LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES (Details 2) - Loans Receivable - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Loans receivable pledged to secure borrowings and to provide additional borrowing capacity from the FHLB and the Federal Reserve Bank	$ 15,620	$ 15,910
Residential | Real estate loan | Single-family | Minimum
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Adjustable rate mortgage, term of initial fixed interest rates, option one	1 year
Residential | Real estate loan | Single-family | Maximum
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Adjustable rate mortgage, term of initial fixed interest rates, option one	5 years
Residential | Real estate loan | Multifamily
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Adjustable rate mortgage, term of floating rate period, option one	6 months
Residential | Real estate loan | Multifamily | Minimum
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Adjustable rate mortgage, term of initial fixed interest rates, option one	3 years
Residential | Real estate loan | Multifamily | Maximum
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Adjustable rate mortgage, term of initial fixed interest rates, option one	7 years