Supplemental Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Cash Payments:
Interest	$ 182	$ 367
Income taxes	209	14
Transfers:
Portfolio loans and leases to loans and leases held for sale	220	23
Loans and leases held for sale to portfolio loans and leases	10	7
Portfolio loans and leases to OREO	4	5
Bank premises and equipment to OREO	16	0
Supplemental Disclosures:
Additions to lease liabilities under operating leases	16	17
Additions to lease liabilities under finance leases	18	13
Accounts, Notes, Loans and Financing Receivable
Portfolio loans and leases to loans and leases held for sale	220	$ 23
Residential mortgage loans \| GNMA loans
Transfers:
Portfolio loans and leases to loans and leases held for sale	64
Accounts, Notes, Loans and Financing Receivable
Portfolio loans and leases to loans and leases held for sale	$ 64

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