RELATED PARTY TRANSACTIONS - Schedule of Related Party Swap Agreements (Details) - Interest rate swaps - Derivatives designated as hedging instruments: - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Schedule of Related Party Swap Agreements [Line Items]
Notional amount	[1]	$ 11,000	$ 5,750
RBS
Schedule of Related Party Swap Agreements [Line Items]
Notional amount		7,700	5,750
RBS | Receive-fixed swap
Schedule of Related Party Swap Agreements [Line Items]
Notional amount		$ 5,200	$ 4,750
Minimum fixed interest rate		1.66%	1.66%
Maximum fixed interest rate		2.04%	2.04%
RBS | Pay-fixed swap
Schedule of Related Party Swap Agreements [Line Items]
Notional amount		$ 2,500	$ 1,000
Minimum fixed interest rate		2.03%	4.18%
Maximum fixed interest rate		4.30%	4.30%

[1] The notional or contractual amount of interest rate derivatives and foreign exchange contracts is the amount upon which interest and other payments under the contract are based. For interest rate derivatives, the notional amount is typically not exchanged. Therefore, notional amounts should not be taken as the measure of credit or market risk, as they tend to greatly overstate the true economic risk of these contracts.