Fee-based Revenue from Contracts with Customers - Corporate & Institutional Banking Noninterest Income Disaggregation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 7,411	$ 7,221	$ 6,771
Corporate & Institutional Banking
Disaggregation of Revenue [Line Items]
Noninterest Income	2,406	$ 2,271	$ 2,035
Corporate & Institutional Banking | In-Scope Corporate and Institutional Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	1,454
Corporate & Institutional Banking | Out-of-Scope Corporate and Institutional Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	952
Corporate & Institutional Banking | Treasury Management Fees [Member] | In-Scope Corporate and Institutional Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	776
Corporate & Institutional Banking | Capital Markets Fees [Member] | In-Scope Corporate and Institutional Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	510
Corporate & Institutional Banking | Commercial Mortgage Banking Activities [Member] | In-Scope Corporate and Institutional Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	87
Corporate & Institutional Banking | Other | In-Scope Corporate and Institutional Banking Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 81