Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Cash Payments:
Interest	$ 1,294	$ 682
Income taxes	10	21
Transfers:
Portfolio loans and leases to loans and leases held for sale	110	3
Loans and leases held for sale to portfolio loans and leases	1	4
Portfolio loans and leases to OREO	1	3
Bank premises and equipment to OREO	4	8
Available-for-sale debt securities to held-to-maturity securities	11,593	0
Supplemental Disclosures:
Net additions to lease liabilities under operating leases	13	1
Net additions to lease liabilities under finance leases	$ 46	$ 0

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