XML 93 R94.htm IDEA: XBRL DOCUMENT v2.4.1.9
Finance Receivables and Loans, Net (Commercial Concentration Risk) (Details)
Dec. 31, 2014
Dec. 31, 2013
Concentration Risk [Line Items]    
Commercial Concentration Risk 100.00%ally_CommercialConcentrationRisk 100.00%ally_CommercialConcentrationRisk
TEXAS    
Concentration Risk [Line Items]    
Commercial Concentration Risk 13.80%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 13.20%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_TX
FLORIDA    
Concentration Risk [Line Items]    
Commercial Concentration Risk 12.30%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_FL		 12.60%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_FL
MICHIGAN    
Concentration Risk [Line Items]    
Commercial Concentration Risk 9.90%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_MI		 11.60%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_MI
CALIFORNIA    
Concentration Risk [Line Items]    
Commercial Concentration Risk 9.00%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_CA		 9.20%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_CA
VIRGINIA    
Concentration Risk [Line Items]    
Commercial Concentration Risk 4.10%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_VA		 3.80%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_VA
NORTH CAROLINA    
Concentration Risk [Line Items]    
Commercial Concentration Risk 3.90%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_NC		 4.10%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_NC
NEW YORK    
Concentration Risk [Line Items]    
Commercial Concentration Risk 3.90%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_NY		 4.50%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_NY
PENNSYLVANIA    
Concentration Risk [Line Items]    
Commercial Concentration Risk 3.80%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_PA		 3.30%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_PA
GEORGIA    
Concentration Risk [Line Items]    
Commercial Concentration Risk 3.70%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_GA		 3.10%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_GA
ILLINOIS    
Concentration Risk [Line Items]    
Commercial Concentration Risk 2.70%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_IL		 2.50%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= stpr_IL
Other United States [Member]    
Concentration Risk [Line Items]    
Commercial Concentration Risk 32.90%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= ally_OtherUnitedStatesMember		 32.10%ally_CommercialConcentrationRisk
/ us-gaap_StatementGeographicalAxis
= ally_OtherUnitedStatesMember