MORTGAGE BANKING - Economic Assumptions Used to Estimate Value of MSRs (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Residential Mortgages	Sep. 30, 2013 Residential Mortgages
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Fair value			$ 187	$ 193
Weighted average life (in years)	5 years 2 months 12 days	5 years 4 months 24 days	5 years 3 months 18 days	5 years 1 month 6 days
Weighted average constant prepayment rate (percent)	12.20%	13.00%	12.20%	13.90%
Weighted average discount rate (percent)	10.30%	10.80%	10.30%	10.80%