CREDIT FACILITIES AND LONG-TERM DEBT (Details) (USD $) In Millions, unless otherwise specified				3 Months Ended		6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Dec. 31, 2012 Senior Credit Facility due 2017	Jun. 30, 2013 Senior Credit Facility due 2017 LIBOR	Jun. 30, 2012 Senior Credit Facility due 2017 LIBOR	Jun. 30, 2013 Senior Credit Facility due 2017 LIBOR	Jun. 30, 2012 Senior Credit Facility due 2017 LIBOR	Jun. 30, 2013 Senior revolving credit facility	Dec. 31, 2012 Senior revolving credit facility	Jun. 30, 2013 4.65% Senior Notes due 2021	Dec. 31, 2012 4.65% Senior Notes due 2021	Jun. 30, 2013 3.82% Series D Senior Notes due 2017	Dec. 31, 2012 3.82% Series D Senior Notes due 2017
Credit facility and long-term debt
Stated interest rate (as a percent)										4.65%	4.65%	3.82%	3.82%
Total long-term debt	$ 376	$ 688	$ 312							$ 349	$ 349	$ 27	$ 27
Less: current portion of long-term debt	3	3
Long-term debt	373	685
Maximum borrowing capacity								500
Amount outstanding under credit facility									312
Remaining borrowing capacity								$ 500
Variable rate basis				LIBOR	LIBOR	LIBOR	LIBOR
Debt average interest rate (as a percent)				1.45%	1.62%	1.45%	1.64%
Debt interest rate at end of period (as a percent)				1.45%	1.63%	1.45%	1.63%