DERIVATIVES - Effect of Derivative Instruments on Net Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amounts reclassified from OCI to interest income		$ 145	$ 159
Amounts reclassified from OCI to interest expense		(115)	(106)
Amount Reclassified from AOCI
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion of gain (loss) recognized in OCI	[1]	54	104
Amount Reclassified from AOCI | Net Unrealized Gains (Losses) on Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Amounts reclassified from OCI to interest income	[2]	22	18
Amounts reclassified from OCI to interest expense	[2]	(8)	(15)
Ineffective portion of gain recognized in other income	[3]	$ 0	$ 1

[1] The cumulative effective gains and losses on the Company’s cash flow hedging activities are included on the accumulated other comprehensive loss line item on the Consolidated Balance Sheets.

[2] This amount includes both (a) the amortization of effective gains and losses associated with the Company’s terminated cash flow hedges and (b) the current reporting period’s interest settlements realized on the Company’s active cash flow hedges. Both (a) and (b) were previously included on the accumulated other comprehensive loss line item on the Consolidated Balance Sheets and were subsequently recorded as adjustments to the interest expense of the underlying hedged item.

[3] This amount represents the net ineffectiveness recorded during the reporting periods presented plus any amounts excluded from effectiveness testing. These amounts are reflected in the other income line item on the Consolidated Statements of Operations.