Commitments, Contingent Liabilities and Guarantees - Commitments to Extend Credit or Funding (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Guarantor Obligations [Line Items]
Total loan commitments	$ 64,789	$ 61,478
Commercial letters of credit	91	86
Purchase card commitments	729	621
Principal investing commitments	21	26
Tax credit investment commitments	547	520
Total loan and other commitments	66,177	62,731
Commercial and Other [Member]
Guarantor Obligations [Line Items]
Total loan commitments	45,323	42,653
Commercial Real Estate and Construction [Member]
Guarantor Obligations [Line Items]
Total loan commitments	2,961	2,691
Home Equity [Member]
Guarantor Obligations [Line Items]
Total loan commitments	9,945	9,982
Credit Cards [Member]
Guarantor Obligations [Line Items]
Total loan commitments	$ 6,560	$ 6,152