GUARANTEES AND COMMITMENTS - Gurantees (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) trust margin	Dec. 31, 2015 USD ($) trust
Maximum potential amount of future payments
Expire within 1 year	$ 203,900,000,000	$ 198,000,000,000
Expire after 1 year	193,400,000,000	203,900,000,000
Total amount outstanding	397,300,000,000	401,900,000,000
Carrying value	1,855,000,000	2,029,000,000
Compensation for standard representations and warranties	0
Stated or notional amounts included in the indemnification clauses	0
Liability related to VTNs	$ 0	$ 0
Number of trusts funded by the reinsurer | trust	2	2
Fair value of securities in trusts funded by reinsurer relating to indemnification	$ 7,000,000,000	$ 6,300,000,000
Liability related to long-term care insurance indemnification	0	0
Cash collateral available to reimburse losses realized under guarantees and indemnifications	55,000,000,000	52,000,000,000
Securities and other marketable assets held as collateral, the majority of which collateral is held to reimburse losses realized under securities lending indemnifications	39,000,000,000	33,000,000,000
Letters of credit in favor of the Company held as collateral	4,000,000,000	4,200,000,000
Investment grade
Maximum potential amount of future payments
Total amount outstanding	123,300,000,000	127,400,000,000
Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	19,500,000,000	19,600,000,000
Not rated
Maximum potential amount of future payments
Total amount outstanding	254,500,000,000	254,900,000,000
Financial standby letters of credit
Maximum potential amount of future payments
Expire within 1 year	27,600,000,000	23,800,000,000
Expire after 1 year	66,300,000,000	73,000,000,000
Total amount outstanding	93,900,000,000	96,800,000,000
Carrying value	167,000,000	153,000,000
Financial standby letters of credit | Investment grade
Maximum potential amount of future payments
Total amount outstanding	68,700,000,000	69,200,000,000
Financial standby letters of credit | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	15,100,000,000	15,400,000,000
Financial standby letters of credit | Not rated
Maximum potential amount of future payments
Total amount outstanding	10,100,000,000	12,200,000,000
Performance guarantees
Maximum potential amount of future payments
Expire within 1 year	7,700,000,000	7,400,000,000
Expire after 1 year	3,900,000,000	4,100,000,000
Total amount outstanding	11,600,000,000	11,500,000,000
Carrying value	23,000,000	24,000,000
Performance guarantees | Investment grade
Maximum potential amount of future payments
Total amount outstanding	6,500,000,000	6,600,000,000
Performance guarantees | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	4,300,000,000	4,100,000,000
Performance guarantees | Not rated
Maximum potential amount of future payments
Total amount outstanding	800,000,000	800,000,000
Derivative instruments deemed to be guarantees
Maximum potential amount of future payments
Expire within 1 year	3,900,000,000	3,600,000,000
Expire after 1 year	74,800,000,000	74,900,000,000
Total amount outstanding	78,700,000,000	78,500,000,000
Carrying value	1,594,000,000	1,779,000,000
Derivative instruments deemed to be guarantees | Investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Derivative instruments deemed to be guarantees | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Derivative instruments deemed to be guarantees | Not rated
Maximum potential amount of future payments
Total amount outstanding	78,700,000,000	78,500,000,000
Loans sold with recourse
Maximum potential amount of future payments
Expire within 1 year	0	0
Expire after 1 year	200,000,000	200,000,000
Total amount outstanding	200,000,000	200,000,000
Carrying value	15,000,000	17,000,000
Repurchase reserve for Consumer mortgages representations and warranties	148,000,000	152,000,000
Loans sold with recourse | Investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Loans sold with recourse | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Loans sold with recourse | Not rated
Maximum potential amount of future payments
Total amount outstanding	200,000,000	200,000,000
Securities lending indemnifications
Maximum potential amount of future payments
Expire within 1 year	88,000,000,000	79,000,000,000
Expire after 1 year	0	0
Total amount outstanding	88,000,000,000	79,000,000,000
Carrying value	0	0
Securities lending indemnifications | Investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Securities lending indemnifications | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Securities lending indemnifications | Not rated
Maximum potential amount of future payments
Total amount outstanding	88,000,000,000	79,000,000,000
Credit card merchant processing
Maximum potential amount of future payments
Expire within 1 year	76,700,000,000	84,200,000,000
Expire after 1 year	0	0
Total amount outstanding	76,700,000,000	84,200,000,000
Carrying value	0	0
Maximum potential contingent liability related to bankcard and private-label merchant processing services	77,000,000,000	84,000,000,000
Credit card merchant processing | Investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Credit card merchant processing | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	0	0
Credit card merchant processing | Not rated
Maximum potential amount of future payments
Total amount outstanding	76,700,000,000	84,200,000,000
Custody indemnifications and other
Maximum potential amount of future payments
Expire within 1 year	0	0
Expire after 1 year	48,200,000,000	51,700,000,000
Total amount outstanding	48,200,000,000	51,700,000,000
Carrying value	56,000,000	56,000,000
Custody indemnifications and other | Investment grade
Maximum potential amount of future payments
Total amount outstanding	48,100,000,000	51,600,000,000
Custody indemnifications and other | Non-investment grade
Maximum potential amount of future payments
Total amount outstanding	100,000,000	100,000,000
Custody indemnifications and other | Not rated
Maximum potential amount of future payments
Total amount outstanding	$ 0	0
Futures and over-the-counter derivatives clearing
Maximum potential amount of future payments
Number of types of margin | margin	2
Amount of cash initial margin collected and remitted	$ 4,900,000,000	$ 4,300,000,000