Goodwill and Mortgage Servicing Rights - by Business Segment (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Goodwill [Line Items]
Total goodwill	$ 47,818	$ 47,477	$ 47,471	$ 47,483	$ 47,488	$ 47,507
Consumer & Community Banking
Goodwill [Line Items]
Total goodwill	31,038		30,984
Corporate & Investment Bank
Goodwill [Line Items]
Total goodwill	6,941		6,770
Commercial Banking
Goodwill [Line Items]
Total goodwill	2,982		2,860
Asset & Wealth Management
Goodwill [Line Items]
Total goodwill	$ 6,857		$ 6,857