DEBT (Revolving Credit Facility) (Details) - USD ($)	Jun. 19, 2015	Sep. 30, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Letters of credit issued		$ 3,800,000	$ 3,800,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 2,000,000,000
Line of credit facility, term	5 years
Line of credit, Current		$ 0	$ 0
Letter of Credit
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 70,000,000
Swingline Loans
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 50,000,000.0
Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee rate	0.085%
Minimum | Rate 2C | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee rate	0.20%
Maximum | Rate 2C | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
London Interbank Offered Rate (LIBOR) | Minimum | Rate 1 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
London Interbank Offered Rate (LIBOR) | Maximum | Rate 1 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.50%
Federal Funds Purchased | Rate 2B | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
One Month LIBOR | Rate 2C | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%