Debt and Borrowing Arrangements (Details 3) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Contractual debt maturities
Within one year	$ 3,055
Between one and two years	917
Between two and three years	994
Between three and four years	893
Between four and five years	99
Thereafter	357
Total	6,315
Vehicle Management Asset-Backed Debt
Contractual debt maturities
Within one year	952
Between one and two years	917
Between two and three years	744
Between three and four years	443
Between four and five years	99
Thereafter	99
Total	3,254
Mortgage Asset-Backed Debt
Contractual debt maturities
Within one year	1,484
Total	1,484
Unsecured Debt
Contractual debt maturities
Within one year	619
Between two and three years	250
Between three and four years	450
Thereafter	258
Total	$ 1,577

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

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)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Paragraph 31

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Amount of long-term debt maturities after year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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