Debt (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total debt	$ 2,270		$ 2,355
Interest rate of convertible senior notes	(10.00%)
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 Net of Discount [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	0	72	72
Interest rate of convertible senior notes	(10.00%)		(10.00%)
Ship Mortgage Facility [Member]
Debt Instrument [Line Items]
Total debt	23		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