STOCK-BASED COMPENSATION - Stock Options (Details) - Stock Options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Options
Vesting period	5 years
Expiration period	10 years
Shares
Outstanding at the beginning of the period (in shares)	18,000,000	24,000,000	30,000,000
Granted (in shares)	452,380		1,000,000
Exercised (in shares)	5,000,000	2,000,000	3,000,000
Forfeited (in shares)	3,200,000	4,000,000	4,000,000
Modification upon spin off	2,000,000
Outstanding at the end of the period (in shares)	12,000,000	18,000,000	24,000,000
Option shares vested and expected to vest at the end of the period	12,000,000	18,000,000	24,000,000
Option shares exercisable at the end of the period	10,000,000	15,000,000	20,000,000
Weighted average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 21	$ 22	$ 21
Granted (in dollars per share)	26	22	20
Exercised (in dollars per share)	17	16	12
Forfeited (in dollars per share)	29	28	26
Forfeitures upon spin off (in dollars per share)	19
Outstanding at the end of the period (in dollars per share)	17	21	22
Option shares vested and expected to vest at the end of the period (in dollars per share)	17	21	22
Option shares exercisable at the end of the period (in dollars per share)	$ 18	$ 22	$ 24
Aggregate intrinsic value
Exercised	$ 50	$ 22	$ 23
Option shares vested and expected to vest at the end of the period	133	110	109
Option shares exercisable at the end of the period	$ 113	$ 84	$ 62
Weighted average remaining option term
Outstanding at the end of the period	3 years	4 years	4 years
Option shares vested and expected to vest at the end of the period	3 years	4 years	4 years
Option shares exercisable at the end of the period	3 years	3 years	3 years
Additional disclosures
Total unrecognized compensation expense	$ 6	$ 6	$ 9
Weighted average remaining vesting period	2 years	2 years	2 years