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Fair Value Measurements - Narrative (Details) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Oct. 01, 2017 USD ($) | Oct. 02, 2016 USD ($) | Oct. 01, 2017 USD ($) segment | Oct. 02, 2016 USD ($) | Jan. 01, 2017 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Unrealized gain (loss) on available-for-sale investments, net of tax | $ 28.8 | $ 1.3 | $ 48.6 | $ 8.8 |
Number of reportable segments | segment |  |  | 3 |  |
Temp Holdings Investment |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Unrealized gain (loss) on available-for-sale investments, net of tax | 28.8 | $ 1.3 | $ 48.6 | $ 8.8 |
Cost of available-for-sale investments | $ 18.4 |  | $ 18.4 |  | $ 17.7

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- Definition This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
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- Definition Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669646-108580 + Details
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