Fair Value Measurements (Fair Value Measurements At Reporting Date) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Assets:
Derivative Asset	$ 443	$ 624
Available-for-sale Securities, Fair Value Disclosure	468	483
Deferred receivables consideration	399	540
Liabilities:
Derivative Liability	564	651
Fair Value, Measurements, Recurring [Member]
Assets:
Inventories carried at market	4,455	4,424
Cash Equivalents, at Carrying Value	49	286
Available-for-sale Securities, Fair Value Disclosure	468	477
Restricted Investments, at Fair Value	1,827	1,613
Deferred receivables consideration	399	540
Total Assets	7,641	7,964
Liabilities:
Inventory-related payables	513	521
Total Liabilities	1,077	1,172
Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	360	511
Liabilities:
Derivative Liability	445	561
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	81	102
Liabilities:
Derivative Liability	119	90
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	2	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	49	286
Available-for-sale Securities, Fair Value Disclosure	376	408
Restricted Investments, at Fair Value	1,827	1,613
Deferred receivables consideration	0	0
Total Assets	2,252	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	3,361	3,102
Cash Equivalents, at Carrying Value	0	0
Available-for-sale Securities, Fair Value Disclosure	92	69
Restricted Investments, at Fair Value	0	0
Deferred receivables consideration	399	540
Total Assets	4,175	4,195
Liabilities:
Inventory-related payables	493	491
Total Liabilities	912	1,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	240	371
Liabilities:
Derivative Liability	300	419
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Contracts [Member]
Assets:
Derivative Asset	81	102
Liabilities:
Derivative Liability	119	90
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contracts [Member]
Assets:
Derivative Asset	2	11
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Inventories carried at market	1,094	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	1,214	1,462
Liabilities:
Inventory-related payables	20	30
Total Liabilities	165	172
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commodity Contracts [Member]
Assets:
Derivative Asset	120	140
Liabilities:
Derivative Liability	145	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