CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Parenthetical	Dec. 31, 2012 6.625% Senior Notes Due 2019 [Member]	Dec. 31, 2011 6.625% Senior Notes Due 2019 [Member]	Feb. 07, 2011 6.625% Senior Notes Due 2019 [Member]	Dec. 31, 2010 6.625% Senior Notes Due 2019 [Member]	Dec. 31, 2012 6.50% Senior Notes Due 2021 [Member]	Dec. 31, 2011 6.50% Senior Notes Due 2021 [Member]	Nov. 09, 2011 6.50% Senior Notes Due 2021 [Member]	Dec. 31, 2010 6.50% Senior Notes Due 2021 [Member]	Dec. 31, 2012 6.50% Senior Notes Due 2023 [Member]	Jun. 29, 2012 6.50% Senior Notes Due 2023 [Member]	Dec. 31, 2011 6.50% Senior Notes Due 2023 [Member]	Dec. 31, 2010 6.50% Senior Notes Due 2023 [Member]	Dec. 31, 2012 Convertible Debt [Member]	Dec. 31, 2011 Convertible Debt [Member]	Dec. 31, 2010 Convertible Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage	6.625%	6.625%	6.625%	0.00%	6.50%	6.50%	6.50%	0.00%	6.50%	6.50%	0.00%	0.00%	3.50%	3.50%	3.50%