Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interest [Member]
Number of shares, Beginning balance at Dec. 31, 2012		508.4
Stockholders' equity, Beginning balance at Dec. 31, 2012	$ 6,999.5		$ 9,905.7	$ 4.7	$ (2,911.4)	$ 0.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	439.8				439.8
Other comprehensive income (loss), net	59.9			59.9
Issuance of common stock (in number of shares)		16.0
Issuance of common stock	142.2		142.2
Dissolution of non-controlling interest	(0.5)					(0.5)
Repurchase and retirement of common stock (in number of shares)		(29.2)
Repurchase and retirement of common stock	(577.8)		(418.1)		(159.7)
Share-based compensation expense	244.9		244.9
Tax effects from employee stock option plans			(5.8)
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	(5.8)
Number of shares, Ending balance at Dec. 31, 2013		495.2
Stockholders' equity, Ending balance at Dec. 31, 2013	7,302.2		9,868.9	64.6	(2,631.3)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	(334.3)				(334.3)
Other comprehensive income (loss), net	(78.4)			(78.4)
Issuance of common stock (in number of shares)		17.7
Issuance of common stock	159.1		159.1
Repurchase and retirement of common stock (in number of shares)		(96.7)
Repurchase and retirement of common stock	(2,262.5)		(1,367.0)		(895.5)
Share-based compensation expense	240.0		240.0
Tax effects from employee stock option plans			(21.0)
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	(21.0)
Payment of cash dividends	(86.0)		(86.0)
Number of shares, Ending balance at Dec. 31, 2014		416.2
Stockholders' equity, Ending balance at Dec. 31, 2014	4,919.1		8,794.0	(13.8)	(3,861.1)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	633.7				633.7
Other comprehensive income (loss), net	(5.4)			(5.4)
Issuance of common stock (in number of shares)		13.6
Issuance of common stock	121.2		121.2
Repurchase and retirement of common stock (in number of shares)		(45.8)
Repurchase and retirement of common stock	(1,153.6)		(639.8)		(513.8)
Share-based compensation expense	217.3		217.3
Tax effects from employee stock option plans			(1.6)
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	(1.6)
Payment of cash dividends	(156.3)		(156.3)
Number of shares, Ending balance at Dec. 31, 2015		384.0
Stockholders' equity, Ending balance at Dec. 31, 2015	$ 4,574.4		$ 8,334.8	$ (19.2)	$ (3,741.2)	$ 0.0