Parent Company (Balance Sheet) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Other assets	[1]	$ 27,894	$ 27,506
Total assets		380,768	366,380
Subordinated debt		5,200	8,009
Total liabilities		333,183	319,526
Shareholders’ equity		47,513	45,699
Total liabilities and equity		380,768	366,380
Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash held at banking subsidiary		1	1	$ 1	$ 1
Restricted deposits with banking subsidiary		175	175
Nonrestricted interest-earning deposits		5,800	4,684
Loans with affiliates		1,244	1,358
Other assets		1,243	1,322
Total assets		55,221	52,760
Subordinated debt		1,645	2,242
Senior debt (a)		5,203	3,959
Commercial Paper		100
Other borrowed funds from affiliates		108	223
Accrued expenses and other liabilities		652	637
Total liabilities		7,708	7,061
Shareholders’ equity		47,513	45,699
Total liabilities and equity		55,221	52,760
Parent Company | Bank Subsidiaries And Bank Holding Company
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries		44,360	42,361
Parent Company | Non Bank Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries		$ 2,398	$ 2,859

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $1.7 billion, Loans of $.9 billion, and Other assets of $.3 billion at December 31, 2017 and Loans held for sale of $2.4 billion, Loans of $.9 billion, and Other assets of $.5 billion at December 31, 2016.