Segments (Results of Operations and Average Assets by Segment) (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information
Net interest income	$ 1,043	$ 970		$ 3,059		$ 2,842
Provision for (benefit from) loan and lease losses	86	67		142		193
Net interest income after provision for loan and lease losses	957	903		2,917		2,649
Noninterest Income
Service charges on deposits	139	138		414		415
Wealth and asset management revenue	114	102		335		313
Corporate banking revenue	100	101		308		276
Card and processing revenue	82	79		245		232
Mortgage banking net revenue	49	63		158		170
Other noninterest income	86	1,076	[1]	794		1,237
Securities gains (losses), net	(6)	0		(21)		1
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	(1)	2		(18)		4
Total noninterest income	563	1,561		2,215		2,648
Noninterest Expense
Salaries, wages and incentives	421	407		1,339		1,215
Employee benefits	82	77		270		274
Net occupancy expense	70	74		219		221
Technology and communications	71	62		206		177
Equipment expense	31	30		92		88
Card and processing expense	31	32		91		95
Other noninterest expense	302	293		873		848
Total noninterest expense	1,008	975		3,090		2,918
Income (Loss) Before Income Taxes	512	1,489		2,042		2,379
Applicable income tax expense	79	475		321		694
Net income (loss)	433	1,014		1,721	$ 1,721	1,685
Goodwill	2,462	2,423		2,462	2,462	2,423	$ 2,445	$ 2,416
Total Assets	141,685	142,264		141,685	141,685	142,264	142,193
Intersegment Elimination
Segment Reporting Information
Net interest income	0	0		0		0
Provision for (benefit from) loan and lease losses	0	0		0		0
Net interest income after provision for loan and lease losses	0	0		0		0
Noninterest Income
Service charges on deposits	0	0		0		0
Wealth and asset management revenue	(35)	(32)	[2]	(104)		(99)
Corporate banking revenue	0	0		0		0
Card and processing revenue	0	0		0		0
Mortgage banking net revenue	0	0		0		0
Other noninterest income	0	0	[1]	0		0
Securities gains (losses), net	0			0		0
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	0	0		0		0
Total noninterest income	(35)	(32)		(104)		(99)
Noninterest Expense
Salaries, wages and incentives	0	0		0		0
Employee benefits	0	0		0		0
Net occupancy expense	0	0		0		0
Technology and communications	0	0		0		0
Equipment expense	0	0		0		0
Card and processing expense	0	0		0		0
Other noninterest expense	(35)	(32)		(104)		(99)
Total noninterest expense	(35)	(32)		(104)		(99)
Income (Loss) Before Income Taxes	0	0		0		0
Applicable income tax expense	0	0		0		0
Net income (loss)	0	0		0		0
Goodwill	0	0		0	0	0
Total Assets	0	0		0	0	0
Branch Banking
Segment Reporting Information
Net interest income	525	453		1,490		1,320
Provision for (benefit from) loan and lease losses	34	35		124		115
Net interest income after provision for loan and lease losses	491	418		1,366		1,205
Noninterest Income
Service charges on deposits	71	67		205		196
Wealth and asset management revenue	38	35		113		106
Corporate banking revenue	1	1		4		4
Card and processing revenue	67	64		199		185
Mortgage banking net revenue	1	2		4		5
Other noninterest income	26	22	[1]	33		67
Securities gains (losses), net	0			0		0
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	0	0		0		0
Total noninterest income	204	191		558		563
Noninterest Expense
Salaries, wages and incentives	109	104		329		312
Employee benefits	22	22		75		75
Net occupancy expense	44	43		131		133
Technology and communications	1	1		4		3
Equipment expense	12	13		37		39
Card and processing expense	30	31		89		93
Other noninterest expense	215	205		638		592
Total noninterest expense	433	419		1,303		1,247
Income (Loss) Before Income Taxes	262	190		621		521
Applicable income tax expense	55	66		131		183
Net income (loss)	207	124		490		338
Goodwill	1,655	1,655		1,655	1,655	1,655	1,655	1,655
Total Assets	60,222	57,246		60,222	60,222	57,246
Commercial Banking
Segment Reporting Information
Net interest income	427	422		1,273		1,261
Provision for (benefit from) loan and lease losses	(11)	(3)		(41)		25
Net interest income after provision for loan and lease losses	438	425		1,314		1,236
Noninterest Income
Service charges on deposits	68	71		207		217
Wealth and asset management revenue	1	1		3		2
Corporate banking revenue	100	100		304		272
Card and processing revenue	14	14		42		43
Mortgage banking net revenue	0	0		0		0
Other noninterest income	52	30	[1]	125		111
Securities gains (losses), net	0			0		0
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	0	0		0		0
Total noninterest income	235	216		681		645
Noninterest Expense
Salaries, wages and incentives	71	64		214		191
Employee benefits	8	7		36		34
Net occupancy expense	6	6		20		20
Technology and communications	2	2		6		7
Equipment expense	6	5		18		14
Card and processing expense	2	1		3		2
Other noninterest expense	250	256		792		763
Total noninterest expense	345	341		1,089		1,031
Income (Loss) Before Income Taxes	328	300		906		850
Applicable income tax expense	30	56		63		152
Net income (loss)	298	244		843		698
Goodwill	630	613		630	630	613	613	613
Total Assets	60,135	58,752		60,135	60,135	58,752
Consumer Lending
Segment Reporting Information
Net interest income	60	59		178		179
Provision for (benefit from) loan and lease losses	10	8		30		30
Net interest income after provision for loan and lease losses	50	51		148		149
Noninterest Income
Service charges on deposits	0	0		0		0
Wealth and asset management revenue	0	0		0		0
Corporate banking revenue	0	0		0		0
Card and processing revenue	0	0		0		0
Mortgage banking net revenue	48	61		153		164
Other noninterest income	3	5	[1]	11		14
Securities gains (losses), net	0			0		0
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	(1)	2		(18)		4
Total noninterest income	50	68		146		182
Noninterest Expense
Salaries, wages and incentives	38	38		120		113
Employee benefits	8	8		28		29
Net occupancy expense	3	3		8		8
Technology and communications	2	0		3		2
Equipment expense	0	0		0		0
Card and processing expense	0	0		0		0
Other noninterest expense	49	52		151		161
Total noninterest expense	100	101		310		313
Income (Loss) Before Income Taxes	0	18		(16)		18
Applicable income tax expense	0	6		(3)		7
Net income (loss)	0	12		(13)		11
Goodwill	0	0		0	0	0	0	0
Total Assets	22,188	22,447		22,188	22,188	22,447
Wealth and Asset Management
Segment Reporting Information
Net interest income	46	38		134		114
Provision for (benefit from) loan and lease losses	3	(1)		8		2
Net interest income after provision for loan and lease losses	43	39		126		112
Noninterest Income
Service charges on deposits	0	0		1		1
Wealth and asset management revenue	110	99		324		304
Corporate banking revenue	0	0		1		1
Card and processing revenue	1	1		4		4
Mortgage banking net revenue	0	0		1		1
Other noninterest income	4	1	[1]	13		1
Securities gains (losses), net	0			0		0
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	0	0		0		0
Total noninterest income	115	101		344		312
Noninterest Expense
Salaries, wages and incentives	44	37		131		114
Employee benefits	6	5		23		22
Net occupancy expense	3	3		9		8
Technology and communications	0	0		1		0
Equipment expense	0	0		0		0
Card and processing expense	0	0		0		0
Other noninterest expense	73	66		217		201
Total noninterest expense	126	111		381		345
Income (Loss) Before Income Taxes	32	29		89		79
Applicable income tax expense	7	10		19		27
Net income (loss)	25	19		70		52
Goodwill	177	155		177	177	155	$ 177	$ 148
Total Assets	9,171	8,821		9,171	9,171	8,821
General Corporate and Other
Segment Reporting Information
Net interest income	(15)	(2)		(16)		(32)
Provision for (benefit from) loan and lease losses	50	28		21		21
Net interest income after provision for loan and lease losses	(65)	(30)		(37)		(53)
Noninterest Income
Service charges on deposits	0	0		1		1
Wealth and asset management revenue	0	(1)		(1)		0
Corporate banking revenue	(1)	0		(1)		(1)
Card and processing revenue	0	0		0		0
Mortgage banking net revenue	0	0		0		0
Other noninterest income	1	1,018	[1]	612		1,044
Securities gains (losses), net	(6)			(21)		1
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights	0	0		0		0
Total noninterest income	(6)	1,017		590		1,045
Noninterest Expense
Salaries, wages and incentives	159	164		545		485
Employee benefits	38	35		108		114
Net occupancy expense	14	19		51		52
Technology and communications	66	59		192		165
Equipment expense	13	12		37		35
Card and processing expense	(1)	0		(1)		0
Other noninterest expense	(250)	(254)		(821)		(770)
Total noninterest expense	39	35		111		81
Income (Loss) Before Income Taxes	(110)	952		442		911
Applicable income tax expense	(13)	337		111		325
Net income (loss)	(97)	615		331		586
Goodwill	0	0		0	0	0
Total Assets	$ (10,031)	$ (5,002)		$ (10,031)	$ (10,031)	$ (5,002)

[1] Includes impairment charges of $ 1 for branches and land. For more information refer to Note 7 and Note 22 .

[2] Revenue sharing agreements between wealth and asset management and branch b anking are eliminated in the Condensed Consolidated Statements of Income.