CREDIT FACILITIES AND LONG-TERM DEBT (Details) (USD $) In Millions, unless otherwise specified					3 Months Ended		9 Months Ended					0 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended											9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Senior Credit Facility due 2017	Dec. 31, 2013 Senior Credit Facility due 2017	Sep. 30, 2014 Senior Credit Facility due 2017 LIBOR	Sep. 30, 2013 Senior Credit Facility due 2017 LIBOR	Sep. 30, 2014 Senior Credit Facility due 2017 LIBOR	Sep. 30, 2013 Senior Credit Facility due 2017 LIBOR	Dec. 31, 2013 Senior Credit Facility due 2017 LIBOR	Sep. 30, 2014 Senior revolving credit facility	Dec. 31, 2013 Senior revolving credit facility	Jul. 02, 2013 Term Loan Facility due 2018	Sep. 30, 2014 Term Loan Facility due 2018	Dec. 31, 2013 Term Loan Facility due 2018	Jul. 01, 2013 Term Loan Facility due 2018	Sep. 30, 2014 Term Loan Facility due 2018 LIBOR borrowings LIBOR	Sep. 30, 2013 Term Loan Facility due 2018 LIBOR borrowings LIBOR	Sep. 30, 2014 Term Loan Facility due 2018 LIBOR borrowings LIBOR	Dec. 31, 2013 Term Loan Facility due 2018 LIBOR borrowings LIBOR	Sep. 30, 2014 Term Loan Facility due 2018 LIBOR borrowings LIBOR Hedges of cash flows Interest rate swaps	Sep. 30, 2013 Term Loan Facility due 2018 LIBOR borrowings LIBOR Hedges of cash flows Interest rate swaps	Sep. 30, 2014 Term Loan Facility due 2018 LIBOR borrowings LIBOR Hedges of cash flows Interest rate swaps	Sep. 30, 2014 4.65% Senior Notes due 2021	Dec. 31, 2013 4.65% Senior Notes due 2021	Sep. 30, 2014 5.09% Unsecured Senior Notes due 2015	Dec. 31, 2013 5.09% Unsecured Senior Notes due 2015	Sep. 30, 2014 5.29% Unsecured Senior Notes due 2020	Dec. 31, 2013 5.29% Unsecured Senior Notes due 2020	Sep. 30, 2014 5.69% Unsecured Senior Notes due 2035	Dec. 31, 2013 5.69% Unsecured Senior Notes due 2035	Sep. 30, 2014 3.82% Series D Senior Notes due 2017	Dec. 31, 2013 3.82% Series D Senior Notes due 2017	Sep. 30, 2014 GTN Senior Notes Maximum
Credit facilities and long-term debt
Stated interest rate (as a percent)																							4.65%	4.65%	5.09%	5.09%	5.29%	5.29%	5.69%	5.69%	3.82%	3.82%
Total long-term debt	$ 1,533	$ 1,578	$ 335	$ 380									$ 500	$ 500									$ 349	$ 349	$ 75	$ 75	$ 100	$ 100	$ 150	$ 150	$ 24	$ 24
Less: current portion of long-term debt	79	3
Long-term debt	1,454	1,575
Maximum borrowing capacity										500					500
Borrowings under the facility												500
Amount outstanding under credit facility										335	380
Remaining borrowing capacity										$ 165
Debt average interest rate (as a percent)					1.41%	1.44%	1.41%	1.45%								1.41%	1.44%	1.41%		1.83%	1.56%	1.83%
Debt interest rate, at period end (as a percent)					1.41%		1.41%		1.42%							1.41%		1.41%	1.42%
Percentage of debt to total capitalization																																	70.00%