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New Accounting Standards (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Tax expense (benefit) | $ 2.9 | $ 17.0 | $ 5.1 | $ 23.9
Accounting Standards Update 2016-09 [Member] |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Excess tax benefit from share-based compensation, Operating activities |  |  | 25.5 |
Tax expense (benefit) | (9.6) |  | (25.5) |
Accounting Standards Update 2016-02 [Member] |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Operating leases, Future minimum payments due | 71.8 |  | 71.8 |
Accounting Standards Update 2016-16 [Member] |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
New accounting pronouncement cumulative effect of change on equity | $ (4.1) |  | $ (4.1) |

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- Definition Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 20 -Section 55 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=65896087&loc=d3e11374-113907 + Details
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