Estimated Annual Amortization Expense (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012
Expected Amortization Expense [Line Items]
2012	$ 384
2013	335
2014	298
2015	267
2016	$ 237

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The amount of amortization expense expected to be recognized during year five of the five succeeding fiscal years.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of amortization expense expected to be recognized during year four of the five succeeding fiscal years.

+ References

+ Details

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- Definition

The amount of amortization expense expected to be recognized during year one of the five succeeding fiscal years.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of amortization expense expected to be recognized during year three of the five succeeding fiscal years.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of amortization expense expected to be recognized during year two of the five succeeding fiscal years.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration