Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Millions	Mar. 31, 2019	Dec. 31, 2018
Condensed Consolidated Balance Sheets
Common stock, par value (in dollars per share)	$ 0.0001
Common stock, no par value		$ 0
Common stock, authorized shares	240.0
Common stock, shares outstanding	59.6	59.4

Face amount per share of no-par value common stock.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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