Equity (Reconciliation of Ordinary Shares) (Details) (Ordinary shares [Member]) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2009	Dec. 31, 2008
Ordinary shares [Member]
Beginning balance, shares	328.2	320.6	318.8
Shares issued under incentive plans	5.2
Repurchase of ordinary shares	(36.3)
Ending balance, shares	297.1	320.6	318.8