Fair Value Measurements (Reconciliation Of Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	$ (683)	$ (253)	$ (1,100)	$ (463)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	734	329	963	226
Total increase (decrease) in unrealized losses included in cost of products sold	651	248	1,052	456
Purchases	17	2	29	8
Sales		(9)	(2)	(25)
Settlements	(447)	(211)	(1,013)	(333)
Transfers into Level 3	170	19	235	55
Transfers out of Level 3	(26)	(1)	(165)	(10)
Balance at end of period	1,099	377	1,099	377
Significant Unobservable Inputs (Level 3) [Member] | Long-term Debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	54		34
Total increase (decrease) in unrealized losses included in cost of products sold	(30)		(10)
Purchases	0		0
Balance at end of period	24		24
Significant Unobservable Inputs (Level 3) [Member] | Inventory Related Payables [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	21	20	11	27
Total increase (decrease) in unrealized losses included in cost of products sold	0	1	0	4
Purchases	17	2	29	8
Sales		(9)	(2)	(25)
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance at end of period	38	14	38	14
Significant Unobservable Inputs (Level 3) [Member] | Commodity Derivative Contracts Losses [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	648	309	918	199
Total increase (decrease) in unrealized losses included in cost of products sold	681	247	1,062	452
Purchases	0	0	0	0
Sales		0	0	0
Settlements	(447)	(211)	(1,013)	(333)
Transfers into Level 3	170	19	224	55
Transfers out of Level 3	(15)	(1)	(154)	(10)
Balance at end of period	1,037	$ 363	1,037	$ 363
Significant Unobservable Inputs (Level 3) [Member] | Foreign Exchange Contracts [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	11		0
Total increase (decrease) in unrealized losses included in cost of products sold	0		0
Purchases	0		0
Sales			0
Settlements	0		0
Transfers into Level 3	0		11
Transfers out of Level 3	(11)		(11)
Balance at end of period	$ 0		$ 0