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		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings per share:
Net income attributable to Bancorp	$ 363	$ 381	$ 1,178	$ 983
Dividends on preferred stock	9	8	26	194
Net income (loss) available to common shareholders	354	373	1,152	789
Less: Income allocated to participating securities	(2)	(2)	(7)	(4)
Net income allocated to common shareholders	352	371	1,145	785
Earnings per diluted share:
Net income available to common shareholders	354	373	1,152	789
Series G convertible preferred stock	9	9	26	26
Net income available to common shareholders plus assumed conversions	363	382	1,178	815
Less: Income allocated to participating securities	(2)	(2)	(7)	(4)
Net income allocated to common shareholders plus assumed conversions	$ 361	$ 380	$ 1,171	$ 811
Earnings per share:
Net income allocated to common shareholders	904	915	911	904
Effect of dilutive securities:
Stock-based awards	5	5	5	5
Series G convertible preferred stock	36	35	36	36
Warrant related to Series F preferred stock				2
Net income allocated to common shareholders plus assumed converstions	945	955	952	947
Earnings per share:
Net income allocated to common shareholders	$ 0.39	$ 0.41	$ 1.26	$ 0.87
Effect of dilutive securities:
Series G convertible preferred stock	$ (0.01)	$ (0.01)	$ (0.03)	$ (0.01)
Net income allocated to common shareholders plus assumed conversions	$ 0.38	$ 0.40	$ 1.23	$ 0.86