Reconciliation of Net Income to Net Income Available to Common Shareholders (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018		Sep. 30, 2017
Net Income (Loss) Attributable to Parent	$ 752	$ 538	[1],[2]	$ 2,117		$ 1,533	[3],[4]
Dividends, Preferred Stock, Cash	(26)	(26)		(81)	[5]	(65)	[5]
Net Income (Loss) Available to Common Stockholders, Basic	$ 726	$ 512		$ 2,036		$ 1,468
Average basic common shares	460,252	478,258		464,804		483,711
Weighted Average Number of Shares Outstanding, Diluted	464,164	483,640		469,006		489,176
Net income/(loss) per average common share - diluted	$ 1.56	$ 1.06		$ 4.34		$ 3.00
Earnings Per Share, Basic	$ 1.58	$ 1.07		$ 4.38		$ 3.04
Restricted Stock Units (RSUs) [Member]
Dilutive securities	3,000	2,900		2,800		2,900
Warrants, options, and restricted stock [Member]
Dilutive securities	900	2,400		1,400		2,600

[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 nine months ended September 30, 2018, dividends were $3,044 per share for both Series A and B Preferred Stock, $1,469 per share for Series E Preferred Stock, $4,219 per share for Series F Preferred Stock, $3,788 per share for Series G Preferred Stock, and $4,285 per share for Series H Preferred Stock.For the nine months ended September 30, 2017, dividends were $3,044 per share for both Series A and B Preferred Stock, $4,406 per share for Series E Preferred Stock, $4,219 per share for Series F Preferred Stock, and $2,090 per share for Series G Preferred Stock.