MSR (Changes in the Servicing Assets) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Servicing Assets at Fair Value
Carrying amount before valuation allowance as of the beginning of the period		$ 1,156	$ 1,204
Servicing rights that result from the transfer of residential mortgage loans			83
Amortization			(131)	$ (140)
Other-than-temporary impairment			0
Carrying amount before valuation allowance			1,156	1,204
Valuation allowance for servicing rights:
Beginning balance		(412)	(419)
(Provision for) recovery of MSR impairment			7
Other-than-temporary impairment			0
Ending balance			(412)	$ (419)
Carrying amount as of the end of the period	[1]	858	744
Fair value at beginning of period		744
Servicing rights originated		127
Servicing rights acquired		109
Changes in fair value due to changes in inputs or assumptions	[2]	(1)
Changes in fair value due to other changes in fair value	[3]	(121)
Fair value at end of period		$ 858	$ 744

[1] Effective January 1, 2017, the Bancorp has elected the fair value measurement method for all existing classes of its residential mortgage servicing rights. The servicing rights were measured at fair value at December 31, 2017 and were measured under the amortization method at December 31, 2016. For further information refer to Note 12 .

[2] Primarily reflects changes in prepayment speed and OAS spread assumptions which are updated based on market interest rates.

[3] Primarily reflects changes due to collection of contractual cash flows and the passage of time.