Fair Value Measurements - Assets and Liabilities Recorded at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Jun. 30, 2019		Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Netting, Assets	[1],[2]	$ (24,555)		$ (25,172)
Netting Liabilities	[1],[2]	(24,555)		(25,172)
Trading assets		33,502		21,978
Trading liabilities		4,026		3,643
Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		2,747		751
Precious metals [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		3,895		1,889
Trading liabilities		106		215
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading liabilities		3,086		2,690
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Trading assets		3,045		3,048
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		99,332		81,030
Netting, Assets	[3]	(27,994)		(27,192)
Net Balance, Assets		71,338		53,838
Gross Balance, Liabilities		53,059		52,587
Netting Liabilities	[3]	(28,182)		(28,847)
Net Balance, Liabilities		24,877		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		8,455	[4]	8,154
Net Balance, Liabilities		8,455	[4]	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		940		953
Net Balance, Liabilities		940		953
Fair Value, Recurring [Member] | Derivative financial liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Liabilities	[4]	31,463		31,671
Netting Liabilities	[3],[4]	(28,182)		(28,847)
Net Balance, Liabilities	[4]	3,281		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	[4]	12,804		11,185
Netting Liabilities	[3],[4]	0		0
Net Balance, Liabilities	[4]	12,804		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	[4]	13,052		15,733
Netting Liabilities	[3],[4]	0		0
Net Balance, Liabilities	[4]	13,052		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	[4]	2,901		2,866
Netting Liabilities	[3],[4]	0		0
Net Balance, Liabilities	[4]	2,901		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	[4]	1,391		900
Netting Liabilities	[3],[4]	0		0
Net Balance, Liabilities	[4]	1,391		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	[4]	1,275		947
Netting Liabilities	[3],[4]	0		0
Net Balance, Liabilities	[4]	1,275		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	[4],[5]	40		40
Netting Liabilities	[3],[4]	0		0	[5]
Net Balance, Liabilities	[4],[5]	40		40
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	[4]	0		0
Netting Liabilities	[3],[4]	(28,182)		(28,847)
Net Balance, Liabilities	[4]	(28,182)		(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		222		560	[4]
Net Balance, Liabilities		222		560	[4]
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		11,979		11,249
Net Balance, Liabilities		11,979		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		10,698		5,520
Net Balance, Assets		10,698		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		86		100
Net Balance, Assets		86		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		16		16
Net Balance, Assets		16		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		90		92
Net Balance, Assets		90		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		12,415		8,759
Net Balance, Assets		12,415		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		2,747		751
Net Balance, Assets		2,747		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		3,895		1,889
Net Balance, Assets		3,895		1,889
Fair Value, Recurring [Member] | Derivative financial assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[4]	31,190		30,330
Netting, Assets	[3],[4]	(27,994)		(27,192)
Net Balance, Assets	[4]	3,196		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	[4]	11,560		10,057
Netting, Assets	[3],[4]	0		0
Net Balance, Assets	[4]	11,560		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	[4]	13,370		15,921
Netting, Assets	[3],[4]	0		0
Net Balance, Assets	[4]	13,370		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	[4]	3,776		2,546
Netting, Assets	[3],[4]	0		0
Net Balance, Assets	[4]	3,776		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	[4]	1,360		845
Netting, Assets	[3],[4]	0		0
Net Balance, Assets	[4]	1,360		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	[4]	1,119		956
Netting, Assets	[3],[4]	0		0
Net Balance, Assets	[4]	1,119		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	[4],[5]	5		5
Netting, Assets	[3],[4],[5]	0		0
Net Balance, Assets	[4],[5]	5		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	[4]	0		0
Netting, Assets	[3],[4]	(27,994)		(27,192)
Net Balance, Assets	[4]	(27,994)		(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	[6]	34,130		27,897
Net Balance, Assets	[6]	34,130		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	[6]	2,975		3,333
Net Balance, Assets	[6]	2,975		3,333
Fair Value, Recurring [Member] | Securities available-for-sale [Member] | Home Equity Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[6]	36		42
Net Balance, Assets	[6]	36		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	[6]	113		107
Net Balance, Assets	[6]	113		107
Fair Value, Recurring [Member] | Loans [Member] | Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		128		109
Net Balance, Assets		128		109
Fair Value, Recurring [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	1		4
Net Balance, Assets	[7]	1		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		193		190	[6]
Net Balance, Assets		193		190	[6]
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]	109		88
Net Balance, Assets	[8]	109		88
Fair Value, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		47,938		33,249
Gross Balance, Liabilities		1,022		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		0	[4]	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		834		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	[4]	188		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	[4]	51		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	[4]	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	[4]	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	[4]	137		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	[4]	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	[4],[5]	0		0
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	[4]	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		0		0	[4]
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		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		10,620		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		12,199		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		2,747		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	[4]	222		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	[4]	99		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	[4]	1		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	[4]	16		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	[4]	106		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	[4]	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	[4],[5]	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	[4]	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	[6]	19,559		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	[6]	2,591		2,362
Fair Value, Recurring [Member] | Level 1 [Member] | Securities available-for-sale [Member] | Home Equity Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[6]	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	[6]	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
Fair Value, Recurring [Member] | Level 1 [Member] | Other assets [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] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		0		0	[6]
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		50,193		45,392
Gross Balance, Liabilities		50,472		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		7,525	[4]	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		106		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	[4]	31,081		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	[4]	12,752		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	[4]	13,044		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	[4]	2,778		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	[4]	1,254		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	[4]	1,253		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	[4],[5]	0		0
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	[4]	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		222		560	[4]
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		11,538		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		78		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		0		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		0		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		216		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		3,895		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	[4]	30,692		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	[4]	11,450		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	[4]	13,362		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	[4]	3,575		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	[4]	1,254		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	[4]	1,051		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	[4],[5]	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	[4]	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	[6]	14,571		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	[6]	384		971
Fair Value, Recurring [Member] | Level 2 [Member] | Securities available-for-sale [Member] | Home Equity Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[6]	36		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	[6]	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		128		109
Fair Value, Recurring [Member] | Level 2 [Member] | Other assets [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] | Other assets [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets		193		190	[6]
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		1,092		2,301
Gross Balance, Liabilities		1,565		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		930	[4]	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	[4]	194		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	[4]	1		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	[4]	8		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	[4]	123		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	[4]	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	[4]	22		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	[4],[5]	40		40
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	[4]	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		0		0	[4]
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		441		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		86		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		16		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		90		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	[4]	276		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	[4]	11		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	[4]	7		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	[4]	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	[4]	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	[4]	68		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	[4],[5]	5		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	[4]	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	[6]	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	[6]	0		0
Fair Value, Recurring [Member] | Level 3 [Member] | Securities available-for-sale [Member] | Home Equity Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[6]	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	[6]	113		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
Fair Value, Recurring [Member] | Level 3 [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gross Balance, Assets	[7]	1		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	[6]
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] Includes trading derivative assets of $3,045 million and $3,048 million and trading derivative liabilities of $3,086 million and $2,690 million at June 30, 2019 and December 31, 2018, 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 (loss), derivative assets and liabilities are recorded at fair value through net income

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

[6] Securities available-for-sale are recorded at fair value through other comprehensive income (loss).

[7] Represents contingent consideration receivable associated with the sale of a portion of our PB business.

[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.