Income Taxes (Applicable Income Taxes Included in the Consolidated Statements of Income) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Reconciliation Of Provision Of Income Taxes
U.S. Federal income taxes	$ 463	$ 986		$ 751
State and local income taxes	71	68		55
Foreign income taxes	8	(3)		0
Total current tax expense (benefit)	542	1,051		806
U.S. Federal income taxes	24	(254)		(126)
State and local income taxes	4	2		(14)
Foreign income taxes	2	0		(1)
Total deferred tax expense (benefit)	30	(252)	[1]	(141)	[1]
Applicable income tax expense	$ 572	$ 799		$ 665

[1] Effective in the fourth quarter of 2018, Fifth Third retrospectively applied a change in its accounting policy for investments in affordable housing projects that qualify for LIHTC in accordance with ASU 2014-01. Refer to Note 1 for additional information.