SUBSEQUENT EVENTS - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
	Nov. 03, 2015	Oct. 22, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Subsequent Event [Line Items]
Dividends declared and paid (in Dollars per Share)			$ 0.10	$ 0.68	$ 0.30	$ 1.34
Dividends paid to common stockholders					$ 90
Subsequent Event
Subsequent Event [Line Items]
RBS sale of CFG's common stock (in Shares)	110,461,782
Percent of outstanding common stock held by RBS prior to sale of shares	20.90%
Sale of CFG common stock by RBS (in Dollars per Share)	$ 23.38
Dividends declared and paid (in Dollars per Share)		$ 0.10
Dividends paid to common stockholders		$ 53