1)		26	32
Houston Electric [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Investments, including money market funds (1)		0	0
Houston Electric [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Investments, including money market funds (1)		0	0
CERC Corp [Member]
Assets
Total assets		13	13
CERC Corp [Member] | Carrying amount [Member]
Estimated Fair Value of Financial Instruments
Long-term Debt, Fair Value		2,428	2,546
CERC Corp [Member] | Fair value [Member]
Estimated Fair Value of Financial Instruments
Long-term Debt, Fair Value		2,855	2,803
CERC Corp [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Total assets		13	13
CERC Corp [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Total assets		0	0
CERC Corp [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Total assets		0	0
CERC Corp [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Corporate equities		2	2
Investments, including money market funds (1)		11	11
CERC Corp [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Corporate equities		2	2
Investments, including money market funds (1)		11	11
CERC Corp [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Corporate equities		0	0
Investments, including money market funds (1)		0	0
CERC Corp [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Corporate equities		0	0
Investments, including money market funds (1)		0	0
Infrastructure Services Disposal Group [Member]
Estimated Fair Value of Financial Instruments
Goodwill impairment		82
Fair Value Of Disposal Group		864
Energy Services [Member]
Estimated Fair Value of Financial Instruments
Fair Value Of Disposal Group		402,000,000
Enable Midstream Partners [Member]
Estimated Fair Value of Financial Instruments
Equity Method Investment, Other than Temporary Impairment		1,541	0	0
Equity Method Investments, Fair Value Disclosure					$ 848
Goodwill impairment		$ 28	$ 86	$ 0
Common Units [Member] | Enable Midstream Partners [Member]
Estimated Fair Value of Financial Instruments
Percentage Reduction of Dividend or Distribution Amount	50.00%

Unconsolidated Affiliate (Cen_3

Unconsolidated Affiliate (CenterPoint Energy and CERC) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / shares	Feb. 18, 2021	Dec. 31, 2017USD ($)
Enable Units [Abstract]
Preferred units - unconsolidated affiliate	$ 363	$ 363
Percentage of sales that trigger right of first refusal	5.00%
Enable Distributions [Abstract]
Distributions from unconsolidated affiliates	$ 113	261	$ 267
Total distributions received from Enable	229	339	333
Income Statement [Abstract]
Operating revenues	7,418	7,564	6,277
Goodwill impairment	185	0	0
Net income (loss) attributable to Enable common units	(949)	674	333
CenterPoint Energy’s equity in earnings (losses), net	(1,428)	230	307
ASSETS
Current assets	2,920	3,937
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities	4,825	3,978
Enable partners' equity	8,348	8,359	8,058
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
CenterPoint Energy’s equity method investment in Enable	$ 783	2,408
Enable Series A Distribution Rate	0.10
Subsequent Event [Member]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
Enable Series A Distribution Rate				0.085
Common Units [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Enable partners' equity	$ 6	5	5		$ 4
Series A Preferred Units [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Enable partners' equity	2,363	1,740	1,740		0
CERC Corp [Member]
Enable Distributions [Abstract]
Distributions from unconsolidated affiliates	0	0	176
Transaction with Enable [Abstract]
Natural gas expenses, including transportation and storage costs (1)	23
Income Statement [Abstract]
Operating revenues	2,763	3,018	3,031
CenterPoint Energy’s equity in earnings (losses), net	0	0	184
ASSETS
Current assets	707	1,489
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities	726	1,111
Enable partners' equity	2,567	2,641	2,443
CERC Corp [Member] | Common Units [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Enable partners' equity	0	0	0		$ 0
CenterPoint Energy [Member]
Income Statement [Abstract]
Operating revenues	$ 7,418	7,564	6,277
Enable Midstream Partners [Member]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
Share Price | $ / shares	$ 5.26
OGE [Member]
Enable Units [Abstract]
Percentage of sales that trigger right of first refusal	5.00%
Non-utility Investments [Member]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
CenterPoint Energy’s equity method investment in Enable	$ 1
Proliance Holdings LLC [Member]
Income Statement [Abstract]
CenterPoint Energy’s equity in earnings (losses), net	$ 0	1	0
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
CenterPoint Energy’s equity method investment in Enable		$ 2
Enable Midstream Partners [Member]
Enable Partnership Interest [Abstract]
Limited partner ownership interest	53.70%	53.70%
Limited partner ownership interest	100.00%	100.00%
Enable Units [Abstract]
Maximum incentive distribution right	50.00%
Income Statement [Abstract]
Operating revenues	$ 2,463	$ 2,960	3,431
Cost of sales, excluding depreciation and amortization	965	1,279	1,819
Depreciation and amortization	420	433	398
Operating income	465	569	648
Goodwill impairment	28	86	0
Net income (loss) attributable to Enable common units	52	360	485
CenterPoint Energy’s interest	28	193	262
Basis difference amortization (1)	87	47	47
Loss on dilution, net of proportional basis difference recognition	(2)	(11)	(2)
Impairment of CenterPoint Energy’s equity method investment in Enable	(1,541)	0	0
Equity Method Investment's Impairment on an equity method investment	225
CenterPoint Energy’s equity in earnings (losses), net	(1,428)	229	$ 307
ASSETS
Current assets	381	389
Non-current assets	11,348	11,877
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities	582	780
Non-current liabilities	4,052	4,077
Non-controlling interest	26	37
Preferred equity	362	362
Accumulated other comprehensive loss	(6)	(3)
Enable partners' equity	6,713	7,013
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
CenterPoint Energy’s ownership interest in Enable partners’ equity	3,601	3,767
CenterPoint Energy’s basis difference (1)	(2,819)	(1,361)
CenterPoint Energy’s equity method investment in Enable	$ 782	$ 2,406
Equity Method Investment Carrying Value Per Unit | $ / shares	$ 3.34
Enable Midstream Partners [Member] | Common Units [Member]
Enable Distributions [Abstract]
Distribution per share of common units | $ / shares	$ 0.8263	$ 1.2970	$ 1.2720
Distributions from unconsolidated affiliates	$ 193	$ 303	$ 297
Enable Midstream Partners [Member] | Series A Preferred Units [Member]
Enable Distributions [Abstract]
Distribution per share of Series A preferred units | $ / shares	$ 2.5000	$ 2.5000	$ 2.5000
Distributions received from Enable cost method investment	$ 36	$ 36	$ 36
Enable Midstream Partners [Member] | OGE [Member]
Enable Partnership Interest [Abstract]
Limited partner ownership interest	25.50%	25.50%
Enable Midstream Partners [Member] | Public unitholders [Member]
Enable Partnership Interest [Abstract]
Limited partner ownership interest	20.80%	20.80%
Maximum [Member] | Enable Midstream Partners [Member]
Enable Units [Abstract]
Incentive distribution per unit | $ / shares	$ 0.330625
Common Units [Member] | Enable Midstream Partners [Member]
Enable Units [Abstract]
Limited partner interest units held | shares	233,856,623	233,856,623
Limited partner interest units held | shares	435,549,892	435,201,365
Common Units [Member] | Enable Midstream Partners [Member] | OGE [Member]
Enable Units [Abstract]
Limited partner interest units held | shares	110,982,805	110,982,805
Common Units [Member] | Enable Midstream Partners [Member] | Public unitholders [Member]
Enable Units [Abstract]
Limited partner interest units held | shares	90,710,464	90,361,937
Series A Preferred Units [Member] | Enable Midstream Partners [Member]
Enable Units [Abstract]
Preferred units held | shares	14,520,000	14,520,000
Series A Preferred Units [Member] | Enable Midstream Partners [Member] | OGE [Member]
Enable Units [Abstract]
Preferred units held | shares	0	0
Series A Preferred Units [Member] | Enable Midstream Partners [Member] | Public unitholders [Member]
Enable Units [Abstract]
Preferred units held | shares	0	0
Enable Midstream Partners [Member] | CERC Corp [Member]
Transaction with Enable [Abstract]
Accounts Receivable, Related Parties	$ 1	$ 2
Natural Gas Expenses [Member] | Enable Midstream Partners [Member]
Transaction with Enable [Abstract]
Natural gas expenses, including transportation and storage costs (1)	86	86	86
Accounts payable for natural gas purchases from Enable	9	9
Natural Gas Expenses [Member] | Enable Midstream Partners [Member] | CERC Corp [Member]
Transaction with Enable [Abstract]
Natural gas expenses, including transportation and storage costs (1)	86	86	86
Accounts payable for natural gas purchases from Enable	9	9
Transitional Service [Member] | Enable Midstream Partners [Member]
Transaction with Enable [Abstract]
Related Party Transaction, Other Revenues from Transactions with Related Party	0	0	4
Accounts Receivable, Related Parties	1	2
Transitional Service [Member] | Enable Midstream Partners [Member] | CERC Corp [Member]
Transaction with Enable [Abstract]
Related Party Transaction, Other Revenues from Transactions with Related Party	$ 0	$ 0	$ 4
Enable GP, LLC [Member]
Enable Units [Abstract]
Management rights ownership percentage	50.00%
Incentive distribution right	40.00%
Enable GP, LLC [Member] | CenterPoint Energy [Member]
Enable Units [Abstract]
Management rights ownership percentage	50.00%
Incentive distribution right	40.00%
Enable GP, LLC [Member] | OGE [Member]
Enable Units [Abstract]
Management rights ownership percentage	50.00%
Incentive distribution right	60.00%

Indexed Debt Securities (ZENS_3

Indexed Debt Securities (ZENS) and Securities Related to ZENS (CenterPoint Energy) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Indexed Debt Securities [Line Items]
Target Annual Yield On Reference Shares	2.309%
ZENS-Related Securities
ZENS-Related Securities	$ 822,000,000
Proceeds from sale and maturity of marketable securities	0	$ 0	$ (398,000,000)
Gain (loss) on ZENS-Related Securities	49,000,000	282,000,000	(22,000,000)
ZENS-Related Securities	871,000,000	822,000,000
Debt component of ZENS
Debt Component of ZENS	19,000,000
Distribution to ZENS holders	0	0	(398,000,000)
Debt Component of ZENS	15,000,000	19,000,000
Derivative component of ZENS
Derivative Component of ZENS	893,000,000
Distribution to ZENS holders	0	0	(398,000,000)
Loss (gain) on indexed debt securities	60,000,000	292,000,000	232,000,000
Derivative Component of ZENS	$ 953,000,000	$ 893,000,000
AT&T Common [Member]
Indexed Debt Securities [Line Items]
Balance of investment owned (in shares)	10,212,945	10,212,945
Charter Common [Member]
Indexed Debt Securities [Line Items]
Balance of investment owned (in shares)	872,503	872,503
ZENS-Related Securities [Member]
ZENS-Related Securities
ZENS-Related Securities	$ 822,000,000	$ 540,000,000	960,000,000
Proceeds from sale and maturity of marketable securities			(398,000,000)
Gain (loss) on ZENS-Related Securities	49,000,000	282,000,000	(22,000,000)
ZENS-Related Securities	871,000,000	822,000,000	540,000,000
Debt component of ZENS
Accretion of debt component of ZENS	0	0	0
2 % interest paid	0	0	0
Distribution to ZENS holders	0	0	0
Derivative component of ZENS
Distribution to ZENS holders	0	0	0
Loss (gain) on indexed debt securities	0	0	0
Debt Component Of ZENS [Member]
ZENS-Related Securities
Proceeds from sale and maturity of marketable securities			0
Gain (loss) on ZENS-Related Securities	0	0	0
Debt component of ZENS
Debt Component of ZENS	19,000,000	24,000,000	122,000,000
Accretion of debt component of ZENS	17,000,000	17,000,000	21,000,000
2 % interest paid	(16,000,000)	(17,000,000)	(17,000,000)
Distribution to ZENS holders	(5,000,000)	(5,000,000)	(102,000,000)
Debt Component of ZENS	15,000,000	19,000,000	24,000,000
Derivative component of ZENS
Distribution to ZENS holders	(5,000,000)	(5,000,000)	(102,000,000)
Loss (gain) on indexed debt securities	0	0	0
Derivative Component Of ZENS [Member]
ZENS-Related Securities
Proceeds from sale and maturity of marketable securities			0
Gain (loss) on ZENS-Related Securities	0	0	0
Debt component of ZENS
Accretion of debt component of ZENS	0	0	0
2 % interest paid	0	0	0
Distribution to ZENS holders	0	0	(46,000,000)
Derivative component of ZENS
Derivative Component of ZENS	893,000,000	601,000,000	668,000,000
Distribution to ZENS holders	0	0	(46,000,000)
Loss (gain) on indexed debt securities	60,000,000	292,000,000	(21,000,000)
Derivative Component of ZENS	953,000,000	$ 893,000,000	$ 601,000,000
Subordinated Debt ZENS Member
Indexed Debt Securities [Line Items]
Principal amount of debt issued	1,000,000,000
Outstanding debt balance	$ 828,000,000
Subordinated note cash exchangeable percentage of fair value	95.00%
ZENS annual interest rate	2.00%
Contingent principal amount of indexed debt securities issued by CenterPoint Energy in September 1999 and outstanding and exchangeable	$ 56,000,000
The cash exchange amount from referenced shares per $1,000 face amount of individual notes	999
Face amount of each indexed debt security notes issued by CenterPoint Energy in September 1999	$ 1,000
Subordinated Debt ZENS Member | AT&T Common [Member]
Indexed Debt Securities [Line Items]
Number of shares referenced in exchangeable subordinated note	0.7185	0.7185
Subordinated Debt ZENS Member | Charter Common [Member]
Indexed Debt Securities [Line Items]
Number of shares referenced in exchangeable subordinated note	0.061382	0.061382

Equity (CenterPoint Energy) (De

Equity (CenterPoint Energy) (Details) $ / shares in Units, $ in Millions	Dec. 10, 2020USD ($)$ / shares	Oct. 29, 2020USD ($)$ / shares	Jul. 29, 2020USD ($)$ / shares	May 06, 2020USD ($)$ / sharesshares	Apr. 24, 2020USD ($)$ / shares	Apr. 01, 2020$ / shares	Feb. 03, 2020USD ($)$ / shares	Oct. 17, 2019USD ($)$ / shares	Jul. 31, 2019USD ($)$ / shares	Apr. 25, 2019USD ($)$ / shares	Dec. 12, 2018USD ($)$ / shares	Oct. 23, 2018USD ($)$ / shares	Oct. 01, 2018USD ($)$ / sharesshares	Aug. 22, 2018USD ($)$ / sharesshares	Jul. 26, 2018USD ($)$ / shares	Apr. 26, 2018USD ($)$ / shares	Dec. 31, 2020USD ($)day$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Nov. 27, 2020shares	Nov. 06, 2020shares	Nov. 02, 2020shares	Jun. 01, 2020shares
Income allocated to preferred shareholders																	$ 144	$ 117	$ 35
Proceeds from the issuance of Series A Preferred Stock, net																	723	0	1,740
Proceeds from issuance of common stock																	672	0	1,844
Amortization of Beneficial Conversion Feature																	32	0	0
Income allocated to preferred shareholders																	176	117	35
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance																	(98)	(108)
Reclassified to earnings																	0	1	0
Other comprehensive loss from unconsolidated affiliates																	(2)	(1)
Prior service cost (2)																	0	1
Actuarial losses (2)																	7	8
Reclassification of net deferred loss from cash flow hedges (3)																	19	0
Tax benefit (expense)																	(4)	(3)
Net current period other comprehensive income (loss)																	8	10	(25)
Ending Balance																	(90)	(98)	$ (108)
Common Stock, Capital Shares Reserved for Future Issuance | shares																							58,051,121
Enable Midstream Partners [Member]
Undistributed earnings from equity method investments included in retained earnings																	$ 0	$ 0
Common Stock [Member]
Declaration Date	Dec. 10, 2020	Oct. 29, 2020						Oct. 17, 2019	Jul. 31, 2019	Apr. 25, 2019	Dec. 12, 2018	Oct. 23, 2018			Jul. 26, 2018	Apr. 26, 2018
Record Date	Feb. 18, 2021	Nov. 19, 2020						Nov. 21, 2019	Aug. 15, 2019	May 16, 2019	Feb. 21, 2019	Nov. 15, 2018			Aug. 16, 2018	May 17, 2018
Payment Date	Mar. 11, 2021	Dec. 10, 2020						Dec. 12, 2019	Sep. 12, 2019	Jun. 13, 2019	Mar. 14, 2019	Dec. 13, 2018			Sep. 13, 2018	Jun. 14, 2018
Dividends declared per share | $ / shares	$ 0.1600	$ 0.1500	$ 0.1500		$ 0.1500		$ 0.2900	$ 0.2875	$ 0.2875	$ 0.2875	$ 0.2875	$ 0.2775			$ 0.2775	$ 0.2775	$ 0.9000	$ 0.8625	$ 1.1200
Dividends declared	$ 88	$ 83						$ 144	$ 145	$ 144	$ 144	$ 139			$ 120	$ 120	$ 480	$ 433	$ 523
Stock issued (in shares) | shares				41,977,612
Common stock issued per share price | $ / shares				$ 16.08
Proceeds from issuance of common stock				$ 673
SharesIssuedUponConversion | shares																				3,064	6,531,677
Common Stock [Member] | Previous Dividend or Distribution [Member]
Dividends declared per share | $ / shares						$ 0.2900
Common Stock [Member] | Revised Dividend or Distribution [Member]
Dividends declared per share | $ / shares						$ 0.1500
Common Stock [Member] | First Quarter 2020 [Member]
Declaration Date							Feb. 3, 2020
Record Date							Feb. 20, 2020
Payment Date							Mar. 12, 2020
Dividends declared							$ 145
Common Stock [Member] | Second Quarter 2020 [Member]
Declaration Date					Apr. 24, 2020
Record Date					May 21, 2020
Payment Date					Jun. 11, 2020
Dividends declared					$ 82
Common Stock [Member] | Third Quarter 2020 [Member]
Declaration Date			Jul. 29, 2020
Record Date			Aug. 20, 2020
Payment Date			Sep. 10, 2020
Dividends declared			$ 82
Series A Preferred Stock [Member]
Declaration Date									Jul. 31, 2019		Dec. 12, 2018
Record Date									Aug. 15, 2019		Feb. 15, 2019
Payment Date									Sep. 3, 2019		Mar. 1, 2019
Dividends declared per share | $ / shares	$ 30.6250		$ 30.6250				$ 30.6250		$ 30.6250		$ 32.1563						$ 91.8750	$ 30.6250	$ 32.1563
Dividends declared									$ 24		$ 26						$ 73	$ 24	$ 26
Income allocated to preferred shareholders																	$ 49	$ 49	$ 18
Preferred stock par value (in dollars per share) | $ / shares																	$ 0.01	$ 0.01	$ 0.01
Preferred stock liquidation preference														$ 800			$ 800	$ 800
Preferred stock liquidation preference (per share) | $ / shares														$ 1,000			$ 1,000
Preferred stock convertible threshold (in days) | day																	120
Proceeds from the issuance of Series B Preferred Stock, net														$ 790
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred Stock, Shares Issued | shares														800,000
Preferred stock dividend rate																	6.125%
Preferred stock redemption price (per share) | $ / shares																	$ 1,000
Series A Preferred Stock [Member] | First Quarter 2020 [Member]
Declaration Date							Feb. 3, 2020
Record Date							Feb. 14, 2020
Payment Date							Mar. 2, 2020
Dividends declared							$ 25
Series A Preferred Stock [Member] | Third Quarter 2020 [Member]
Declaration Date	Dec. 10, 2020		Jul. 29, 2020
Record Date	Feb. 15, 2021		Aug. 14, 2020
Payment Date	Mar. 1, 2021		Sep. 1, 2020
Dividends declared	$ 24		$ 24
Series B Preferred Stock [Member]
Declaration Date	Dec. 10, 2020	Oct. 29, 2020						Oct. 17, 2019	Jul. 31, 2019	Apr. 25, 2019	Dec. 12, 2018	Oct. 23, 2018
Record Date	Feb. 15, 2021	Nov. 13, 2020						Nov. 15, 2019	Aug. 15, 2019	May 15, 2019	Feb. 15, 2019	Nov. 15, 2018
Payment Date	Mar. 1, 2021	Dec. 1, 2020						Dec. 2, 2019	Sep. 3, 2019	Jun. 3, 2019	Mar. 1, 2019	Dec. 1, 2018
Dividends declared per share | $ / shares	$ 17.5000	$ 17.5000						$ 17.5000	$ 17.5000	$ 17.5000	$ 17.5000	$ 11.6667						$ 52.5000	$ 29.1667
Dividends declared	$ 17	$ 17						$ 17	$ 17	$ 17	$ 17	$ 11					$ 85	$ 51	$ 28
Preferred Stock, Dividends, Per Share, Cash Paid | $ / shares																	$ 87.5000
Income allocated to preferred shareholders																	$ 68	$ 68	$ 17
Stock issued (in shares) | shares													2,550,000
Preferred stock par value (in dollars per share) | $ / shares																	$ 0.01	$ 0.01	$ 0.01
Preferred stock liquidation preference													$ 978				$ 977	$ 977
Preferred stock liquidation preference (per share) | $ / shares													$ 1,000				$ 1,000
Proceeds from the issuance of Series B Preferred Stock, net													$ 950
Preferred Stock, Convertible, Conversion Price | $ / shares																	$ 1,000
Preferred stock threshold consecutive calendar days | day																	20
PreferredStockSharesToBeConvertedToCommon | shares																				2,000
Income allocated to preferred shareholders																	$ 144	117	$ 35
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred stock dividend rate																	7.00%
Series B Preferred Stock [Member] | Minimum [Member]
Conversion rate per share | shares																	30.5820
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred Stock, Convertible, Stock Price Trigger | $ / shares																	$ 27.2494
Series B Preferred Stock [Member] | Maximum [Member]
Conversion rate per share | shares																	36.6980
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred Stock, Convertible, Stock Price Trigger | $ / shares																	$ 32.6990
Series B Preferred Stock [Member] | First Quarter 2020 [Member]
Declaration Date					Apr. 24, 2020		Feb. 3, 2020
Record Date							Feb. 14, 2020
Payment Date							Mar. 2, 2020
Dividends declared per share | $ / shares							$ 17.5000
Dividends declared							$ 17
Series B Preferred Stock [Member] | Second Quarter 2020 [Member]
Record Date					May 15, 2020
Payment Date					Jun. 1, 2020
Dividends declared per share | $ / shares					$ 17.5000
Dividends declared					$ 17
Series B Preferred Stock [Member] | Third Quarter 2020 [Member]
Declaration Date			Jul. 29, 2020
Record Date			Aug. 14, 2020
Payment Date			Sep. 1, 2020
Dividends declared per share | $ / shares			$ 17.5000
Dividends declared			$ 17
Depositary Share [Member]
Stock issued (in shares) | shares													19,550,000
Depositary share par value (in dollars per depositary share) | $ / shares													$ 50				$ 50
Number of depositary shares eligible for conversion (in shares) | shares																	20
Depositary Share [Member] | Minimum [Member]
Conversion rate per share | shares																	1.5291
Depositary Share [Member] | Maximum [Member]
Conversion rate per share | shares																	1.8349
Series C Preferred Stock [Member]
Declaration Date	Dec. 10, 2020	Oct. 29, 2020
Record Date	Feb. 18, 2021	Nov. 19, 2020
Payment Date	Mar. 11, 2021	Dec. 10, 2020
Dividends declared per share | $ / shares																	$ 0.6100
Dividends declared	$ 7	$ 6															$ 27
Preferred Stock, Dividends, Per Share, Cash Paid | $ / shares	$ 0.1600	$ 0.1500
Income allocated to preferred shareholders																	$ 27	$ 0	$ 0
Preferred stock par value (in dollars per share) | $ / shares																	$ 0.01	$ 0.01	$ 0.01
Preferred stock liquidation preference																	$ 625
Preferred stock liquidation preference (per share) | $ / shares				$ 1,000
Proceeds from the issuance of Series B Preferred Stock, net				$ 724
Conversion rate per share | shares				47,354,670
Preferred Stock, Convertible, Conversion Price | $ / shares				$ 15.31
Number of depositary shares eligible for conversion (in shares) | shares																	0	0	0
PreferredStockSharesToBeConvertedToCommon | shares																						100,000
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred Stock, Shares Issued | shares				725,000
Preferred Stock, Convertible, Conversion Limit				4.90%
Preferred Stock, Convertible, Percent Outstanding Shares To Amend				66 2/3%
Series C Preferred Stock [Member] | Second Quarter 2020 [Member]
Declaration Date					Apr. 24, 2020
Record Date					May 21, 2020
Payment Date					Jun. 11, 2020
Dividends declared					$ 7
Preferred Stock, Dividends, Per Share, Cash Paid | $ / shares					$ 0.1500
Series C Preferred Stock [Member] | Third Quarter 2020 [Member]
Declaration Date			Jul. 29, 2020
Record Date			Aug. 20, 2020
Payment Date			Sep. 10, 2020
Dividends declared			$ 7
Preferred Stock, Dividends, Per Share, Cash Paid | $ / shares			$ 0.1500
Series B [Member] | Maximum [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred Stock, Convertible, Stock Price Trigger | $ / shares																	$ 32.6990
120 Days After Conclusion of Review or Appeal [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred stock redemption price (per share) | $ / shares																	$ 1,020
120 Days After Conclusion of Review or Appeal [Member] | Series A Preferred Stock [Member]
Preferred stock redemption percentage liquidation value																	102.00%
London Interbank Offered Rate (LIBOR) [Member] | Series A Preferred Stock [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Preferred Stock, Dividend Payment Rate, Variable																	3.270
Interest Rate Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans																	$ 0	$ (3)
Deferred loss from interest rate derivatives (1)																	0	(3)
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Gain (loss) reclassified from accumulated OCI into income																	0	1
Houston Electric [Member]
Amortization of Beneficial Conversion Feature																	0	0	$ 0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance																	(15)	(14)
Reclassified to earnings																	0	0
Other comprehensive loss from unconsolidated affiliates																	0	0
Prior service cost (2)																	0	0
Actuarial losses (2)																	0	0
Reclassification of net deferred loss from cash flow hedges (3)																	19	0
Tax benefit (expense)																	(4)	0
Net current period other comprehensive income (loss)																	15	(1)	(14)
Ending Balance																	0	(15)	(14)
Houston Electric [Member] | Interest Rate Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans																	0	(1)
Deferred loss from interest rate derivatives (1)																	0	(1)
CERC Corp [Member]
Amortization of Beneficial Conversion Feature																	0	0	0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance																	10	5
Reclassified to earnings																	0	0
Other comprehensive loss from unconsolidated affiliates																	0	0
Prior service cost (2)																	1	0
Actuarial losses (2)																	0	0
Reclassification of net deferred loss from cash flow hedges (3)																	0	0
Tax benefit (expense)																	(1)	(2)
Net current period other comprehensive income (loss)																	0	5	0
Ending Balance																	10	10	$ 5
CERC Corp [Member] | Interest Rate Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans																	0	0
Deferred loss from interest rate derivatives (1)																	0	0
Pension and Other Postretirement Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans																	(12)	7
Deferred loss from interest rate derivatives (1)																	(12)	7
Pension and Other Postretirement Plans [Member] | Houston Electric [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans																	0	0
Deferred loss from interest rate derivatives (1)																	0	0
Pension and Other Postretirement Plans [Member] | CERC Corp [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans																	0	7
Deferred loss from interest rate derivatives (1)																	$ 0	$ 7

Short Term Borrowings and Lon_3

Short Term Borrowings and Long Term Debt Schedule of Debt (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)day	Dec. 31, 2019USD ($)
Long-term debt:
Unamortized Discount (Premium), Net	$ 6	$ 7
Long-term Debt	11,521	14,244
Debt, Current	1,919	868
Long-term Debt, Term	$ 11,521	14,244
Number of days until commercial paper maturity | day	60
CERC Corp [Member]
Long-term debt:
Current	$ 0
Unamortized Discount (Premium), Net	4	11
Long-term Debt	2,428	2,546
Debt, Current	24	0
Long-term Debt, Term	$ 2,428	2,546
Number of days until commercial paper maturity | day	30
Houston Electric [Member]
Long-term debt:
Unamortized Discount (Premium), Net	$ 14	15
Long-term Debt	4,406	4,719
Debt, Current	613	231
Long-term Debt, Term	4,406	4,719
ZENS due 2029 (2)
Long-term debt:
Long-Term	0	0
Current	15	19
Principal amount of debt issued	$ 1,000
Debt instrument interest rate	2.00%
CenterPoint Energy senior notes 2.50% to 4.25% due 2021 to 2049 (3)
Long-term debt:
Long-Term	$ (2,700)	(3,200)
Current	500	0
Variable rate term loan [Member]
Long-term debt:
Long-Term	0	(1,000)
Current	700	0
Bonds Pollution Control Due Range 1 [Member]
Long-term debt:
Long-Term	(68)	(68)
Current	0	0
Commercial paper (4)
Long-term debt:
Long-Term	(1,078)	(1,633)
Current	0	0
Commercial paper (4) | CERC Corp [Member]
Long-term debt:
Long-Term	(347)	(377)
Current	0	0
First mortgage bonds 9.15% due 2021 | Houston Electric [Member]
Long-term debt:
Long-Term	0	(102)
Current	$ 102	0
Debt instrument interest rate	9.15%
Amount of debt secured by general mortgage bonds	$ 102
General mortgage bonds 1.85% to 6.95% due 2021 to 2048 | Houston Electric [Member]
Long-term debt:
Long-Term	(3,912)	(3,912)
Current	300	0
Amount of debt secured by general mortgage bonds	$ 4,000
General mortgage bonds 1.85% to 6.95% due 2021 to 2048 | Minimum [Member] | Houston Electric [Member]
Long-term debt:
Debt instrument interest rate	1.85%
General mortgage bonds 1.85% to 6.95% due 2021 to 2048 | Maximum [Member] | Houston Electric [Member]
Long-term debt:
Debt instrument interest rate	6.95%
System restoration bonds 4.243% due 2022 | Houston Electric [Member]
Long-term debt:
Long-Term	$ (69)	(134)
Current	$ 66	62
Debt instrument interest rate	4.243%
Transition bonds 5.234% due 2020 | Houston Electric [Member]
Long-term debt:
Long-Term	$ 0	0
Current	$ 0	29
Debt instrument interest rate	5.234%
Transition bonds 2.161% to 3.028% due 2020 to 2024 | Houston Electric [Member]
Long-term debt:
Long-Term	$ (467)	(613)
Current	$ 145	140
Transition bonds 2.161% to 3.028% due 2020 to 2024 | Maximum [Member] | Houston Electric [Member]
Long-term debt:
Debt instrument interest rate	3.028%
Senior notes 3.55% to 6.625% due 2021 to 2047 | CERC Corp [Member]
Long-term debt:
Long-Term	$ (2,100)	(2,193)
Current	$ 0	0
Senior notes 3.55% to 6.625% due 2021 to 2047 | Minimum [Member] | CERC Corp [Member]
Long-term debt:
Debt instrument interest rate	1.75%
Senior notes 3.55% to 6.625% due 2021 to 2047 | Maximum [Member] | CERC Corp [Member]
Long-term debt:
Debt instrument interest rate	6.625%
Other Debt
Long-term debt:
Long-Term	$ (6)	(18)
Current	12	18
Unamortized Debt
Long-term debt:
Unamortized Issuance Costs	(17)	(22)
Unamortized Debt | CERC Corp [Member]
Long-term debt:
Long-Term	(15)	(13)
Unamortized Debt | Houston Electric [Member]
Long-term debt:
Unamortized Issuance Costs	(28)	$ (27)
Parent Company [Member] | Bonds Pollution Control Due Range 1 [Member]
Long-term debt:
Long-Term	$ (68)

Short Term Borrowings and Lon_4

Short Term Borrowings and Long Term Debt Long-term Debt (Details)	Feb. 04, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2020USD ($)day	Feb. 03, 2021USD ($)	Oct. 01, 2020USD ($)	Jun. 02, 2020USD ($)	Dec. 31, 2019USD ($)
Line of Credit Facility [Abstract]
Size of credit facility			$ 4,900,000,000	$ 4,900,000,000
Number of days until commercial paper maturity | day				60
Unamortized Discount (Premium), Net			6,000,000	$ 6,000,000				$ 7,000,000
Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract]
Debt, Current			1,919,000,000	1,919,000,000				868,000,000
Variable rate term loan [Member]
Line of Credit Facility [Abstract]
Long-Term			0	0				1,000,000,000
Current			700,000,000	700,000,000				0
Commercial paper (4)
Line of Credit Facility [Abstract]
Long-Term			1,078,000,000	1,078,000,000				1,633,000,000
Current			0	0				0
Bonds Pollution Control Due Range 1 [Member]
Line of Credit Facility [Abstract]
Long-Term			68,000,000	68,000,000				68,000,000
Current			0	0				0
Securitization Bonds [Member]
Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract]
2021			211,000,000	211,000,000
2022			219,000,000	219,000,000
2023			156,000,000	156,000,000
2024			162,000,000	162,000,000
2025			0	0
Long term Debt Excluding ZENS [Member]
Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract]
2021			1,868,000,000	1,868,000,000
2022			2,542,000,000	2,542,000,000
2023			713,000,000	713,000,000
2024			1,184,000,000	1,184,000,000
2025			51,000,000	51,000,000
SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055
Line of Credit Facility [Abstract]
Long-Term			293,000,000	293,000,000				293,000,000
Current			0	0				0
Other Debt
Line of Credit Facility [Abstract]
Long-Term			6,000,000	6,000,000				18,000,000
Current			12,000,000	12,000,000				18,000,000
Senior Notes
Line of Credit Facility [Abstract]
Long-Term			2,700,000,000	2,700,000,000				3,200,000,000
Current			500,000,000	500,000,000				0
Houston Electric [Member]
Line of Credit Facility [Abstract]
Size of credit facility			300,000,000	300,000,000
Additional first mortgage bonds and general mortgage bonds that could be issued			$ 4,300,000,000	$ 4,300,000,000
Percentage of property additions			70.00%	70.00%
Unamortized Discount (Premium), Net			$ 14,000,000	$ 14,000,000				15,000,000
Debt, Capital Ratio				67.50%
Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract]
2021			613,000,000	$ 613,000,000
2022			519,000,000	519,000,000
2023			356,000,000	356,000,000
2024			162,000,000	162,000,000
2025			0	0
Restoration Costs				100,000,000
Debt, Current			$ 613,000,000	$ 613,000,000				231,000,000
Houston Electric [Member] | First mortgage bonds 9.15% due 2021
Long-term debt:
Debt instrument interest rate			9.15%	9.15%
Line of Credit Facility [Abstract]
Secured debt amount with asset liens			$ 102,000,000	$ 102,000,000
Replacement fund requirements to be satisfied in 2018			317,000,000	317,000,000
Sinking fund requirements to be satisfied in 2018			1,600,000	1,600,000
Long-Term			0	0				102,000,000
Current			102,000,000	102,000,000				0
Houston Electric [Member] | General mortgage bonds 1.85% to 6.95% due 2021 to 2048
Line of Credit Facility [Abstract]
Secured debt amount with asset liens			4,000,000,000	4,000,000,000
Long-Term			3,912,000,000	3,912,000,000				3,912,000,000
Current			300,000,000	300,000,000				0
Houston Electric [Member] | General Mortgage Bonds Due 2050 [Member]
Long-term debt:
Debt instrument interest rate							2.90%
Principal amount of debt issued							$ 300,000,000
Long-term Debt, Gross							$ 296,000,000
CERC Corp [Member]
Line of Credit Facility [Abstract]
Size of credit facility			900,000,000	$ 900,000,000
Number of days until commercial paper maturity | day				30
Current			0	$ 0
Unamortized Discount (Premium), Net			4,000,000	4,000,000				11,000,000
Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract]
2021			0	0
2022			347,000,000	347,000,000
2023			300,000,000	300,000,000
2024			0	0
2025			0	0
Debt, Current			24,000,000	24,000,000				0
CERC Corp [Member] | Commercial paper (4)
Line of Credit Facility [Abstract]
Long-Term			347,000,000	347,000,000				377,000,000
Current			0	0				0
CERC Corp [Member] | Senior notes 3.55% to 6.625% due 2021 to 2047
Line of Credit Facility [Abstract]
Long-Term			2,100,000,000	2,100,000,000				2,193,000,000
Current			0	0				0
VCC [Member] | Variable rate term loan [Member]
Line of Credit Facility [Abstract]
Long-Term			0	0				0
Repayments of Debt				200,000,000
Current			0	$ 0				200,000,000
VUHI [Member]
Line of Credit Facility [Abstract]
Number of days until commercial paper maturity | day				30
VUHI [Member] | Variable rate term loan [Member]
Line of Credit Facility [Abstract]
Long-Term			0	$ 0				0
Repayments of Debt				300,000,000
Current			0	0				300,000,000
VUHI [Member] | Commercial paper (4)
Line of Credit Facility [Abstract]
Long-Term			92,000,000	92,000,000				268,000,000
Current			$ 0	$ 0				0
VUHI [Member] | Senior Notes [Member]
Long-term debt:
Debt instrument interest rate			6.28%	6.28%
Line of Credit Facility [Abstract]
Repayments of Debt				$ 100,000,000
VUHI [Member] | Senior notes 3.55% to 6.625% due 2021 to 2047
Line of Credit Facility [Abstract]
Long-Term			$ 377,000,000	377,000,000				432,000,000
Current			$ 55,000,000	$ 55,000,000				100,000,000
CenterPoint Energy [Member]
Line of Credit Facility [Abstract]
Number of days until commercial paper maturity | day				60
Debt, Capital Ratio				65.00%
CenterPoint Energy [Member] | Variable rate term loan [Member]
Long-term debt:
Debt instrument interest rate			0.865%	0.865%
Principal amount of debt issued			$ 1,000,000,000	$ 1,000,000,000
Line of Credit Facility [Abstract]
Repayments of Debt				$ 300,000,000
CenterPoint Energy [Member] | Bonds Pollution Control Due Range 1 [Member]
Long-term debt:
Debt instrument interest rate			5.125%	5.125%
CenterPoint Energy [Member] | 3.75% Senior notes [Member]
Long-term debt:
Debt instrument interest rate			3.85%	3.85%
Long-term Debt, Gross			$ 500,000,000	$ 500,000,000
Line of Credit Facility [Abstract]
Repayments of Debt			250,000,000
Make-Whole Amount				26,000,000
SIGECO [Member]
Long-term debt:
Long-term Debt, Gross			293,000,000	293,000,000
Additional Debt Issueable			$ 1,300,000,000	$ 1,300,000,000
Line of Credit Facility [Abstract]
Percentage of property additions			60.00%	60.00%
IGC | Senior Notes [Member]
Line of Credit Facility [Abstract]
Long-Term			$ 96,000,000	$ 96,000,000				96,000,000
Current			0	0				0
CERC Senior notes 4.50% due 2021 [Member] | CERC Corp [Member]
Long-term debt:
Principal amount of debt issued			$ 593,000,000	$ 593,000,000
Line of Credit Facility [Abstract]
Debt Instrument, Redemption Price, Percentage		100.00%
CERC Senior notes 4.50% due 2021 [Member] | CERC Corp [Member] | Senior Notes [Member]
Long-term debt:
Debt instrument interest rate			4.50%	4.50%		4.50%
CERC Senior notes 1.75% due 2030 [Member] | CERC Corp [Member] | Senior Notes [Member]
Long-term debt:
Debt instrument interest rate						1.75%
Principal amount of debt issued						$ 500,000,000
Long-term Debt, Gross						$ 495,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 0	$ 0				0
Revolving Credit Facility [Member] | Houston Electric [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			0	0				0
Revolving Credit Facility [Member] | CERC Corp [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 0	$ 0				0
Line of Credit [Member] | Houston Electric [Member]
Line of Credit Facility [Abstract]
Percentage on limitation of debt to total capitalization under covenant (in hundredths)				65.00%
Ratio of indebtedness to net capital			0.531	0.531
Line of Credit [Member] | CERC Corp [Member]
Line of Credit Facility [Abstract]
Percentage on limitation of debt to total capitalization under covenant (in hundredths)				65.00%
Ratio of indebtedness to net capital			0.489	0.489
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Houston Electric [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR				1.25%
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | CERC Corp [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR				1.125%
Letter of Credit [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 11,000,000	$ 11,000,000				7,000,000
Letter of Credit [Member] | Houston Electric [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			0	0				0
Letter of Credit [Member] | CERC Corp [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			0	0				1,000,000
Commercial paper (4)
Line of Credit Facility [Abstract]
Long-term Line of Credit			1,517,000,000	1,517,000,000				2,278,000,000
Commercial paper (4) | Houston Electric [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 0	$ 0				0
Debt, Weighted Average Interest Rate			0.00%	0.00%
Commercial paper (4) | CERC Corp [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 347,000,000	$ 347,000,000				$ 377,000,000
Debt, Weighted Average Interest Rate			0.23%	0.23%				1.94%
Subsequent Event [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit	$ 2,400,000,000				$ 3,300,000,000
Subsequent Event [Member] | London Interbank Offered Rate (LIBOR) [Member] | Houston Electric [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR	1.375%
Subsequent Event [Member] | London Interbank Offered Rate (LIBOR) [Member] | CERC Corp [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR	1.25%
Subsequent Event [Member] | London Interbank Offered Rate (LIBOR) [Member] | VUHI [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR	1.25%
Subsequent Event [Member] | London Interbank Offered Rate (LIBOR) [Member] | CenterPoint Energy [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR	1.625%
SIGECO [Member] | First Mortgage [Member]
Long-term debt:
Principal amount of debt issued			$ 38,000,000	$ 38,000,000
SIGECO [Member] | SIGECO 2020 First Mortgage Bonds Remarketing, 0.875%, Series 2015 [Member] | First Mortgage [Member]
Long-term debt:
Debt instrument interest rate		0.875%
Debt Instrument, Initial Interest Rate, Stated Percentage		2.375%
SIGECO [Member] | Environmental Improvement Revenue Bonds, Warrick County, 0.875%, Series 2015 [Member] | First Mortgage [Member]
Long-term debt:
Principal amount of debt issued		$ 15,000,000
SIGECO [Member] | Environmental Improvement Revenue Bonds, Mount Vernon, 0.875%, Series 2015 [Member] | First Mortgage [Member]
Long-term debt:
Principal amount of debt issued		$ 23,000,000
SIGECO [Member] | Letter of Credit [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			1,000,000	1,000,000
Parent Company [Member]
Line of Credit Facility [Abstract]
Size of credit facility			3,300,000,000	3,300,000,000
Parent Company [Member] | Bonds Pollution Control Due Range 1 [Member]
Line of Credit Facility [Abstract]
Long-Term			68,000,000	68,000,000
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 0	$ 0				$ 0
Parent Company [Member] | Line of Credit [Member]
Line of Credit Facility [Abstract]
Percentage on limitation of debt to total capitalization under covenant (in hundredths)				65.00%
Ratio of indebtedness to net capital			0.539	0.539
Percentage on limitation of debt to total capitalization under covenant amended (in hundredths)				70.00%
System restoration costs threshold for increase in permitted debt to EBITDA covenant ratio				$ 100,000,000
Consecutive period for system restoration costs to exceed $100 million (in months)				12
Parent Company [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR				1.50%
Parent Company [Member] | Letter of Credit [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 11,000,000	$ 11,000,000				6,000,000
Parent Company [Member] | Commercial paper (4)
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 1,078,000,000	$ 1,078,000,000				$ 1,633,000,000
Debt, Weighted Average Interest Rate			0.23%	0.23%				1.95%
VUHI [Member]
Line of Credit Facility [Abstract]
Size of credit facility			$ 400,000,000	$ 400,000,000
Credit facility swing line sublimit			10,000,000	10,000,000
Letters of credit swing line sublimit			20,000,000	20,000,000
VUHI [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 0	$ 0				$ 0
VUHI [Member] | Line of Credit [Member]
Line of Credit Facility [Abstract]
Percentage on limitation of debt to total capitalization under covenant (in hundredths)				65.00%
Ratio of indebtedness to net capital			0.497	0.497
VUHI [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Abstract]
Basis spread on LIBOR				1.125%
VUHI [Member] | Letter of Credit [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 0	$ 0				0
VUHI [Member] | Commercial paper (4)
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 92,000,000	$ 92,000,000				$ 268,000,000
Debt, Weighted Average Interest Rate			0.22%	0.22%				2.08%
VCC [Member] | Variable rate term loan [Member]
Long-term debt:
Principal amount of debt issued			$ 200,000,000	$ 200,000,000
Minimum [Member] | Houston Electric [Member] | General mortgage bonds 1.85% to 6.95% due 2021 to 2048
Long-term debt:
Debt instrument interest rate			1.85%	1.85%
Minimum [Member] | CERC Corp [Member] | Senior notes 3.55% to 6.625% due 2021 to 2047
Long-term debt:
Debt instrument interest rate			1.75%	1.75%
Minimum [Member] | VUHI [Member] | Senior notes 3.55% to 6.625% due 2021 to 2047
Long-term debt:
Debt instrument interest rate			3.72%	3.72%
Minimum [Member] | CenterPoint Energy [Member] | Senior Notes
Long-term debt:
Debt instrument interest rate			2.50%	2.50%
Minimum [Member] | SIGECO [Member] | SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055
Long-term debt:
Debt instrument interest rate			0.875%	0.875%
Minimum [Member] | IGC | Senior Notes [Member]
Long-term debt:
Debt instrument interest rate			6.34%	6.34%
Maximum [Member] | Houston Electric [Member]
Line of Credit Facility [Abstract]
Debt, Capital Ratio				70.00%
Maximum [Member] | Houston Electric [Member] | General mortgage bonds 1.85% to 6.95% due 2021 to 2048
Long-term debt:
Debt instrument interest rate			6.95%	6.95%
Maximum [Member] | CERC Corp [Member] | Senior notes 3.55% to 6.625% due 2021 to 2047
Long-term debt:
Debt instrument interest rate			6.625%	6.625%
Maximum [Member] | VUHI [Member] | Senior notes 3.55% to 6.625% due 2021 to 2047
Long-term debt:
Debt instrument interest rate			6.10%	6.10%
Maximum [Member] | CenterPoint Energy [Member] | Senior Notes
Long-term debt:
Debt instrument interest rate			4.25%	4.25%
Maximum [Member] | SIGECO [Member] | SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055
Long-term debt:
Debt instrument interest rate			6.72%	6.72%
Maximum [Member] | IGC | Senior Notes [Member]
Long-term debt:
Debt instrument interest rate			7.08%	7.08%
Maximum [Member] | Vectren [Member] | Letter of Credit [Member]
Line of Credit Facility [Abstract]
Long-term Line of Credit			$ 20,000,000	$ 20,000,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax expense (benefit):
Total deferred expense (benefit)	$ (429)	$ 69	$ 48
Total income tax expense (benefit)	(274)	92	155
Income tax reconciliation [Abstract]
Income (loss) before income taxes	(865)	774	551
Income (loss) before income taxes	37	155	(37)
Increase (decrease) in tax expense resulting from:
State valuation allowance, net of federal income tax		4	11
State law change, net of federal income tax	39		32
Excess deferred income tax amortization	(76)	(55)	(24)
Total income tax expense (benefit)	(274)	92	155
Deferred tax assets:
Benefits and compensation	141	152
Regulatory liabilities	435	447
Loss and credit carryforwards	103	111
Asset retirement obligations	152	89
Deferred Tax Assets, Derivative Instruments	47	34
Other	52	40
Valuation allowance	(26)	(25)
Total deferred tax assets	904	848
Deferred tax liabilities:
Property, plant, and equipment	2,790	2,656
Investment in unconsolidated affiliates	624	1,010
Regulatory assets	325	344
Investment in marketable securities and indexed debt	649	586
Other	119	180
Total deferred tax liabilities	4,507	4,776
Net deferred tax liabilities	3,603	3,928
Reconciliation of Unrecognized Tax Benefits, excluding interest and penalties:
Balance, beginning of year	8	0
Unrecognized tax benefits assumed through the Merger	0	9
Increases related to tax positions of prior years	3	0
Decreases related to tax positions of prior years	(4)	(1)
Balance, end of year	7	8	0
State and Local Jurisdiction
Increase (decrease) in tax expense resulting from:
Federal income tax rate reduction		(21)
Deferred tax liabilities:
Operating loss carryforwards	979
Deferred tax assets tax credit carryforwards	22
Houston Electric [Member]
Current income tax expense (benefit):
Federal	76	84	109
State	19	20	18
Total current expense (benefit)	95	104	127
Deferred income tax expense (benefit):
Federal	(42)	(24)	(38)
Total deferred expense (benefit)	(42)	(24)	(38)
Total income tax expense (benefit)	53	80	89
Income tax reconciliation [Abstract]
Income (loss) before income taxes	$ 387	$ 436	$ 425
Federal statutory income tax rate	21.00%	21.00%	21.00%
Expected federal income tax expense (benefit)	$ 81	$ 92	$ 89
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	15	16	14
Excess deferred income tax amortization	(42)	(21)	(9)
Other, net	(1)	(7)	(5)
Total	(28)	(12)	0
Total income tax expense (benefit)	$ 53	$ 80	$ 89
Effective tax rate (in hundredths)	14.00%	18.00%	21.00%
Deferred tax assets:
Benefits and compensation	$ 17	$ 14
Regulatory liabilities	201	195
Asset retirement obligations	9	9
Other	9	7
Total deferred tax assets	236	225
Deferred tax liabilities:
Property, plant, and equipment	1,159	1,129
Regulatory assets	118	126
Total deferred tax liabilities	1,277	1,255
Net deferred tax liabilities	1,041	1,030
CERC Corp [Member]
Deferred income tax expense (benefit):
Total deferred expense (benefit)	91	7	$ 64
Total income tax expense (benefit)	97	(3)	31
Income tax reconciliation [Abstract]
Income (loss) before income taxes	244	186	129
Increase (decrease) in tax expense resulting from:
State valuation allowance, net of federal income tax		4
Excess deferred income tax amortization	(16)	(18)
Total income tax expense (benefit)	97	(3)	31
Deferred tax assets:
Valuation allowance	(15)
CERC Corp [Member] | State and Local Jurisdiction
Increase (decrease) in tax expense resulting from:
Federal income tax rate reduction		(4)
Deferred tax liabilities:
Operating loss carryforwards	592
Deferred tax assets tax credit carryforwards	17
CERC Corp [Member] | Domestic Tax Authority
Deferred tax liabilities:
Deferred tax assets tax credit carryforwards	425
Continuing Operations [Member]
Current income tax expense (benefit):
Federal	(1)	30	77
State	32	15	6
Total current expense (benefit)	31	45	83
Deferred income tax expense (benefit):
Federal	(257)	55	(6)
State	(48)	(8)	78
Total deferred expense (benefit)	(305)	47	72
Total income tax expense (benefit)	(274)	92	155
Income tax reconciliation [Abstract]
Income (loss) before income taxes	$ (865)	$ 774	$ 551
Federal statutory income tax rate	21.00%	21.00%	21.00%
Expected federal income tax expense (benefit)	$ (182)	$ 163	$ 116
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	(15)	30	23
State valuation allowance, net of federal income tax	1	(4)	11
State law change, net of federal income tax	0	(21)	32
Goodwill impairment	39	0	0
Net operating loss carryback	(37)	0	0
Excess deferred income tax amortization	(76)	(55)	(24)
Other, net	(4)	(21)	(3)
Total	(92)	(71)	39
Total income tax expense (benefit)	$ (274)	$ 92	$ 155
Effective tax rate (in hundredths)	32.00%	12.00%	28.00%
Continuing Operations [Member] | CERC Corp [Member]
Current income tax expense (benefit):
State	$ 4	$ 5	$ (3)
Total current expense (benefit)	4	5	(3)
Deferred income tax expense (benefit):
Total deferred expense (benefit)	93	(8)	34
Total income tax expense (benefit)	97	(3)	31
Income tax reconciliation [Abstract]
Income (loss) before income taxes	$ 244	$ 186	$ 129
Federal statutory income tax rate	21.00%	21.00%	21.00%
Expected federal income tax expense (benefit)	$ 51	$ 39	$ 27
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	55	(15)	5
State law change, net of federal income tax	0	(4)	0
Excess deferred income tax amortization	(16)	(18)	(15)
Other, net	6	(1)	3
Total	46	(42)	4
Total income tax expense (benefit)	$ 97	$ (3)	$ 31
Effective tax rate (in hundredths)	40.00%	(2.00%)	24.00%
Deferred tax assets:
Benefits and compensation	$ 28	$ 24
Regulatory liabilities	147	144
Loss and credit carryforwards	143	183
Asset retirement obligations	140	80
Other	26	23
Valuation allowance	(15)	(15)
Total deferred tax assets	469	439
Deferred tax liabilities:
Property, plant, and equipment	916	821
Regulatory assets	53	45
Other	84	43
Total deferred tax liabilities	1,053	909
Net deferred tax liabilities	584	470
Continuing Operations [Member] | CERC Corp [Member] | State and Local Jurisdiction
Deferred income tax expense (benefit):
Federal	67
State		(34)	$ 25
Continuing Operations [Member] | CERC Corp [Member] | Domestic Tax Authority
Deferred income tax expense (benefit):
Federal	26	26	9
Discontinued Operations [Member]
Current income tax expense (benefit):
Federal	117	18	12
State	28	6	3
Total current expense (benefit)	145	24	15
Deferred income tax expense (benefit):
Federal	(102)	19	(19)
State	(22)	3	(5)
Total deferred expense (benefit)	(124)	22	(24)
Total income tax expense (benefit)	21	46	(9)
Income tax reconciliation [Abstract]
Income (loss) before income taxes	$ (161)	$ 155	$ (37)
Federal statutory income tax rate	21.00%	21.00%	21.00%
Expected federal income tax expense (benefit)	$ (34)	$ 32	$ (8)
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	(5)	6	(1)
Goodwill impairment	25	8	0
Tax impact of sale of Energy Services and Infrastructure Services Disposal Groups	30	0	0
Other, net	5	0	0
Total	55	14	(1)
Total income tax expense (benefit)	$ 21	$ 46	$ (9)
Effective tax rate (in hundredths)	(13.00%)	30.00%	24.00%
Discontinued Operations [Member] | CERC Corp [Member]
Current income tax expense (benefit):
State	$ 0	$ 2	$ 7
Total current expense (benefit)	0	2	7
Deferred income tax expense (benefit):
Federal	0	13	30
State	(2)	2	0
Total deferred expense (benefit)	(2)	15	30
Total income tax expense (benefit)	(2)	17	37
Income tax reconciliation [Abstract]
Income (loss) before income taxes	$ (68)	$ 40	$ 147
Federal statutory income tax rate	21.00%	21.00%	21.00%
Expected federal income tax expense (benefit)	$ (14)	$ 8	$ 31
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	(2)	3	7
Goodwill impairment	10	8	0
Other, net	4	(2)	(1)
Total	12	9	6
Total income tax expense (benefit)	$ (2)	$ 17	$ 37
Effective tax rate (in hundredths)	3.00%	43.00%	25.00%
State Valuation Allowance, net of Federal Income Taxes [Member] | Continuing Operations [Member] | CERC Corp [Member]
Increase (decrease) in tax expense resulting from:
State valuation allowance, net of federal income tax	$ 1	$ (4)	$ 11
Vectren [Member]
Deferred tax liabilities:
Operating loss carryforwards	177
Reconciliation of Unrecognized Tax Benefits, excluding interest and penalties:
Unrecognized tax benefits assumed through the Merger	9	$ 9
Vectren [Member] | Charitable Contribution [Member]
Deferred tax liabilities:
Deferred tax assets tax credit carryforwards	$ 60

Income Taxes Merger with Vectre

Income Taxes Merger with Vectren (Details) - USD ($) $ in Millions	Feb. 01, 2019	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Deferred tax assets, valuation allowance		$ 26	$ 25
Unrecognized tax benefits assumed through the Merger		0	9
CERC Corp [Member]
Business Acquisition [Line Items]
Deferred tax assets, valuation allowance		15
State and Local Jurisdiction
Business Acquisition [Line Items]
Operating loss carryforwards		979
Deferred tax assets tax credit carryforwards		22
State and Local Jurisdiction | CERC Corp [Member]
Business Acquisition [Line Items]
Operating loss carryforwards		592
Deferred tax assets tax credit carryforwards		17
Domestic Tax Authority | CERC Corp [Member]
Business Acquisition [Line Items]
Deferred tax assets tax credit carryforwards		425
Vectren [Member]
Business Acquisition [Line Items]
Cash paid to acquire Vectren	$ 6,000		5,982
Operating loss carryforwards		177
Unrecognized tax benefits assumed through the Merger		9	$ 9
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		2
Unrecognized Tax benefit, impacting ETR if recognized		3
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations		6
Charitable Contribution [Member] | Vectren [Member]
Business Acquisition [Line Items]
Deferred tax assets tax credit carryforwards		$ 60

Commitments and Contingencies_2

Commitments and Contingencies (Details)	12 Months Ended
	Dec. 31, 2020USD ($)site	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Guarantees & Product Warranties [Abstract]
Number of surety bond obligations outstanding	61
Performance guarantee obligations outstanding face amount	$ 610,000,000
Number of warranty obligations outstanding	31
Warranty obligations outstanding face amount	$ 558,000,000
Energy savings commitments not guaranteed	$ 1,200,000,000
Percentage of work yet to be completed on projects with open surety bonds	33.00%
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 518,000,000
Legal, Environmental and Other Matters
Asset Retirement Obligation	787,000,000	$ 539,000,000	$ 258,000,000
Natural Gas and Coal
Purchase Obligations
2021	708,000,000
2022	542,000,000
2023	465,000,000
2024	387,000,000
2025	370,000,000
2026 and beyond	1,930,000,000
Technology Hardware and Software
Purchase Obligations
2021	17,000,000
2022	12,000,000
2023	10,000,000
2024	190,000,000
2025	0
2026 and beyond	$ 0
Indiana Gas Service Territory [Member]
Legal, Environmental and Other Matters
Environmental remediation number of sites with potential remedial responsibility | site	26
Minnesota and Indiana Gas Service Territories [Member]
Legal, Environmental and Other Matters
Liability recorded for remediation of Minnesota sites	$ 12,000,000
Minnesota and Indiana Gas Service Territories [Member] | Minimum [Member]
Legal, Environmental and Other Matters
Estimated remediation costs for the Minnesota sites	$ 7,000,000
Years to resolve contingency	5
Minnesota and Indiana Gas Service Territories [Member] | Maximum [Member]
Legal, Environmental and Other Matters
Estimated remediation costs for the Minnesota sites	$ 54,000,000
Years to resolve contingency	50
SIGECO [Member]
Legal, Environmental and Other Matters
Environmental remediation number of sites with potential remedial responsibility | site	5
Minnehaha Academy Gas Explosion [Member]
Legal, Environmental and Other Matters
Contested amount of fines imposed	$ 200,000
Indiana Electric [Member]
Legal, Environmental and Other Matters
Asset Retirement Obligation	74,000,000
Indiana Electric [Member] | Minimum [Member]
Legal, Environmental and Other Matters
Estimated capital expenditure to clean ash ponds	60,000,000
Indiana Electric [Member] | Maximum [Member]
Legal, Environmental and Other Matters
Estimated capital expenditure to clean ash ponds	80,000,000
CERC Corp [Member]
Legal, Environmental and Other Matters
Asset Retirement Obligation	571,000,000	$ 325,000,000	$ 221,000,000
CERC Corp [Member] | Natural Gas and Coal
Purchase Obligations
2021	491,000,000
2022	328,000,000
2023	275,000,000
2024	254,000,000
2025	227,000,000
2026 and beyond	1,547,000,000
CERC Corp [Member] | Minnesota and Indiana Gas Service Territories [Member]
Legal, Environmental and Other Matters
Liability recorded for remediation of Minnesota sites	7,000,000
CERC Corp [Member] | Minnesota and Indiana Gas Service Territories [Member] | Minimum [Member]
Legal, Environmental and Other Matters
Estimated remediation costs for the Minnesota sites	$ 4,000,000
Years to resolve contingency	30
CERC Corp [Member] | Minnesota and Indiana Gas Service Territories [Member] | Maximum [Member]
Legal, Environmental and Other Matters
Estimated remediation costs for the Minnesota sites	$ 32,000,000
Years to resolve contingency	50
CERC Corp [Member] | Minnehaha Academy Gas Explosion [Member]
Legal, Environmental and Other Matters
Contested amount of fines imposed	$ 200,000
Energy Services Disposal Group [Member] | CERC Corp [Member]
Guarantees & Product Warranties [Abstract]
Annualized fee received for retained CES obligation guarantees	3.00%
Quarterly increase of fee received for retained CES guarantee exposure	1.00%
Estimated Remaining Exposure	$ 61,000,000

Earnings Per Share (CenterPoi_3

Earnings Per Share (CenterPoint Energy) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Beneficial Conversion Feature	$ 32	$ 0	$ 0
Numerator:
Income (loss) from continuing operations	(591)	682	396
Less: Preferred stock dividend requirement (Note 13)	176	117	35
Less: Amortization of Beneficial Conversion Feature	32	0	0
Less: Undistributed earnings allocated to preferred shareholders (1)	0	0	0
Income (loss) available to common shareholders from continuing operations - basic and diluted	(949)	674	333
Income (Loss) from Discontinued Operations	$ (182)	$ 109	$ (28)
Denominator:
Weighted average common shares outstanding - basic	531,031,000	502,050,000	448,829,000
Weighted average common shares outstanding - diluted	531,031,000	505,157,000	452,465,000
Earnings Per Share, Basic [Abstract]
Basic earnings (loss) per common share - continuing operations	$ (1.45)	$ 1.12	$ 0.80
Basic earnings (loss) per common share - discontinued operations	(0.34)	0.22	(0.06)
Earnings Per Share, Basic	(1.79)	1.34	0.74
Earnings Per Share, Diluted [Abstract]
Diluted earnings (loss) per common share - continuing operations	(1.45)	1.12	0.80
Diluted earnings (loss) per common share - discontinued operations	(0.34)	0.21	(0.06)
Diluted Earnings (Loss) Per Common Share	$ (1.79)	$ 1.33	$ 0.74
Continuing Operations [Member]
Numerator:
Income (loss) available to common shareholders from continuing operations - basic and diluted	$ (767)	$ 565	$ 361
Restricted Stock [Member]
Denominator:
Restricted stock (2)	0	3,107,000	3,636,000
Series B Preferred Stock [Member]
Amount of antidilutive securities excluded from computation of earnings per share	35,922,000	34,354,000	8,885,000
Numerator:
Less: Preferred stock dividend requirement (Note 13)	$ 144	$ 117	$ 35
Denominator:
Preferred Stock	0	0	0
Series C Preferred Stock [Member]
Amount of antidilutive securities excluded from computation of earnings per share	23,807,000
Denominator:
Preferred Stock	0	0	0
Restricted Stock [Member]
Amount of antidilutive securities excluded from computation of earnings per share	3,690,000

Reportable Segments Financial D

Reportable Segments Financial Data (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating revenues	$ 7,418	$ 7,564	$ 6,277
Equity in earnings (loss) of unconsolidated affiliates, net	(1,428)	230	307
Depreciation and Amortization	1,189	1,225	1,230
Interest Income	3	17	24
Interest Expense	(501)	(528)	(361)
Income Tax Expense (Benefit)	(274)	92	155
Net income (loss)	(773)	791	368
Total Assets	33,471	35,529	27,093
Expenditures for Long-Lived Assets	2,536	2,587	1,720
Regulatory Assets	2,127	2,129
Income (Loss) from Discontinued Operations	(182)	109	(28)
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	7,418	7,564	6,277
Equity in earnings (loss) of unconsolidated affiliates, net	(1,428)	230	307
Depreciation and Amortization	1,189	1,225	1,230
Interest Income	4	22	28
Interest Expense	(529)	(567)	(420)
Income Tax Expense (Benefit)	(274)	92	155
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(591)	682	396
Total Assets	33,471	33,565	25,984
Expenditures for Long-Lived Assets	2,515	2,508	1,700
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)	21	46	(9)
Total Assets	0	1,964	1,109
Expenditures for Long-Lived Assets	21	79	20
Income (Loss) from Discontinued Operations	(182)	109	(28)
Electric | Affiliates of NRG Energy, Inc. [Member]
Segment Reporting Information [Line Items]
Operating revenues	749	727	705
Electric | Affiliates of Vistra Energy Corp. [Member]
Segment Reporting Information [Line Items]
Operating revenues	404	263	251
Operating Segments [Member] | Electric
Segment Reporting Information [Line Items]
Operating revenues	3,470	3,519	3,232
Equity in earnings (loss) of unconsolidated affiliates, net	0	0	0
Depreciation and Amortization	663	739	917
Interest Income	3	27	5
Interest Expense	(220)	(225)	(197)
Income Tax Expense (Benefit)	72	96	89
Net income (loss)	230	419	334
Total Assets	14,493	14,432	10,509
Expenditures for Long-Lived Assets	1,281	1,216	952
Operating Segments [Member] | Natural Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	3,631	3,750	3,031
Equity in earnings (loss) of unconsolidated affiliates, net	0	0	0
Depreciation and Amortization	454	420	280
Interest Income	8	6	1
Interest Expense	(153)	(144)	(122)
Income Tax Expense (Benefit)	125	2	31
Net income (loss)	278	251	98
Total Assets	14,976	14,002	7,188
Expenditures for Long-Lived Assets	1,139	1,098	638
Operating Segments [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0
Equity in earnings (loss) of unconsolidated affiliates, net	(1,428)	229	307
Depreciation and Amortization	0	0	0
Interest Income	1	8	0
Interest Expense	(54)	(53)	(10)
Income Tax Expense (Benefit)	(364)	53	73
Net income (loss)	(1,116)	131	224
Total Assets	913	2,473	2,482
Expenditures for Long-Lived Assets	0	0	0
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	317	295	14
Equity in earnings (loss) of unconsolidated affiliates, net	0	1	0
Depreciation and Amortization	72	66	33
Interest Income	103	126	66
Interest Expense	(213)	(290)	(135)
Income Tax Expense (Benefit)	(107)	(59)	(38)
Net income (loss)	17	(119)	(260)
Total Assets	3,089	2,658	5,805
Expenditures for Long-Lived Assets	95	194	110
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0
Equity in earnings (loss) of unconsolidated affiliates, net	0	0	0
Depreciation and Amortization	0	0	0
Interest Income	(111)	(145)	(44)
Interest Expense	111	145	44
Income Tax Expense (Benefit)	0	0	0
Net income (loss)	0	0	0
Houston Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,911	2,990	3,234
Depreciation and Amortization	560	648	917
Interest Income	2	22	1
Interest Expense	(171)	(164)	(138)
Income Tax Expense (Benefit)	53	80	89
Net income (loss)	334	356	336
Total Assets	11,316	11,262
Regulatory Assets	848	915
Houston Electric [Member] | Electric Transmission & Distribution [Member] | Affiliates of NRG Energy, Inc. [Member]
Segment Reporting Information [Line Items]
Operating revenues	749	727	705
Houston Electric [Member] | Electric Transmission & Distribution [Member] | Affiliates of Vistra Energy Corp. [Member]
Segment Reporting Information [Line Items]
Operating revenues	404	263	251
CERC Corp [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,763	3,018	3,031
Equity in earnings (loss) of unconsolidated affiliates, net	0	0	184
Depreciation and Amortization	304	293	280
Interest Income	0	5	1
Interest Expense	(111)	(116)	(122)
Income Tax Expense (Benefit)	97	(3)	31
Net income (loss)	81	212	208
Total Assets	8,308	8,512
Regulatory Assets	253	203
Income (Loss) from Discontinued Operations	(66)	23	110
CERC Corp [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)	97	(3)	31
CERC Corp [Member] | Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)	(2)	17	37
Pension and Other Postretirement Plans Costs [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Regulatory Assets	540	$ 584	$ 665
Cash and Cash Equivalents [Member]
Segment Reporting Information [Line Items]
Short-term Investments	$ 3,900

Reportable Segments Revenues by

Reportable Segments Revenues by Products and Services (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)state	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Operating revenues	$ 7,418	$ 7,564	$ 6,277
CenterPoint Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	7,418	7,564	6,277
CenterPoint Energy [Member] | Electric Delivery [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,941	3,019	3,232
CenterPoint Energy [Member] | Retail Electric Sales [Member]
Segment Reporting Information [Line Items]
Operating revenues	515	486
CenterPoint Energy [Member] | Wholesale Electric Sales [Member]
Segment Reporting Information [Line Items]
Operating revenues	14	14
CenterPoint Energy [Member] | Retail Gas Sales [Member]
Segment Reporting Information [Line Items]
Operating revenues	3,462	3,563	2,857
CenterPoint Energy [Member] | Gas Transportation and Processing [Member]
Segment Reporting Information [Line Items]
Operating revenues	15	33	32
CenterPoint Energy [Member] | Energy Products and Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	471	449	156
Houston Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,911	2,990	3,234
Houston Electric [Member] | Electric Delivery [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,911	2,990	3,234
Houston Electric [Member] | Retail Gas Sales [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0
Houston Electric [Member] | Gas Transportation and Processing [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0
Houston Electric [Member] | Energy Products and Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0
CERC Corp [Member]
Segment Reporting Information [Line Items]
Operating revenues	$ 2,763	3,018	3,031
CERC Corp [Member] | Natural Gas Distribution
Segment Reporting Information [Line Items]
Number of States in which the Entity Performs Gas Delivery Services | state	48
CERC Corp [Member] | Electric Delivery [Member]
Segment Reporting Information [Line Items]
Operating revenues	$ 0	0	0
CERC Corp [Member] | Retail Gas Sales [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,594	2,831	2,857
CERC Corp [Member] | Gas Transportation and Processing [Member]
Segment Reporting Information [Line Items]
Operating revenues	15	33	32
CERC Corp [Member] | Energy Products and Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	$ 154	$ 154	$ 142

Supplemental Disclosure of Ca_3

Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest, net of capitalized interest	$ 471	$ 436	$ 363
Income taxes (refunds), net	143	155	89
Accounts payable related to capital expenditures	153	236	201
Capital distribution to parent associated with the sale of CES	0	0	0
ROU Asset Obtained In Exchange for Operating Lease Liability, Including Transition Impact of ASC 842 Adoption	15	44	0
Beneficial Conversion Feature	32	0	0
Amortization of Beneficial Conversion Feature	(32)	0	0
Cash and cash equivalents	147	241
Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows	167	271	4,278	$ 296
Prepaid Expenses and Other Current Assets [Member]
Restricted cash	20	30
Houston Electric [Member]
Interest, net of capitalized interest	201	229	200
Income taxes (refunds), net	65	87	154
Accounts payable related to capital expenditures	102	117	124
Capital distribution to parent associated with the sale of CES	0	0	0
ROU Asset Obtained In Exchange for Operating Lease Liability, Including Transition Impact of ASC 842 Adoption	1	1	0
Beneficial Conversion Feature	0	0	0
Amortization of Beneficial Conversion Feature	0	0	0
Cash and cash equivalents	139	216
Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows	154	235	370	274
Houston Electric [Member] | Prepaid Expenses and Other Current Assets [Member]
Restricted cash	15	19
CERC Corp [Member]
Interest, net of capitalized interest	114	109	105
Income taxes (refunds), net	4	7	3
Accounts payable related to capital expenditures	69	86	80
Capital distribution to parent associated with the sale of CES	0	28	1,473
ROU Asset Obtained In Exchange for Operating Lease Liability, Including Transition Impact of ASC 842 Adoption	5	29	0
Beneficial Conversion Feature	0	0	0
Amortization of Beneficial Conversion Feature	0	0	0
Cash and cash equivalents	1	2
Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows	1	2	$ 25	$ 12
CERC Corp [Member] | Prepaid Expenses and Other Current Assets [Member]
Restricted cash	0	0
Bond Companies [Member] | Houston Electric [Member]
Cash and cash equivalents	$ 139	$ 216

Related Party Transactions (H_3

Related Party Transactions (Houston Electric and CERC) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Capital distribution to parent associated with the sale of CES	$ 0	$ 0	$ 0
Houston Electric [Member]
Related Party Transaction [Line Items]
Cash dividends paid to parent	551	376	209
Capital distribution to parent associated with the sale of CES	0	0	0
Property, plant and equipment from parent (2)	36
Houston Electric [Member] | Other, net [Member]
Related Party Transaction [Line Items]
Interest income (expense), net (1)	0	18	1
Houston Electric [Member] | Operation And Maintenance Expense [Member]
Related Party Transaction [Line Items]
Net affiliate service charges (billings)	(16)	(8)	(17)
Houston Electric [Member] | Operation And Maintenance Expense [Member] | CenterPoint Energy [Member]
Related Party Transaction [Line Items]
Corporate service charges	197	177	190
Houston Electric [Member] | Accounts and notes receivable (payable) - affiliate companies [Member]
Related Party Transaction [Line Items]
Money pool investments (borrowings) (1)		$ 481
Money Pool Borrowings	$ (8)
Houston Electric [Member] | Investments [Member]
Related Party Transaction [Line Items]
Weighted average interest rate	0.24%	1.98%
CERC Corp [Member]
Related Party Transaction [Line Items]
Cash dividends paid to parent	$ 80	$ 120	360
Capital distribution to parent associated with the sale of CES	0	28	1,473
Property, plant and equipment from parent (2)	23
CERC Corp [Member] | Discontinued Operations [Member]
Related Party Transaction [Line Items]
Capital distribution to parent associated with the sale of CES	286
CERC Corp [Member] | Other, net [Member]
Related Party Transaction [Line Items]
Interest income (expense), net (1)	0	4	0
CERC Corp [Member] | Operation And Maintenance Expense [Member]
Related Party Transaction [Line Items]
Net affiliate service charges (billings)	16	8	17
CERC Corp [Member] | Operation And Maintenance Expense [Member] | CenterPoint Energy [Member]
Related Party Transaction [Line Items]
Corporate service charges	212	141	147
CERC Corp [Member] | Accounts and notes receivable (payable) - affiliate companies [Member]
Related Party Transaction [Line Items]
Money pool investments (borrowings) (1)	$ 0	$ 0
CERC Corp [Member] | Investments [Member]
Related Party Transaction [Line Items]
Weighted average interest rate	0.24%	1.98%
Additional Paid-in Capital [Member] | Houston Electric [Member]
Related Party Transaction [Line Items]
Contribution From Parent	$ 62	$ 590	200
Additional Paid-in Capital [Member] | CERC Corp [Member]
Related Party Transaction [Line Items]
Contribution From Parent	$ 217	$ 129	$ 960

Leases (Details)

Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 9	$ 7
Short-term lease cost	14	25
Total lease cost	23	32
Operating Leases, Lease Income [Abstract]
Operating lease income	5	4
Variable lease income	1	2
Total lease income	6	6
Assets and Liabilities, Lessee [Abstract]
Operating ROU assets (1)	31	31
Total leased assets	$ 31	$ 31	$ 22
Weighted-average remaining lease term (in years) - operating leases	6 years	6 years 6 months
Weighted-average discount rate - operating leases	3.14%	3.57%
Operating Lease Liabilities, Payments Due [Abstract]
2021	$ 8
2022	6
2023	6
2024	4
2025	3
2026 and beyond	10
Total lease payments	37
Less: Interest	5
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2021	4
2022	2
2023	2
2024	2
2025	2
2026 and beyond	8
Total lease payments to be received	20
Other Information Related to Leases [Abstract]
Operating cash flows from operating leases included in the measurement of lease liabilities	8
Lessee Operating Lease Not Yet Commenced	847
Other Current Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Current operating lease liability (2)	6	$ 7
Other Liabilities
Assets and Liabilities, Lessee [Abstract]
Total leased liabilities	32	31
Other Noncurrent Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Non-current operating lease liability (3)	26	24
Houston Electric [Member]
Lease, Cost [Abstract]
Operating lease cost	0	0
Short-term lease cost	12	23
Total lease cost	12	23
Operating Leases, Lease Income [Abstract]
Operating lease income	0	2
Variable lease income	0	0
Total lease income	0	2
Assets and Liabilities, Lessee [Abstract]
Operating ROU assets (1)	1	1
Total leased assets	1	1	1
Current operating lease liability (2)	0	0
Non-current operating lease liability (3)	$ 1	$ 1
Weighted-average remaining lease term (in years) - operating leases	4 years	5 years 2 months 12 days
Weighted-average discount rate - operating leases	2.59%	3.52%
Operating Lease Liabilities, Payments Due [Abstract]
2021	$ 1
2022	0
2023	0
2024	0
2025	0
2026 and beyond	0
Total lease payments	1
Less: Interest	0
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2021	0
2022	0
2023	0
2024	0
2025	0
2026 and beyond	0
Total lease payments to be received	0
Other Information Related to Leases [Abstract]
Operating cash flows from operating leases included in the measurement of lease liabilities	1
Houston Electric [Member] | Other Liabilities
Assets and Liabilities, Lessee [Abstract]
Total leased liabilities	1	$ 1
CERC Corp [Member]
Lease, Cost [Abstract]
Operating lease cost	5	4
Short-term lease cost	0	0
Total lease cost	5	4
Operating Leases, Lease Income [Abstract]
Operating lease income	2	1
Variable lease income	0	0
Total lease income	2	1
Assets and Liabilities, Lessee [Abstract]
Operating ROU assets (1)	19	18
Total leased assets	19	18	$ 19
Current operating lease liability (2)	3	3
Non-current operating lease liability (3)	$ 18	$ 15
Weighted-average remaining lease term (in years) - operating leases	7 years 6 months	7 years 1 month 6 days
Weighted-average discount rate - operating leases	3.36%	3.61%
Operating Lease Liabilities, Payments Due [Abstract]
2021	$ 4
2022	4
2023	4
2024	3
2025	2
2026 and beyond	7
Total lease payments	24
Less: Interest	3
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2021	1
2022	0
2023	0
2024	0
2025	0
2026 and beyond	0
Total lease payments to be received	1
Other Information Related to Leases [Abstract]
Operating cash flows from operating leases included in the measurement of lease liabilities	4
CERC Corp [Member] | Other Liabilities
Assets and Liabilities, Lessee [Abstract]
Total leased liabilities	$ 21	$ 18

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions

Feb. 12, 2021

Dec. 10, 2020

Oct. 29, 2020

Jul. 29, 2020

Apr. 24, 2020

Feb. 03, 2020

Oct. 17, 2019

Jul. 31, 2019

Apr. 25, 2019

Dec. 12, 2018

Oct. 23, 2018

Jul. 26, 2018

Apr. 26, 2018

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Feb. 24, 2021

Feb. 16, 2021

Subsequent Event [Line Items]

Expected cash distribution on Enable Common Units

$ 113

$ 261

$ 267

Subsequent Event [Member]

Subsequent Event [Line Items]

Proceeds from Merger - Preferred Units

$ 385

Proceeds from Merger - Interest

$ 5

Merger Exchange Ratio

0.8595

Series A Preferred Units [Member] | Subsequent Event [Member] | Enable Midstream Partners [Member]

Subsequent Event [Line Items]

Declaration Date

Feb. 12, 2021

Record Date

Feb. 12, 2021

Payment Date

Feb. 12, 2021

Distributions Declared, Per Unit

$ 0.62500

Expected cash distribution on Enable's Series A Preferred Units

$ 9

Common Units [Member] | Subsequent Event [Member] | Enable Midstream Partners [Member]

Subsequent Event [Line Items]

Declaration Date

Feb. 12, 2021

Record Date

Feb. 22, 2021

Payment Date

Mar. 1, 2021

Distributions Declared, Per Unit

$ 0.16525

Expected cash distribution on Enable Common Units

$ 39

Common Stock [Member]

Subsequent Event [Line Items]

Declaration Date

Dec. 10, 2020

Oct. 29, 2020

Oct. 17, 2019

Jul. 31, 2019

Apr. 25, 2019

Dec. 12, 2018

Oct. 23, 2018

Jul. 26, 2018

Apr. 26, 2018

Record Date

Feb. 18, 2021

Nov. 19, 2020

Nov. 21, 2019

Aug. 15, 2019

May 16, 2019

Feb. 21, 2019

Nov. 15, 2018

Aug. 16, 2018

May 17, 2018

Payment Date

Mar. 11, 2021

Dec. 10, 2020

Dec. 12, 2019

Sep. 12, 2019

Jun. 13, 2019

Mar. 14, 2019

Dec. 13, 2018

Sep. 13, 2018

Jun. 14, 2018

Common Stock, Dividends, Per Share, Declared

$ 0.1600

$ 0.1500

$ 0.1500

$ 0.1500

$ 0.2900

$ 0.2875

$ 0.2875

$ 0.2875

$ 0.2875

$ 0.2775

$ 0.2775

$ 0.2775

$ 0.9000

$ 0.8625

$ 1.1200

Series A Preferred Stock [Member]

Subsequent Event [Line Items]

Declaration Date

Jul. 31, 2019

Dec. 12, 2018

Record Date

Aug. 15, 2019

Feb. 15, 2019

Payment Date

Sep. 3, 2019

Mar. 1, 2019

Preferred stock dividends declared per share

$ 30.6250

$ 30.6250

$ 30.6250

$ 30.6250

$ 32.1563

$ 91.8750

30.6250

32.1563

Series B Preferred Stock [Member]

Subsequent Event [Line Items]

Declaration Date

Dec. 10, 2020

Oct. 29, 2020

Oct. 17, 2019

Jul. 31, 2019

Apr. 25, 2019

Dec. 12, 2018

Oct. 23, 2018

Record Date

Feb. 15, 2021

Nov. 13, 2020

Nov. 15, 2019

Aug. 15, 2019

May 15, 2019

Feb. 15, 2019

Nov. 15, 2018

Payment Date

Mar. 1, 2021

Dec. 1, 2020

Dec. 2, 2019

Sep. 3, 2019

Jun. 3, 2019

Mar. 1, 2019

Dec. 1, 2018

Preferred stock dividends declared per share

$ 17.5000

$ 17.5000

$ 17.5000

$ 17.5000

$ 17.5000

$ 17.5000

$ 11.6667

$ 52.5000

$ 29.1667

CERC Corp [Member]

Subsequent Event [Line Items]

Expected cash distribution on Enable Common Units

$ 0

$ 0

$ 176

CERC Corp [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Financing Commitments

$ 1,700