The number of shares converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 230
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-Section 50
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-Name Accounting Standards Codification
-Topic 230
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-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

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- Definition

Number of non-option equity instruments exercised by participants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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Per share or per unit amount of equity securities issued.

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Employee Share-Based Incentive Compensation Plans (WTM - Stock options) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended
	Jan. 20, 2017	Mar. 31, 2017	Dec. 31, 2016
Share-based compensation arrangement by share-based payment award
Shares issued, price per share			$ 742
Common Stock
Share-based compensation arrangement by share-based payment award
Conversion of stock, shares converted		5,142
Chief Executive Officer \| Employee Stock Option
Share-based compensation arrangement by share-based payment award
Non-option equity instruments, exercised	125,000	40,000
Options, exercises in period, intrinsic value		$ 4.4
Combination One \| Employee Stock Option
Share-based compensation arrangement by share-based payment award
Non-option equity instruments, exercised			5,000
Options, exercises in period, intrinsic value			$ 0.4
Shares issued, price per share			$ 742
Combination Two \| Employee Stock Option
Share-based compensation arrangement by share-based payment award
Non-option equity instruments, exercised			80,000
Options, exercises in period, intrinsic value			$ 8.4
Conversion of stock, shares converted			9,930