Regulatory Matters - EGTS - 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
Regulatory liabilities, noncurrent	6,644		7,070
Deferred income taxes
Regulatory Liabilities [Line Items]
Total regulatory liabilities	2,733	$ 24	2,901
Other postretirement benefit costs
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 211		180
Cost of removal
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	26 years
Total regulatory liabilities	$ 2,741		2,578
EGTS
Regulatory Liabilities [Line Items]
Total regulatory liabilities	545		627
Regulatory liabilities, current	22		109
Regulatory liabilities, noncurrent	523		518
EGTS | Deferred income taxes
Regulatory Liabilities [Line Items]
Total regulatory liabilities	377		382
EGTS | Other postretirement benefit costs
Regulatory Liabilities [Line Items]
Total regulatory liabilities	124		123
EGTS | Provision for rate refunds
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 0		90
EGTS | Cost of removal
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	47 years
Total regulatory liabilities	$ 28		24
Regulatory liabilities, noncurrent	28		24
EGTS | Other
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 16		$ 8