Financial and Other Derivative Instruments (Effect of Derivatives Not Designated as Hedging Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Total	$ 373	$ 347	$ 383
Natural gas | Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Total	112	(169)	153
Natural gas | Fuel, purchased power, gas, and other — non-utility
Derivative Instruments, Gain (Loss) [Line Items]
Total	(160)	233	122
Electricity | Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Total	361	266	105
Environmental & Other | Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Total	61	14	5
Foreign currency exchange contracts | Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Total	$ (1)	$ 3	$ (2)