Contractual interest rate for funds borrowed, under the debt agreement.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Debt (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Oct. 31, 2013	Aug. 01, 2014
Debt Instrument [Line Items]
Amount of debt outstanding	$ 2,209us-gaap_LongTermDebt	$ 2,355us-gaap_LongTermDebt
Current portion of long-term debt	4us-gaap_LongTermDebtCurrent	63us-gaap_LongTermDebtCurrent
5.875% senior notes due 2021
Debt Instrument [Line Items]
Amount of debt outstanding	350	350	350
Stated interest rate	5.875%	5.875%
6.3% senior notes due 2016
Debt Instrument [Line Items]
Amount of debt outstanding	500	500
Stated interest rate	6.30%	6.30%
7.75% senior notes due 2018
Debt Instrument [Line Items]
Amount of debt outstanding	500	500
Stated interest rate	7.75%	7.75%
7.875% senior notes due 2020 (net of discount: 2014 - $1; 2013 - $1)
Debt Instrument [Line Items]
Amount of debt outstanding	249	249
Stated interest rate	7.875%	7.875%
Unamortized discount	1	1
8.375% senior notes due 2018
Debt Instrument [Line Items]
Amount of debt outstanding	350	350
Stated interest rate	8.375%	8.375%
9.75% senior notes due 2014
Debt Instrument [Line Items]
Amount of debt outstanding	0	59		59
Stated interest rate	9.75%	9.75%
10% convertible senior notes due 2018 (net of discount: 2013 - $3)
Debt Instrument [Line Items]
Amount of debt outstanding	0	72
Stated interest rate	10.00%	10.00%
Unamortized discount	0	3
Ship mortgage facility (includes current portion of long-term debt: 2014 - $4; 2013 - $4)
Debt Instrument [Line Items]
Amount of debt outstanding	21	25
Current portion of long-term debt	4	4
Credit facilities of Oman joint ventures
Debt Instrument [Line Items]
Amount of debt outstanding	0	11
Industrial revenue bonds (due 2028 through 2034)
Debt Instrument [Line Items]
Amount of debt outstanding	$ 239	$ 239