SHORT-TERM DEBT AND LINES OF CREDIT (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Short-term borrowings
Short-term borrowings	$ 756.4	$ 482.4
Commercial paper
Short-term borrowings
Short-term borrowings	556.4	482.4
Average discount rate (as a percent)	0.33%	0.40%
Average amount of short-term borrowings	400.7	357.5
Loan under term credit facility
Short-term borrowings
Short-term borrowings	200.0
Average interest rate (as a percent)	0.80%
Average amount of short-term borrowings	$ 8.9