Income Taxes Schedule of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal income tax provision (benefit)	$ (55.5)	$ (112.3)	$ (324.0)
Deferred federal income tax provision (benefit)	(614.3)	34.5	110.3
State and Local Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current state income tax provision (benefit)	(1.5)	(6.6)	(15.5)
Deferred state income tax provision (benefit)	(36.9)	(9.2)	(3.3)
Total income tax provision (benefit)	$ (708.2)	$ (93.6)	$ (232.5)