EPS (Calculation of Earnings Per Share and the Reconciliation of Earnings Per Share to Earnings Per Diluted Share) (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings per share:
Net income (loss) attributable to Bancorp	$ 2,194	$ 1,564	$ 1,712
Dividends on preferred stock	75	75	75
Net income (loss) available to common shareholders	2,119	1,489	1,637
Less: Income allocated to participating securities	23	15	15
Net income allocated to common shareholders	2,096	1,474	1,622
Earnings per diluted share:
Net income available to common shareholders	2,119	1,489	1,637
Stock-based awards	0	0	0
Net income available to common shareholders plus assumed conversions	2,119	1,489	1,637
Less: Income allocated to participating securities	22	15	15
Net income allocated to common shareholders plus assumed conversions	$ 2,097	$ 1,474	$ 1,622
Earnings per share:
Net income allocated to common shareholders	728,289,200	757,432,291	798,628,173
Effect of dilutive securities:
Stock-based awards	13,000,000	7,000,000	9,000,000
Net income allocated to common shareholders	740,691,433	764,495,353	807,658,669
Earnings per share:
Net income allocated to common shareholders	$ 2.88	$ 1.95	$ 2.03
Earnings per diluted share:
Net income allocated to common shareholders plus assumed conversions	$ 2.83	$ 1.93	$ 2.01