Share Capital (Movements In Shares Issued And Outstanding) (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Stockholders' Equity Attributable to Parent [Abstract]
Common shares issued - beginning balance	490.4	459.5
Issue of new shares	0	11.7
Common shares issued - ending balance	490.4	471.2
Less: Treasury shares for which dividend and voting rights do not apply	(39.4)	(28.4)
Common shares outstanding	451.0	442.8
Participating preferred shares, on an as converted basis		$ 19.2
Common shares and common share equivalents outstanding	$ 451.0	$ 462.0