Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets:
Derivative Asset	$ 660	$ 636
Deferred receivables consideration	430	379
Liabilities:
Derivative Liability	621	761
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,511	4,547
Cash Equivalents, at Carrying Value	432	1,288
Available-for-sale Securities, Fair Value Disclosure	31	13
Restricted Investments, at Fair Value	1,073	1,044
Deferred receivables consideration	430	379
Total Assets	7,137	7,907
Liabilities:
Inventory-related payables	1,139	597
Total Liabilities	1,760	1,358
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	469	461
Liabilities:
Derivative Liability	434	589
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	191	175
Liabilities:
Derivative Liability	155	152
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	32	20
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	432	1,288
Available-for-sale Securities, Fair Value Disclosure	30	12
Restricted Investments, at Fair Value	1,073	1,044
Deferred receivables consideration	0	0
Total Assets	1,535	2,344
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	3,000	3,032
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	430	379
Total Assets	3,879	3,893
Liabilities:
Inventory-related payables	1,123	579
Total Liabilities	1,601	1,095
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	257	306
Liabilities:
Derivative Liability	291	344
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	191	175
Liabilities:
Derivative Liability	155	152
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Liabilities:
Derivative Liability	32	20
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,511	1,515
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	1,723	1,670
Liabilities:
Inventory-related payables	16	18
Total Liabilities	159	263
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	212	155
Liabilities:
Derivative Liability	143	245
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