Fair Value Measurements - Schedule of Assets and Liabilities Measured On Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Liabilities
Derivative Liability	$ 543	$ 617
CERC
Liabilities
Derivative Liability	4	11
Fair Value, Recurring
Assets
Equity securities	477	541
Investments, including money market funds	35	31
Total assets	512	572
Liabilities
Total liabilities	543	617
Fair Value, Recurring | Houston Electric
Assets
Investments, including money market funds	20	14
Total assets	20	14
Fair Value, Recurring | CERC
Assets
Investments, including money market funds	15	15
Total assets	15	15
Liabilities
Total liabilities	4	11
Fair Value, Recurring | Indexed debt securities derivative
Liabilities
Derivative Liability	538	605
Fair Value, Recurring | Natural gas derivatives
Liabilities
Derivative Liability	5	12
Fair Value, Recurring | Natural gas derivatives | CERC
Liabilities
Derivative Liability	4	11
Level 1 | Fair Value, Recurring
Assets
Equity securities	477	541
Investments, including money market funds	35	31
Total assets	512	572
Liabilities
Total liabilities	0	0
Level 1 | Fair Value, Recurring | Houston Electric
Assets
Investments, including money market funds	20	14
Total assets	20	14
Level 1 | Fair Value, Recurring | CERC
Assets
Investments, including money market funds	15	15
Total assets	15	15
Liabilities
Total liabilities	0	0
Level 1 | Fair Value, Recurring | Indexed debt securities derivative
Liabilities
Derivative Liability	0	0
Level 1 | Fair Value, Recurring | Natural gas derivatives
Liabilities
Derivative Liability	0	0
Level 1 | Fair Value, Recurring | Natural gas derivatives | CERC
Liabilities
Derivative Liability	0	0
Level 2 | Fair Value, Recurring
Assets
Equity securities	0	0
Investments, including money market funds	0	0
Total assets	0	0
Liabilities
Total liabilities	543	617
Level 2 | Fair Value, Recurring | Houston Electric
Assets
Investments, including money market funds	0	0
Total assets	0	0
Level 2 | Fair Value, Recurring | CERC
Assets
Investments, including money market funds	0	0
Total assets	0	0
Liabilities
Total liabilities	4	11
Level 2 | Fair Value, Recurring | Indexed debt securities derivative
Liabilities
Derivative Liability	538	605
Level 2 | Fair Value, Recurring | Natural gas derivatives
Liabilities
Derivative Liability	5	12
Level 2 | Fair Value, Recurring | Natural gas derivatives | CERC
Liabilities
Derivative Liability	4	11
Level 3 | Fair Value, Recurring
Assets
Equity securities	0	0
Investments, including money market funds	0	0
Total assets	0	0
Liabilities
Total liabilities	0	0
Level 3 | Fair Value, Recurring | Houston Electric
Assets
Investments, including money market funds	0	0
Total assets	0	0
Level 3 | Fair Value, Recurring | CERC
Assets
Investments, including money market funds	0	0
Total assets	0	0
Liabilities
Total liabilities	0	0
Level 3 | Fair Value, Recurring | Indexed debt securities derivative
Liabilities
Derivative Liability	0	0
Level 3 | Fair Value, Recurring | Natural gas derivatives
Liabilities
Derivative Liability	0	0
Level 3 | Fair Value, Recurring | Natural gas derivatives | CERC
Liabilities
Derivative Liability	$ 0	$ 0