RELATED PARTY TRANSACTIONS AND SIGNIFICANT TRANSACTIONS WITH RBS - Schedule of Related Party Transactions, Recorded Interest Expense (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transactions [Abstract]
Interest expense on subordinated debt	$ 76	$ 64	$ 16

Amount of interest expense incurred on a debt or other obligation to related party.

No definition available.

Name:	us-gaap_InterestExpenseRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration