RELATED PARTY TRANSACTIONS - Schedule of Related Party Fee Impact on Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Related Party Fees Effect on Income [Line Items]
The effect of related party service fees on outside services	$ 89	$ 106	$ 267	$ 314
RBS
Schedule of Related Party Fees Effect on Income [Line Items]
The effect of related party service and referral fees, net of occupancy expense, on total fee income	2	5	9	13
The effect of related party service fees on outside services	$ 3	$ 3	$ 8	$ 19