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.

(2)In 2020 and 2019, the Registrants reflected an increase in their respective ARO liability, which is primarily attributable to decreases in the long-term interest rates used for discounting in the ARO calculation and in 2019 reflected an increase in estimated closure costs for CenterPoint Energy’s electric generation.