SHORT-TERM DEBT AND LINES OF CREDIT (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Short-term borrowings
Short-term borrowings outstanding	$ 303.3	$ 10.0
Average amount of borrowings under revolving credit facilities			114.5
Commercial paper
Short-term borrowings
Short-term borrowings outstanding	303.3		212.1
Average discount rate (as a percent)	0.31%		0.52%
Average amount of short-term borrowings outstanding	134.9	66.9	193.8
Short-term notes payable
Short-term borrowings
Short-term borrowings outstanding		10.0	10.0
Average interest rate (as a percent)		0.32%	0.18%
Average amount of short-term borrowings outstanding	$ 3.6	$ 10.0	$ 48.0