Change in Valuation Allowance (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Valuation Allowance [Abstract]
Balance at beginning of period	$ 392.9	$ 489.9	$ 508.1
(Reversed) charged to costs and expenses	65.2	(49.5)	(25.1)
Charged (reversed) to gross tax assets and other accounts	9.2	(47.5)	6.9
Balance at end of period	$ 467.3	$ 392.9	$ 489.9