Condensed Consolidated Statements of Stockholders' Deficit Statement - USD ($) $ in Millions	Total	Common Stock Including Additional Paid in Capital [Member]	Accumulated Deficit [Member]	AOCI Attributable to Parent [Member]
Stockholders' Deficit	$ (1,581.0)	$ 11,808.0	$ (13,386.4)	$ (2.6)
Stock Repurchased During Period, Value		(660.2)
Dividends, Common Stock, Cash		0.0
Stock-based compensation expense		29.9
Stock Issued During Period, Value, Employee Stock Purchase Plan		8.3
Excise tax on repurchase of common stock	(6.1)
Net Income	392.9		392.9
Other Comprehensive Income (Loss), Net of Tax	$ (0.2)			(0.2)
Common Stock, Dividends, Per Share, Cash Paid	$ 0
Stockholders' Deficit	$ (1,635.7)	11,559.4	(13,192.3)	(2.8)
Stock Repurchased During Period, Value		(390.3)
Dividends, Common Stock, Cash		0.0
Stock-based compensation expense		14.6
Stock Issued During Period, Value, Employee Stock Purchase Plan		0.0
Excise tax on repurchase of common stock	(3.8)
Net Income	198.8		198.8
Other Comprehensive Income (Loss), Net of Tax	$ 0.0			0.0
Common Stock, Dividends, Per Share, Cash Paid	$ 0
Stockholders' Deficit	$ (1,816.4)	11,179.9	(12,993.5)	(2.8)
Stockholders' Deficit	(1,957.9)	10,645.3	(12,600.7)	(2.5)
Stock Repurchased During Period, Value		(408.5)
Dividends, Common Stock, Cash		(72.1)
Stock-based compensation expense		33.9
Stock Issued During Period, Value, Employee Stock Purchase Plan		7.9
Excise tax on repurchase of common stock	(3.5)
Net Income	406.7		406.7
Other Comprehensive Income (Loss), Net of Tax	$ (0.3)			(0.3)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.77
Stockholders' Deficit	$ (1,977.0)	10,427.2	(12,401.4)	(2.8)
Stock Repurchased During Period, Value		(166.8)
Dividends, Common Stock, Cash		(72.1)
Stock-based compensation expense		16.2
Stock Issued During Period, Value, Employee Stock Purchase Plan		0.0
Excise tax on repurchase of common stock	(1.5)
Net Income	207.4		207.4
Other Comprehensive Income (Loss), Net of Tax	$ 0.0			0.0
Common Stock, Dividends, Per Share, Cash Paid	$ 0.77
Stockholders' Deficit	$ (1,993.8)	$ 10,203.0	$ (12,194.0)	$ (2.8)