Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Assets:
Unrealized derivative gains	$ 2,392	$ 2,676
Deferred receivables consideration	597	900
Liabilities:
Unrealized derivative losses	2,376	2,591
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Assets:
Marketable securities	2,045	2,451
Total Assets	3,275	3,877
Liabilities:
Total Liabilities	1,445	1,600
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Commodity Contracts [Member]
Assets:
Unrealized derivative gains	1,230	1,426
Liabilities:
Unrealized derivative losses	1,445	1,600
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Inventories carried at market	4,746	5,291
Marketable securities	17	16
Deferred receivables consideration	597	900
Total Assets	6,299	7,314
Liabilities:
Inventory-related payables	547	903
Total Liabilities	1,307	1,756
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Unrealized derivative gains	757	936
Liabilities:
Unrealized derivative losses	634	638
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Unrealized derivative gains	181	170
Liabilities:
Unrealized derivative losses	126	215
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Assets:
Unrealized derivative gains	1	1
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	2,022	1,745
Total Assets	2,245	1,888
Liabilities:
Inventory-related payables	216	33
Total Liabilities	387	171
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Unrealized derivative gains	223	143
Liabilities:
Unrealized derivative losses	171	138
Fair Value, Measurements, Recurring [Member] | Total Fair Value [Member]
Assets:
Inventories carried at market	6,768	7,036
Marketable securities	2,062	2,467
Deferred receivables consideration	597	900
Total Assets	11,819	13,079
Liabilities:
Inventory-related payables	763	936
Total Liabilities	3,139	3,527
Fair Value, Measurements, Recurring [Member] | Total Fair Value [Member] | Commodity Contracts [Member]
Assets:
Unrealized derivative gains	2,210	2,505
Liabilities:
Unrealized derivative losses	2,250	2,376
Fair Value, Measurements, Recurring [Member] | Total Fair Value [Member] | Foreign Exchange Contracts [Member]
Assets:
Unrealized derivative gains	181	170
Liabilities:
Unrealized derivative losses	126	215
Fair Value, Measurements, Recurring [Member] | Total Fair Value [Member] | Interest Rate Contracts [Member]
Assets:
Unrealized derivative gains	$ 1	$ 1