Retirement and Benefit Plans (Defined Benefit Retirement Plans with Overfunded and Underfunded Status) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Change In Fair Value Roll Forward
Fair value of plan assets at January 1	[1]	$ 164
Fair value of plan assets at December 31	[1]	175	$ 164
Defined Benefit Plan, Change in Benefit Obligation
Projected benefit obligation at January 1		181	21
Interest cost		7	7	$ 8
Projected benefit obligation at December 31			181	21
Underfunded defined benefit pension plans
Defined Benefit Plan Change In Fair Value Roll Forward
Fair value of plan assets at January 1		164
Actual return on assets		26	0
Contributions		2	3
Settlement		(9)	0
Benefits paid		(8)	(3)
Fair value of plan assets at December 31		175	164
Defined Benefit Plan, Change in Benefit Obligation
Projected benefit obligation at January 1		18
Interest cost		7	1
Settlement		(9)	0
Actuarial (gain) loss		23	(1)
Benefits paid		(8)	(3)
Projected benefit obligation at December 31		194	18
Projected benefit obligation at December 31		(19)	(18)
Accumulated benefit obligation at December 31	[2]	194	18
Overfunded defined benefit pension plans
Defined Benefit Plan Change In Fair Value Roll Forward
Fair value of plan assets at January 1	[3]	164	185
Actual return on assets	[3]		(6)
Settlement	[3]		(9)
Benefits paid	[3]		(6)
Fair value of plan assets at December 31	[3]		164	185
Defined Benefit Plan, Change in Benefit Obligation
Projected benefit obligation at January 1	[3]	$ 163	188
Interest cost	[3]		6
Settlement	[3]		(9)
Actuarial (gain) loss	[3]		(16)
Benefits paid	[3]		(6)
Projected benefit obligation at December 31	[3]		163	$ 188
Projected benefit obligation at December 31	[3]		1
Accumulated benefit obligation at December 31	[3]		$ 163

[1] For further information on fair value hierarchy levels, refer to Note 1.

[2] Since the Plan’s benefits are frozen, the rate of compensation increase is no longer an assumption used to calculate the accumulated benefit obligation. Therefore, the accumulated benefit obligation was the same as the projected benefit obligation at both December 31, 2019 and 2018.

[3] The Bancorp’s qualified defined benefit plan had an underfunded status at December 31, 2019 and is reflected in the underfunded status table. The Plan had an overfunded status at December 31, 2018.