Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 62.0	$ 61.2	$ 30.9	$ 81.6
Available-for-sale debt securities:
Change in net unrealized gains, net	1.3	8.7	0.1	5.7
Net realized (gains) and losses reclassified into net income, net	(0.2)	(0.2)	(1.0)	0.3
Net change on available-for-sale debt securities, net	1.1	8.5	(0.9)	6.0
Cash flow hedges:
Change in net unrealized gains and (losses), net of tax benefit (provision) of $7.2 and $(7.3) during the three and six months ended June 30, 2021, respectively, and tax benefit (provision) of $(1.8) and $2.4 for the comparable periods in 2020, respectively	(19.7)	16.1	18.8	(8.8)
Net realized (gains) and losses reclassified into net income, net	(7.2)	6.1	(16.1)	7.5
Net change on cash flow hedges, net	(26.9)	22.2	2.7	(1.3)
Change in foreign currency translation adjustments	0.4	5.6	(1.5)	(9.1)
Other comprehensive income (loss), net	(25.4)	36.3	0.3	(4.4)
Comprehensive income	$ 36.6	$ 97.5	$ 31.2	$ 77.2