Condensed Consolidating Financial Statements Condensed Consolidating Financial Statements (Details) (USD $)
In Millions, unless otherwise specified |
Jun. 30, 2012
|
Dec. 31, 2011
|
Jun. 30, 2012
Senior Notes [Member]
6% convertible senior notes [Domain]
|
Dec. 31, 2011
Senior Notes [Member]
6% convertible senior notes [Domain]
|
Feb. 23, 2010
Senior Notes [Member]
6% convertible senior notes [Domain]
|
Jun. 30, 2012
Senior Notes [Member]
Senior A Notes [Domain]
|
Dec. 31, 2011
Senior Notes [Member]
Senior A Notes [Domain]
|
Jul. 22, 2011
Senior Notes [Member]
Senior A Notes [Domain]
|
Jun. 30, 2012
Senior Notes [Member]
Senior B Notes [Domain]
|
Dec. 31, 2011
Senior Notes [Member]
Senior B Notes [Domain]
|
Jul. 22, 2011
Senior Notes [Member]
Senior B Notes [Domain]
|
---|---|---|---|---|---|---|---|---|---|---|---|
Debt Instrument, Face Amount | $ 1,388.3 | $ 1,358.8 | $ 69.4 | $ 69.4 | $ 70.0 | $ 153.6 | $ 146.3 | $ 140.0 | $ 94.3 | $ 98.0 | $ 100.0 |