Capital Stock (Summary Of Stock Option Activity) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period, Number of Shares	17.8
Granted, Number of Shares	2.0
Exercised, Number of Shares	(6.2)
Forfeited or expired, Number of Shares	(1.3)
Outstanding at end of period, Number of Shares	12.3
Exercisable at end of period, Number of Shares	9.7
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of period, Weighted-Average Option Price per Share	$ 64.67
Granted, Weighted-Average Option Price per Share	$ 62.37
Exercised, Weighted-Average Option Price per Share	$ 60.28
Forfeited or expired, Weighted-Average Option Price per Share	$ 70.88
Outstanding at end of period, Weighted-Average Option Price per Share	$ 65.85
Exercisable at end of period, Weighted-Average Option Price per Share	$ 66.54
Outstanding at end of period, Weighted-Average Remaining Contractual Life	3 years 4 months 24 days
Exercisable at end of period, Weighted-Average Remaining Contractual Life	2 years 10 months 0 days
Outstanding at end of period, Aggregate Intrinsic Value	$ 217.5
Exercisable at end of period, Aggregate Intrinsic Value	$ 166.5

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Net number of share options (or share units) granted during the period.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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