FINANCING ARRANGEMENTS (Details) (USD $)									9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Unsecured debt Unsecured senior notes 2020	Dec. 31, 2013 Unsecured debt Unsecured senior notes 2020	Jul. 30, 2012 Unsecured debt Unsecured senior notes 2020	Sep. 30, 2014 Unsecured debt Unsecured senior notes 2021	Dec. 31, 2013 Unsecured debt Unsecured senior notes 2021	Dec. 07, 2012 Unsecured debt Unsecured senior notes 2021	Sep. 30, 2014 Parent and domestic subsidiaries	Sep. 30, 2014 Canadian subsidiaries
Financing arrangements
Senior unsecured notes			$ 800,000,000	$ 800,000,000		$ 595,000,000	$ 600,000,000
Long-term obligations	1,395,000,000	1,400,000,000
Senior unsecured notes principal amount					800,000,000			600,000,000
Stated interest rate			5.25%	5.25%	5.25%	5.125%	5.125%	5.125%
Long-term Debt, Fair Value			794,900,000	804,200,000		586,200,000	601,600,000
Revolving credit facility, maximum borrowing capacity	0	0
Line of credit facility available borrowing capacity	262,100,000	259,700,000
Letters of credit amount outstanding	$ 110,400,000	$ 140,300,000
Credit available subject to percentage of accounts receivable									85.00%	85.00%
Credit available subject to percentage of cash deposited									100.00%	100.00%