Impairment loss on marketable securities and investments in associated companies	12 Months Ended
Dec. 31, 2012
Impairment loss on marketable securities and investments in associated companies [Abstract]
Impairment loss on marketable securities and investments in associated companies	Note 10 – Impairment loss on marketable securities and investments in associated companies As at December 31, 2012, the Company owns a number of shares, share purchase agreements and bonds in companies including Archer Ltd., Asia Offshore Drilling Ltd., Varia Perdana Bhd., Tioman Drilling, Sevan Drilling, Seabras Sapura, Itaunas Drilling, Camburi Drilling, Sahy Drilling, Petromena and SapuraKencana Petroleum Berhad. In 2012, the Company determined that the decline in fair value of the Archer investment was other than temporary based primarily upon its evaluation of the severity of the excess of its cost basis over the market price of the security and the prospects for recovery within 2013. As a result, an impairment loss was recognized reducing its cost basis of this associated company to the market price of the shares in question as of December 31, 2012, which was $121 million. The impairment loss amounted to $221 million and is presented as share of result from associated companies in the consolidated statements of operations. In 2011, the Company determined that the decline in fair value of the Archer investment was other than temporary based primarily upon its evaluation of the severity of the excess of its cost basis over the market price of the security and the future prospects. As a result, an impairment loss was recognized reducing its cost basis of this associated company to the market price of the shares in question as of December 31, 2011, which was $393 million. The impairment loss amounted to $463 million and is presented as share of result from associated companies in the consolidated statements of operations. In 2011, the Company determined that the decline in fair value of its Seahawk Drilling Inc, "Seahawk", shares was other than temporary and as a result, an impairment loss was recognized reducing its cost basis to the market price of the shares in question as of December 31, 2011. The impairment loss amounted to $10 million and has been classified as a separate line item in the consolidated statements of operations. In 2010, the Company determined that the decline in fair value of its Seahawk shares was other than temporary and as a result, an impairment loss was recognized reducing its cost basis to the market price of the shares in question as of December 31, 2010. The loss of $15 million was classified as a separate line item in the income statement.

Note 10 – Impairment loss on marketable securities and investments in associated companies

As at December 31, 2012, the Company owns a number of shares, share purchase agreements and bonds in companies including Archer Ltd., Asia Offshore Drilling Ltd., Varia Perdana Bhd., Tioman Drilling, Sevan

Drilling, Seabras Sapura, Itaunas Drilling, Camburi Drilling, Sahy Drilling, Petromena and SapuraKencana Petroleum Berhad.

In 2012, the Company determined that the decline in fair value of the Archer investment was other than temporary based primarily upon its evaluation of the severity of the excess of its cost basis over the market price of the security and the prospects for recovery within 2013. As a result, an impairment loss was recognized reducing its cost basis of this associated company to the market price of the shares in question as of December 31, 2012, which was $121 million. The impairment loss amounted to $221 million and is presented as share of result from associated companies in the consolidated statements of operations.

In 2011, the Company determined that the decline in fair value of the Archer investment was other than temporary based primarily upon its evaluation of the severity of the excess of its cost basis over the market price of the security and the future prospects. As a result, an impairment loss was recognized reducing its cost basis of this associated company to the market price of the shares in question as of December 31, 2011, which was $393 million. The impairment loss amounted to $463 million and is presented as share of result from associated companies in the consolidated statements of operations.

In 2011, the Company determined that the decline in fair value of its Seahawk Drilling Inc, "Seahawk", shares was other than temporary and as a result, an impairment loss was recognized reducing its cost basis to the market price of the shares in question as of December 31, 2011. The impairment loss amounted to $10 million and has been classified as a separate line item in the consolidated statements of operations.

In 2010, the Company determined that the decline in fair value of its Seahawk shares was other than temporary and as a result, an impairment loss was recognized reducing its cost basis to the market price of the shares in question as of December 31, 2010. The loss of $15 million was classified as a separate line item in the income statement.