| **Derivative Financial Instruments and Risk Management (Tables)**                                                       | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
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| **Derivative Instruments and Hedging Activities Disclosure [Abstract]**                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| Location and fair value of derivative instruments reported in the Consolidated Statements of Financial Position         | The location and fair value of derivative instruments reported in the Consolidated Statements of Financial Position were as follows: (Millions of dollars)            Asset (Liability) Fair Value    December 31,  Consolidated Statements of Financial Position Location 2012 2011 2010Designated derivatives        Interest rate contracts Other assets $226 $248 $211Interest rate contracts Accrued expenses (8) (6) (18)    $218 $242 $193Undesignated derivatives        Foreign exchange contracts Other assets $10 $7 $6Foreign exchange contracts Accrued expenses (5) (16) (9)Cross currency contracts Accrued expenses (1) — —Interest rate contracts Other assets 2 — —Interest rate contracts Accrued expenses (1) (1) (1)    $5 $(10) $(4)                                                                                                                                                                                                                                                  |
| Deferred gains (losses) recorded in AOCI on the Consolidated Statements of Changes in Stockholder's Equity              | For the years ended December 31, 2012, 2011 and 2010, the deferred gains (losses) recorded in AOCI on the Consolidated Statements of Changes in Stockholder’s Equity associated with our cash flow interest rate contract hedges were as follows: (Millions of dollars) Balance as of December 31, 2011, net of tax of $3$(6)Gains (losses) deferred during the year, net of tax of $-1(Gains) losses reclassified to earnings, net of tax of $(1)(3)Balance as of December 31, 2012, net of tax of $4$(8)  (Millions of dollars) Balance as of December 31, 2010, net of tax of $6$(14)Gains (losses) deferred during the year, net of tax of $-(1)(Gains) losses reclassified to earnings, net of tax of $39Balance as of December 31, 2011, net of tax of $3$(6)   (Millions of dollars) Balance as of December 31, 2009, net of tax of $21$(41)Gains (losses) deferred during the year, net of tax of $1(6)(Gains) losses reclassified to earnings, net of tax of $1633Balance as of December 31, 2010, net of tax of $6$(14)                                                                                                                                                                                                                                                                                                                                                                                    |
| Schedule of effect of derivatives designated as fair value hedging instruments in the Consolidated Statements of Profit | The effect of derivatives designated as hedging instruments on the Consolidated Statements of Profit was as follows: Fair Value Hedges(Millions of dollars)    Year Ended December 31, 2012  Classification Gains (Losses)on Derivatives Gains (Losses)on BorrowingsInterest rate contracts Other income (expense) $(20) $36           Year Ended December 31, 2011  Classification Gains (Losses)on Derivatives Gains (Losses)on BorrowingsInterest rate contracts Other income (expense) $39 $(44)           Year Ended December 31, 2010  Classification Gains (Losses)on Derivatives Gains (Losses)on BorrowingsInterest rate contracts Other income (expense) $107 $(98)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Schedule of effect of derivatives designated as cash flow hedging instruments in the Consolidated Statements of Profit  | Cash Flow Hedges(Millions of dollars)    Year Ended December 31, 2012  Classification ofGains (Losses) Reclassified from AOCIto Earnings(Effective Portion) Recognized in Earnings(Ineffective Portion)Interest rate contracts Interest expense $4 $—Interest rate contracts Other income (expense) — (1)    $4 $(1)           Year Ended December 31, 2011  Classification ofGains (Losses) Reclassified from AOCIto Earnings(Effective Portion) Recognized in Earnings(Ineffective Portion)Interest rate contracts Interest expense $(12) $—Interest rate contracts Other income (expense) — (2)    $(12) $(2)           Year Ended December 31, 2010  Classification ofGains (Losses) Reclassified from AOCIto Earnings(Effective Portion) Recognized in Earnings(Ineffective Portion)Interest rate contracts Interest expense $(49) $—Interest rate contracts Other income (expense) — (1)    $(49) $(1)                                                                                                                                 |
| Schedule of effect of derivatives not designated as hedging instruments on the Consolidated Statements of Profit        | The effect of derivatives not designated as hedging instruments on the Consolidated Statements of Profit was as follows for the years ended December 31: Undesignated Derivatives      (Millions of dollars)          Classification of Gains (Losses) 2012 2011 2010Foreign exchange contracts Other income (expense) $7 $(15) $16Cross currency contracts Other income (expense) (1) — —Interest rate contracts Other income (expense) — — 2    $6 $(15) $18                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Schedule of offsetting of derivative assets and liabilities                                                             | The effect of the net settlement provisions of the master netting agreements on our derivative balances upon an event of default or a termination event is as follows: Offsetting of Derivative Assets and Liabilities      (Millions of dollars)        December 31, 2012 December 31, 2011 December 31, 2010Derivative Assets      Gross Amount of Recognized Assets $238 $255 $217Gross Amounts Offset — — —Net Amount of Assets(1) 238 255 217Gross Amounts Not Offset      Financial Instruments (12) (11) (26)Cash Collateral Received — — —Net Amount $226 $244 $191       Derivative Liabilities      Gross Amount of Recognized Liabilities $(15) $(23) $(28)Gross Amounts Offset — — —Net Amount of Liabilities(1) (15) (23) (28)Gross Amounts Not Offset      Financial Instruments 12 11 26Cash Collateral Received — — —Net Amount $(3) $(12) $(2)       (1) As presented in the Consolidated Statements of Financial Position. |

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| - Definition
Tabular disclosure of derivative and other financial assets and liabilities that are subject to offsetting, including master netting arrangements.
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No definition available.
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| - Definition
Tabular disclosure of the effective portion of gains and losses on derivative instruments (and nonderivative instruments) designated and qualifying in cash flow hedges recorded in accumulated other comprehensive income (loss) during the term of the hedging relationship and reclassified into earnings during the current period.
+ References
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| - Definition
Tabular disclosure for cash flow hedging instruments of (a) the location and amount of gains and losses reported in the statement of financial performance and (b) the location and fair value amounts of the instruments reported in the statement of financial position.
+ References
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| - Definition
Tabular disclosure of the location and amount of gains and losses reported in the statement of financial performance, or when applicable, the statement of financial position. For example,  (a) gains and losses recognized in the income statement on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges and (b) gains and losses initially recognized in other comprehensive income on derivative instruments designated and qualifying as cash flow hedges.
+ References
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| - Definition
Tabular disclosure of the location and fair value amounts of derivative instruments (and nonderivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position.
+ References
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| - Definition
Tabular disclosure for other derivative instruments not designated as hedging instruments of (a) the location and amount of gains and losses reported in the statement of financial performance and (b) the location and fair value amounts of the instruments reported in the statement of financial position.
+ References
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