Goodwill and Identifiable Intangible Assets and Liabilities - Schedule of Amortization Expense Related to Intangible Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	$ 125	$ 135	$ 300	$ 273
Retail customer relationships | Depreciation and amortization
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	22	31	45	53
Software and other technology-related assets | Depreciation and amortization
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	18	15	36	28
Retail and wholesale contracts | Operating revenues/Fuel, purchased power costs, and delivery fees
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	(2)	(3)	(4)	(4)
Other identifiable intangible assets | Fuel, purchased power costs, and delivery fees/Depreciation and amortization
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	$ 87	$ 92	$ 223	$ 196