Credit Quality (Summary of the Average Impaired Loans and Leases and Interest Income by Class) (Parenthetical) (Detail)		12 Months Ended
		Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Financing Receivable, Impaired
Average Recorded Investment		$ 1,677,000,000	$ 1,946,000,000	$ 2,062,000,000
Number of Contracts	[1],[2]	9,256	10,978	14,472
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-Occupied
Financing Receivable, Impaired
Average Recorded Investment	[3]	$ 35,000,000	$ 63,000,000	$ 92,000,000
Number of Contracts	[1],[2]	9	12	18
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-Occupied | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired
Average Recorded Investment		$ 13,000,000	$ 26,000,000	$ 27,000,000

[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] Excludes five restructured loans associated with a consolid ated 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 $ 13 , $ 26 and $ 27 for t he years ended December 31, 2017 , 2016, and 2015, respectively. An immaterial amount of interest income was recognized during t he years ended December 31, 2017 , 2016, and 2015. Refer to Note 11 for further discus sion on the deconsolidation of the VIE associated with these loans i n the third quarter of 2017.