Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 1,391	$ 567
Derivative Liabilities	(1,508)	(533)
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative Assets	1,035	446
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative Assets	356	121
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(1,037)	(386)
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(471)	(147)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(4)	(5)
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	454	233
Derivative Liabilities	(594)	(223)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	643	180
Derivative Liabilities	(622)	(168)
Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	294	154
Derivative Liabilities	(288)	(137)
Derivatives designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(4)	(4)
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	1,391	567
Derivative Liabilities	(1,504)	(529)
Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	0	(1)
Derivatives not designated as hedging instruments | Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	454	233
Derivative Liabilities	(594)	(223)
Derivatives not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	643	180
Derivative Liabilities	(622)	(168)
Derivatives not designated as hedging instruments | Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	294	154
Derivative Liabilities	$ (288)	$ (137)