Share capital (Tables)

12 Months Ended

Dec. 31, 2012

Share capital [Abstract]

Share capital

	2012					2011						2010
All shares are common shares of $2.00 par value each	Shares			$millions		Shares			$millions			Shares			$millions
Authorized share capital		800,000,000			1,600		800,000,000			1,600			800,000,000			1,600
Issued and fully paid share capital		469,250,933			938		469,250,933			938			443,308,487			887
Treasury shares held by Company		(72,859	)		-		(1,478,759	)		(3	)		(182,796	)		(1	)
Outstanding shares in issue		469,178,074			938		467,772,174			935			443,125,691			886