Other Noninterest Income and Other Noninterest Expense (Other Nonint Income and Expense) (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Noninterest Income
Gain on sale of Worldpay, Inc. shares	$ 562	$ 205	$ 414	$ 562	$ 205	$ 1,037
Income from the tax receivable agreement associated with Worldpay, Inc.				346	20	44
Operating lease income				151	84	96
Private equity investment income				65	63	36
BOLI income				60	56	52
Cardholder fees				58	56	54
Consumer loan and lease fees				23	23	23
Banking center income				22	21	20
Insurance income				19	20	8
Net gain (losses) on loan sales				3	2	(2)
Equity method income from interest in Worldpay Holding, LLC				2	1	47
Loss on swap associated with the sale of Visa, Inc. class B shares				(107)	(59)	(80)
Gain (Loss) on Sale of Assets and Asset Impairment Charges				(23)	(43)	0
Loss on sale of business				(4)
Gain related to Vantiv acquisition of Worldpay				0	414	0
Other, net				47	24	22
Total other noninterest income				1,224	887	1,357
Other Noninterest Expense
Marketing				162	147	114
Loan and lease				142	112	102
Operating Lease				124	76	87
Losses and adjustments				102	61	59
FDIC insurance and other taxes				81	119	127
Professional services fees				70	67	83
Data processing				70	57	58
Travel				68	52	46
Intangible amortization				45	5	2
Postal and courier				38	35	42
Donations				30	21	28
Recruitment and education				28	32	35
Supplies				14	13	14
Insurance				14	13	12
Loss (gain) on partnership investments				2	(4)	14
Other, net				239	214	184
Total other noninterest expense				$ 1,229	$ 1,020	$ 1,007