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Fair Value - Inputs - Narrative (Detail) (Significant Unobservable Inputs (Level 3) [Member], Auction-rate securities [Member])
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3 Months Ended |
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Apr. 28, 2012
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Minimum [Member]
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| Fair Value Inputs, Assets, Quantitative Information [Line Items] | |
| Durations until redemption | 6 months |
| Discount rates | 0.57% |
| Loss severities | 0.00% |
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Maximum [Member]
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| Fair Value Inputs, Assets, Quantitative Information [Line Items] | |
| Durations until redemption | 31 years |
| Discount rates | 6.10% |
| Loss severities | 25.00% |
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Weighted Average [Member]
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| Fair Value Inputs, Assets, Quantitative Information [Line Items] | |
| Durations until redemption | 5 years |
| Discount rates | 2.43% |
| Loss severities | 6.90% |