Equity (Reconciliation of Ordinary Shares) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Stock repurchased and retired during period, shares				8.4
Stock repurchased and retired during period, value, excluding commissions				$ 374,700,000
Stock repurchase program, authorized amount				$ 2,000,000,000
Dividends declared per ordinary share	$ 0.16	$ 0.16	$ 0.12	$ 0.32	$ 0.31
Common Stock [Member]
December 31, 2011				297.1
Shares issued under incentive plans, net				3.1
Shares issued for settlement of Exchangeable Senior Notes				10.8
Repurchase of ordinary shares				(8.4)
September 30, 2012		302.6		302.6