Parent Company Financial Statements (Condensed Balance Sheet - Parent Company Only) (Detail) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments in subsidiaries:
Goodwill		$ 2,445	$ 2,416	$ 2,416
Other assets	[1]	6,975	7,844
Total Assets		142,193	142,177	141,048
Liabilities
Other short-term borrowings		4,012	3,535
Accrued expenses and other liabilities	[1]	2,144	2,269
Long-term debt (external)	[1]	14,904	14,388
Total liabilities		125,808	125,945
Shareholders' Equity
Common stock	[2]	2,051	2,051
Preferred stock	[3]	1,331	1,331
Capital surplus		2,790	2,756
Retained earnings		15,122	13,441
Accumulated other comprehensive income		73	59	197	$ 429
Treasury stock	[2]	(5,002)	(3,433)
Noncontrolling interests		20	27
Total Equity		16,365	16,205
Total Equity		16,385	16,232	$ 15,870	$ 15,665
Total Liabilities and Equity		142,193	142,177
Parent Company Only
Assets
Cash		80	130
Short-term Investments		3,493	3,074
Loans to subsidiaries:
Nonbank subsidiaries		843	969
Total loans to subsidiaries		843	969
Investments in subsidiaries:
Nonbank subsidiaries		17,695	17,588
Total investment in subsidiaries		17,695	17,588
Goodwill		80	80
Other assets		329	366
Total Assets		22,520	22,207
Liabilities
Other short-term borrowings		315	344
Accrued expenses and other liabilities		472	461
Long-term debt (external)		5,348	5,170
Total liabilities		6,135	5,975
Shareholders' Equity
Common stock		2,051	2,051
Preferred stock		1,331	1,331
Capital surplus		2,790	2,756
Retained earnings		15,122	13,441
Accumulated other comprehensive income		73	59
Treasury stock		(5,002)	(3,433)
Noncontrolling interests		20	27
Total Equity		16,385	16,232
Total Liabilities and Equity		$ 22,520	$ 22,207

[1] Includes $ 0 and $ 85 of cash and due from banks, $ 62 and $ 0 of other short-term investments, $ 1,297 and $ 1,216 of portfolio loans and leases, $ (6) and $ (26) of ALLL, $ 7 and $ 9 of other assets, $ 2 and $ 3 of other liabilities and $ 1,190 and $ 1,094 of long-term debt from consolidated VIEs that are included in their respective captions above at December 31, 2017 and 2016 , respectively. For further information, refer to Note 11 .

[2] Common shares: Stated value $ 2.22 per share; authorized 2,000,000,000 ; outstanding at December 31, 2017 – 693,804,893 (excludes 230,087,688 treasury shares) , 2016 – 750,479,299 (excludes 173,413,282 treasury shares).

[3] 446,000 shares of undesignated no par value preferred stock are authorized and unissued at December 31, 2017 and 2016 ; fixed-to-floating rate non-cumulative Series H perpetual preferred stock with a $ 25,000 liquidation preference: 24,000 authorized shares, issued and outstanding at December 31, 2017 and 2016 ; fixed-to-floating rate non-cumulative Series I perpetual preferred stock with a $ 25,000 liquidation preference: 18,000 authorized shares, issued and outstanding at December 31, 2017 and 2016 ; and fixed-to-floating rate non-cumulative Series J perpetual preferred stock with a $ 25,000 liquidation preference: 12,000 authorized shares, issue d and outstanding at December 31, 2017 and 2016 .