Calculation of Earnings Per Share and the Reconciliation of Earnings Per Share to Earnings Per Diluted Share (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings per share:
Net income attributable to Bancorp	$ 591	$ 385	$ 1,013	$ 815
Dividends on preferred stock	9	9	18	18
Net income (loss) available to common shareholders	582	376	995	797
Less: Income allocated to participating securities	(4)	(3)	(7)	(5)
Net income allocated to common shareholders	578	373	988	792
Earnings per diluted share:
Net income available to common shareholders	582	376	995	797
Series G convertible preferred stock	9	9	18	18
Net income available to common shareholders plus assumed conversions	591	385	1,013	815
Less: Income allocated to participating securities	(4)	(3)	(7)	(5)
Net income allocated to common shareholders plus assumed conversions	$ 587	$ 382	$ 1,006	$ 810
Earnings per share:
Net income allocated to common shareholders	859	914	865	914
Effect of dilutive securities:
Stock-based awards	6	5	6	6
Series G convertible preferred stock	36	36	36	36
Net income allocated to common shareholders plus assumed converstions	901	955	907	956
Earnings per share:
Net income allocated to common shareholders	$ 0.67	$ 0.41	$ 1.14	$ 0.87
Effect of dilutive securities:
Series G convertible preferred stock	$ (0.02)	$ (0.01)	$ (0.03)	$ (0.02)
Net income allocated to common shareholders plus assumed conversions	$ 0.65	$ 0.40	$ 1.11	$ 0.85