Subsequent Events (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	0 Months Ended	1 Months Ended
Apr. 30, 2013 Automotive Segment [Member] United States Welfare Benefit Plan [Member]	Feb. 11, 2013 Depositary units [Member]	Apr. 29, 2013 Depositary units [Member] Limited partners Dividend Declared [Member]	Apr. 30, 2013 Principal Owners and Affiliates [Member] Investment Funds [Member]
Subsequent Event [Line Items]
Distribution declared per depositary unit		$ 1.00	$ 1.00
OPEB curtailment gain	$ 19
Investment in funds				$ 45

The amount of net gain (loss) recognized in net periodic benefit cost as a result of an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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-Name Statement of Financial Accounting Standard (FAS)

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

-Publisher FASB

-Name Accounting Standards Codification

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

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-Name Statement of Financial Accounting Standard (FAS)

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

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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Reference 7: 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details