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	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings per share:
Net income attributable to Bancorp	$ 1,481	$ 1,836	$ 1,576
Dividends on preferred stock	67	37	35
Net income (loss) available to common shareholders	1,414	1,799	1,541
Less: Income allocated to participating securities	12	14	10
Net income allocated to common shareholders	1,402	1,785	1,531
Earnings per diluted share:
Net income available to common shareholders	1,414	1,799	1,541
Series G convertible preferred stock		18	35
Net income available to common shareholders plus assumed conversions	1,414	1,817	1,576
Less: Income allocated to participating securities	12	14	10
Net income allocated to common shareholders plus assumed conversions	$ 1,402	$ 1,803	$ 1,566
Earnings per share:
Net income allocated to common shareholders	833,000,000	869,000,000	904,000,000
Effect of dilutive securities:
Stock-based awards	10,000,000	8,000,000	6,000,000
Series G convertible preferred stock		18,000,000	36,000,000
Net income allocated to common shareholders plus assumed converstions	843,000,000	895,000,000	946,000,000
Earnings per share:
Net income allocated to common shareholders	$ 1.68	$ 2.05	$ 1.69
Earnings per diluted share:
Net income allocated to common shareholders plus assumed conversions	$ 1.66	$ 2.02	$ 1.66