Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 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			(24.8)	(78.2)
Amounts reclassified from accumulated other comprehensive income loss			15.3	1.3
Net current period other comprehensive income loss	$ 9.4	$ (18.1)	(9.5)	(76.9)
Balance, as of the end of the period	(329.4)	(300.9)	(329.4)	(300.9)
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			5.5	1.2
Amounts reclassified from accumulated other comprehensive income loss			1.1	0.4
Net current period other comprehensive income loss			6.6	1.6
Balance, as of the end of the period	(4.2)	0.8	(4.2)	0.8
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			(176.5)	(17.9)
Amounts reclassified from accumulated other comprehensive income loss			14.2	0.9
Net current period other comprehensive income loss			(162.3)	(17.0)
Balance, as of the end of the period	(104.5)	(6.8)	(104.5)	(6.8)
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			(0.5)	1.3
Amounts reclassified from accumulated other comprehensive income loss			0.0	0.0
Net current period other comprehensive income loss			(0.5)	1.3
Balance, as of the end of the period	(33.2)	(36.5)	(33.2)	(36.5)
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			146.7	(62.8)
Amounts reclassified from accumulated other comprehensive income loss			0.0	0.0
Net current period other comprehensive income loss			146.7	(62.8)
Balance, as of the end of the period	$ (187.5)	$ (258.4)	$ (187.5)	$ (258.4)