Credit Quality (Summarizes the Bancorp's Recorded Investment in Portfolio Loans and Leases by Age and Class) (Detail) - USD ($) $ in Millions	Sep. 30, 2018		Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	$ 92,674	[1],[2]	$ 91,195	[3],[4]
Total Past Due	597	[2]	638	[4]
Total portfolio loans and leases	93,271		91,833
90-Days past Due and Still Accruing	87	[2]	97	[4]
30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	290		333
90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	307		305
Commercial and Industrial Loans
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	42,481		41,027
Total Past Due	150		143
Total portfolio loans and leases	42,631		41,170
90-Days past Due and Still Accruing	3		3
Commercial and Industrial Loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	22		42
Commercial and Industrial Loans | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	128		101
Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	3,314		3,351
Total Past Due	10		11
Total portfolio loans and leases	3,324		3,362
90-Days past Due and Still Accruing	1		0
Commercial Mortgage Loans, Owner-occupied | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3		3
Commercial Mortgage Loans, Owner-occupied | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	7		8
Commercial Mortgage Loans, Nonowner-Occupied
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	3,363		3,235
Total Past Due	8		7
Total portfolio loans and leases	3,371		3,242
90-Days past Due and Still Accruing	0		0
Commercial Mortgage Loans, Nonowner-Occupied | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	5		0
Commercial Mortgage Loans, Nonowner-Occupied | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3		7
Commercial construction loans
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	4,884		4,552
Total Past Due	8		1
Total portfolio loans and leases	4,892		4,553
90-Days past Due and Still Accruing	0		0
Commercial construction loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	8		1
Commercial construction loans | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	0		0
Commercial Leases
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	3,693		4,065
Total Past Due	4		3
Total portfolio loans and leases	3,697		4,068
90-Days past Due and Still Accruing	0		0
Commercial Leases | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	0		3
Commercial Leases | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	4		0
Residential Mortgage
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	15,321		15,301
Total Past Due	92		153
Total portfolio loans and leases	15,413		15,454
90-Days past Due and Still Accruing	40		57
Residential Mortgage | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	29		66
Residential Mortgage | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	63		87
Home Equity
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	6,366		6,888
Total Past Due	119		126
Total portfolio loans and leases	6,485		7,014
90-Days past Due and Still Accruing	0		0
Home Equity | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	68		70
Home Equity | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	51		56
Automobile Loans
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	8,891		8,992
Total Past Due	111		120
Total portfolio loans and leases	9,002		9,112
90-Days past Due and Still Accruing	11		10
Automobile Loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	99		107
Automobile Loans | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	12		13
Credit Card
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	2,245		2,230
Total Past Due	80		69
Total portfolio loans and leases	2,325		2,299
90-Days past Due and Still Accruing	32		27
Credit Card | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	42		36
Credit Card | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	38		33
Other consumer loans
Financing Receivable, Recorded Investment, Past Due
Current Loans and Leases	2,116		1,554
Total Past Due	15		5
Total portfolio loans and leases	2,131		1,559
90-Days past Due and Still Accruing	0		0
Other consumer loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	14		5
Other consumer loans | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 1		$ 0

[1] Includes accrual and nonaccrual loans and leases.

[2] Excludes $ 172 of residential mortgage loans measured at fair value at September 30, 2018 .

[3] Includes accrual and nonaccrual loans and leases.

[4] Excludes $ 137 of residential mortgage loans measured at fair value at December 31, 2017 .