Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Assets:
Marketable securities	$ 877	$ 1,000
Deferred receivables consideration	513	511
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,066	4,699
Cash Equivalents	328	491
Marketable securities	873	940
Segregated investments	1,938	2,158
Deferred receivables consideration		511
Total Assets	8,476	9,696
Liabilities:
Inventory-related payables	721	652
Total Liabilities	1,326	1,578
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	646	690
Liabilities:
Derivative Liability	419	776
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	93	186
Liabilities:
Derivative Liability	186	150
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	19	21
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	328	491
Marketable securities	698	860
Segregated investments	1,938	2,158
Deferred receivables consideration	0	0
Total Assets	2,965	3,509
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	1	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]
Assets:
Derivative Asset	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Inventories carried at market	3,062	3,208
Marketable securities	175	80
Deferred receivables consideration	513	511
Total Assets	4,264	4,493
Liabilities:
Inventory-related payables	705	612
Total Liabilities	1,197	1,326
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	403	487
Liabilities:
Derivative Liability	306	564
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	92	186
Liabilities:
Derivative Liability	186	150
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	19	21
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,004	1,491
Marketable securities	0	0
Deferred receivables consideration	0	0
Total Assets	1,247	1,694
Liabilities:
Inventory-related payables	16	40
Total Liabilities	129	252
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	243	203
Liabilities:
Derivative Liability	113	212
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