Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 711	$ 694
Derivative Liabilities	(627)	(605)
Current derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	462	488
Current derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(381)	(441)
Noncurrent derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	249	206
Noncurrent derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(246)	(164)
Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	2	20
Derivative Liabilities	(1)	0
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	1
Derivative Liabilities	(1)	(1)
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	327	428
Derivative Liabilities	(321)	(410)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	253	187
Derivative Liabilities	(225)	(150)
Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	129	58
Derivative Liabilities	(79)	(44)
Derivatives designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	2	20
Derivative Liabilities	(2)	(1)
Derivatives designated as hedging instruments \| Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	2	20
Derivative Liabilities	(1)	0
Derivatives designated as hedging instruments \| Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(1)	(1)
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	709	674
Derivative Liabilities	(625)	(604)
Derivatives not designated as hedging instruments \| Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	1
Derivative Liabilities	0	0
Derivatives not designated as hedging instruments \| Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	327	428
Derivative Liabilities	(321)	(410)
Derivatives not designated as hedging instruments \| Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	253	187
Derivative Liabilities	(225)	(150)
Derivatives not designated as hedging instruments \| Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	129	58
Derivative Liabilities	$ (79)	$ (44)