Credit Quality (Summarizes the Bancorp's Recorded Investment in Impaired Loans and Related Allowance by Class) (Parenthetical) (Detail)		12 Months Ended
		Dec. 31, 2017 USD ($)		Dec. 31, 2016 USD ($)		Dec. 31, 2015
Financing Receivable, Impaired
Unpaid Principal Balance		$ 1,679,000,000		$ 2,052,000,000
Recorded Investment		1,545,000,000	[1]	1,901,000,000	[2]
Allowance		$ 200,000,000		$ 212,000,000
Number of Contracts	[3],[4]	9,256		10,978		14,472
Commercial Portfolio Segment | Commercial and Industrial Loans
Financing Receivable, Impaired
Allowance		$ 87,000,000		$ 94,000,000
Number of Contracts	[3],[4]	75		74		77
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-Occupied
Financing Receivable, Impaired
Allowance		$ 7,000,000		$ 5,000,000	[5]
Number of Contracts	[3],[4]	9		12		18
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-Occupied | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired
Unpaid Principal Balance				$ 26,000,000
Recorded Investment				26,000,000
Allowance	[5],[6]			18,000,000
Commercial Portfolio Segment | Commercial Mortgage Loans, Nonowner-Occupied
Financing Receivable, Impaired
Allowance		$ 0		$ 1,000,000
Number of Contracts	[3],[4]	4		4		12
Commercial Portfolio Segment | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired
Unpaid Principal Balance		$ 249,000,000		$ 322,000,000
Commercial Portfolio Segment | Troubled Debt Restructuring On Nonaccrual Status
Financing Receivable, Impaired
Unpaid Principal Balance		150,000,000		192,000,000
Residential Portfolio Segment
Financing Receivable, Impaired
Allowance		$ 64,000,000		$ 68,000,000
Number of Contracts	[3],[4]	830		924		1,089
Residential Portfolio Segment | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired
Unpaid Principal Balance		$ 652,000,000		$ 635,000,000
Residential Portfolio Segment | Troubled Debt Restructuring On Nonaccrual Status
Financing Receivable, Impaired
Unpaid Principal Balance		13,000,000		17,000,000
Consumer Portfolio Segment | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired
Unpaid Principal Balance		275,000,000		323,000,000
Consumer Portfolio Segment | Troubled Debt Restructuring On Nonaccrual Status
Financing Receivable, Impaired
Unpaid Principal Balance		$ 45,000,000		$ 48,000,000

[1] Includes $ 249 , $ 652 and $ 275 , respectively, of commercial, residential mortgage and consumer portfolio TDRs on accrual status and $ 150 , $ 13 and $ 45 , respectively, of commercial, residential mortgage and consumer portfolio TDRs on nonaccrual status at December 31, 2017 .

[2] Includes $ 322 , $ 635 and $ 323 , respectively, of commercial, residential mortgage and consumer portfolio TDRs 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] Ex cludes 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 o f a VIE associated with these loans in the third quarter of 2017.

[6] 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.