Fair Value Measurements - Assets and Liabilities Recorded at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Mar. 31, 2021		Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Netting, Assets	[1],[2]	$ (18,641)		$ (25,537)
Netting Liabilities	[1],[2]	(18,641)		(25,537)
Trading assets		25,822		27,284
Trading liabilities		2,319		5,397
Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		8,167		7,971
Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		7,750		6,043
Precious metals trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		4,497		4,989
Trading liabilities		0		2,312
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading liabilities		1,664		2,358
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		2,560		2,801
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		83,954		97,982
Netting, Assets	[3]	(23,001)		(29,616)
Net Balance, Assets		60,953		68,366
Gross Balance, Liabilities		36,700		49,380
Netting Liabilities	[3]	(20,594)		(28,914)
Net Balance, Liabilities		16,106		20,466
Fair Value, Recurring [Member] | Domestic Deposits [Member] | Domestic Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	3,765		4,155
Net Balance, Liabilities	[4]	3,765		4,155
Fair Value, Recurring [Member] | Trading liabilities, excluding derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities		655		3,039
Net Balance, Liabilities		655		3,039
Fair Value, Recurring [Member] | Derivative financial liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	22,410		31,461
Netting Liabilities	[3],[5]	(20,594)		(28,914)
Net Balance, Liabilities	[5]	1,816		2,547
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	3,309		6,625
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	3,309		6,625
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	14,695		18,603
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	14,695		18,603
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	2,894		4,291
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	2,894		4,291
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	1,228		1,578
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	1,228		1,578
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	227		297
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	227		297
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	57	[4]	67	[6]
Netting Liabilities	[3],[5]	0		0	[6]
Net Balance, Liabilities	[5]	57	[4]	67	[6]
Fair Value, Recurring [Member] | Derivative financial liabilities [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Netting Liabilities	[3],[5]	(20,594)		(28,914)
Net Balance, Liabilities	[5]	(20,594)		(28,914)
Fair Value, Recurring [Member] | Long-term Debt [Member] | Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	9,870		10,725
Net Balance, Liabilities	[4]	9,870		10,725
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		2,695		5,337
Net Balance, Assets		2,695		5,337
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		66		63
Net Balance, Assets		66		63
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		24		15
Net Balance, Assets		24		15
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		63		65
Net Balance, Assets		63		65
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		8,167		7,971
Net Balance, Assets		8,167		7,971
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		7,750		6,043
Net Balance, Assets		7,750		6,043
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Precious metals trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		4,497		4,989
Net Balance, Assets		4,497		4,989
Fair Value, Recurring [Member] | Derivative financial assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	25,627		32,468
Netting, Assets	[3],[5]	(23,001)		(29,616)
Net Balance, Assets	[5]	2,626		2,852
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	3,680		6,687
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	3,680		6,687
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	15,767		18,467
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	15,767		18,467
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	4,457		5,616
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	4,457		5,616
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	1,377		1,323
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	1,377		1,323
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	339		367
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	339		367
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5],[6]	7		8
Netting, Assets	[3],[5],[6]	0		0
Net Balance, Assets	[5],[6]	7		8
Fair Value, Recurring [Member] | Derivative financial assets [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Netting, Assets	[3],[5]	(23,001)		(29,616)
Net Balance, Assets	[5]	(23,001)		(29,616)
Fair Value, Recurring [Member] | Securities available-for-sale [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	31,508		35,408
Net Balance, Assets	[7]	31,508		35,408
Fair Value, Recurring [Member] | Securities available-for-sale [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	3,021		5,133
Net Balance, Assets	[7]	3,021		5,133
Fair Value, Recurring [Member] | Securities available-for-sale [Member] | Home equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	25		27
Net Balance, Assets	[7]	25		27
Fair Value, Recurring [Member] | Securities available-for-sale [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	105		104
Net Balance, Assets	[7]	105		104
Fair Value, Recurring [Member] | Loans [Member] | Student Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[4]	30		32
Net Balance, Assets	[4]	30		32
Fair Value, Recurring [Member] | Loans [Member] | Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		83	[4]	36
Net Balance, Assets		83	[4]	36
Fair Value, Recurring [Member] | Other assets [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		11		7
Net Balance, Assets		11		7
Fair Value, Recurring [Member] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		145		149
Net Balance, Assets		145		149
Fair Value, Recurring [Member] | Other assets [Member] | Equity Securities Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]	137		135
Net Balance, Assets	[8]	137		135
Fair Value, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		36,580		43,978
Gross Balance, Liabilities		660		764
Fair Value, Recurring [Member] | Level 1 [Member] | Domestic Deposits [Member] | Domestic Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Trading liabilities, excluding derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities		655		727
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	5		37
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	5		9
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		28
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0	[4]	0	[6]
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial liabilities [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Long-term Debt [Member] | Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		2,616		5,145
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		8,155		7,953
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		7,750		6,043
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Precious metals trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	21		15
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	7		15
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	14		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5],[6]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Derivative financial assets [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Securities available-for-sale [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	15,091		22,880
Fair Value, Recurring [Member] | Level 1 [Member] | Securities available-for-sale [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	2,947		1,942
Fair Value, Recurring [Member] | Level 1 [Member] | Securities available-for-sale [Member] | Home equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Securities available-for-sale [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Loans [Member] | Student Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[4]	0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Loans [Member] | Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0	[4]	0
Fair Value, Recurring [Member] | Level 1 [Member] | Other assets [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 1 [Member] | Other assets [Member] | Equity Securities Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]	0		0
Fair Value, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		46,531		53,024
Gross Balance, Liabilities		34,451		46,996
Fair Value, Recurring [Member] | Level 2 [Member] | Domestic Deposits [Member] | Domestic Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	3,166		3,509
Fair Value, Recurring [Member] | Level 2 [Member] | Trading liabilities, excluding derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities		0		2,312
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	21,901		30,898
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	3,303		6,615
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	14,678		18,597
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	2,470		3,845
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	1,228		1,550
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	222		291
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0	[4]	0	[6]
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial liabilities [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Long-term Debt [Member] | Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	9,384		10,277
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		79		192
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		66		63
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		63		65
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		12		18
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Precious metals trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		4,497		4,989
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	25,065		31,761
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	3,670		6,637
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	15,752		18,452
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	3,991		5,051
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	1,363		1,323
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	289		298
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5],[6]	0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Derivative financial assets [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Securities available-for-sale [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	16,417		12,528
Fair Value, Recurring [Member] | Level 2 [Member] | Securities available-for-sale [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	74		3,191
Fair Value, Recurring [Member] | Level 2 [Member] | Securities available-for-sale [Member] | Home equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Securities available-for-sale [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Loans [Member] | Student Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[4]	30		32
Fair Value, Recurring [Member] | Level 2 [Member] | Loans [Member] | Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		83	[4]	36
Fair Value, Recurring [Member] | Level 2 [Member] | Other assets [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 2 [Member] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		145		149
Fair Value, Recurring [Member] | Level 2 [Member] | Other assets [Member] | Equity Securities Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]	0		0
Fair Value, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		706		845
Gross Balance, Liabilities		1,589		1,620
Fair Value, Recurring [Member] | Level 3 [Member] | Domestic Deposits [Member] | Domestic Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	599		646
Fair Value, Recurring [Member] | Level 3 [Member] | Trading liabilities, excluding derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	504		526
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	1		1
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	17		6
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	424		446
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	5		6
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	57	[4]	67	[6]
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial liabilities [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Long-term Debt [Member] | Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	486		448
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		24		15
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Precious metals trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	541		692
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	3		35
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	15		15
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Equity contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	466		565
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Precious metals contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Credit contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	50		69
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Other Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5],[6]	7		8
Fair Value, Recurring [Member] | Level 3 [Member] | Derivative financial assets [Member] | Derivatives netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Securities available-for-sale [Member] | U.S. Treasury, U.S. Government agencies and sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Securities available-for-sale [Member] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Securities available-for-sale [Member] | Home equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	25		27
Fair Value, Recurring [Member] | Level 3 [Member] | Securities available-for-sale [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	105		104
Fair Value, Recurring [Member] | Level 3 [Member] | Loans [Member] | Student Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[4]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Loans [Member] | Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0	[4]	0
Fair Value, Recurring [Member] | Level 3 [Member] | Other assets [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		11		7
Fair Value, Recurring [Member] | Level 3 [Member] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Other assets [Member] | Equity Securities Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]	$ 0		$ 0

[1] Netting is performed at a counterparty level in cases where enforceable master netting agreements are in place, regardless of the type of derivative instrument. Therefore, we have not allocated netting to the different types of derivative instruments shown in the table above.

[2] Represents the netting of derivative receivable and payable balances for the same counterparty under enforceable netting agreements.

[3] Represents counterparty and cash collateral netting which allow the offsetting of amounts relating to certain contracts if certain conditions are met.

[4] See Note 10, "Fair Value Option," for additional information. Excluding the fair value movement on fair value option liabilities attributable to our own credit spread, which is recorded in other comprehensive income, fair value option assets and liabilities are recorded at fair value through net income (loss).

[5] Includes trading derivative assets of $2,560 million and $2,801 million and trading derivative liabilities of $1,664 million and $2,358 million at March 31, 2021 and December 31, 2020, respectively, as well as derivatives held for hedging and commitments accounted for as derivatives. See Note 9, "Derivative Financial Instruments," for additional information. Excluding changes in fair value of a derivative instrument associated with a qualifying cash flow hedge, which are recognized initially in other comprehensive income, derivative assets and liabilities are recorded at fair value through net income (loss).

[6] Consists of swap agreements entered into in conjunction with the sales of Visa Class B Shares.

[7] Securities available-for-sale are recorded at fair value through other comprehensive income. Changes in the allowance for credit losses on securities available-for-sale are recorded through net income (loss).

[8] Investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy.