Loans and Leases - Net Loans (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 25,421	$ 25,789
Allowance for loan and lease losses	(72)	(67)
Loans and leases, net of allowance	25,349	25,722
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	19,050	20,353
Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	6,371	5,436
Loans to investment funds | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	13,823	15,050
Loans to investment funds | Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	5,265	4,505
Senior secured bank loans | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3,456	3,490
Senior secured bank loans | Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,106	931
Loans to municipalities | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	575	902
Other | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	32	37
Commercial Real Estate | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 1,164	$ 874