RELATED PARTY TRANSACTIONS - Schedule of Related Party Transactions, Recorded Income (Expense) (Details) - RBS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest rate swaps
Schedule of Related Party Transactions, Recorded Income (Expense) [Line Items]
Derivative revenue	$ 18
Derivative expense		$ (82)	$ (50)	$ (135)
Foreign exchange contracts
Schedule of Related Party Transactions, Recorded Income (Expense) [Line Items]
Foreign exchange and trade finance expense	$ (19)	$ (1)		$ (7)
Foreign exchange and trade finance revenue			$ 16