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
	Mar. 31, 2013	Mar. 31, 2012
Earnings per share:
Net income attributable to Bancorp	$ 422	$ 430
Dividends on preferred stock	9	9
Net income (loss) available to common shareholders	413	421
Less: Income allocated to participating securities	(3)	(2)
Net income allocated to common shareholders	410	419
Earnings per diluted share:
Net income available to common shareholders	413	421
Series G convertible preferred stock	9	9
Net income available to common shareholders plus assumed conversions	422	430
Less: Income allocated to participating securities	(3)	(2)
Net income allocated to common shareholders plus assumed conversions	$ 419	$ 428
Earnings per share:
Net income allocated to common shareholders	871	915
Effect of dilutive securities:
Stock-based awards	6	6
Series G convertible preferred stock	36	36
Net income allocated to common shareholders plus assumed converstions	913	957
Earnings per share:
Net income allocated to common shareholders	$ 0.47	$ 0.46
Effect of dilutive securities:
Series G convertible preferred stock	$ (0.01)	$ (0.01)
Net income allocated to common shareholders plus assumed conversions	$ 0.46	$ 0.45