Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Income Taxes
U.S. corporate statutory income tax rate (as a percent)	35.00%		35.00%	35.00%	35.00%
Increase in net deferred tax liabilities resulting from enactment of tax legislation	$ 58.1			$ 58.1
Impact of court ruling on uncertain tax positions		(47.5)
Changes in Unrecognized Tax Benefits
Beginning balance, Unrecognized tax benefits				108.9	119.5	119.5
Additions based on tax positions related to the current year				9.4		10.5
Additions for tax positions of prior years				64.4		10.9
Reductions for tax positions related to the current year				(6.3)		(3.3)
Reductions for tax positions of prior years						(28.7)
Ending balance, Unrecognized tax benefits	176.4			176.4		108.9
Amount of unrecognized tax benefits that would reduce the effective income tax rate, if recognized	61.6			61.6
Accumulated pre-tax interest and penalties related to unrecognized tax benefits	$ 100.0			$ 100.0		$ 37.0