| **Long-Term Debt (Tables)**                       | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
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| **Long-term Debt, Unclassified [Abstract]**       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Long-term debt                                    | Long-term debt outstanding as of December 31, was comprised of the following: (Millions of dollars)        2012 2011 2010  Balance Avg. Rate Balance Avg. Rate Balance Avg. RateMedium-term notes $23,488 3.2% $20,058 3.9% $17,690 4.6%Unamortized discount (13)   (10)   (9)  Medium-term notes, net 23,475   20,048   17,681  Bank borrowings 1,602 4.1% 1,583 3.7% 1,603 3.8%Secured borrowings —   —   78 4.9%Total $25,077   $21,631   $19,362                |
| Aggregate amounts of maturities of long-term debt |  Long-term debt outstanding as of December 31, 2012, matures as follows: (Millions of dollars)   2013$5,99120146,55920154,64820162,02720172,693Thereafter3,159Total$25,077                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |

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| - Definition
Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.
+ References
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| - Definition
Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented.
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