| **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, 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, 2012 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, 2011162 $35.54 393 $48.80Granted50 27.27 285 37.10Vested(93) 27.58 (158) 46.18Forfeited(1) 33.97 (57) 43.58Nonvested at October 31, 2012118 38.28 463 43.20                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 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:  2012 2011 2010Risk-free interest rate0.8% 2.0% 2.3%Dividend yield—% —% —%Expected volatility55.6% 45.9% 53.2%Expected life (in years)4.8 4.8 4.7                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]                                             | The following summarizes stock option activity for the years ended October 31:  2012 2011 2010 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 year4,500 $39.65 4,911 $33.81 5,917 $33.09Granted1,289 31.69 1,069 60.32 599 38.71Exercised(71) 27.66 (1,440) 34.87 (1,147) 30.94Forfeited/expired(82) 44.66 (40) 47.06 (458) 38.14Options outstanding, at end of year5,636 37.89 4,500 39.65 4,911 33.81Options exercisable, at end of year3,672 36.96 3,064 36.07 3,767 34.67                                                                                                                                                                                                                                                       |
| Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block] | The following table summarizes information about stock options outstanding at October 31, 2012:  Options Outstanding NumberOutstanding  Weighted Average Remaining Contractual Life  Weighted Average Exercise Price   Aggregate Intrinsic ValueRange of Exercise Prices:(in thousands) (in years)   (in millions)$ 21.22 - $ 31.812,059 3.5 $24.53 $—$ 32.18 - $ 40.921,773 4.3 38.13 —$ 42.48 - $ 69.911,804 2.9 52.91 —The following table summarizes information about stock options exercisable at October 31, 2012:  Options Exercisable NumberOutstanding  Weighted Average Remaining Contractual Life  Weighted Average Exercise Price   Aggregate Intrinsic ValueRange of Exercise Prices:(in thousands) (in years)   (in millions)$ 21.22 - $ 31.811,558 3.1 $25.02 $—$ 32.18 - $ 40.92863 2.7 39.34 —$ 42.48 - $ 69.911,251 2.0 50.20 — |

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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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No definition available.
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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 Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901Reference 2: 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 3: 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.
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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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