Credit Quality (Summary of Average Impaired Loans and Leases and Interest Income by Class) (Parenthetical) (Detail) $ in Millions	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2017 USD ($)		Sep. 30, 2016 USD ($)		Sep. 30, 2017 USD ($)		Sep. 30, 2016 USD ($)		Dec. 31, 2016
Financing Receivable, Impaired
Average Recorded Investment	$ 1,660		$ 1,973		$ 1,738		$ 1,963
Number of contracts	2,353	[1],[2]	2,687	[3],[4]	6,842	[5],[6]	8,366	[7],[8]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Impaired
Average Recorded Investment	$ 50		$ 62	[9]	$ 55		$ 66	[9]
Number of contracts	1	[1],[2]	1	[3],[4]	8	[5],[6]	11	[7],[8]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired
Average Recorded Investment			$ 27				$ 27
Number of contracts			5				5		5

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

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

[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] (a) Excludes five restructured loans 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 average recorded investment of $ 27 and an immaterial amount of interest income recognized for both the three and nine months ended September 30, 2016 . Refer to Note 11 for further discussion on the deconsolidation of a VIE associated with these loans in the third quarter of 2017.