XML 102 R80.htm IDEA: XBRL DOCUMENT v2.4.1.9
GOODWILL -Narrative (Details) (USD $)
In Millions, unless otherwise specified
 207 Months Ended
Mar. 31, 2015
business
Mar. 31, 2014
Goodwill [Line Items]    
Number of acquisitions of banks or assets of banks 25us-gaap_NumberOfBusinessesAcquired  
Consumer Banking    
Goodwill [Line Items]    
Goodwill accumulated impairment loss 5,900us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
/ us-gaap_StatementBusinessSegmentsAxis
= cfg_ConsumerBankingMember		 $ 5,900us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
/ us-gaap_StatementBusinessSegmentsAxis
= cfg_ConsumerBankingMember
Commercial Banking    
Goodwill [Line Items]    
Goodwill accumulated impairment loss 50us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
/ us-gaap_StatementBusinessSegmentsAxis
= cfg_CommercialBankingMember		 $ 50us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
/ us-gaap_StatementBusinessSegmentsAxis
= cfg_CommercialBankingMember