Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued [Abstract]
Balance at beginning of period	$ 238.0	$ 219.2	$ 194.6
Increases as a result of tax positions taken during a prior year	5.2	29.0	8.3
Decreases as a result of tax positions taken during a prior year	(19.7)	(16.3)	(1.9)
Settlements with taxing authorities	(4.1)	(1.1)	(34.9)
Lapse of statutes of limitation	(3.8)	(4.1)	(10.6)
Increases as a result of tax positions taken during the current year	11.3	11.3	63.7
Balance at end of period	226.9	238.0	$ 219.2
Income Tax Contingency [Line Items]
Unrecognized tax benefits that would impact effective tax rate	206.5
Income tax penalties and interest accrued	20.1	15.3
Income tax penalties and interest expense	(4.8)	$ (5.4)
Minimum [Member]
Income Tax Contingency [Line Items]
Anticipated decrease in unrecognized tax benefits	25.0
Maximum [Member]
Income Tax Contingency [Line Items]
Anticipated decrease in unrecognized tax benefits	$ 35.0