EARNINGS PER COMMON SHARE - Reconciliations of the Numerators and Denominators Used in the Computations of Basic and Diluted Earnings per Common Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator (basic and diluted):
Income from continuing operations	$ 98	$ 134	$ 150	$ 109	$ 76	$ 111	$ 109	$ 61	$ 491	$ 357	$ 821
Less: Allocation to unvested restricted stock awards									6	5	16
Income from continuing operations attributable to common shareholders									485	352	805
(Loss) income from discontinued operations, net									0	(2)	35
Less: Allocation to unvested restricted stock awards									0	0	(1)
(Loss) income from discontinued operations attributable to common shareholders									0	(2)	34
Net income available to common shareholders									$ 485	$ 350	$ 839
Denominator:
Basic common shares (based upon weighted average) (in shares)									326	338	349
Add: Stock option dilution (in shares)									4	3	3
Diluted common shares (in shares)									330	341	352