Reconciliation Between the Statutory U.S. Income Tax Rate and the Bancorp's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation Of Statutory Federal Tax Rate [Abstract]
Statutory tax rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	1.20%	1.70%	1.40%
Tax-exempt income	(1.10%)	(2.10%)	(1.40%)
Credits	(6.00%)	(6.70%)	(7.30%)
Unrealized stock-based compensation benefits	0.30%	0.80%	1.30%
Other, net	0.30%	0.10%	0.10%
Effective tax rate	29.70%	28.80%	29.10%