FINANCING ARRANGEMENTS (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 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	Jun. 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
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			806,500,000	804,200,000		607,300,000	601,600,000
Revolving credit facility, maximum borrowing capacity	0	0
Line of credit facility available borrowing capacity	287,800,000	259,700,000
Letters of credit amount outstanding	$ 112,200,000	$ 140,300,000