Regulatory Matters - Regulatory Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 01, 2023	Dec. 31, 2022
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 6,818		$ 7,369
Other current liabilities
Regulatory Liabilities [Line Items]
Total regulatory liabilities	174		299
Regulatory liabilities
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 6,644		7,070
Cost of removal
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	26 years
Total regulatory liabilities	$ 2,741		2,578
Deferred income taxes
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 2,733	$ 24	2,901
Asset retirement obligations
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	30 years
Total regulatory liabilities	$ 364		250
Revenue sharing mechanisms
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 243		426
Levelized depreciation
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	27 years
Total regulatory liabilities	$ 230		245
Employee benefit plans
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 211		180
Unrealized gains on regulated derivative contracts
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	1 year
Total regulatory liabilities	$ 7		343
Other
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 289		$ 446