Lease Obligations - Lessee - Lease Assets and Lease Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease right-of-use assets	$ 513	$ 508
Finance lease right-of-use assets	130	150
Total right-of-use assets	643	658
Operating lease liabilities	604	599
Finance lease liabilities	138	156
Total lease liabilities	$ 742	$ 755
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	$ 279	$ 255
Finance lease right of use asset, accumulated amortization	$ 72	$ 66