Supplemental Cash Flow - Noncash Investing and Financing Activities (Details) - USD ($) $ in Millions		6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Jun. 30, 2019
Cash Payments:
Interest		$ 528	$ 710
Income taxes		268	318
Transfers:
Portfolio loans and leases to loans and leases held for sale		31	192
Loans and leases held for sale to portfolio loans and leases		29	27
Portfolio loans and leases to OREO		6	18
Loans and leases held for sale to OREO		2	0
Supplemental Disclosures:
Additions to right-of-use assets under operating leases		27	15
Additions to right-of-use assets under finance leases		76	1
Right-of-use assets recognized at adoption of ASU 2016-02		$ 0	$ 509
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member		us-gaap:AccountingStandardsUpdate201602Member