Income Taxes - Components of Income Tax Provision (Benefit) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Current - Federal	$ (6.4)	$ (72.0)	$ (1.0)
Current - State	(82.6)	5.6	(16.4)
Deferred - Federal	(1,421.4)	(726.7)	(450.6)
Deferred - State	(51.2)	(87.1)	(70.1)
Current - Ouside of the U.S.	28.5	13.0	8.8
Deferred - Ouside of the U.S.	(16.6)	(3.3)	(5.3)
Total income tax benefit	$ (1,549.7)	$ (870.5)	$ (534.6)