FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Fair Value Measurements (Details)	Jun. 30, 2022 USD ($) year	Dec. 31, 2021 USD ($) year
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities	$ 1,046,000,000	$ 1,032,000,000
Derivative assets	81,885,000,000	69,776,000,000
Model-based | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	183,000,000	231,000,000
State and municipal, foreign government, corporate and other debt securities	499,000,000	415,000,000
Marketable equity securities		43,000,000
Non-marketable equities		83,000,000
Loans and leases	309,000,000	691,000,000
Mortgage servicing rights	71,000,000	73,000,000
Interest-bearing deposits	18,000,000	183,000,000
Securities loaned and sold under agreement to repurchase	593,000,000	643,000,000
Short-term borrowings and long-term debt	28,623,000,000	25,514,000,000
Model-based | Level 3 | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	5,279,000,000	6,054,000,000
Model-based | Level 3 | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,754,000,000	1,364,000,000
Model-based | Level 3 | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	4,366,000,000	4,690,000,000
Model-based | Level 3 | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	4,043,000,000	3,172,000,000
Model-based | Level 3 | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	2,396,000,000	1,480,000,000
Price-based | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	243,000,000	279,000,000
State and municipal, foreign government, corporate and other debt securities	2,483,000,000	2,264,000,000
Marketable equity securities	136,000,000	128,000,000
Asset-backed securities	328,000,000	386,000,000
Non-marketable equities	150,000,000	121,000,000
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	57,000,000	69,000,000
Securities sold, not yet purchased and other trading liabilities	46,000,000	63,000,000
Price-based | Level 3 | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	434,000,000	427,000,000
Yield analysis | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	804,000,000	526,000,000
Asset-backed securities	192,000,000	208,000,000
Securities sold, not yet purchased and other trading liabilities	24,000,000
Comparable analysis | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	148,000,000	112,000,000
Cash flow | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	$ 529,000,000	$ 331,000,000
Minimum | Model-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	1.50%	0.26%
Securities loaned and sold under agreement to repurchase	0.0180	0.0012
Minimum | Model-based | Level 3 | Yield | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.0020)
Minimum | Model-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		$ 3
Minimum | Model-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.33
Minimum | Model-based | Level 3 | IR Basis | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.0120)
Minimum | Model-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		19.80
Minimum | Model-based | Level 3 | IR Normal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits	0.0030	0.0034
Short-term borrowings and long-term debt	0.0030	0.0007
Minimum | Model-based | Level 3 | IR Normal Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0030	0.0024
Minimum | Model-based | Level 3 | IR Normal Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0040	0.0024
Minimum | Model-based | Level 3 | FX Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.0006
Minimum | Model-based | Level 3 | FX Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.0213
Minimum | Model-based | Level 3 | Cost of Capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.1750
Minimum | Model-based | Level 3 | Equity - Equity Correlation | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.0649)	(0.0649)
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%
Minimum | Model-based | Level 3 | Credit Spread | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.0140
Minimum | Model-based | Level 3 | Credit Spread | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0016	0.000100
Minimum | Model-based | Level 3 | Equity-IR Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		(0.0353)
Minimum | Model-based | Level 3 | Equity Forward
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits		0.5799
Short-term borrowings and long-term debt	0.4900
Minimum | Model-based | Level 3 | Equity Forward | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.4900	0.5799
Minimum | Model-based | Level 3 | Equity - FX Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		(0.9500)
Minimum | Model-based | Level 3 | Equity - FX Correlation | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.9500)	(0.9500)
Minimum | Model-based | Level 3 | Forward Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.1245	0.2695
Interest-bearing deposits	1.0000
Minimum | Model-based | Level 3 | Forward Price | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.1245	0.0800
Minimum | Model-based | Level 3 | Commodity Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	(0.5302)	(0.5052)
Minimum | Model-based | Level 3 | Commodity Correlation | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.5300)	(0.5052)
Minimum | Model-based | Level 3 | Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
State and municipal, foreign government, corporate and other debt securities		0.0008
Loans and leases	0.6088	0.2248
Interest-bearing deposits		0.0008
Short-term borrowings and long-term debt	0.0010	0.0008
Minimum | Model-based | Level 3 | Equity Volatility | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0010	0.0008
Minimum | Model-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities | year		1.73
Mortgage servicing rights | year	4	2.75
Minimum | Model-based | Level 3 | Recovery
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 7,148,000,000
Minimum | Model-based | Level 3 | Commodity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.1304	0.1087
Minimum | Model-based | Level 3 | Commodity Volatility | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.1300	0.1087
Minimum | Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	$ 0.80	$ 4
State and municipal, foreign government, corporate and other debt securities	0	0
Marketable equity securities	0	0
Asset-backed securities	4.10	5
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	84.35	94
Securities sold, not yet purchased and other trading liabilities	$ 0	0
Minimum | Price-based | Level 3 | Price | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		$ 40
Minimum | Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.1000
Minimum | Price-based | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	15.20
Minimum | Price-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.30
Minimum | Price-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	12.80
Minimum | Price-based | Level 3 | EBITDA multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	17.40
Minimum | Price-based | Level 3 | Cost of Capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.1750
Minimum | Price-based | Level 3 | Credit Spread Volatility | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.2340
Minimum | Price-based | Level 3 | Credit Correlation | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.1500	0.3000
Minimum | Price-based | Level 3 | Upfront Points | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0	0.0274
Minimum | Price-based | Level 3 | Recovery Rate | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0500	0.2000
Minimum | Yield analysis | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	3.50%	1.43%
Asset-backed securities	4.20%	2.43%
Securities sold, not yet purchased and other trading liabilities	0.0340
Minimum | Yield analysis | Level 3 | Upfront Points
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased and other trading liabilities	0.0400
Minimum | Comparable analysis | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.1500
Minimum | Comparable analysis | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		11.00
Minimum | Cash flow | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	0	(0.0120)
Maximum | Model-based | Level 3 | Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities borrowed and purchased under agreements to resell	2.80%	0.72%
Securities loaned and sold under agreement to repurchase	0.0370	0.0195
Maximum | Model-based | Level 3 | Yield | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0160
Maximum | Model-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		$ 2,601
Maximum | Model-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.44
Maximum | Model-based | Level 3 | IR Basis | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0520
Maximum | Model-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		30.00
Maximum | Model-based | Level 3 | IR Normal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits	0.0090	0.0088
Short-term borrowings and long-term debt	0.0170	0.0088
Maximum | Model-based | Level 3 | IR Normal Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0170	0.0094
Maximum | Model-based | Level 3 | IR Normal Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0160	0.0074
Maximum | Model-based | Level 3 | FX Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.4176
Maximum | Model-based | Level 3 | FX Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		1.0742
Maximum | Model-based | Level 3 | Cost of Capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.2000
Maximum | Model-based | Level 3 | Equity - Equity Correlation | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.9970	0.9900
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%
Maximum | Model-based | Level 3 | Credit Spread | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.0696
Maximum | Model-based | Level 3 | Credit Spread | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0601	0.087472
Maximum | Model-based | Level 3 | Equity-IR Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.6000
Maximum | Model-based | Level 3 | Equity Forward
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits		1.6583
Short-term borrowings and long-term debt	2.4710
Maximum | Model-based | Level 3 | Equity Forward | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	2.4710	1.6583
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 | Equity - FX Correlation | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.8000	0.8000
Maximum | Model-based | Level 3 | Forward Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	3.6911	3.3308
Interest-bearing deposits	1.0000
Maximum | Model-based | Level 3 | Forward Price | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	3.8182	5.9944
Maximum | Model-based | Level 3 | Commodity Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.9352	0.8983
Maximum | Model-based | Level 3 | Commodity Correlation | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.9350	0.8983
Maximum | Model-based | Level 3 | Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
State and municipal, foreign government, corporate and other debt securities		2.9064
Loans and leases	0.9902	0.8544
Interest-bearing deposits		2.9064
Short-term borrowings and long-term debt	3.1390	2.9064
Maximum | Model-based | Level 3 | Equity Volatility | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	3.1390	2.9064
Maximum | Model-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities | year		1.73
Mortgage servicing rights | year	9.7	5.86
Maximum | Model-based | Level 3 | Recovery
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 7,148,000,000
Maximum | Model-based | Level 3 | Commodity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	1.0731	1.8830
Maximum | Model-based | Level 3 | Commodity Volatility | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1.0730	1.8830
Maximum | Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	$ 100.10	$ 118
State and municipal, foreign government, corporate and other debt securities	934.30	995
Marketable equity securities	8,922.8	73,000
Asset-backed securities	100.00	754
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	785.00	2,598
Securities sold, not yet purchased and other trading liabilities	$ 12,100	12,875
Maximum | Price-based | Level 3 | Price | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		$ 103
Maximum | Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.3600
Maximum | Price-based | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	18.00
Maximum | Price-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.50
Maximum | Price-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	30.00
Maximum | Price-based | Level 3 | EBITDA multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	17.40
Maximum | Price-based | Level 3 | Cost of Capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.2000
Maximum | Price-based | Level 3 | Credit Spread Volatility | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.7920
Maximum | Price-based | Level 3 | Credit Correlation | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.8500	0.8000
Maximum | Price-based | Level 3 | Upfront Points | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.9900	0.9996
Maximum | Price-based | Level 3 | Recovery Rate | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.7500	0.7500
Maximum | Yield analysis | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	22.00%	23.79%
Asset-backed securities	16.00%	19.35%
Securities sold, not yet purchased and other trading liabilities	0.0460
Maximum | Yield analysis | Level 3 | Upfront Points
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased and other trading liabilities	0.0400
Maximum | Comparable analysis | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.3200
Maximum | Comparable analysis | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		29.00
Maximum | Cash flow | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	0.1290	0.1210
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	2.20%	0.50%
Securities loaned and sold under agreement to repurchase	0.0310	0.0147
Weighted Average | Model-based | Level 3 | Yield | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0050
Weighted Average | Model-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		$ 2,029
Weighted Average | Model-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.34
Weighted Average | Model-based | Level 3 | IR Basis | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0020
Weighted Average | Model-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		20.48
Weighted Average | Model-based | Level 3 | IR Normal Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits	0.0050	0.0068
Short-term borrowings and long-term debt	0.0080	0.0060
Weighted Average | Model-based | Level 3 | IR Normal Volatility | Interest rate contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0090	0.0070
Weighted Average | Model-based | Level 3 | IR Normal Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0060	0.0058
Weighted Average | Model-based | Level 3 | FX Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.0938
Weighted Average | Model-based | Level 3 | FX Volatility | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.1121
Weighted Average | Model-based | Level 3 | Cost of Capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.1757
Weighted Average | Model-based | Level 3 | Equity - Equity Correlation | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.8680	0.8561
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%
Weighted Average | Model-based | Level 3 | Credit Spread | Foreign exchange contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		0.0639
Weighted Average | Model-based | Level 3 | Credit Spread | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.0123	0.006883
Weighted Average | Model-based | Level 3 | Equity-IR Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Short-term borrowings and long-term debt		0.3212
Weighted Average | Model-based | Level 3 | Equity Forward
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest-bearing deposits		0.8939
Short-term borrowings and long-term debt	0.9690
Weighted Average | Model-based | Level 3 | Equity Forward | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.9700	0.8945
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		(0.1598)
Weighted Average | Model-based | Level 3 | Equity - FX Correlation | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	(0.1720)	(0.1600)
Weighted Average | Model-based | Level 3 | Forward Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.8372	1.0697
Interest-bearing deposits	1.0000
Weighted Average | Model-based | Level 3 | Forward Price | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.8652	1.2322
Weighted Average | Model-based | Level 3 | Commodity Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.1908	(0.0711)
Weighted Average | Model-based | Level 3 | Commodity Correlation | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.1910	(0.0711)
Weighted Average | Model-based | Level 3 | Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
State and municipal, foreign government, corporate and other debt securities		0.5394
Loans and leases	0.9464	0.5056
Interest-bearing deposits		0.5405
Short-term borrowings and long-term debt	0.5260	0.5321
Weighted Average | Model-based | Level 3 | Equity Volatility | Equity contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.4670	0.4767
Weighted Average | Model-based | Level 3 | WAL
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities | year		1.73
Mortgage servicing rights | year	7.70	5.14
Weighted Average | Model-based | Level 3 | Recovery
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Marketable equity securities		$ 7,148,000,000
Weighted Average | Model-based | Level 3 | Commodity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases	0.2633	0.2685
Weighted Average | Model-based | Level 3 | Commodity Volatility | Commodity and other contracts (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.2630	0.2685
Weighted Average | Price-based | Level 3 | Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	$ 59.70	$ 79
State and municipal, foreign government, corporate and other debt securities	186.50	193
Marketable equity securities	52.70	6,477
Asset-backed securities	79.60	87
Nontrading derivatives and other financial assets and liabilities measured on a recurring basis (gross)	181.80	591
Securities sold, not yet purchased and other trading liabilities	$ 2,133	1,707
Weighted Average | Price-based | Level 3 | Price | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets		$ 80
Weighted Average | Price-based | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		0.2643
Weighted Average | Price-based | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	15.90
Weighted Average | Price-based | Level 3 | Adjustment Factor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.30
Weighted Average | Price-based | Level 3 | Revenue Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	14.00
Weighted Average | Price-based | Level 3 | EBITDA multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	17.40
Weighted Average | Price-based | Level 3 | Cost of Capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.1760
Weighted Average | Price-based | Level 3 | Credit Spread Volatility | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.4700
Weighted Average | Price-based | Level 3 | Credit Correlation | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.4360	0.5457
Weighted Average | Price-based | Level 3 | Upfront Points | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.4390	0.5937
Weighted Average | Price-based | Level 3 | Recovery Rate | Credit derivatives (gross)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0.3700	0.4472
Weighted Average | Yield analysis | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage-backed securities	8.80%	7.25%
Asset-backed securities	7.90%	8.18%
Securities sold, not yet purchased and other trading liabilities	0.0400
Weighted Average | Yield analysis | Level 3 | Upfront Points
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities sold, not yet purchased and other trading liabilities	0.0400
Weighted Average | Comparable analysis | Level 3 | Illiquidity Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities	0.2760
Weighted Average | Comparable analysis | Level 3 | PE Ratio
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-marketable equities		15.42
Weighted Average | Cash flow | Level 3 | Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	0.0530	0.0451