SHARE REPURCHASE PLAN (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Share repurchase plan authorized at 2012 extraordinary general meeting	Jun. 29, 2012 Share repurchase plan authorized at 2011 extraordinary general meeting
Repurchase plan information
Aggregate shares repurchased	$ 51.7
Aggregate purchase value of shares repurchased	334.0
Aggregate limit on share repurchases under the share repurchase plans (as a percent)	10.00%
Stock repurchased and retired during period (in shares)		31.3	20.4
Purchase price of stock repurchased and retired during period		$ 200.0	$ 134.0
Shares available to be repurchased under the plans		35.3