Condensed Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale securities, tax (provision) benefit	$ (0.2)	$ 0.4	$ 1.2	$ (0.3)
Reclassification adjustment for realized net loss (gain) on available-for-sale securities included in net income, tax provisions	0.0	0.0	0.0	0.0
Unrealized (loss) gain on cash flow hedges, tax (provision) benefit	1.5	(0.8)	1.2	(2.5)
Reclassification adjustment for realized net (gain) loss on cash flow hedges included in net income, tax (provisions)	$ (0.2)	$ (0.6)	$ (0.8)	$ (0.9)

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount of tax expense (benefit), before reclassification adjustments, related to increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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-Publisher FASB
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Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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-Publisher FASB
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