Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets:
Derivative Asset	$ 950	$ 449
Deferred receivables consideration	475	307
Liabilities:
Derivative Liability	1,173	464
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,731	4,886
Cash Equivalents, at Carrying Value	492	352
Available-for-sale Securities, Fair Value Disclosure	26	92
Restricted Investments, at Fair Value	1,193	1,733
Deferred receivables consideration	475	307
Total Assets	7,867	7,819
Liabilities:
Inventory-related payables	701	719
Total Liabilities	1,874	1,183
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	678	386
Liabilities:
Derivative Liability	822	371
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	272	63
Liabilities:
Derivative Liability	338	92
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	13	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	492	352
Available-for-sale Securities, Fair Value Disclosure	25	91
Restricted Investments, at Fair Value	1,193	1,733
Deferred receivables consideration	0	0
Total Assets	1,710	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	2,932	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	475	307
Total Assets	4,141	4,046
Liabilities:
Inventory-related payables	657	680
Total Liabilities	1,627	1,041
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	461	275
Liabilities:
Derivative Liability	619	268
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	272	63
Liabilities:
Derivative Liability	338	92
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	13	1
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,799	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	2,016	1,597
Liabilities:
Inventory-related payables	44	39
Total Liabilities	247	142
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	217	111
Liabilities:
Derivative Liability	203	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