Lease Obligations - Lessee - Lease Assets and Lease Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Operating lease right-of-use assets	$ 510	$ 511
Finance lease right-of-use assets	164	126
Total right-of-use assets	674	637
Operating lease liabilities	596	601
Finance lease liabilities	176	134
Total lease liabilities	$ 772	$ 735
Operating lease right-of-use assets [Extensible List]	Other assets	Other assets
Finance lease, right-of-use assets [Extensible List]	Bank premises and equipment	Bank premises and equipment
Operating lease liabilities [Extensible List]	Accrued Liabilities [Member]	Accrued Liabilities [Member]
Finance lease liabilities [Extensible List]	Long-term debt	Long-term debt
Operating lease right of use asset, accumulated amortization	$ 304	$ 292
Finance lease right of use asset, accumulated amortization	$ 48	$ 77