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Income Taxes - Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Reconciliation of beginning and ending amount of unrecognized tax benefits |  |  |
Balance, beginning of period | $ 33.1 | $ 32.4 | $ 26.8
Additions based on current year tax positions | 39.8 | 2.4 | 6.0
Additions based on prior years’ tax positions | 3.2 | 8.4 | 1.5
Reduction for prior years’ tax positions | (3.5) | (2.0) | 0.0
Reductions related to lapses of statutes of limitations | (4.0) | (6.3) | (2.3)
Settlements | (0.4) | (1.3) | 0.0
Additions (reductions) related to foreign exchange rates | (2.8) | (0.5) | 0.4
Balance, end of period | $ 65.4 | $ 33.1 | $ 32.4

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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 10B -URI http://asc.fasb.org/extlink&oid=116821951&loc=SL37586934-109318 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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