Leases (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) branch	Dec. 31, 2019 USD ($)
Leases [Abstract]
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Finance Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebt	us-gaap:LongTermDebt
Number of branches | branch	422
Number of branches owned | branch	273
Number of branches leased | branch	149
Operating lease right-of-use assets	$ 213	$ 218
Finance lease right-of-use assets	4
Operating lease income	12
Sales-type or direct financing leases	320	334
Sales-type or direct financing leases income	$ 13	$ 14