Credit Quality (Summarizes the Bancorp's Recorded Investment in Impaired Loans and Related Allowance by Class) (Parenthetical) (Detail) $ in Millions	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2017 USD ($)		Sep. 30, 2016		Sep. 30, 2017 USD ($)		Sep. 30, 2016		Dec. 31, 2016 USD ($)
Financing Receivable, Impaired
Unpaid principal balance	$ 1,704				$ 1,704				$ 2,052
Recorded investment	1,587	[1]			1,587	[1]			1,901	[2]
Allowance	$ 192				$ 192				212
Number of contracts	2,353	[3],[4]	2,687	[5],[6]	6,842	[7],[8]	8,366	[9],[10]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Impaired
Allowance	$ 8				$ 8				5	[11]
Number of contracts	1	[3],[4]	1	[5],[6]	8	[7],[8]	11	[9],[10]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired
Unpaid principal balance									26
Recorded investment									26
Allowance									$ 18
Number of contracts			5				5		5
Commercial Portfolio Segment | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired
Recorded investment	$ 232				$ 232				$ 322
Commercial Portfolio Segment | Troubled Debt Restructuring On Nonaccrual Status
Financing Receivable, Impaired
Recorded investment	214				214				192
Residential Mortgage Loans
Financing Receivable, Impaired
Allowance	$ 64				$ 64				68
Number of contracts	247	[3],[4]	240	[5],[6]	649	[7],[8]	745	[9],[10]
Residential Mortgage Loans | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired
Recorded investment	$ 646				$ 646				635
Residential Mortgage Loans | Troubled Debt Restructuring On Nonaccrual Status
Financing Receivable, Impaired
Recorded investment	12				12				17
Consumer Portfolio Segment | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired
Recorded investment	283				283				323
Consumer Portfolio Segment | Troubled Debt Restructuring On Nonaccrual Status
Financing Receivable, Impaired
Recorded investment	$ 46				$ 46				$ 48

[1] Includes $ 232 , $ 646 and $ 283 , respectively, of commercial, residential mortgage and consumer portfolio TDRs on accrual status and $ 214 , $ 12 an d $ 46 , respectively, of commercial, residential mortgage a nd consumer portfolio TDRs on nonaccrual status at September 30, 2017 .

[2] Includes $ 322 , $ 635 and $ 323 , respectively, of commercial, residential mortgage and consumer portfolio TDR s on accrual status and $ 192 , $ 17 and $ 48 , respectively , of commercial, residential mortgage and consumer portfolio TDRs on nonaccrual status at December 31, 2016 .

[3] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[4] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[5] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[6] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[7] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[8] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[9] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[10] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[11] Excludes five restructured loans at December 31, 2016 associated with a consolidated VIE in which the Bancorp had no continuing credit risk due to the risk being assumed by a third party, with an unpaid principal balance of $ 26 , a recorded investment of $ 26 and an ALLL of $ 18 . Refer to Note 11 for further discussion on the deconsolidation of a VIE associated with these loans in the third quarter of 2017.