| **Long-Term Debt**                          | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Long-term Debt, Unclassified [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Long-Term Debt                              | LONG-TERM DEBT During 2015, we issued $3.76 billion of medium-term notes, of which $2.87 billion were at fixed interest rates and $891 million were at floating interest rates, primarily indexed to LIBOR.  At December 31, 2015, the outstanding medium-term notes had remaining maturities ranging up to 12 years.  Debt issuance costs are capitalized and amortized to Interest expense using the straight-line method over the term of the debt issuance.  The balance of our Medium-term notes contains unamortized fair value adjustments for debt in a fair value hedge relationship.   Long-term debt outstanding as of December 31, was comprised of the following: (Millions of dollars)      2015 2014  Balance Avg. Rate Balance Avg. RateMedium-term notes $20,611 2.4% $23,094 2.4%Unamortized discount (1)   (4)  Medium-term notes, net 20,610   23,090  Bank borrowings 995 4.0% 1,484 3.4%Total $21,605   $24,574            Long-term debt outstanding as of December 31, 2015, matures as follows: (Millions of dollars) 2016$5,36220175,86620184,15420192,53120201,125Thereafter2,567Total$21,605   |

| X                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**us-gaap_LongTermDebtAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The entire disclosure for long-term debt.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
+ Details**Name:**us-gaap_LongTermDebtTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |