Commitments, Contingent Liabilities and Guarantees - Commitments to Extend Credit or Funding (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Guarantor Obligations [Line Items]
Total loan commitments	$ 61,478	$ 58,652
Commercial letters of credit	86	231
Purchase card commitments	621	425
Principal investing commitments	26	29
Tax credit investment commitments	520	481
Securities underwriting	0	9
Total loan and other commitments	62,731	59,827
Commercial and Other [Member]
Guarantor Obligations [Line Items]
Total loan commitments	42,653	40,315
Commercial Real Estate and Construction [Member]
Guarantor Obligations [Line Items]
Total loan commitments	2,691	2,774
Home Equity [Member]
Guarantor Obligations [Line Items]
Total loan commitments	9,982	9,673
Credit Cards [Member]
Guarantor Obligations [Line Items]
Total loan commitments	$ 6,152	$ 5,890