SHAREHOLDERS' EQUITY - Stock Repurchase (Details) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2014
SHAREHOLDERS' EQUITY
Number of shares authorized to be repurchased for retirement				50,000
Remaining number of shares authorized to be repurchased	27,800
Repurchase and retirement of common stock (in shares)	17,200	6,700	1,700
Repurchase and retirement of common stock	$ 456	$ 158	$ 35
Repurchase and retirement of common stock to offset the dilutive impact of the grant of long-term stock awards (shares)	741	1,700