Fair Value Measurements - Assets and Liabilities Recorded at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Dec. 31, 2019		Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Netting, Assets	[1],[2]	$ (29,510)		$ (25,172)
Netting Liabilities	[1],[2]	(29,510)		(25,172)
Trading assets		28,452		21,978
Trading liabilities		3,235		3,643
Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		5,693		751
Precious metals [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		1,909		1,889
Trading liabilities		124		215
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading liabilities		1,929		2,690
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		3,055		3,048
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		97,866		81,030
Netting, Assets	[3]	(33,193)		(27,192)
Net Balance, Assets		64,673		53,838
Gross Balance, Liabilities		55,224		52,587
Netting Liabilities	[3]	(33,900)		(28,847)
Net Balance, Liabilities		21,324		23,740
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]	7,209		8,154
Net Balance, Liabilities	[4]	7,209		8,154
Fair Value, Recurring [Member] | Trading liabilities, excluding derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities		1,306		953
Net Balance, Liabilities		1,306		953
Fair Value, Recurring [Member] | Derivative financial liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[5]	35,989		31,671
Netting Liabilities	[3],[5]	(33,900)		(28,847)
Net Balance, Liabilities	[5]	2,089		2,824
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]	13,573		11,185
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	13,573		11,185
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]	15,806		15,733
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	15,806		15,733
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]	4,068		2,866
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	4,068		2,866
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]	1,389		900
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	1,389		900
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]	1,068		947
Netting Liabilities	[3],[5]	0		0
Net Balance, Liabilities	[5]	1,068		947
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]	85	[4]	40	[6]
Netting Liabilities	[3],[5]	0		0	[6]
Net Balance, Liabilities	[5]	85	[4]	40	[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]	(33,900)		(28,847)
Net Balance, Liabilities	[5]	(33,900)		(28,847)
Fair Value, Recurring [Member] | Short-term borrowings [Member] | Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	373		560
Net Balance, Liabilities	[4]	373		560
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]	10,347		11,249
Net Balance, Liabilities	[4]	10,347		11,249
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		6,801		5,520
Net Balance, Assets		6,801		5,520
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		71		100
Net Balance, Assets		71		100
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		17		16
Net Balance, Assets		17		16
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		80		92
Net Balance, Assets		80		92
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Corporate and other domestic debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		510		1,803
Net Balance, Assets		510		1,803
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		10,316		8,759
Net Balance, Assets		10,316		8,759
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		5,693		751
Net Balance, Assets		5,693		751
Fair Value, Recurring [Member] | Trading assets, excluding derivatives [Member] | Precious metals [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		1,909		1,889
Net Balance, Assets		1,909		1,889
Fair Value, Recurring [Member] | Derivative financial assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[5]	36,345		30,330
Netting, Assets	[3],[5]	(33,193)		(27,192)
Net Balance, Assets	[5]	3,152		3,138
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]	12,395		10,057
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	12,395		10,057
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]	16,536		15,921
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	16,536		15,921
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]	5,107		2,546
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	5,107		2,546
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]	1,158		845
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	1,158		845
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]	1,139		956
Netting, Assets	[3],[5]	0		0
Net Balance, Assets	[5]	1,139		956
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]	10		5
Netting, Assets	[3],[5],[6]	0		0
Net Balance, Assets	[5],[6]	10		5
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]	(33,193)		(27,192)
Net Balance, Assets	[5]	(33,193)		(27,192)
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]	32,234		27,897
Net Balance, Assets	[7]	32,234		27,897
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]	3,286		3,333
Net Balance, Assets	[7]	3,286		3,333
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]	32		42
Net Balance, Assets	[7]	32		42
Fair Value, Recurring [Member] | Securities available-for-sale [Member] | Other asset-backed securities available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	111		107
Net Balance, Assets	[7]	111		107
Fair Value, Recurring [Member] | Loans [Member] | Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		178		109	[4]
Net Balance, Assets		178		109	[4]
Fair Value, Recurring [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]			4
Net Balance, Assets	[8]			4
Fair Value, Recurring [Member] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		147		190
Net Balance, Assets		147		190
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	[9]	136		88
Net Balance, Assets	[9]	136		88
Fair Value, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		43,501		33,249
Gross Balance, Liabilities		1,265		1,072
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		1,182		738
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]	83		334
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]	3		45
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		15
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]	80		274
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] | Short-term borrowings [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] | 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		6,763		5,368
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 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] | Corporate and other domestic debt 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		10,095		8,552
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		5,693		751
Fair Value, Recurring [Member] | Level 1 [Member] | Trading assets, excluding derivatives [Member] | Precious metals [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]	260		18
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]	110		2
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]	80		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]	70		16
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]	17,532		16,198
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]	3,158		2,362
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 asset-backed securities available-for-sale [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] | Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0	[4]
Fair Value, Recurring [Member] | Level 1 [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]			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	[9]	0		0
Fair Value, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		53,304		45,392
Gross Balance, Liabilities		52,609		49,965
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]	6,435		7,229
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		124		215
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]	35,684		31,124
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]	13,570		11,140
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]	15,805		15,715
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]	3,955		2,717
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]	1,306		626
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]	1,048		926
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] | Short-term borrowings [Member] | Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	373		560
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]	9,993		10,837
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		38		152
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		71		0
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Residential Mortgage 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		80		0
Fair Value, Recurring [Member] | Level 2 [Member] | Trading assets, excluding derivatives [Member] | Corporate and other domestic debt 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] | Foreign debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		221		207
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 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		1,909		1,889
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]	35,798		30,133
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]	12,275		10,053
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]	16,456		15,919
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]	4,922		2,449
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]	1,085		829
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]	1,060		883
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]	14,702		11,699
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]	128		971
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]	32		42
Fair Value, Recurring [Member] | Level 2 [Member] | Securities available-for-sale [Member] | Other asset-backed securities available-for-sale [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] | Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		178		109	[4]
Fair Value, Recurring [Member] | Level 2 [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]			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		147		190
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	[9]	0		0
Fair Value, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		925		2,301
Gross Balance, Liabilities		1,350		1,550
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]	774		925
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]	222		213
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]	0		0
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]	1		3
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]	113		149
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]	3		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]	20		21
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]	85	[4]	40	[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] | Short-term borrowings [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 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]	354		412
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		100
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		17		16
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		92
Fair Value, Recurring [Member] | Level 3 [Member] | Trading assets, excluding derivatives [Member] | Corporate and other domestic debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		510		1,803
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 [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]	287		179
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]	10		2
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]	0		2
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]	185		97
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]	3		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]	79		73
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]	10		5
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]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Securities available-for-sale [Member] | Other asset-backed securities available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	111		107
Fair Value, Recurring [Member] | Level 3 [Member] | Loans [Member] | Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0	[4]
Fair Value, Recurring [Member] | Level 3 [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[8]			4
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	[9]	$ 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 16, "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 $3,055 million and $3,048 million and trading derivative liabilities of $1,929 million and $2,690 million at December 31, 2019 and 2018, respectively, as well as derivatives held for hedging and commitments accounted for as derivatives. See Note 15, "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.

[8] Represented contingent consideration receivable associated with the sale of a portion of our PB business, which concluded in 2019.

[9] 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.