Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Detail) - USD ($) $ in Millions	Sep. 30, 2015		Jun. 30, 2015	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 216	[1]		$ 305	[2]
Collectively evaluated for impairment	931	[1]		911	[2]
Unallocated	114	[1]		106	[2]
Total allowance for loan and lease losses	1,261	[3]	$ 1,293	1,322	[3]	$ 1,414	$ 1,458	$ 1,582
Individually evaluated for impairment	1,944	[4]		2,261	[5]
Collectively evaluated for impairment	91,455	[4]		87,713	[5]
Loans acquired with deteriorated credit quality	2	[4]		2	[5]
Total Loans and Leases	93,401	[6]		89,976	[7]
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	101	[1],[8]		179	[2],[9]
Collectively evaluated for impairment	727	[1]		696	[2]
Total allowance for loan and lease losses	828	[1]	855	875	[2]	913	961	1,058
Individually evaluated for impairment	895	[4],[8]		1,260	[5],[9]
Collectively evaluated for impairment	56,113	[4]		52,693	[5]
Total Loans and Leases	57,008	[4]		53,953	[5]
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	65	[1]		65	[2]
Collectively evaluated for impairment	33	[1]		39	[2]
Total allowance for loan and lease losses	98	[1]	104	104	[2]	164	174	189
Individually evaluated for impairment	613	[4]		518	[5]
Collectively evaluated for impairment	12,604	[4]		11,761	[5]
Loans acquired with deteriorated credit quality	2	[4]		2	[5]
Total Loans and Leases	13,219	[4]		12,281	[5]
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	50	[1]		61	[2]
Collectively evaluated for impairment	171	[1]		176	[2]
Total allowance for loan and lease losses	221	[1]	231	237	[2]	238	221	225
Individually evaluated for impairment	436	[4]		483	[5]
Collectively evaluated for impairment	22,738	[4]		23,259	[5]
Total Loans and Leases	23,174	[4]		23,742	[5]
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Unallocated	114	[1]		106	[2]
Total allowance for loan and lease losses	$ 114	[1]	$ 103	$ 106	[2]	$ 99	$ 102	$ 110

[1] Includes $5 related to leveraged leases at September 30, 2015.

[2] Includes $6 related to leveraged leases at December 31, 2014.

[3] Includes $137 and $179 of cash and due from banks, $2,179 and $3,378 of portfolio loans and leases, $(27) and $(22) of ALLL, $18 and $25 of other assets, $3 and $5 of other liabilities, and $2,136 and $3,434 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2015 and December 31, 2014, respectively. For further information refer to Note 11.

[4] Excludes $173 of residential mortgage loans measured at fair value, and includes $854 of leveraged leases, net of unearned income at September 30, 2015.

[5] Excludes $108 of residential mortgage loans measured at fair value, and includes $874 of leveraged leases, net of unearned income at December 31, 2014.

[6] Excludes $173 of residential mortgage loans measured at fair value.

[7] Excludes $108 of residential mortgage loans measured at fair value.

[8] Includes five restructured loans at September 30, 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 $15.

[9] 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.