RELATED PARTY TRANSACTIONS - Schedule of Related Party Transactions, Recorded Income (Expense) (Details) - RBS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest rate swaps
Schedule of Related Party Transactions, Recorded Income (Expense) [Line Items]
Derivative expense	$ (75)		$ (125)	$ (130)
Derivative revenue		$ 5
Foreign exchange contracts
Schedule of Related Party Transactions, Recorded Income (Expense) [Line Items]
Foreign exchange and trade finance revenue	$ 5	$ 59	$ 21	$ 52