Loans and Leases - Net Loans (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 29,582	$ 23,294
Allowance for loan and lease losses	(54)	(54)
Loans and leases, net of allowance	29,528	23,240
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to investment funds	18,524	13,618
Senior secured bank loans	3,065	2,923
Loans to municipalities	1,946	2,105
Other	46	50
Commercial real estate	257	98
Lease financing	261	267
Total loans and leases	24,099	19,061
Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to investment funds	4,289	3,213
Senior secured bank loans	791	624
Lease financing	403	396
Total loans and leases	$ 5,483	$ 4,233

Loans Receivable, Gross, Commercial, Financial Institutions, Secured

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Loans and Leases Receivable, Gross, Commercial, Other

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Amount before allowance of commercial leases and leveraged lease transactions where the entity is long-term creditor. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes leases covered under loss sharing agreements.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases issued to a unit or agency of a federal, state or local jurisdiction within the country of domicile of the reporting entity. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Amount before allowance of loans issued to financial institutions, including, but not limited to, real estate investment trusts, mortgage companies, and banks. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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