Goodwill and Identifiable Intangible Assets and Liabilities - Schedule of Amortization Expense Related to Intangible Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	$ 165	$ 170	$ 465	$ 443
Retail customer relationships | Depreciation and amortization
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	23	29	68	82
Software and other technology-related assets | Depreciation and amortization
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortization of intangible assets and liabilities	17	15	53	43
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)	(5)	(6)	(9)
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	$ 127	$ 131	$ 350	$ 327