Reconciliation of Net Income to Net Income Available to Common Shareholders (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Net Income (Loss) Attributable to Parent		$ 2,273	$ 1,878	[1]	$ 1,933	[2]
Dividends, Preferred Stock, Cash	[3]	(94)	(66)		(64)
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic		0	(1)		(6)
Net Income (Loss) Available to Common Stockholders, Basic		$ 2,179	$ 1,811		$ 1,863
Average basic common shares		481,339	498,638		514,844
Weighted Average Number of Shares Outstanding, Diluted		486,954	503,466		520,586
Net income/(loss) per average common share - diluted		$ 4.47	$ 3.60		$ 3.58
Earnings Per Share, Basic		$ 4.53	$ 3.63		$ 3.62
Restricted Stock Units (RSUs) [Member]
Restricted stock		3,000	2,900		2,600
Warrant [Member]
Restricted stock		2,000	1,000		2,000
Employee Stock Option [Member]
Restricted stock		900	1,400		1,500

[1] Beginning in the second quarter of 2017, the Company realigned its business segment structure from three segments to two segments. Specifically, the Company retained the previous composition of the Wholesale Banking segment and changed the basis of presentation of the Consumer Banking and Private Wealth Management segment and Mortgage Banking segment such that those segments were combined into a single Consumer segment. Accordingly, business segment information presented for the year ended December 31, 2016 has been revised to conform to the new business segment structure and updated internal funds transfer pricing methodology for consistent presentation.

[2] Beginning in the second quarter of 2017, the Company realigned its business segment structure from three segments to two segments. Specifically, the Company retained the previous composition of the Wholesale Banking segment and changed the basis of presentation of the Consumer Banking and Private Wealth Management segment and Mortgage Banking segment such that those segments were combined into a single Consumer segment. Accordingly, business segment information presented for the year ended December 31, 2015 has been revised to conform to the new business segment structure and updated internal funds transfer pricing methodology for consistent presentation.

[3] For the year ended December 31, 2017, dividends were $4,056 per share for both Perpetual Preferred Stock Series A and B, $5,875 per share for Perpetual Preferred Stock Series E, $5,625 per share for Perpetual Preferred Stock Series F, $3,128 per share for Perpetual Preferred Stock Series G, and $669 per share for Perpetual Preferred Stock Series H.For the year ended December 31, 2016, dividends were $4,067 per share for both Perpetual Preferred Stock Series A and B, $5,875 per share for Perpetual Preferred Stock Series E, and $5,625 per share for Perpetual Preferred Stock Series F.For the year ended December 31, 2015, dividends were $4,056 per share for both Perpetual Preferred Stock Series A and B, and $5,875 per share for Perpetual Preferred Stock Series E, and $6,219 per share for Perpetual Preferred Stock Series F.