|
Debt (Narrative) (Details) (USD $)
|
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2011
|
Dec. 31, 2010
|
|
| Debt Instrument [Line Items] | ||
| Senior unsecured notes outstanding | $ 1,249,281,000 | $ 1,249,221,000 |
| Accrued interest related to senior notes | 31,000,000 | 32,000,000 |
|
7.456% Senior Notes Due 2018 [Member]
|
||
| Debt Instrument [Line Items] | ||
| Senior unsecured notes outstanding | 500,000,000 | 500,000,000 |
| Senior notes, maturity date | August 2018 | |
| Senior notes, interest rate | 7.456% | |
| Redemption at option of holder | Repayable in whole or in part on August 15, 2013, at the option of the holders, at 100% of the principal amount plus accrued interest | |
| Redemption at option of Company | We may redeem the 7.456% Notes at a redemption price of 100% of the principal plus accrued interest, plus a "make-whole" premium, in whole or in part at any time at our option | |
| Senior notes redemption price percentage at the option of holder | 100.00% | |
| Fair value of senior notes | 563,000,000 | 561,000,000 |
|
5.95% Senior Notes Due 2020 [Member]
|
||
| Debt Instrument [Line Items] | ||
| Senior unsecured notes principal amount | 750,000,000 | |
| Senior unsecured notes outstanding | 749,281,000 | 749,221,000 |
| Senior notes, maturity date | August 2020 | |
| Senior notes, interest rate | 5.95% | |
| Senior notes issued price percentage | 99.893% | |
| Redemption at option of Company | We may redeem the 5.95% Notes at our option in whole or in part at any time or from time to time at a specified "make-whole" premium | |
| Fair value of senior notes | 760,000,000 | 743,000,000 |
|
8.5% Senior Notes Due 2016 [Member]
|
||
| Debt Instrument [Line Items] | ||
| Senior unsecured notes principal amount | 400,000,000 | 400,000,000 |
| Senior notes, maturity date | 2016 | |
| Senior notes, interest rate | 8.50% | |
|
Prior Credit Facility [Member]
|
||
| Debt Instrument [Line Items] | ||
| Unsecured revolving credit facility | 1,000,000,000 | |
|
Credit Facility [Member]
|
||
| Debt Instrument [Line Items] | ||
| Unsecured revolving credit facility | 750,000,000 | |
| Interest, on drawn amount | LIBOR plus 150 basis points | |
| Commitment fee on undrawn amounts | 22.5 basis points | |
| Line of credit, outstanding | 0 | 0 |
| Line of credit facility, maturity date | August 2016 | |
| Letters of credit issued under the credit facility | $ 22,000,000 | $ 27,000,000 |