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		(963.3)
Dividends, Common Stock, Cash		0.0
Stock-based compensation expense		46.0
Stock Issued During Period, Value, Employee Stock Purchase Plan		12.3
Excise tax on repurchase of common stock	(9.0)
Net Income	594.2		594.2
Other Comprehensive Income (Loss), Net of Tax	$ 0.2			0.2
Common Stock, Dividends, Per Share, Cash Paid	$ 0
Stockholders' Deficit	$ (1,816.4)	11,179.9	(12,993.5)	(2.8)
Stock Repurchased During Period, Value		(303.1)
Dividends, Common Stock, Cash		0.0
Stock-based compensation expense		16.1
Stock Issued During Period, Value, Employee Stock Purchase Plan		4.0
Excise tax on repurchase of common stock	(2.9)
Net Income	201.3		201.3
Other Comprehensive Income (Loss), Net of Tax	$ 0.4			0.4
Common Stock, Dividends, Per Share, Cash Paid	$ 0
Stockholders' Deficit	$ (1,900.6)	10,894.0	(12,792.2)	(2.4)
Stockholders' Deficit	(1,957.9)	10,645.3	(12,600.7)	(2.5)
Stock Repurchased During Period, Value		(627.2)
Dividends, Common Stock, Cash		(144.1)
Stock-based compensation expense		52.5
Stock Issued During Period, Value, Employee Stock Purchase Plan		12.3
Excise tax on repurchase of common stock	(5.4)
Net Income	619.5		619.5
Other Comprehensive Income (Loss), Net of Tax	$ (0.2)			(0.2)
Common Stock, Dividends, Per Share, Cash Paid	$ 1.54
Stockholders' Deficit	$ (1,993.8)	10,203.0	(12,194.0)	(2.8)
Stock Repurchased During Period, Value		(218.7)
Dividends, Common Stock, Cash		(72.0)
Stock-based compensation expense		18.6
Stock Issued During Period, Value, Employee Stock Purchase Plan		4.4
Excise tax on repurchase of common stock	(1.9)
Net Income	212.8		212.8
Other Comprehensive Income (Loss), Net of Tax	$ 0.1			0.1
Common Stock, Dividends, Per Share, Cash Paid	$ 0.77
Stockholders' Deficit	$ (2,050.5)	$ 9,933.4	$ (11,981.2)	$ (2.7)