ALLOWANCE FOR CREDIT LOSSES - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Allowance for loan losses disclosures
Reduction of allowance for loan and leases losses due to loans sold or transferred to held-for-sale or to discontinued operations	$ 110	$ 88	$ 1,000	$ 259	$ 480	$ 79
Reduction of allowance for loan and leases losses due to transfer to real estate loan portfolio	14	34	281	151	66
Reduction of allowance related to foreign currency translation	255	39	$ 145	181
EMEA
Allowance for loan losses disclosures
Reduction of allowance for loan and leases losses due to loans sold or transferred to held-for-sale or to discontinued operations				$ 108
Greece
Allowance for loan losses disclosures
Reduction of allowance for loan and leases losses due to loans sold or transferred to held-for-sale or to discontinued operations					204
Spain
Allowance for loan losses disclosures
Reduction of allowance for loan and leases losses due to loans sold or transferred to held-for-sale or to discontinued operations					177
Honduras
Allowance for loan losses disclosures
Reduction of allowance for loan and leases losses due to loans sold or transferred to held-for-sale or to discontinued operations					$ 29
OneMain Financial Business | Disposal Group, Held-for-sale, Not Discontinued Operations
Allowance for loan losses disclosures
Reduction of allowance for loan and leases losses due to loans sold or transferred to held-for-sale or to discontinued operations	$ 116	$ 160