Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Assets:
Derivative Asset	$ 664	$ 624
Available-for-sale Securities, Fair Value Disclosure	468	483
Deferred receivables consideration	298	540
Liabilities:
Derivative Liability	574	651
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,590	4,424
Cash Equivalents, at Carrying Value	27	286
Available-for-sale Securities, Fair Value Disclosure	468	477
Restricted Investments, at Fair Value	1,443	1,613
Deferred receivables consideration	298	540
Total Assets	7,490	7,964
Liabilities:
Inventory-related payables	364	521
Total Liabilities	938	1,172
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	594	511
Liabilities:
Derivative Liability	478	561
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	64	102
Liabilities:
Derivative Liability	96	90
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	6	11
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	27	286
Available-for-sale Securities, Fair Value Disclosure	373	408
Restricted Investments, at Fair Value	1,443	1,613
Deferred receivables consideration	0	0
Total Assets	1,843	2,307
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]
Assets:
Derivative Asset	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Inventories carried at market	3,461	3,102
Cash Equivalents, at Carrying Value	0	0
Available-for-sale Securities, Fair Value Disclosure	95	69
Restricted Investments, at Fair Value	0	0
Deferred receivables consideration	298	540
Total Assets	4,345	4,195
Liabilities:
Inventory-related payables	336	491
Total Liabilities	787	1,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	421	371
Liabilities:
Derivative Liability	355	419
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	64	102
Liabilities:
Derivative Liability	96	90
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	6	11
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,129	1,322
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	1,302	1,462
Liabilities:
Inventory-related payables	28	30
Total Liabilities	151	172
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	173	140
Liabilities:
Derivative Liability	123	142
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