CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Change in Each Compenant of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	$ (24,691)	$ (19,146)	$ (23,216)	$ (19,133)	$ (19,133)
End-of-period balance, net of tax	(25,104)	(18,147)	(25,104)	(18,147)	(23,216)
Net unrealized gains (losses) on investment securities
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	648	(1,212)	57	(1,640)	(1,640)
Other comprehensive income before reclassifications	(844)	1,037	(103)	1,415
Increase (decrease) due to amounts reclassified from AOCI	(91)	(31)	(241)	19
Change, net of taxes	(935)	1,006	(344)	1,434
End-of-period balance, net of tax	(287)	(206)	(287)	(206)	57
Cash flow hedges
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	(823)	(1,127)	(909)	(1,245)	(1,245)
Other comprehensive income before reclassifications	22	58	54	104
Increase (decrease) due to amounts reclassified from AOCI	70	62	124	134
Change, net of taxes	92	120	178	238
End-of-period balance, net of tax	(731)	(1,007)	(731)	(1,007)	(909)
Benefit plans
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	(5,249)	(4,022)	(5,159)	(3,989)	(3,989)
Other comprehensive income before reclassifications	539	(195)	408	(257)
Increase (decrease) due to amounts reclassified from AOCI	39	51	80	80
Change, net of taxes	578	(144)	488	(177)
End-of-period balance, net of tax	(4,671)	(4,166)	(4,671)	(4,166)	(5,159)
Foreign currency translation adjustment
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	(19,267)	(12,785)	(17,205)	(12,259)	(12,259)
Other comprehensive income before reclassifications	(148)	17	(2,210)	(509)
Increase (decrease) due to amounts reclassified from AOCI	0	0	0	0
Change, net of taxes	(148)	17	(2,210)	(509)
End-of-period balance, net of tax	(19,415)	(12,768)	(19,415)	(12,768)	(17,205)
Reclassification for allocation between net unrealized gains (losses) on investment securities to CTA, before tax					137
Reclassification for allocation between net unrealized gains (losses) on investment securities to CTA, net of tax					84
Accumulated other comprehensive income (loss)
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	(24,691)	(19,146)	(23,216)	(19,133)	(19,133)
Other comprehensive income before reclassifications	(431)	917	(1,851)	753
Increase (decrease) due to amounts reclassified from AOCI	18	82	(37)	233
Change, net of taxes	(413)	999	(1,888)	986
End-of-period balance, net of tax	$ (25,104)	$ (18,147)	$ (25,104)	$ (18,147)	$ (23,216)