Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Assets:
Derivative Asset	$ 782	$ 758
Available-for-sale Securities, Fair Value Disclosure	718	877
Deferred receivables consideration	661	513
Liabilities:
Derivative Liability	774	605
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	3,697	4,066
Cash Equivalents, at Carrying Value	249	328
Available-for-sale Securities, Fair Value Disclosure	718	873
Restricted Investments, at Fair Value	1,878	1,938
Deferred receivables consideration	661	513
Total Assets	7,985	8,476
Liabilities:
Inventory-related payables	409	721
Total Liabilities	1,183	1,326
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	699	646
Liabilities:
Derivative Liability	675	419
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	55	93
Liabilities:
Derivative Liability	99	186
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	28	19
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	249	328
Available-for-sale Securities, Fair Value Disclosure	647	698
Restricted Investments, at Fair Value	1,878	1,938
Deferred receivables consideration	0	0
Total Assets	2,778	2,965
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	4	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	1
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]
Assets:
Derivative Asset	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Inventories carried at market	2,533	3,062
Cash Equivalents, at Carrying Value	0	0
Available-for-sale Securities, Fair Value Disclosure	71	175
Restricted Investments, at Fair Value	0	0
Deferred receivables consideration	661	513
Total Assets	3,839	4,264
Liabilities:
Inventory-related payables	394	705
Total Liabilities	1,050	1,197
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	491	403
Liabilities:
Derivative Liability	557	306
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	55	92
Liabilities:
Derivative Liability	99	186
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	28	19
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,164	1,004
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	1,368	1,247
Liabilities:
Inventory-related payables	15	16
Total Liabilities	133	129
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	204	243
Liabilities:
Derivative Liability	118	113
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]
Assets:
Derivative Asset	$ 0	$ 0