Segments (Results of Operations and Average Assets by Segment) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Segment Reporting Information
Net interest income		$ 4,797		$ 4,140		$ 3,798
Provision for credit losses		471		207		261
Net interest income after provision for credit losses		4,326		3,933		3,537
Noninterest Income:
Corporate Banking Revenue		570		438		353
Service charges on deposits		565		549		554
Wealth and asset management revenue		487		444		419
Card And Processing Revenue		360		329		313
Mortgage banking net revenue		287		212		224
Other noninterest income		1,224		887		1,357
Securities gains, net		40		(54)		2
Securities gains, non - qualifying hedges on MSRs		3		(15)		2
Total noninterest income		3,536		2,790		3,224
Noninterest expense:
Salaries, wages and incentives		2,001		1,783		1,633
Employee benefits		417		332		356
Net occupancy expense		332		292		295
Technology and communications		422		285		245
Equipment Expense		129		123		117
Card And Processing Expense		130		123		129
Other noninterest expense (income)		1,229		1,020		1,007
Total noninterest expense		4,660		3,958		3,782
Income (Loss) Before Income Taxes		3,202		2,765		2,979
Applicable income tax expense (benefit)		690		572		799
Net income		2,512		2,193		2,180
Total goodwill		4,252		2,478		2,445
Total assets		169,369		146,069		142,081
Inter segment Elimination
Segment Reporting Information
Net interest income		0		0		0
Provision for credit losses		0		0		0
Net interest income after provision for credit losses		0		0		0
Noninterest Income:
Corporate Banking Revenue		0		0		0
Service charges on deposits		0		0		0
Wealth and asset management revenue	[1]	(143)		(138)		(132)
Card And Processing Revenue		0		0		0
Mortgage banking net revenue		0		0		0
Other noninterest income		0		0		0
Securities gains, net		0		0		0
Securities gains, non - qualifying hedges on MSRs		0		0		0
Total noninterest income		(143)		(138)		(132)
Noninterest expense:
Salaries, wages and incentives		0		0		0
Employee benefits		0		0		0
Net occupancy expense		0		0		0
Technology and communications		0		0		0
Equipment Expense		0		0		0
Card And Processing Expense		0		0		0
Other noninterest expense (income)		(143)		(138)		(132)
Total noninterest expense		(143)		(138)		(132)
Income (Loss) Before Income Taxes		0		0		0
Applicable income tax expense (benefit)		0		0		0
Net income		0		0		0
Total goodwill		0		0		0
Total assets		0		0		0
Commercial Banking
Segment Reporting Information
Net interest income		2,360		1,713		1,652
Provision for credit losses		183		(26)		38
Net interest income after provision for credit losses		2,177		1,739		1,614
Noninterest Income:
Corporate Banking Revenue		565	[2]	432	[3]	348	[4]
Service charges on deposits		308		273		287
Wealth and asset management revenue		3		3		3
Card And Processing Revenue		66		58		57
Mortgage banking net revenue		0		0		0
Other noninterest income		245		151		143
Securities gains, net		0		0		0
Securities gains, non - qualifying hedges on MSRs		0		0		0
Total noninterest income		1,187		917		838
Noninterest expense:
Salaries, wages and incentives		406		300		252
Employee benefits		60		44		42
Net occupancy expense		28		26		26
Technology and communications		11		7		9
Equipment Expense		25		23		18
Card And Processing Expense		8		4		3
Other noninterest expense (income)		1,083		859		884
Total noninterest expense		1,621		1,263		1,234
Income (Loss) Before Income Taxes		1,743		1,393		1,218
Applicable income tax expense (benefit)		319		254		391
Net income		1,424		1,139		827
Total goodwill		1,954		630		613
Total assets		74,570		61,630		58,456
Branch Banking
Segment Reporting Information
Net interest income		2,371		2,034		1,782
Provision for credit losses		224		171		153
Net interest income after provision for credit losses		2,147		1,863		1,629
Noninterest Income:
Corporate Banking Revenue		4		5		5
Service charges on deposits		260		275		265
Wealth and asset management revenue		158		150		141
Card And Processing Revenue		285		266		251
Mortgage banking net revenue		6		5		6
Other noninterest income		89		53		88
Securities gains, net		0		0		0
Securities gains, non - qualifying hedges on MSRs		0		0		0
Total noninterest income		802		754		756
Noninterest expense:
Salaries, wages and incentives		489		438		425
Employee benefits		112		98		101
Net occupancy expense		173		175		176
Technology and communications		4		5		4
Equipment Expense		48		50		52
Card And Processing Expense		123		121		127
Other noninterest expense (income)		911		841		796
Total noninterest expense		1,860		1,728		1,681
Income (Loss) Before Income Taxes		1,089		889		704
Applicable income tax expense (benefit)		229		187		249
Net income		860		702		455
Total goodwill		2,046		1,655		1,655
Total assets		69,413		61,040		57,931
Consumer Lending
Segment Reporting Information
Net interest income		325		237		240
Provision for credit losses		49		42		40
Net interest income after provision for credit losses		276		195		200
Noninterest Income:
Corporate Banking Revenue		0		0		0
Service charges on deposits		0		0		0
Wealth and asset management revenue		0		0		0
Card And Processing Revenue		0		0		0
Mortgage banking net revenue		279		206		217
Other noninterest income		14		14		18
Securities gains, net		0		0		0
Securities gains, non - qualifying hedges on MSRs		3		(15)		2
Total noninterest income		296		205		237
Noninterest expense:
Salaries, wages and incentives		158		156		152
Employee benefits		38		36		37
Net occupancy expense		10		10		10
Technology and communications		8		5		2
Equipment Expense		0		0		0
Card And Processing Expense		0		0		0
Other noninterest expense (income)		241		195		210
Total noninterest expense		455		402		411
Income (Loss) Before Income Taxes		117		(2)		26
Applicable income tax expense (benefit)		25		(1)		9
Net income		92		(1)		17
Total goodwill		0		0		0
Total assets		26,555		22,044		22,218
Wealth and Asset Management
Segment Reporting Information
Net interest income		182		182		154
Provision for credit losses		0		12		6
Net interest income after provision for credit losses		182		170		148
Noninterest Income:
Corporate Banking Revenue		1		2		1
Service charges on deposits		1		1		1
Wealth and asset management revenue		469		429		407
Card And Processing Revenue		3		5		5
Mortgage banking net revenue		2		1		1
Other noninterest income		13		18		4
Securities gains, net		0		0		0
Securities gains, non - qualifying hedges on MSRs		0		0		0
Total noninterest income		489		456		419
Noninterest expense:
Salaries, wages and incentives		185		173		154
Employee benefits		32		29		27
Net occupancy expense		13		12		11
Technology and communications		1		1		0
Equipment Expense		1		1		0
Card And Processing Expense		1		0		0
Other noninterest expense (income)		296		288		276
Total noninterest expense		529		504		468
Income (Loss) Before Income Taxes		142		122		99
Applicable income tax expense (benefit)		30		25		34
Net income		112		97		65
Total goodwill		252		193		177
Total assets		10,500		10,337		9,494
General Corporate and Other
Segment Reporting Information
Net interest income		(441)		(26)		(30)
Provision for credit losses		15		8		24
Net interest income after provision for credit losses		(456)		(34)		(54)
Noninterest Income:
Corporate Banking Revenue		0		(1)		(1)
Service charges on deposits		(4)		0		1
Wealth and asset management revenue		0		0		0
Card And Processing Revenue		6		0		0
Mortgage banking net revenue		0		0		0
Other noninterest income		863		651		1,104
Securities gains, net		40		(54)		2
Securities gains, non - qualifying hedges on MSRs		0		0		0
Total noninterest income		905		596		1,106
Noninterest expense:
Salaries, wages and incentives		763		716		650
Employee benefits		175		125		149
Net occupancy expense		108		69		72
Technology and communications		398		267		230
Equipment Expense		55		49		47
Card And Processing Expense		(2)		(2)		(1)
Other noninterest expense (income)		(1,159)		(1,025)		(1,027)
Total noninterest expense		338		199		120
Income (Loss) Before Income Taxes		111		363		932
Applicable income tax expense (benefit)		87		107		116
Net income		24		256		816
Total goodwill		0		0		0
Total assets		$ (11,669)	[5]	$ (8,982)	[6]	$ (6,018)	[7]

[1] Revenue sharing agreements between wealth and asset management and branch banking are eliminated in the Consolidated Statements of Income.

[2] Includes impairment charges of $3 for operating lease equipment. For more information, refer to Note 9 and Note 29.

[3] Includes impairment charges of $4 for operating lease equipment. For more information, refer to Note 9 and Note 29.

[4] Includes impairment charges of $52 for operating lease equipment. For more information, refer to Note 9.

[5] Includes bank premises and equipment of $27 classified as held for sale. For more information, refer to Note 8.

[6] Includes bank premises and equipment of $42 classified as held for sale. For more information, refer to Note 8.

[7] Includes bank premises and equipment of $27 classified as held for sale.