MSR (Activity Related to the MSR Portfolio) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Servicing Assets at Fair Value
Securities gains (losses), net - non-qualifying hedges on mortgage servcing rights		$ (15)	$ 2		$ 0
Changes in fair value and settlement of free-standing derivatives purchased to economically hedge the MSR portfolio (Mortgage banking net revenue)	[1]	(21)	2		24
MSR fair value adjustments due to change in inputs or assumptions		83	122	[2]	0	[2]
Recovery of MSR impairment (Mortgage banking net revenue)		0	0	[2]	7	[2]
Mortgage Servicing Rights
Servicing Assets at Fair Value
MSR fair value adjustments due to change in inputs or assumptions	[1]	$ 42	$ (1)		$ 0

[1] Included in mortgage banking net reven ue in the Consolidated Statements of Income.

[2] 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.