INVESTMENTS (REPURCHASE AGREEMENTS ACCCOUNTED FOR AS BORROWINGS) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	$ 2,038	$ 1,890
Reverse repurchase agreements	205	79
Maturity Overnight
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	0	0
Reverse repurchase agreements	0	0
Maturity up to 30 days
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	2,038	1,865
Reverse repurchase agreements	205	79
Maturity 30 to 90 Days
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	0	25
Reverse repurchase agreements	0	0
Maturity over 90 days
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	0	0
Reverse repurchase agreements	0	0
U.S. Treasury, government and agency
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	2,038	1,890
U.S. Treasury, government and agency | Maturity Overnight
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	0	0
U.S. Treasury, government and agency | Maturity up to 30 days
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	2,038	1,865
U.S. Treasury, government and agency | Maturity 30 to 90 Days
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	0	25
U.S. Treasury, government and agency | Maturity over 90 days
Repurchase agreements accounted for as secured borrowings [Line Items]
Repurchase agreements	0	0
Public corporate
Repurchase agreements accounted for as secured borrowings [Line Items]
Reverse repurchase agreements	205	79
Public corporate | Maturity Overnight
Repurchase agreements accounted for as secured borrowings [Line Items]
Reverse repurchase agreements	0	0
Public corporate | Maturity up to 30 days
Repurchase agreements accounted for as secured borrowings [Line Items]
Reverse repurchase agreements	205	79
Public corporate | Maturity 30 to 90 Days
Repurchase agreements accounted for as secured borrowings [Line Items]
Reverse repurchase agreements	0	0
Public corporate | Maturity over 90 days
Repurchase agreements accounted for as secured borrowings [Line Items]
Reverse repurchase agreements	0	0
Investment Management
Repurchase agreements accounted for as secured borrowings [Line Items]
Securities Loaned	0	0
Securities Borrowed | Investment Management
Repurchase agreements accounted for as secured borrowings [Line Items]
Net amounts presented in the balance sheets	$ 26	$ 75