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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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-Name Accounting Standards Codification
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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

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Amount remaining of a stock repurchase plan authorized.

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No definition available.

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- Definition

Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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- Definition

The percentage of the original award that is paid out to employees at the end of the vesting period.

+ References

No definition available.

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Value of aggregate grant date fair value during the period.

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No definition available.

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- Definition

The maximum potential share payout at each balance sheet date.

+ References

No definition available.

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-- None. No documentation exists for this element. --

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Share Capital - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Feb. 17, 2017	May 13, 2016
Shareholders Equity Disclosure [Line Items]
Share repurchase program, number of shares repurchased and retired in the period	5.1
Share repurchase program, value of shares repurchased and retired during the period	$ 200.5
Minimum
Stock plans
Award vesting period	3 years
Maximum
Stock plans
Award vesting period	4 years
Settling of employee withholding taxes
Shareholders Equity Disclosure [Line Items]
Share repurchase program, value of shares repurchased and retired during the period	$ 0.5
Stock options
Stock plans
Options granted (in shares)	0.9
Options, weighted average grant date fair value, per share	$ 6.74
Restricted stock units
Stock plans
Other awards granted during the period (in shares)	1.1
Aggregate grant date fair value	$ 43.4
Restricted stock units \| Three Year Option
Stock plans
Award vesting period	3 years
Restricted stock units \| Four Year Option
Stock plans
Award vesting period	4 years
Liability-classed cash units
Stock plans
Other awards granted during the period (in shares)	0.6
Aggregate grant date fair value	$ 22.6
Liability-classed cash units \| Three Year Option
Stock plans
Award vesting period	3 years
Liability-classed cash units \| Four Year Option
Stock plans
Award vesting period	4 years
Performance Shares
Stock plans
Other awards granted during the period (in shares)	0.6
Aggregate grant date fair value	$ 24.6
Maximum number of performance shares	1.2
Performance Shares \| Minimum
Stock plans
Pinal payout percentage	0.00%
Performance Shares \| Maximum
Stock plans
Pinal payout percentage	200.00%
May 2016 Program
Shareholders Equity Disclosure [Line Items]
Share repurchase program, authorized amount			$ 1,000.0
Share repurchase program, number of shares repurchased and retired in the period	2.6
Share repurchase program, value of shares repurchased and retired during the period	$ 100.0
Share repurchase program, remaining authorization		$ 349.0
February 2017 Program
Shareholders Equity Disclosure [Line Items]
Share repurchase program, authorized amount		$ 1,000.0
Share repurchase program, number of shares repurchased and retired in the period	2.5
Share repurchase program, value of shares repurchased and retired during the period	$ 100.0
Share repurchase program, remaining authorization	$ 900.0