Reconciliation of Net Income to Net Income Available to Common Shareholders (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018		Jun. 30, 2017
Net Income (Loss) Attributable to Parent	$ 722	$ 528	[1],[2]	$ 1,365		$ 995	[3],[4]
Dividends, Preferred Stock, Cash	(25)	(23)		(55)	[5]	(39)	[5]
Net Income (Loss) Available to Common Stockholders, Basic	$ 697	$ 505		$ 1,310		$ 956
Average basic common shares	465,529	482,913		467,117		486,482
Weighted Average Number of Shares Outstanding, Diluted	469,339	488,020		471,468		491,989
Net income/(loss) per average common share - diluted	$ 1.49	$ 1.03		$ 2.78		$ 1.94
Earnings Per Share, Basic	$ 1.50	$ 1.05		$ 2.80		$ 1.97
Restricted Stock Units (RSUs) [Member]
Dilutive securities	2,600	2,700		2,700		2,900
Warrant [Member]
Dilutive securities	600	1,600		1,100		1,700
Employee Stock Option [Member]
Dilutive securities	600	800		600		900

[1] During the fourth quarter of 2017, the Company sold PAC, the results of which were previously reported within the Wholesale business segment. For all periods prior to January 1, 2018, PAC's financial results, including the gain on sale, have been transferred to Corporate Other for enhanced comparability of the Wholesale business segment excluding PAC.

[2] During the second quarter of 2018, certain of the Company's business banking clients were transferred from the Wholesale business segment to the Consumer business segment. For all periods prior to the second quarter of 2018, the corresponding financial results have been transferred to the Consumer business segment for comparability purposes.

[3] During the fourth quarter of 2017, the Company sold PAC, the results of which were previously reported within the Wholesale business segment. For all periods prior to January 1, 2018, PAC's financial results, including the gain on sale, have been transferred to Corporate Other for enhanced comparability of the Wholesale business segment excluding PAC.

[4] During the second quarter of 2018, certain of the Company's business banking clients were transferred from the Wholesale business segment to the Consumer business segment. For all periods prior to the second quarter of 2018, the corresponding financial results have been transferred to the Consumer business segment for comparability purposes.

[5] For the six months ended June 30, 2018, dividends were $2,022 per share for both Series A and B Preferred Stock, $1,469 per share for Series E Preferred Stock, $2,813 per share for Series F Preferred Stock, $2,525 per share for Series G Preferred Stock, and $3,004 per share for Series H Preferred Stock.For the six months ended June 30, 2017, dividends were $2,022 per share for both Series A and B Preferred Stock, $2,938 per share for Series E Preferred Stock, $2,813 per share for Series F Preferred Stock, and $828 per share for Series G Preferred Stock.