Loans & Leases (Net Charge-Offs (Recoveries) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	$ 122	$ 77
Residential mortgage loans
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	1	1
Commercial Portfolio Segment | Commercial and Industrial Loans
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	50	18
Commercial Portfolio Segment | Commercial Mortgage Loans
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	2	(1)
Commercial Portfolio Segment | Commercial Leases
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	5
Consumer Portfolio Segment | Home Equity
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	3	3
Consumer Portfolio Segment | Indirect secured consumer loans
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	12	13
Consumer Portfolio Segment | Credit Card
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	36	33
Consumer Portfolio Segment | Other Consumer Loans
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together
Net Charge-Offs	$ 13	$ 10