Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 295	[1]	$ 305	[1]
Collectively evaluated for impairment	901	[1]	911	[1]
Unallocated	104	[1]	106	[1]
Total allowance for loan and lease losses	1,300	[2]	1,322	[2]	1,483	1,582
Individually evaluated for impairment	2,225	[3]	2,261	[4]
Collectively evaluated for impairment	88,891	[3]	87,713	[4]
Loans acquired with deteriorated credit quality	2	[3]	2	[4]
Total Loans and Leases	91,118	[5]	89,976	[6]
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	175	[1],[7]	179	[1],[8]
Collectively evaluated for impairment	677	[1]	696	[1]
Total allowance for loan and lease losses	852	[1]	875	[1]	981	1,058
Individually evaluated for impairment	1,192	[3],[7]	1,260	[4],[8]
Collectively evaluated for impairment	54,157	[3]	52,693	[4]
Total Loans and Leases	55,349	[3]	53,953	[4]
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	64	[1]	65	[1]
Collectively evaluated for impairment	39	[1]	39	[1]
Total allowance for loan and lease losses	103	[1]	104	[1]	180	189
Individually evaluated for impairment	569	[3]	518	[4]
Collectively evaluated for impairment	11,872	[3]	11,761	[4]
Loans acquired with deteriorated credit quality	2	[3]	2	[4]
Total Loans and Leases	12,443	[3]	12,281	[4]
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	56	[1]	61	[1]
Collectively evaluated for impairment	185	[1]	176	[1]
Total allowance for loan and lease losses	241	[1]	237	[1]	217	225
Individually evaluated for impairment	464	[3]	483	[4]
Collectively evaluated for impairment	22,862	[3]	23,259	[4]
Total Loans and Leases	23,326	[3]	23,742	[4]
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Unallocated	104	[1]	106	[1]
Total allowance for loan and lease losses	$ 104	[1]	$ 106	[1]	$ 105	$ 110

[1] Includes $6 related to leveraged leases.

[2] Includes $176 and $179 of cash and due from banks, $48 and $47 of commercial mortgage loans, $2,900 and $3,331 of automobile loans, $(23) and $(22) of ALLL, $26 and $25 of other assets, $4 and $5 of other liabilities, and $2,983 and $3,434 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2015 and December 31, 2014, respectively. For further information refer to Note 10.

[3] Excludes $126 of residential mortgage loans measured at fair value, and includes $873 of leveraged leases, net of unearned income.

[4] Excludes $108 of residential mortgage loans measured at fair value, and includes $874 of leveraged leases, net of unearned income.

[5] Excludes $126 of loans measured at fair value.

[6] Excludes $108 of loans measured at fair value.

[7] Includes five restructured loans at March 31, 2015 associated with a consolidated VIE in which the Bancorp has no continuing credit risk due to the risk being assumed by a third party, with a recorded investment of $28 and an ALLL of $10.

[8] Includes five restructured loans at December 31, 2014 associated with a consolidated VIE in which the Bancorp has no continuing credit risk due to the risk being assumed by a third party, with a recorded investment of $28 and an ALLL of $10.