Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total debt	$ 2,343	$ 2,355
Current portion of long-term debt	63	63
Five Point Eight Seven Five Percent Senior Notes Due Two Thousand Twenty One [Member]
Debt Instrument [Line Items]
Total debt	350	350
Interest rate of convertible senior notes		5.875%
Six Point Three Percent Senior Notes due Two Thousand Sixteen [Member]
Debt Instrument [Line Items]
Total debt	500	500
Interest rate of convertible senior notes	6.30%	6.30%
Seven Point Seven Five Percent Senior Notes due Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Total debt	500	500
Interest rate of convertible senior notes	7.75%	7.75%
Seven Point Eight Seven Five Percent Senior Notes due Two Thousand Twenty [Member]
Debt Instrument [Line Items]
Total debt	249	249
Interest rate of convertible senior notes	7.875%	7.875%
Eight Point Three Seven Five Percent Senior Notes due Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Total debt	350	350
Interest rate of convertible senior notes	8.375%	8.375%
Nine Point Seven Five Percent Senior Notes due Two Thousand Fourteen [Member]
Debt Instrument [Line Items]
Total debt	59	59
Interest rate of convertible senior notes	9.75%	9.75%
Ten Percent Convertible Senior Notes due Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Total debt	72	72
Interest rate of convertible senior notes	10.00%	10.00%
Ship Mortgage Facility [Member]
Debt Instrument [Line Items]
Total debt	24	25
Current portion of long-term debt	4	4
Oman Credit Facilities [Member]
Debt Instrument [Line Items]
Total debt	0	11
Industrial Revenue Bonds [Member]
Debt Instrument [Line Items]
Total debt	$ 239	$ 239