Debt Obligations (Changes In Debt Obligations) (Details) (USD $)				12 Months Ended				12 Months Ended						12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended									12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 3.75% Convertible Notes Due October 22, 2012 [Member]		Dec. 31, 2010 3.75% Convertible Notes Due October 22, 2012 [Member]		Dec. 31, 2011 2.50% Convertible Senior Notes Due August 15, 2013 [Member]		Dec. 31, 2010 2.50% Convertible Senior Notes Due August 15, 2013 [Member]		Feb. 28, 2010 2.50% Convertible Senior Notes Due August 15, 2013 [Member]	Mar. 31, 2008 2.50% Convertible Senior Notes Due August 15, 2013 [Member]	Dec. 31, 2011 4.00% Senior Unsecured Notes Due January 15, 2015 [Member]		Dec. 31, 2010 4.00% Senior Unsecured Notes Due January 15, 2015 [Member]		Dec. 31, 2011 5.55% Senior Unsecured Notes Due January 15, 2020 [Member]		Dec. 31, 2010 5.55% Senior Unsecured Notes Due January 15, 2020 [Member]		Dec. 31, 2011 5.25% Senior Unsecured Notes Due January 16, 2018 [Member]		Dec. 31, 2010 5.25% Senior Unsecured Notes Due January 16, 2018 [Member]		Dec. 31, 2011 $450 Million Senior Unsecured Term Loan Facility Credit Agreement Due September 19, 2016 [Member]		Dec. 31, 2011 $750 Million Revolving Credit Commitment Due September 19, 2016 [Member]		Dec. 31, 2011 $700 Million Senior Unsecured Term Loan Facility Credit Agreement Due September 19, 2011 [Member]		Dec. 31, 2010 $700 Million Senior Unsecured Term Loan Facility Credit Agreement Due September 19, 2011 [Member]		Dec. 31, 2011 2011 Credit Facility [Member]	Dec. 31, 2011 Senior Unsecured Term Loan Facility [Member] 2016 Term Loan [Member]	Dec. 31, 2011 Revolving Credit Facility [Member] 2011 Credit Facility [Member]	Dec. 31, 2011 Revolving Credit Facility [Member] 2011 Credit Facility [Member]
Debt Instrument [Line Items]
Total debt obligations	$ 2,117,000,000	$ 2,321,000,000			[1]		[1]	$ 88,000,000	[2]	$ 388,000,000	[2]			$ 399,000,000	[3]	$ 398,000,000	[3]	$ 598,000,000	[3]	$ 598,000,000	[3]	$ 367,000,000	[3]	$ 367,000,000	[3]	$ 439,000,000	[4]	$ 226,000,000	[4]			$ 570,000,000	[5]
Total debt obligations, Additions	700,000,000																									450,000,000	[4]	250,000,000	[4]
Less current portion	(45,000,000)	(140,000,000)
Total long-term debt obligations, Additions	655,000,000
Less current portion, Additions	(45,000,000)
Less current portion Payments, Conversion, Accretion and Other	140,000,000
Debt obligations	2,072,000,000	2,181,000,000
Unsecured debt																																		1,200,000,000
Debt instrument, increase, additional borrowings					[1]
Payments, Conversions, Accretion and Other					[1]			(300,000,000)	[2]					1,000,000	[3]											(11,000,000)	[4]	(24,000,000)	[4]	(570,000,000)	[5]
Total debt obligations, Payments, Conversions, Accretion and Other	(904,000,000)
Total debt obligations ending balance	2,117,000,000	2,321,000,000			[1]		[1]	88,000,000	[2]	388,000,000	[2]			399,000,000	[3]	398,000,000	[3]	598,000,000	[3]	598,000,000	[3]	367,000,000	[3]	367,000,000	[3]	439,000,000	[4]	226,000,000	[4]			570,000,000	[5]
Debt instrument, interest rate	3.75%	3.75%	3.75%	3.75%				2.50%				2.50%	2.50%	4.00%				5.55%				5.25%
Debt instrument, interest rate during period																														2.25%					1.66%	1.43%
Debt instrument, maturity date				Oct. 22, 2012				Aug. 15, 2013						Jan. 15, 2015				Jan. 15, 2020				Jan. 16, 2018								Sep. 19, 2011					Sep. 19, 2016		Sep. 19, 2016
Debt instrument, principal outstanding				500,000		500,000							475,000,000																	700,000,000					450,000,000	750,000,000	750,000,000
Total long-term debt obligations, payments, conversions, accretion and other	$ (764,000,000)

[1] As of December 31, 2011 and 2010, approximately $0.5 million aggregate principal amount of the 3.75% convertible notes remained outstanding.

[2] See "2.50% Convertible Senior Notes" below for further discussion.

[3] See "Senior Unsecured Notes" below for further discussion.

[4] See "2011 Credit Facility" below for further discussion.

[5] See "2010 Credit Facility" below for further discussion.