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Investments - Summary of Available-for-sale Securities (Details) - USD ($) $ in Millions | Feb. 03, 2018 | Jan. 28, 2017
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | $ 28.1 | $ 27.9
Unrealized Gain (Loss) | (0.2) | (0.7)
Fair Value | 27.9 | 27.2
US Treasury securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 8.3 | 8.8
Unrealized Gain (Loss) | (0.8) | (0.7)
Fair Value | 7.5 | 8.1
US government agency securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 5.3 | 4.6
Unrealized Gain (Loss) | (0.2) | (0.2)
Fair Value | 5.1 | 4.4
Corporate bonds and notes |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 11.0 | 11.0
Unrealized Gain (Loss) | (0.2) | (0.1)
Fair Value | 10.8 | 10.9
Corporate equity securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 3.5 | 3.5
Unrealized Gain (Loss) | 1.0 | 0.3
Fair Value | $ 4.5 | $ 3.8

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562 + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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