FAIR VALUE MEASUREMENT - Items Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed or purchased under agreements to resell, Netting	$ (80,843)	$ (80,843)	$ (73,476)
Trading account assets	262,949	262,949	252,790
Netting of cash collateral received	(39,595)	(39,595)	(38,532)
Investments	349,716	349,716	352,290
Loans at fair value	3,000	3,000	4,374
Mortgage servicing rights	596	596	558
Liabilities, Fair Value Disclosure [Abstract]
Federal funds purchased and securities loaned or sold under agreements to repurchase, Netting	(80,843)	(80,843)	(73,476)
Netting of cash collateral paid	(30,377)	(30,377)	(35,666)
Assets transferred from Level 1 to Level 2	900	1,600	4,800
Assets transferred from Level 2 to Level 1	1,300	5,300	4,000
Liabilities transferred from Level 1 to Level 2	100	200	400
Liabilities transferred from Level 2 to Level 1	300	500	300
Fair value
Liabilities, Fair Value Disclosure [Abstract]
Investments measured at net asset value excluded from Level 3	410	410	404
Fair value | Accounting Standards Update 2015-07
Liabilities, Fair Value Disclosure [Abstract]
Investments measured at net asset value excluded from Level 3	400	400	400
Recurring
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed or purchased under agreements to resell	221,423	221,423	188,587
Federal funds sold and securities borrowed or purchased under agreements to resell, Netting	(52,310)	(52,310)	(55,638)
Federal funds sold and securities borrowed or purchased under agreements to resell	169,113	169,113	132,949
Investments	290,053	290,053	291,716
Loans at fair value	3,000	3,000	4,374
Mortgage servicing rights	596	596	558
Assets before netting	1,171,526	1,171,526	1,101,517
Netting, Assets, total of netting agreements and cash collateral received	(424,112)	(424,112)	(400,571)
Total assets	747,414	747,414	700,946
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	1,628	1,628	1,465
Federal funds purchased and securities loaned or sold under agreements to repurchase, Gross	101,556	101,556	96,276
Federal funds purchased and securities loaned or sold under agreements to repurchase, Netting	(52,310)	(52,310)	(55,638)
Federal funds purchased and securities loaned or sold under agreements to repurchase	49,246	49,246	40,638
Securities sold, not yet purchased	85,868	85,868	76,171
Trading liabilities	87,332	87,332	77,585
Short-term borrowings	4,093	4,093	4,627
Long-term debt	35,462	35,462	31,392
Total liabilities, Gross	663,887	663,887	614,958
Total liabilities, Netting	(414,894)	(414,894)	(397,705)
Total liabilities	248,993	248,993	217,253
Recurring | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	400,363	400,363	375,344
Cash collateral received	15,634	15,634	14,308
Total trading derivatives and cash collateral, liability	415,997	415,997	389,652
Netting agreements	(332,207)	(332,207)	(306,401)
Netting of cash collateral paid	(30,377)	(30,377)	(35,666)
Netting, Liabilities, total of netting agreements and cash collateral received	(362,584)	(362,584)	(342,067)
Total derivative liabilities	53,413	53,413	47,585
Cash collateral received, gross	55,229	55,229	52,840
Recurring | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	157,989	157,989	184,639
Recurring | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	172,852	172,852	120,772
Recurring | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	31,900	31,900	31,373
Recurring | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	21,063	21,063	17,027
Recurring | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	16,559	16,559	21,533
Recurring | Non-trading derivatives and other financial liabilities
Liabilities, Fair Value Disclosure [Abstract]
Netting of cash collateral paid			0
Netting, Liabilities, total of netting agreements and cash collateral received	0	0
Non-trading derivatives and other financial liabilities measured on a recurring basis, gross	17,819	17,819	13,961
Total other assets and cash collateral, gross	17,819	17,819	13,961
Recurring | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	1,464	1,464	1,414
Recurring | Mortgage-backed securities - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	24,349	24,349	22,964
Investments	42,972	42,972	41,741
Recurring | Mortgage-backed securities - Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	825	825	813
Investments	1,858	1,858	2,884
Recurring | Mortgage-backed securities - Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1,471	1,471	1,366
Investments	279	279	332
Recurring | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	26,645	26,645	25,143
Investments	45,109	45,109	44,957
Recurring | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	26,931	26,931	21,137
Investments	118,271	118,271	118,146
Recurring | State and municipal securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	3,372	3,372	4,700
Investments	9,764	9,764	8,765
Recurring | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	68,509	68,509	60,206
Investments	97,825	97,825	100,533
Recurring | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	14,334	14,334	15,705
Investments	12,601	12,601	14,109
Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	51,581	51,581	60,219
Investments	204	204	189
Recurring | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	3,384	3,384	2,788
Investments	1,870	1,870	3,918
Recurring | Other debt securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	12,049	12,049	11,723
Investments	3,591	3,591	297
Recurring | Non-marketable equity investments measured using the measurement alternative
Assets, Fair Value Disclosure [Abstract]
Investments	818	818	802
Recurring | Trading securities (excluding trading account derivatives)
Assets, Fair Value Disclosure [Abstract]
Trading account assets	206,805	206,805	201,621
Recurring | Trading account assets
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	416,052	416,052	388,561
Cash collateral paid	11,894	11,894	7,541
Trading derivative, asset, gross net cash collateral paid	427,946	427,946	396,102
Netting agreements	(332,207)	(332,207)	(306,401)
Netting of cash collateral received	(39,595)	(39,595)	(38,532)
Total trading derivatives, netting	(371,802)	(371,802)	(344,933)
Trading derivatives	56,144	56,144	51,169
Liabilities, Fair Value Disclosure [Abstract]
Cash collateral paid, gross	42,271	42,271	43,207
Recurring | Trading account assets | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	177,288	177,288	204,987
Recurring | Trading account assets | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	177,632	177,632	121,959
Recurring | Trading account assets | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	27,249	27,249	26,978
Recurring | Trading account assets | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	17,582	17,582	14,103
Recurring | Trading account assets | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	16,301	16,301	20,534
Recurring | Non-trading derivatives and other financial assets
Assets, Fair Value Disclosure [Abstract]
Total trading derivatives, netting	0	0	0
Total other assets and cash collateral, gross	21,703	21,703	18,559
Other assets	21,703	21,703	18,559
Recurring | Level 1
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed or purchased under agreements to resell	0	0	0
Investments	169,898	169,898	165,507
Loans at fair value	0	0	0
Mortgage servicing rights	0	0	0
Assets before netting	$ 305,170	$ 305,170	$ 292,700
Total as a percentage of gross assets	26.30%	26.30%	26.80%
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	$ 0	$ 0	$ 0
Federal funds purchased and securities loaned or sold under agreements to repurchase, Gross	0	0	0
Securities sold, not yet purchased	75,843	75,843	65,843
Trading liabilities	75,843	75,843	65,843
Short-term borrowings	0	0	0
Long-term debt	0	0	0
Total liabilities, Gross	$ 96,102	$ 96,102	$ 82,437
Total as a percentage of gross liabilities	14.80%	14.80%	13.70%
Recurring | Level 1 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	$ 2,602	$ 2,602	$ 2,691
Recurring | Level 1 | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	256	256	137
Recurring | Level 1 | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	6	6	9
Recurring | Level 1 | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	2,334	2,334	2,430
Recurring | Level 1 | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	6	6	115
Recurring | Level 1 | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	0	0	0
Recurring | Level 1 | Non-trading derivatives and other financial liabilities
Liabilities, Fair Value Disclosure [Abstract]
Other liabilities, gross	17,657	17,657	13,903
Recurring | Level 1 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	0	0	0
Recurring | Level 1 | Mortgage-backed securities - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0	0
Investments	0	0	0
Recurring | Level 1 | Mortgage-backed securities - Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0	0
Investments	0	0	0
Recurring | Level 1 | Mortgage-backed securities - Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0	0
Investments	0	0	0
Recurring | Level 1 | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0	0
Investments	0	0	0
Recurring | Level 1 | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	22,866	22,866	17,524
Investments	106,316	106,316	106,964
Recurring | Level 1 | State and municipal securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0	0
Investments	0	0	0
Recurring | Level 1 | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	48,875	48,875	39,347
Investments	59,220	59,220	56,456
Recurring | Level 1 | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	318	318	301
Investments	4,172	4,172	1,911
Recurring | Level 1 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	44,031	44,031	53,305
Investments	190	190	176
Recurring | Level 1 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0	0
Investments	0	0	0
Recurring | Level 1 | Other debt securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	5	5	3
Investments	0	0	0
Recurring | Level 1 | Non-marketable equity investments measured using the measurement alternative
Assets, Fair Value Disclosure [Abstract]
Investments	0	0	0
Recurring | Level 1 | Trading securities (excluding trading account derivatives)
Assets, Fair Value Disclosure [Abstract]
Trading account assets	116,095	116,095	110,480
Recurring | Level 1 | Trading account assets
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	2,398	2,398	2,810
Recurring | Level 1 | Trading account assets | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	266	266	145
Recurring | Level 1 | Trading account assets | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	3	3	19
Recurring | Level 1 | Trading account assets | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	2,109	2,109	2,364
Recurring | Level 1 | Trading account assets | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	20	20	282
Recurring | Level 1 | Trading account assets | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	0	0	0
Recurring | Level 1 | Non-trading derivatives and other financial assets
Assets, Fair Value Disclosure [Abstract]
Other assets, gross	16,779	16,779	13,903
Recurring | Level 2
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed or purchased under agreements to resell	221,357	221,357	188,571
Investments	118,163	118,163	123,772
Loans at fair value	2,619	2,619	3,824
Mortgage servicing rights	0	0	0
Assets before netting	$ 843,165	$ 843,165	$ 790,217
Total as a percentage of gross assets	72.70%	72.70%	72.20%
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	$ 1,308	$ 1,308	$ 1,179
Federal funds purchased and securities loaned or sold under agreements to repurchase, Gross	100,590	100,590	95,550
Securities sold, not yet purchased	9,836	9,836	10,306
Trading liabilities	11,300	11,300	11,715
Short-term borrowings	4,003	4,003	4,609
Long-term debt	21,681	21,681	18,310
Total liabilities, Gross	$ 528,262	$ 528,262	$ 494,879
Total as a percentage of gross liabilities	81.50%	81.50%	82.40%
Recurring | Level 2 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	$ 389,218	$ 389,218	$ 363,466
Recurring | Level 2 | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	155,568	155,568	182,372
Recurring | Level 2 | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	172,473	172,473	120,316
Recurring | Level 2 | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	27,822	27,822	26,472
Recurring | Level 2 | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	18,500	18,500	14,482
Recurring | Level 2 | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	14,855	14,855	19,824
Recurring | Level 2 | Non-trading derivatives and other financial liabilities
Liabilities, Fair Value Disclosure [Abstract]
Other liabilities, gross	162	162	50
Recurring | Level 2 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	1,464	1,464	1,409
Recurring | Level 2 | Mortgage-backed securities - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	24,250	24,250	22,801
Investments	42,938	42,938	41,717
Recurring | Level 2 | Mortgage-backed securities - Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	693	693	649
Investments	1,858	1,858	2,884
Recurring | Level 2 | Mortgage-backed securities - Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1,420	1,420	1,309
Investments	273	273	329
Recurring | Level 2 | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	26,363	26,363	24,759
Investments	45,069	45,069	44,930
Recurring | Level 2 | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	4,058	4,058	3,613
Investments	11,955	11,955	11,182
Recurring | Level 2 | State and municipal securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	3,146	3,146	4,426
Investments	9,002	9,002	8,028
Recurring | Level 2 | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	19,598	19,598	20,843
Investments	38,551	38,551	43,985
Recurring | Level 2 | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	13,496	13,496	15,129
Investments	8,361	8,361	12,127
Recurring | Level 2 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	7,257	7,257	6,794
Investments	13	13	11
Recurring | Level 2 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1,696	1,696	1,198
Investments	1,414	1,414	3,091
Recurring | Level 2 | Other debt securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	11,502	11,502	11,105
Investments	3,591	3,591	297
Recurring | Level 2 | Non-marketable equity investments measured using the measurement alternative
Assets, Fair Value Disclosure [Abstract]
Investments	207	207	121
Recurring | Level 2 | Trading securities (excluding trading account derivatives)
Assets, Fair Value Disclosure [Abstract]
Trading account assets	87,116	87,116	87,867
Recurring | Level 2 | Trading account assets
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	408,986	408,986	381,543
Recurring | Level 2 | Trading account assets | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	174,771	174,771	203,134
Recurring | Level 2 | Trading account assets | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	177,017	177,017	121,363
Recurring | Level 2 | Trading account assets | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	24,842	24,842	24,170
Recurring | Level 2 | Trading account assets | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	16,911	16,911	13,252
Recurring | Level 2 | Trading account assets | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	15,445	15,445	19,624
Recurring | Level 2 | Non-trading derivatives and other financial assets
Assets, Fair Value Disclosure [Abstract]
Other assets, gross	4,924	4,924	4,640
Recurring | Level 3
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed or purchased under agreements to resell	66	66	16
Investments	1,992	1,992	2,437
Loans at fair value	381	381	550
Mortgage servicing rights	596	596	558
Assets before netting	$ 11,297	$ 11,297	$ 11,059
Total as a percentage of gross assets	1.00%	1.00%	1.00%
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	$ 320	$ 320	$ 286
Federal funds purchased and securities loaned or sold under agreements to repurchase, Gross	966	966	726
Securities sold, not yet purchased	189	189	22
Trading liabilities	189	189	27
Short-term borrowings	90	90	18
Long-term debt	13,781	13,781	13,082
Total liabilities, Gross	$ 23,889	$ 23,889	$ 23,334
Total as a percentage of gross liabilities	3.70%	3.70%	3.90%
Recurring | Level 3 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	$ 8,543	$ 8,543	$ 9,187
Recurring | Level 3 | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	2,165	2,165	2,130
Recurring | Level 3 | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	373	373	447
Recurring | Level 3 | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	1,744	1,744	2,471
Recurring | Level 3 | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	2,557	2,557	2,430
Recurring | Level 3 | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	1,704	1,704	1,709
Recurring | Level 3 | Non-trading derivatives and other financial liabilities
Liabilities, Fair Value Disclosure [Abstract]
Other liabilities, gross	0	0	8
Recurring | Level 3 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	0	0	5
Recurring | Level 3 | Mortgage-backed securities - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	99	99	163
Investments	34	34	24
Recurring | Level 3 | Mortgage-backed securities - Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	132	132	164
Investments	0	0	0
Recurring | Level 3 | Mortgage-backed securities - Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	51	51	57
Investments	6	6	3
Recurring | Level 3 | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	282	282	384
Investments	40	40	27
Recurring | Level 3 | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	7	7	0
Investments	0	0	0
Recurring | Level 3 | State and municipal securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	226	226	274
Investments	762	762	737
Recurring | Level 3 | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	36	36	16
Investments	54	54	92
Recurring | Level 3 | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	520	520	275
Investments	68	68	71
Recurring | Level 3 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	293	293	120
Investments	1	1	2
Recurring | Level 3 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1,688	1,688	1,590
Investments	456	456	827
Recurring | Level 3 | Other debt securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	542	542	615
Investments	0	0	0
Recurring | Level 3 | Non-marketable equity investments measured using the measurement alternative
Assets, Fair Value Disclosure [Abstract]
Investments	611	611	681
Recurring | Level 3 | Trading securities (excluding trading account derivatives)
Assets, Fair Value Disclosure [Abstract]
Trading account assets	3,594	3,594	3,274
Recurring | Level 3 | Trading account assets
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	4,668	4,668	4,208
Recurring | Level 3 | Trading account assets | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	2,251	2,251	1,708
Recurring | Level 3 | Trading account assets | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	612	612	577
Recurring | Level 3 | Trading account assets | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	298	298	444
Recurring | Level 3 | Trading account assets | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	651	651	569
Recurring | Level 3 | Trading account assets | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	856	856	910
Recurring | Level 3 | Non-trading derivatives and other financial assets
Assets, Fair Value Disclosure [Abstract]
Other assets, gross	$ 0	$ 0	$ 16