Acquisitions - Schedule of Business Acquisitions, by Acquisition (Details) - USD ($) $ in Millions	Mar. 01, 2024	Sep. 30, 2025	Dec. 31, 2024
Business Combination [Line Items]
Goodwill		$ 2,810	$ 2,807
Business combination, contractual cash flow projections, duration	5 years
Energy Harbor
Business Combination [Line Items]
Cash and cash equivalents	$ 35
Trade accounts receivables, inventories, prepaid expenses and other current assets	540
Investments	2,021
Property, plant and equipment	5,616
Identifiable intangible assets	444
Commodity and other derivative contractual assets	129
Other noncurrent assets	62
Total identifiable assets acquired	8,847
Trade accounts payable and other current liabilities	318
Long-term debt, including amounts due currently	413
Commodity and other derivative contractual liabilities	179
Accumulated deferred income taxes	1,314
Asset retirement obligations	1,368
Identifiable intangible liabilities	55
Other noncurrent liabilities and deferred credits	20
Total identifiable liabilities assumed	3,667
Identifiable net assets acquired	5,180
Goodwill	227	$ 0	$ 224
Net assets acquired	5,407
Cash and cash equivalents	5
Trade accounts receivables, inventories, prepaid expenses and other current assets	2
Investments	0
Property, plant and equipment	(4)
Identifiable intangible assets	16
Commodity and other derivative contractual assets	(11)
Other noncurrent assets	54
Total identifiable assets acquired	62
Trade accounts payable and other current liabilities	55
Long-term debt, including amounts due currently	0
Commodity and other derivative contractual liabilities	0
Accumulated deferred income taxes	(50)
Asset retirement obligations	0
Identifiable intangible liabilities	(18)
Other noncurrent liabilities and deferred credits	8
Total identifiable liabilities assumed	(5)
Identifiable net assets acquired	67
Goodwill	$ (67)