FAIR VALUE MEASUREMENT - Level 3 Fair Value Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Trading account assets and liabilities
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset (liability), net	$ (930)	$ 195	$ (1,207)	$ (1,715)
Net realized/unrealized gains (losses) included in principal transactions	421	(481)	664	132
Other	0	0	0	0
Transfers into Level 3	(616)	135	(392)	1,398
Transfers out of Level 3	531	(52)	535	(183)
Purchases	226	47	339	141
Issuances	0	0	(84)	56
Sales	(421)	(20)	(569)	(50)
Settlements	(80)	7	(155)	52
Balance at end of period, asset (liability), net	(869)	(169)	(869)	(169)
Unrealized gains (losses) still held	(50)	(515)	41	(11)
Trading account assets and liabilities | Interest rate contracts
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset (liability), net	1,229	1,755	1,614	1
Net realized/unrealized gains (losses) included in principal transactions	(126)	24	(298)	375
Other	0	0	0	0
Transfers into Level 3	218	231	173	1,614
Transfers out of Level 3	321	20	321	(2)
Purchases	2	1	2	2
Issuances	0	0	(84)	56
Sales	0	0	0	13
Settlements	120	(63)	36	(91)
Balance at end of period, asset (liability), net	1,764	1,968	1,764	1,968
Unrealized gains (losses) still held	(70)	7	(197)	387
Trading account assets and liabilities | Foreign exchange contracts
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset (liability), net	(86)	2	52	(5)
Net realized/unrealized gains (losses) included in principal transactions	59	(37)	(79)	(52)
Other	0	0	0	0
Transfers into Level 3	0	(8)	8	(33)
Transfers out of Level 3	4	2	4	11
Purchases	111	5	134	49
Issuances	0	0	0	0
Sales	(282)	(5)	(297)	(13)
Settlements	10	15	(6)	17
Balance at end of period, asset (liability), net	(184)	(26)	(184)	(26)
Unrealized gains (losses) still held	(28)	(47)	(57)	104
Trading account assets and liabilities | Equity contracts
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset (liability), net	(2,876)	(1,836)	(3,213)	(1,596)
Net realized/unrealized gains (losses) included in principal transactions	309	(354)	612	(564)
Other	0	0	0	0
Transfers into Level 3	(634)	(104)	(598)	(391)
Transfers out of Level 3	892	12	898	236
Purchases	85	21	109	24
Issuances	0	0	0	0
Sales	(94)	(5)	(117)	(6)
Settlements	(232)	31	(241)	62
Balance at end of period, asset (liability), net	(2,550)	(2,235)	(2,550)	(2,235)
Unrealized gains (losses) still held	349	(349)	213	(663)
Trading account assets and liabilities | Commodity contracts
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset (liability), net	732	(542)	292	(59)
Net realized/unrealized gains (losses) included in principal transactions	236	253	550	(206)
Other	0	0	0	0
Transfers into Level 3	(148)	(1)	10	37
Transfers out of Level 3	(612)	(14)	(617)	(70)
Purchases	28	20	94	66
Issuances	0	0	0	0
Sales	(45)	(10)	(155)	(44)
Settlements	(49)	16	(32)	(2)
Balance at end of period, asset (liability), net	142	(278)	142	(278)
Unrealized gains (losses) still held	(194)	241	280	(211)
Trading account assets and liabilities | Credit derivatives
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset (liability), net	71	816	48	(56)
Net realized/unrealized gains (losses) included in principal transactions	(57)	(367)	(121)	579
Other	0	0	0	0
Transfers into Level 3	(52)	17	15	171
Transfers out of Level 3	(74)	(72)	(71)	(358)
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	71	8	88	66
Balance at end of period, asset (liability), net	(41)	402	(41)	402
Unrealized gains (losses) still held	(107)	(367)	(198)	372
Interest-bearing deposits
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	199	491	206	215
Net realized/unrealized gains (losses) included in principal transactions, liabilities	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	2	(5)	18	(11)
Transfers into Level 3, liabilities	0	0	0	278
Transfers out of Level 3, liabilities	(44)	(151)	(44)	(151)
Purchases, liability	0	0	0	0
Issuance, liability	11	30	20	30
Sales, liability	0	0	0	0
Settlements, liability	(10)	(138)	(10)	(146)
Balance at end of period, liability	154	237	154	237
Unrealized gains (losses) still held, liabilities	0	(27)	(45)	(6)
Securities loaned and sold under agreements to repurchase
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	977	730	631	757
Net realized/unrealized gains (losses) included in principal transactions, liabilities	22	0	7	27
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	0	0	0	0
Transfers into Level 3, liabilities	0	0	0	0
Transfers out of Level 3, liabilities	(483)	0	(483)	0
Purchases, liability	80	0	488	0
Issuance, liability	0	0	0	0
Sales, liability	0	0	0	0
Settlements, liability	(64)	(105)	(141)	(105)
Balance at end of period, liability	488	625	488	625
Unrealized gains (losses) still held, liabilities	0	0	19	(33)
Trading account liabilities | Securities sold, not yet purchased
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	167	200	214	48
Net realized/unrealized gains (losses) included in principal transactions, liabilities	7	(28)	61	(129)
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	0	0	0	0
Transfers into Level 3, liabilities	54	43	62	117
Transfers out of Level 3, liabilities	(21)	(8)	(25)	(18)
Purchases, liability	10	0	20	0
Issuance, liability	0	0	0	9
Sales, liability	0	0	0	0
Settlements, liability	(35)	(159)	(42)	(181)
Balance at end of period, liability	168	104	168	104
Unrealized gains (losses) still held, liabilities	26	24	(2)	(7)
Trading account liabilities | Other trading liabilities
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	6	0	26	0
Net realized/unrealized gains (losses) included in principal transactions, liabilities	5	0	25	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	0	0	0	0
Transfers into Level 3, liabilities	0	0	0	0
Transfers out of Level 3, liabilities	0	0	0	0
Purchases, liability	0	0	0	0
Issuance, liability	0	0	0	0
Sales, liability	0	0	0	0
Settlements, liability	0	0	0	0
Balance at end of period, liability	1	0	1	0
Unrealized gains (losses) still held, liabilities	4	0	0	0
Short-term borrowings
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	49	52	219	13
Net realized/unrealized gains (losses) included in principal transactions, liabilities	33	9	32	19
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	0	0	0	0
Transfers into Level 3, liabilities	40	75	42	86
Transfers out of Level 3, liabilities	(32)	(6)	(44)	(6)
Purchases, liability	0	0	0	0
Issuance, liability	17	23	25	61
Sales, liability	0	0	0	0
Settlements, liability	0	(7)	(169)	(7)
Balance at end of period, liability	41	128	41	128
Unrealized gains (losses) still held, liabilities	17	16	17	21
Long-term debt
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Transfers out of Level 3	6,000	(1,500)	6,000	(4,200)
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	26,337	19,269	25,210	17,169
Net realized/unrealized gains (losses) included in principal transactions, liabilities	(849)	(1,691)	1,773	(380)
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	0	0	0	0
Transfers into Level 3, liabilities	3,937	1,875	4,869	5,063
Transfers out of Level 3, liabilities	(5,966)	(1,475)	(5,968)	(4,168)
Purchases, liability	0	0	0	0
Issuance, liability	1,825	2,527	7,545	6,788
Sales, liability	0	0	0	0
Settlements, liability	(1,914)	(2,254)	(4,815)	(3,600)
Balance at end of period, liability	25,068	21,633	25,068	21,633
Unrealized gains (losses) still held, liabilities	(699)	(1,518)	791	(746)
Other financial liabilities
Fair value, liabilities measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, liability	8	0	1	0
Net realized/unrealized gains (losses) included in principal transactions, liabilities	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, liabilities	0	0	(3)	0
Transfers into Level 3, liabilities	0	0	0	0
Transfers out of Level 3, liabilities	(4)	0	(4)	0
Purchases, liability	0	0	0	0
Issuance, liability	0	0	14	2
Sales, liability		0	0	0
Settlements, liability	0	0	(10)	(2)
Balance at end of period, liability	4	0	4	0
Unrealized gains (losses) still held, liabilities	0	0	0	0
Securities borrowed and purchased under agreements to resell
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	262	300	320	303
Net realized/unrealized gains (losses) included in principal transactions	(2)	34	(11)	14
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3, assets	(49)	0	(49)	0
Purchases, assets	43	42	276	108
Issuance, assets	0	0	0	0
Sales, assets	0	0	0	0
Settlements, assets	(43)	(50)	(325)	(99)
Balance at end of period, asset	211	326	211	326
Unrealized gains (losses) still held, assets	1	36	1	39
Trading non-derivative assets
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	2,698	3,319	3,647	2,455
Net realized/unrealized gains (losses) included in principal transactions	279	167	437	327
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	904	779	1,031	1,181
Transfers out of Level 3, assets	(496)	(211)	(711)	(359)
Purchases, assets	1,184	1,060	2,207	2,333
Issuance, assets	0	6	4	14
Sales, assets	(1,583)	(1,147)	(3,625)	(1,968)
Settlements, assets	0	(11)	(4)	(21)
Balance at end of period, asset	2,986	3,962	2,986	3,962
Unrealized gains (losses) still held, assets	(1)	49	59	(303)
Trading non-derivative assets | Mortgage securitizations - U.S. agency-sponsored
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	38	85	27	10
Net realized/unrealized gains (losses) included in principal transactions	2	1	1	(74)
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	238	4	252	16
Transfers out of Level 3, assets	(7)	(6)	(8)	(9)
Purchases, assets	113	67	114	208
Issuance, assets	0	0	0	0
Sales, assets	(8)	(55)	(10)	(55)
Settlements, assets	0	0	0	0
Balance at end of period, asset	376	96	376	96
Unrealized gains (losses) still held, assets	(12)	4	16	5
Trading non-derivative assets | Residential
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	268	304	340	123
Net realized/unrealized gains (losses) included in principal transactions	(1)	14	22	6
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	41	144	69	204
Transfers out of Level 3, assets	(65)	(39)	(68)	(43)
Purchases, assets	57	96	201	274
Issuance, assets	0	0	0	0
Sales, assets	(205)	(86)	(469)	(131)
Settlements, assets	0	0	0	0
Balance at end of period, asset	95	433	95	433
Unrealized gains (losses) still held, assets	2	7	18	0
Trading non-derivative assets | Commercial
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	59	44	136	61
Net realized/unrealized gains (losses) included in principal transactions	16	4	21	4
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	60	140	76	143
Transfers out of Level 3, assets	(8)	(14)	(41)	(17)
Purchases, assets	11	62	24	89
Issuance, assets	0	0	0	0
Sales, assets	(51)	(19)	(129)	(63)
Settlements, assets	0	0	0	0
Balance at end of period, asset	87	217	87	217
Unrealized gains (losses) still held, assets	3	11	2	(10)
Trading non-derivative assets | Mortgage-backed securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	365	433	503	194
Net realized/unrealized gains (losses) included in principal transactions	17	19	44	(64)
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	339	288	397	363
Transfers out of Level 3, assets	(80)	(59)	(117)	(69)
Purchases, assets	181	225	339	571
Issuance, assets	0	0	0	0
Sales, assets	(264)	(160)	(608)	(249)
Settlements, assets	0	0	0	0
Balance at end of period, asset	558	746	558	746
Unrealized gains (losses) still held, assets	(7)	22	36	(5)
Trading non-derivative assets | U.S. Treasury and federal agency securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	0	0	0	0
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3, assets	0	0	0	0
Purchases, assets	0	0	0	0
Issuance, assets	0	0	0	0
Sales, assets	0	0	0	0
Settlements, assets	0	0	0	0
Balance at end of period, asset	0	0	0	0
Unrealized gains (losses) still held, assets	0	0	0	0
Trading non-derivative assets | State and municipal
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	94	92	94	64
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	2
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	0	5	0	15
Transfers out of Level 3, assets	(29)	(1)	(29)	(3)
Purchases, assets	5	41	5	62
Issuance, assets	0	0	0	0
Sales, assets	0	(20)	0	(23)
Settlements, assets	0	0	0	0
Balance at end of period, asset	70	117	70	117
Unrealized gains (losses) still held, assets	0	0	1	1
Trading non-derivative assets | Foreign government
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	81	39	51	52
Net realized/unrealized gains (losses) included in principal transactions	4	57	5	(28)
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	125	2	136	2
Transfers out of Level 3, assets	(28)	(2)	(28)	(2)
Purchases, assets	14	18	71	104
Issuance, assets	0	0	0	0
Sales, assets	(55)	(88)	(94)	(102)
Settlements, assets	0	0	0	0
Balance at end of period, asset	141	26	141	26
Unrealized gains (losses) still held, assets	1	54	(6)	52
Trading non-derivative assets | Corporate
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	290	412	375	313
Net realized/unrealized gains (losses) included in principal transactions	(15)	(12)	75	290
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	312	64	318	86
Transfers out of Level 3, assets	(50)	(78)	(168)	(70)
Purchases, assets	408	204	475	419
Issuance, assets	0	0	0	0
Sales, assets	(122)	(185)	(252)	(633)
Settlements, assets	0	(6)	0	(6)
Balance at end of period, asset	823	399	823	399
Unrealized gains (losses) still held, assets	(36)	(71)	(7)	(87)
Trading non-derivative assets | Marketable equity securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	89	143	73	100
Net realized/unrealized gains (losses) included in principal transactions	2	9	47	9
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	80	10	84	38
Transfers out of Level 3, assets	(40)	0	(42)	(3)
Purchases, assets	23	174	35	206
Issuance, assets	0	0	0	0
Sales, assets	(7)	(244)	(50)	(258)
Settlements, assets	0	0	0	0
Balance at end of period, asset	147	92	147	92
Unrealized gains (losses) still held, assets	15	(3)	32	(19)
Trading non-derivative assets | Asset-backed securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	1,208	1,561	1,606	1,117
Net realized/unrealized gains (losses) included in principal transactions	209	67	248	(102)
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	17	257	35	496
Transfers out of Level 3, assets	(148)	(56)	(198)	(60)
Purchases, assets	352	272	934	740
Issuance, assets	0	0	0	0
Sales, assets	(946)	(316)	(1,933)	(466)
Settlements, assets	0	0	0	0
Balance at end of period, asset	692	1,785	692	1,785
Unrealized gains (losses) still held, assets	22	46	8	(222)
Trading non-derivative assets | Other trading assets
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	571	639	945	555
Net realized/unrealized gains (losses) included in principal transactions	62	27	18	220
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	31	153	61	181
Transfers out of Level 3, assets	(121)	(15)	(129)	(152)
Purchases, assets	201	126	348	231
Issuance, assets	0	6	4	14
Sales, assets	(189)	(134)	(688)	(237)
Settlements, assets	0	(5)	(4)	(15)
Balance at end of period, asset	555	797	555	797
Unrealized gains (losses) still held, assets	4	1	(5)	(23)
Investments
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	1,759	1,567	1,542	1,259
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	15	41	1	(55)
Transfers into Level 3	581	174	589	388
Transfers out of Level 3, assets	(397)	(347)	(397)	(346)
Purchases, assets	350	169	681	468
Issuance, assets	0	0	0	0
Sales, assets	(62)	(63)	(170)	(163)
Settlements, assets	0	(45)	0	(55)
Balance at end of period, asset	2,246	1,496	2,246	1,496
Unrealized gains (losses) still held, assets	(10)	16	(83)	49
Investments | Mortgage securitizations - U.S. agency-sponsored
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	30	47	30	32
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	2	(19)	2	(5)
Transfers into Level 3	22	1	22	1
Transfers out of Level 3, assets	0	0	0	1
Purchases, assets	3	1	3	1
Issuance, assets	0	0	0	0
Sales, assets	(5)	0	(5)	0
Settlements, assets	0	0	0	0
Balance at end of period, asset	52	30	52	30
Unrealized gains (losses) still held, assets	(21)	(36)	(42)	(23)
Investments | Residential
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset		0		0
Net realized/unrealized gains (losses) included in principal transactions		0		0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets		0		0
Transfers into Level 3		0		0
Transfers out of Level 3, assets		0		0
Purchases, assets		0		0
Issuance, assets		0		0
Sales, assets		0		0
Settlements, assets		0		0
Balance at end of period, asset		0		0
Unrealized gains (losses) still held, assets		0		0
Investments | Commercial
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset		0		0
Net realized/unrealized gains (losses) included in principal transactions		0		0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets		0		0
Transfers into Level 3		0		0
Transfers out of Level 3, assets		0		0
Purchases, assets		0		0
Issuance, assets		0		0
Sales, assets		0		0
Settlements, assets		0		0
Balance at end of period, asset		0		0
Unrealized gains (losses) still held, assets		0		0
Investments | Mortgage-backed securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	30	47	30	32
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	2	(19)	2	(5)
Transfers into Level 3	22	1	22	1
Transfers out of Level 3, assets	0	0	0	1
Purchases, assets	3	1	3	1
Issuance, assets	0	0	0	0
Sales, assets	(5)	0	(5)	0
Settlements, assets	0	0	0	0
Balance at end of period, asset	52	30	52	30
Unrealized gains (losses) still held, assets	(21)	(36)	(42)	(23)
Investments | U.S. Treasury and federal agency securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	0	0	0	0
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3, assets	0	0	0	0
Purchases, assets	0	0	0	0
Issuance, assets	0	0	0	0
Sales, assets	0	0	0	0
Settlements, assets	0	0	0	0
Balance at end of period, asset	0	0	0	0
Unrealized gains (losses) still held, assets	0	0	0	0
Investments | State and municipal
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	794	687	834	623
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	8	24	(10)	(7)
Transfers into Level 3	54	172	58	310
Transfers out of Level 3, assets	(108)	(131)	(108)	(131)
Purchases, assets	2	95	3	95
Issuance, assets	0	0	0	0
Sales, assets	(2)	(22)	(29)	(65)
Settlements, assets	0	0	0	0
Balance at end of period, asset	748	825	748	825
Unrealized gains (losses) still held, assets	6	21	(8)	25
Investments | Foreign government
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	523	225	268	96
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	3	7	1	5
Transfers into Level 3	440	0	440	27
Transfers out of Level 3, assets	(289)	(64)	(289)	(64)
Purchases, assets	315	61	645	208
Issuance, assets	0	0	0	0
Sales, assets	(35)	(33)	(108)	(76)
Settlements, assets	0	0	0	0
Balance at end of period, asset	957	196	957	196
Unrealized gains (losses) still held, assets	3	6	3	(9)
Investments | Corporate
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	56	238	60	45
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	(7)	10	(11)	2
Transfers into Level 3	32	0	32	49
Transfers out of Level 3, assets	0	(152)	0	(152)
Purchases, assets	30	10	30	162
Issuance, assets	0	0	0	0
Sales, assets	(7)	0	(7)	0
Settlements, assets	0	0	0	0
Balance at end of period, asset	104	106	104	106
Unrealized gains (losses) still held, assets	(1)	0	(1)	0
Investments | Marketable equity securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset		0		0
Net realized/unrealized gains (losses) included in principal transactions		0		0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets		0		0
Transfers into Level 3		1		1
Transfers out of Level 3, assets		0		0
Purchases, assets		0		0
Issuance, assets		0		0
Sales, assets		0		0
Settlements, assets		0		0
Balance at end of period, asset		1		1
Unrealized gains (losses) still held, assets		0		0
Investments | Asset-backed securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	4	16	1	22
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	(21)	(2)	(21)	3
Transfers into Level 3	33	0	36	0
Transfers out of Level 3, assets	0	0	0	0
Purchases, assets	0	0	0	0
Issuance, assets	0	0	0	0
Sales, assets	(13)	(8)	(13)	(19)
Settlements, assets	0	0	0	0
Balance at end of period, asset	3	6	3	6
Unrealized gains (losses) still held, assets	1	0	(37)	34
Investments | Other trading assets
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset		0		0
Net realized/unrealized gains (losses) included in principal transactions		0		0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets		0		0
Transfers into Level 3		0		0
Transfers out of Level 3, assets		0		0
Purchases, assets		0		0
Issuance, assets		0		0
Sales, assets		0		0
Settlements, assets		0		0
Balance at end of period, asset		0		0
Unrealized gains (losses) still held, assets		0		0
Investments | Non-marketable equity securities
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	352	354	349	441
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	30	21	40	(53)
Transfers into Level 3	0	0	1	0
Transfers out of Level 3, assets	0	0	0	0
Purchases, assets	0	2	0	2
Issuance, assets	0	0	0	0
Sales, assets	0	0	(8)	(3)
Settlements, assets	0	(45)	0	(55)
Balance at end of period, asset	382	332	382	332
Unrealized gains (losses) still held, assets	2	25	2	22
Loans
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	1,944	537	1,985	402
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	476	447	348	368
Transfers into Level 3	60	0	271	217
Transfers out of Level 3, assets	(2,051)	(5)	(2,051)	(6)
Purchases, assets	0	0	0	0
Issuance, assets	0	0	1	0
Sales, assets	0	0	0	0
Settlements, assets	0	(1)	(125)	(3)
Balance at end of period, asset	429	978	429	978
Unrealized gains (losses) still held, assets	169	355	100	509
Fair value, Derivative assets (liabilities) measured on recurring basis, level 3 fair-value category reconciliation
Transfers out of Level 3	(2,100)		(2,100)
Mortgage servicing rights
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	433	367	336	495
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	(21)	(26)	52	(169)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3, assets	0	0	0	0
Purchases, assets	0	0	0	0
Issuance, assets	25	24	68	56
Sales, assets	0	0	0	0
Settlements, assets	(18)	(20)	(37)	(37)
Balance at end of period, asset	419	345	419	345
Unrealized gains (losses) still held, assets	(21)	(14)	59	(147)
Other financial assets measured on a recurring basis
Fair value, assets measured on recurring basis, level 3 fair-value category reconciliation
Balance at beginning of period, asset	0	0	0	1
Net realized/unrealized gains (losses) included in principal transactions	0	0	0	0
Net realized/unrealized gains (losses) included in locations other than principal transactions, assets	0	14	0	14
Transfers into Level 3	55	0	55	0
Transfers out of Level 3, assets	0	0	0	0
Purchases, assets	0	0	0	0
Issuance, assets	0	(6)	0	(6)
Sales, assets	0	(4)	0	(5)
Settlements, assets	0	(4)	0	(4)
Balance at end of period, asset	55	0	55	0
Unrealized gains (losses) still held, assets	$ 0	$ 2	$ 0	$ 16