Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated other comprehensive income [Line Items]
Balance, as of the beginning of the period	$ (319.9)	$ (224.0)
Other comprehensive income loss before reclassifications	1.0	(26.6)
Amounts reclassified from accumulated other comprehensive income loss	(6.3)	(8.7)
Net current period other comprehensive income loss	(5.3)	(35.3)
Balance, as of the end of the period	(325.2)	(259.3)
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated other comprehensive income [Line Items]
Balance, as of the beginning of the period	(10.8)	(0.8)
Other comprehensive income loss before reclassifications	(2.0)	2.5
Amounts reclassified from accumulated other comprehensive income loss	0.4	0.0
Net current period other comprehensive income loss	(1.6)	2.5
Balance, as of the end of the period	(12.4)	1.7
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated other comprehensive income [Line Items]
Balance, as of the beginning of the period	57.8	10.2
Other comprehensive income loss before reclassifications	(17.1)	(38.9)
Amounts reclassified from accumulated other comprehensive income loss	(6.7)	(8.7)
Net current period other comprehensive income loss	(23.8)	(47.6)
Balance, as of the end of the period	34.0	(37.4)
Accumulated Defined Benefit Plans Adjustment
Accumulated other comprehensive income [Line Items]
Balance, as of the beginning of the period	(32.7)	(37.8)
Other comprehensive income loss before reclassifications	0.1	0.2
Amounts reclassified from accumulated other comprehensive income loss	0.0	0.0
Net current period other comprehensive income loss	0.1	0.2
Balance, as of the end of the period	(32.6)	(37.6)
Accumulated Translation Adjustment
Accumulated other comprehensive income [Line Items]
Balance, as of the beginning of the period	(334.2)	(195.6)
Other comprehensive income loss before reclassifications	20.0	9.6
Amounts reclassified from accumulated other comprehensive income loss	0.0	0.0
Net current period other comprehensive income loss	20.0	9.6
Balance, as of the end of the period	$ (314.2)	$ (186.0)