Number of Shares to be issued upon Exercise of Outstanding Stock-Based Awards and Remaining Shares Available for Future Issuance under all Equity Compensation Plans (Parenthetical) (Detail) (USD $)	1 Months Ended
	Apr. 30, 2009	Mar. 31, 2007	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Weighted-average exercise price of the outstanding options			$ 45.00	$ 53.88	$ 52.01	$ 49.29
Number of shares to be issued based on predefined performance targets			9,487,000
Additional shares approved by shareholders included under Bancorp's 1993 Stock Purchase Plan	12,000,000	1,500,000
Performance Incentive Plan 2008 [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Stock authorized for issuance			4,500,000
Performance Units [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Number of shares to be issued based on predefined performance targets			600,000
Series of Individually Immaterial Business Acquisitions [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Outstanding options awarded in connection with mergers and acquisitions			800,000
Weighted-average exercise price of the outstanding options			$ 17.74
2011 Incentive Compensation Plan
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Stock authorized for issuance			39,000,000