Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Assets:
Derivative Asset	$ 963	$ 449
Deferred receivables consideration	386	307
Liabilities:
Derivative Liability	1,161	464
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,168	4,886
Cash Equivalents, at Carrying Value	478	352
Available-for-sale Securities, Fair Value Disclosure	35	92
Restricted Investments, at Fair Value	1,606	1,733
Deferred receivables consideration	386	307
Total Assets	7,636	7,819
Liabilities:
Inventory-related payables	618	719
Total Liabilities	1,779	1,183
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	717	386
Liabilities:
Derivative Liability	818	371
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	246	63
Liabilities:
Derivative Liability	335	92
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	8	1
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Assets:
Inventories carried at market	0	0
Cash Equivalents, at Carrying Value	478	352
Available-for-sale Securities, Fair Value Disclosure	34	91
Restricted Investments, at Fair Value	1,606	1,733
Deferred receivables consideration	0	0
Total Assets	2,118	2,176
Liabilities:
Inventory-related payables	0	0
Total Liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	0	0
Liabilities:
Derivative Liability	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	0	0
Liabilities:
Derivative Liability	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Inventories carried at market	2,790	3,400
Cash Equivalents, at Carrying Value	0	0
Available-for-sale Securities, Fair Value Disclosure	1	1
Restricted Investments, at Fair Value	0	0
Deferred receivables consideration	386	307
Total Assets	3,932	4,046
Liabilities:
Inventory-related payables	596	680
Total Liabilities	1,557	1,041
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	509	275
Liabilities:
Derivative Liability	618	268
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	246	63
Liabilities:
Derivative Liability	335	92
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	8	1
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,378	1,486
Cash Equivalents, at Carrying Value	0	0
Available-for-sale Securities, Fair Value Disclosure	0	0
Restricted Investments, at Fair Value	0	0
Deferred receivables consideration	0	0
Total Assets	1,586	1,597
Liabilities:
Inventory-related payables	22	39
Total Liabilities	222	142
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	208	111
Liabilities:
Derivative Liability	200	103
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	0	0
Liabilities:
Derivative Liability	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	$ 0	$ 0