Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Assets:
Derivative Asset	$ 871	$ 758
Available-for-sale Securities, Fair Value Disclosure	966	877
Deferred receivables consideration	292	513
Liabilities:
Derivative Liability	676	605
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,056	4,066
Cash Equivalents, at Carrying Value	190	328
Available-for-sale Securities, Fair Value Disclosure	968	873
Restricted Investments, at Fair Value	2,184	1,938
Deferred receivables consideration	292	513
Total Assets	8,561	8,476
Liabilities:
Inventory-related payables	473	721
Total Liabilities	1,149	1,326
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	704	646
Liabilities:
Derivative Liability	470	419
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	134	93
Liabilities:
Derivative Liability	206	186
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	33	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	190	328
Available-for-sale Securities, Fair Value Disclosure	879	698
Restricted Investments, at Fair Value	2,184	1,938
Deferred receivables consideration	0	0
Total Assets	3,253	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	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	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	3,087	3,062
Cash Equivalents, at Carrying Value	0	0
Available-for-sale Securities, Fair Value Disclosure	89	175
Restricted Investments, at Fair Value	0	0
Deferred receivables consideration	292	513
Total Assets	4,121	4,264
Liabilities:
Inventory-related payables	450	705
Total Liabilities	1,015	1,197
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	486	403
Liabilities:
Derivative Liability	359	306
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	134	92
Liabilities:
Derivative Liability	206	186
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	33	19
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	969	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	1,187	1,247
Liabilities:
Inventory-related payables	23	16
Total Liabilities	134	129
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	218	243
Liabilities:
Derivative Liability	111	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