Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6	$ 6	$ 12	$ 13
Interest cost	18	19	37	38
Expected return on plan assets	(18)	(19)	(37)	(38)
Amortization of net loss	7	7	14	14
Net periodic cost (benefit)	13	13	26	27
Total contributions expected in current year	9		9
Total contributions to the plans during the period	1		3
Pension plans | Houston Electric
Defined Benefit Plan Disclosure [Line Items]
Total contributions expected in current year	0		0
Total contributions to the plans during the period	0		0
Pension plans | CERC
Defined Benefit Plan Disclosure [Line Items]
Total contributions expected in current year	0		0
Total contributions to the plans during the period	0		0
Postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1	1
Interest cost	3	3	6	6
Expected return on plan assets	(2)	(2)	(3)	(3)
Amortization of prior service cost (credit)	0	(1)	(1)	(1)
Amortization of net loss	(2)	(2)	(4)	(4)
Net periodic cost (benefit)	0	(1)	(1)	(1)
Total contributions expected in current year	8		8
Total contributions to the plans during the period	2		4
Postretirement benefit plans | Houston Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	2	2	3	3
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of prior service cost (credit)	(2)	(2)	(3)	(3)
Amortization of net loss	(1)	(1)	(2)	(2)
Net periodic cost (benefit)	(2)	(2)	(4)	(4)
Total contributions expected in current year	1		1
Total contributions to the plans during the period	0		0
Postretirement benefit plans | CERC
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	1	1	2	2
Expected return on plan assets	0	0	0	0
Amortization of prior service cost (credit)	0	0	1	1
Amortization of net loss	0	0	(1)	(1)
Net periodic cost (benefit)	1	$ 1	2	$ 2
Total contributions expected in current year	4		4
Total contributions to the plans during the period	$ 2		$ 3