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Fair Value Measurements (Notional Amounts and Fair Values of Interest Rate Swaps) (Details) (USD $)
In Millions |
Apr. 30, 2011
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Jan. 31, 2011
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|---|---|---|
| Notional Amount | $ 9,538 | $ 9,779 |
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Fair Value Hedging [Member] | Fixed-Rate Interest Rate Swaps [Member] | Floating-Rate Interest Rate Swaps [Member]
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| Notional Amount | 3,945 | 4,445 |
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Fair Value Hedging [Member] | Fixed-Rate Interest Rate Swaps [Member] | Floating-Rate Interest Rate Swaps [Member] | Fair Value, Inputs, Level 2 [Member]
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| Fair Value | 249 | 267 |
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Net Investment Hedging [Member] | Cross-Currency Interest Rate Contract [Member] | Fixed-Rate Interest Rate Swaps [Member]
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| Notional Amount | 1,250 | 1,250 |
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Net Investment Hedging [Member] | Cross-Currency Interest Rate Contract [Member] | Fixed-Rate Interest Rate Swaps [Member] | Fair Value, Inputs, Level 2 [Member]
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| Fair Value | 165 | 233 |
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Cash Flow Hedging [Member] | Cross-Currency Interest Rate Contract [Member] | Fixed-Rate Interest Rate Swaps [Member]
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| Notional Amount | 3,150 | 2,902 |
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Cash Flow Hedging [Member] | Cross-Currency Interest Rate Contract [Member] | Fixed-Rate Interest Rate Swaps [Member] | Fair Value, Inputs, Level 2 [Member]
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| Fair Value | 241 | 238 |
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Cash Flow Hedging [Member] | Fixed-Rate Interest Rate Swaps [Member] | Floating-Rate Interest Rate Swaps [Member]
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| Notional Amount | 1,193 | 1,182 |
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Cash Flow Hedging [Member] | Fixed-Rate Interest Rate Swaps [Member] | Floating-Rate Interest Rate Swaps [Member] | Fair Value, Inputs, Level 2 [Member]
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| Fair Value | (18) | (18) |
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Fair Value, Inputs, Level 2 [Member]
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| Fair Value | $ 637 | $ 720 |