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Derivative Financial Instruments (Narrative) (Details)
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3 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
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Apr. 30, 2011
USD ($)
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Apr. 30, 2011
JPY (¥)
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Jan. 31, 2011
JPY (¥)
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Apr. 30, 2011
Non-U.S. Denominated Debt [Member]
Net Investment Instrument [Member]
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Apr. 30, 2011
Non-U.S. Denominated Debt [Member]
Cash Flow Instruments [Member]
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Apr. 30, 2011
Fair Value Instruments [Member]
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Apr. 30, 2011
Net Investment Instrument [Member]
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Apr. 30, 2011
Cash Flow Instruments [Member]
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Apr. 30, 2011
GBP [Member]
GBP (£)
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Jan. 31, 2011
GBP [Member]
GBP (£)
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| Cash collateral held from counterparties | $ 505,000,000 | |||||||||
| Threshold of derivative liability position requiring cash collateral | 150,000,000 | |||||||||
| Debt designated as United Kingdom net investment hedge | 3,000,000,000 | 3,000,000,000 | ||||||||
| Debt designated as Japanese net investment hedge | ¥ 437,000,000,000 | ¥ 437,000,000,000 | ||||||||
| Instrument maturity date range start | May 2011 | September 2029 | April 2012 | October 2023 | August 2013 | |||||
| Instrument maturity date range end | January 2039 | March 2034 | May 2014 | February 2030 | July 2015 | |||||