| **Stock-based compensation plans (Tables)**                                                                                  | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
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| **Disclosure of Compensation Related Costs, Share-based Payments [Abstract]**                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]                                             | The following summarizes stock option activity for the years ended October 31:  2011 2010 2009 Shares Weighted Average Exercise Price Shares Weighted Average Exercise Price Shares Weighted Average Exercise Price (in thousands)   (in thousands)   (in thousands)  Options outstanding, at beginning of year4,911 $33.81 5,917 $33.09 5,589 $34.60Granted1,069 60.32 599 38.71 951 22.66Exercised(1,440) 34.87 (1,147) 30.94 (456) 30.29Forfeited/expired(40) 47.06 (458) 38.14 (167) 31.81Options outstanding, at end of year4,500 39.65 4,911 33.81 5,917 33.09Options exercisable, at end of year3,064 $36.07 3,767 $34.67 5,023 $34.95                                                                                                                                                                                                                                                                                                                                                                                  |
| Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block] | The following table summarizes information about stock options outstanding at October 31, 2011: Options Outstanding  NumberOutstanding  WeightedAverageRemainingContractualLife  WeightedAverageExercisePrice   Aggregate Intrinsic ValueRange of Exercise Prices          (in thousands) (in years)   (in millions)$ 21.22 - $ 31.81 1,615 4.2 $24.98 $28$ 32.18 - $ 40.92 1,043 3.9 38.80 3$ 42.48 - $ 69.91 1,842 3.9 53.00 —The following table summarizes information about stock options exercisable at October 31, 2011: Options Exercisable  NumberOutstanding  WeightedAverageRemainingContractualLife  WeightedAverageExercisePrice   Aggregate Intrinsic ValueRange of Exercise Prices          (in thousands) (in years)   (in millions)$ 21.22 - $ 31.81 1,347 3.6 $25.45 $22$ 32.18 - $ 40.92 738 3.3 40.02 2$ 42.48 - $ 69.91 979 2.0 47.70 — |
| Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]                               | The fair value of each option grant was estimated on the grant date using the Black-Scholes option-pricing model with the following weighted average assumptions:   2011 2010 2009Risk-free interest rate 2.27% 2.72% 1.34%Dividend yield —% —% —%Expected volatility 46.80% 52.60% 47.30%Expected life in years 5.4 5.5 5.9                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]                | Restricted stock unit and cash-settled restricted stock unit activity for the year ended October 31, 2011 was as follows:  Share-Settled Restricted Stock Units Cash-Settled Restricted Stock Units  Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value  (in thousands)   (in thousands)  Nonvested at October 31, 2010 459 $45.21 275 $35.81Granted 43 53.72 225 59.25Vested (333) 50.98 (90) 35.81Forfeited (7) 46.75 (17) 46.53Nonvested at October 31, 2011 162 35.54 393 48.80                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |

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| - Definition
Disclosure of the number and weighted-average grant date fair value for restricted stock and restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock and restricted stock units that were granted, vested, or forfeited during the year.
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| - Definition
Tabular disclosure of option exercise prices, by grouped ranges, including the upper and lower limits of the price range, the number of shares under option, weighted average exercise price and remaining contractual option terms.
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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph 64 -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 Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph f -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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901
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| - Definition
Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year.
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| - Definition
Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.
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