FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Fair Value Measurements (Details)	Jun. 30, 2021 USD ($) year	Dec. 31, 2020 USD ($) year
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities	$ 793,000,000	$ 1,066,000,000
Model-based | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	211,000,000	320,000,000
State and municipal, foreign government, corporate and other debt securities	973,000,000	852,000,000
Marketable equity securities		36,000,000
Loans and leases	335,000,000	1,804,000,000
Mortgage servicing rights	80,000,000	78,000,000
Interest-bearing deposits	154,000,000	206,000,000
Securities loaned and sold under agreement to repurchase	488,000,000	631,000,000
Securities sold, not yet purchased	116,000,000	178,000,000
Short-term borrowings and long-term debt	24,881,000,000	24,827,000,000
Model-based | Level 3 | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	3,740,000,000	5,143,000,000
Model-based | Level 3 | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,240,000,000	1,296,000,000
Model-based | Level 3 | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	5,608,000,000	7,330,000,000
Model-based | Level 3 | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,640,000,000	1,636,000,000
Model-based | Level 3 | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,283,000,000	1,854,000,000
Price-based | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	136,000,000	344,000,000
State and municipal, foreign government, corporate and other debt securities	2,069,000,000	1,566,000,000
Marketable equity securities		36,000,000
Asset-backed securities	418,000,000	863,000,000
Non-marketable equities	97,000,000	142,000,000
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	17,000,000
Loans and leases	87,000,000
Securities sold, not yet purchased	52,000,000	62,000,000
Price-based | Level 3 | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	466,000,000	408,000,000
Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities	139,000,000
Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities
Yield analysis | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	452,000,000	168,000,000
Asset-backed securities	211,000,000	744,000,000
Comparable analysis | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	248,000,000	205,000,000
Cash flow | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	$ 339,000,000	$ 258,000,000
Minimum | Model-based | Level 3 | Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	0.15%	0.15%
State and municipal, foreign government, corporate and other debt securities	0.0035	0.0035
Minimum | Model-based | Level 3 | Credit Spread | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0004	0.000350
Minimum | Model-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	0.30%	0.30%
Securities loaned and sold under agreement to repurchase	0.0006	0.0008
Minimum | Model-based | Level 3 | Interest Rate | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.0084
Minimum | Model-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 0
Minimum | Model-based | Level 3 | IR Normal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits	0.0013	0.0011
Short-term borrowings and long-term debt	0.0011	0.0011
Minimum | Model-based | Level 3 | IR Normal Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0010	0.0011
Minimum | Model-based | Level 3 | IR Normal Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0011	0.0011
Minimum | Model-based | Level 3 | Inflation Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0028	0.0027
Minimum | Model-based | Level 3 | IR Basis | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.0070)
Minimum | Model-based | Level 3 | FX Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	0
Minimum | Model-based | Level 3 | FX Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0500	0.0170
Minimum | Model-based | Level 3 | IR-FX Correlation | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.4000
Minimum | Model-based | Level 3 | IR-IR Correlation | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		(0.2171)
Minimum | Model-based | Level 3 | IR Lognormal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased	0.5587	0.5206
Minimum | Model-based | Level 3 | Equity Forward
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	0.5700
Minimum | Model-based | Level 3 | Equity Forward | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.5700
Minimum | Model-based | Level 3 | Equity - FX Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	(0.8100)
Minimum | Model-based | Level 3 | Forward Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.1540
Minimum | Model-based | Level 3 | Forward Price | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.6588
Minimum | Model-based | Level 3 | Forward Price | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0999	0.1540
Minimum | Model-based | Level 3 | Commodity Correlation | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.4900)	(0.4492)
Minimum | Model-based | Level 3 | Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.2206	0.2465
Short-term borrowings and long-term debt	0.0007
Minimum | Model-based | Level 3 | Equity Volatility | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0	0.0500
Minimum | Model-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights | year	3.15	2.66
Minimum | Model-based | Level 3 | Commodity Volatility | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.1000	0.0016
Minimum | Model-based | Level 3 | Contingent Event | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		1.0000
Minimum | Price-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased	0.0017	0.1003
Minimum | Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	$ 4.00	$ 30
State and municipal, foreign government, corporate and other debt securities	5.24	0
Marketable equity securities	0
Asset-backed securities	2.08	2
Non-marketable equities	11.03	136
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	4.96
Loans and leases	35.23
Securities sold, not yet purchased	0	$ 0
Minimum | Price-based | Level 3 | Price | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	$ 15.06
Minimum | Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities	0.2470
Minimum | Price-based | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	12.00
Minimum | Price-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.18	0.20
Minimum | Price-based | Level 3 | EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	5.70	3.30
Minimum | Price-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	10.20	2.70
Minimum | Price-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities | year		1.48
Minimum | Price-based | Level 3 | Recovery
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 5,733,000,000
Minimum | Price-based | Level 3 | Credit Correlation | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.2500
Minimum | Price-based | Level 3 | Upfront Points | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0505	0
Minimum | Price-based | Level 3 | Recovery Rate | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.2500	0.2000
Minimum | Price-based | Level 3 | Appraised Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		$ 287,000
Minimum | Yield analysis | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	1.64%	2.63%
Asset-backed securities	2.29%	3.77%
Minimum | Comparable analysis | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	100,000.00	0.1000
Minimum | Comparable analysis | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		13.60
Minimum | Cash flow | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	0.0200	0.0286
Maximum | Model-based | Level 3 | Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	0.15%	0.15%
State and municipal, foreign government, corporate and other debt securities	0.0583	0.0375
Maximum | Model-based | Level 3 | Credit Spread | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0600	0.035235
Maximum | Model-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	0.30%	0.35%
Securities loaned and sold under agreement to repurchase	0.0204	0.0186
Maximum | Model-based | Level 3 | Interest Rate | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.8409
Maximum | Model-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 31,000
Maximum | Model-based | Level 3 | IR Normal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits	0.0075	0.0073
Short-term borrowings and long-term debt	0.0075	0.0073
Maximum | Model-based | Level 3 | IR Normal Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0075	0.0073
Maximum | Model-based | Level 3 | IR Normal Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0058	0.0052
Maximum | Model-based | Level 3 | Inflation Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0258	0.0236
Maximum | Model-based | Level 3 | IR Basis | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0107
Maximum | Model-based | Level 3 | FX Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	0.3700
Maximum | Model-based | Level 3 | FX Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.2855	0.1263
Maximum | Model-based | Level 3 | IR-FX Correlation | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.6000
Maximum | Model-based | Level 3 | IR-IR Correlation | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.4000
Maximum | Model-based | Level 3 | IR Lognormal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased	1.3901	1.2887
Maximum | Model-based | Level 3 | Equity Forward
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	1.2500
Maximum | Model-based | Level 3 | Equity Forward | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1.2500
Maximum | Model-based | Level 3 | Equity - FX Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	0.8000
Maximum | Model-based | Level 3 | Forward Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		2.6200
Maximum | Model-based | Level 3 | Forward Price | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		1.0520
Maximum | Model-based | Level 3 | Forward Price | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	4.2106	2.6200
Maximum | Model-based | Level 3 | Commodity Correlation | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.9200	0.9591
Maximum | Model-based | Level 3 | Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.6396	0.8309
Short-term borrowings and long-term debt	2.9900
Maximum | Model-based | Level 3 | Equity Volatility | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	2.9900	0.9143
Maximum | Model-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights | year	6.32	5.40
Maximum | Model-based | Level 3 | Commodity Volatility | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.6900	0.8017
Maximum | Model-based | Level 3 | Contingent Event | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		1.0000
Maximum | Price-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased	0.0023	0.2007
Maximum | Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	$ 120.68	$ 111
State and municipal, foreign government, corporate and other debt securities	1,027.67	2,265
Marketable equity securities	97,500.00
Asset-backed securities	166.03	157
Non-marketable equities	1,610.00	2,041
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	44.50
Loans and leases	409.11
Securities sold, not yet purchased	12,351.44	$ 866
Maximum | Price-based | Level 3 | Price | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	$ 103.63
Maximum | Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities	0.2500
Maximum | Price-based | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	31.00
Maximum | Price-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.80	0.61
Maximum | Price-based | Level 3 | EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	19.40	36.70
Maximum | Price-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	15.30	28.00
Maximum | Price-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities | year		1.48
Maximum | Price-based | Level 3 | Recovery
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 5,733,000,000
Maximum | Price-based | Level 3 | Credit Correlation | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.8000
Maximum | Price-based | Level 3 | Upfront Points | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1.0000	1.0720
Maximum | Price-based | Level 3 | Recovery Rate | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.7500	0.6000
Maximum | Price-based | Level 3 | Appraised Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		$ 39,745,000
Maximum | Yield analysis | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	17.78%	21.80%
Asset-backed securities	15.40%	21.77%
Maximum | Comparable analysis | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	350,000.00	0.4500
Maximum | Comparable analysis | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		28.00
Maximum | Cash flow | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	0.1500	0.1600
Weighted Average | Model-based | Level 3 | Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	0.15%	0.15%
State and municipal, foreign government, corporate and other debt securities	0.0246	0.0226
Weighted Average | Model-based | Level 3 | Credit Spread | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0052	0.009989
Weighted Average | Model-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	0.30%	0.32%
Securities loaned and sold under agreement to repurchase	0.0125	0.0071
Weighted Average | Model-based | Level 3 | Interest Rate | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.1755
Weighted Average | Model-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 5,132
Weighted Average | Model-based | Level 3 | IR Normal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits	0.0061	0.0054
Short-term borrowings and long-term debt	0.0055	0.0051
Weighted Average | Model-based | Level 3 | IR Normal Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0055	0.0052
Weighted Average | Model-based | Level 3 | IR Normal Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0051	0.0046
Weighted Average | Model-based | Level 3 | Inflation Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0147	0.0078
Weighted Average | Model-based | Level 3 | IR Basis | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0010
Weighted Average | Model-based | Level 3 | FX Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	0.1012
Weighted Average | Model-based | Level 3 | FX Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0994	0.0541
Weighted Average | Model-based | Level 3 | IR-FX Correlation | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.5000
Weighted Average | Model-based | Level 3 | IR-IR Correlation | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.3809
Weighted Average | Model-based | Level 3 | IR Lognormal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased	1.0626	0.8982
Weighted Average | Model-based | Level 3 | Equity Forward
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	0.8978
Weighted Average | Model-based | Level 3 | Equity Forward | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.8982
Weighted Average | Model-based | Level 3 | Equity - FX Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt	(0.1254)
Weighted Average | Model-based | Level 3 | Forward Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.9248
Weighted Average | Model-based | Level 3 | Forward Price | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.9182
Weighted Average | Model-based | Level 3 | Forward Price | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1.1004	0.9853
Weighted Average | Model-based | Level 3 | Commodity Correlation | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.1834	0.7060
Weighted Average | Model-based | Level 3 | Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.3076	0.5823
Short-term borrowings and long-term debt	0.6451
Weighted Average | Model-based | Level 3 | Equity Volatility | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.5026	0.4274
Weighted Average | Model-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights | year	5.49	4.46
Weighted Average | Model-based | Level 3 | Commodity Volatility | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.2491	0.2372
Weighted Average | Model-based | Level 3 | Contingent Event | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		1.0000
Weighted Average | Price-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased	0.0020	0.1370
Weighted Average | Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	$ 91.67	$ 80
State and municipal, foreign government, corporate and other debt securities	213.01	90
Marketable equity securities	25,976.84
Asset-backed securities	68.96	59
Non-marketable equities	1,269.53	1,647
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	39.76
Loans and leases	111.37
Securities sold, not yet purchased	2,184.24	$ 80
Weighted Average | Price-based | Level 3 | Price | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	$ 72.48
Weighted Average | Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities	0.2487
Weighted Average | Price-based | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	18.52
Weighted Average | Price-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.47	0.25
Weighted Average | Price-based | Level 3 | EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	13.18	15.10
Weighted Average | Price-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	13.58	8.92
Weighted Average | Price-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities | year		1.48
Weighted Average | Price-based | Level 3 | Recovery
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 5,733,000,000
Weighted Average | Price-based | Level 3 | Credit Correlation | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.4336
Weighted Average | Price-based | Level 3 | Upfront Points | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.5873	0.4810
Weighted Average | Price-based | Level 3 | Recovery Rate | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.4624	0.4160
Weighted Average | Price-based | Level 3 | Appraised Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		$ 21,754,000
Weighted Average | Yield analysis | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	7.31%	10.13%
Asset-backed securities	6.35%	9.01%
Weighted Average | Comparable analysis | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	215,300	0.2529
Weighted Average | Comparable analysis | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		22.83
Weighted Average | Cash flow | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	0.0674	0.0632