Leasing (Investments In Operating Leases) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lessee, operating lease, noncancelable lease term	367 days
Lessee, operating lease, lease extension, maximum	48 months
Cash paid for amounts included in the measurement of lease liabilities	$ 49	$ 49
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 93	$ 52
Operating lease, weighted-average remaining lease term	7 years	7 years
Operating lease, weighted average discount rate	2.21%	2.85%
Minimum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	1 month
Lessee, operating lease, option to terminate	5
Maximum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	11 years
Lessee, operating lease, option to terminate	6
Land and Building | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend	1
Land and Building | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend	15