Leasing (Investments In Operating Leases) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
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	$ 13	$ 13
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 337	$ 35
Operating lease, weighted-average remaining lease term	7 years		7 years
Operating lease, weighted average discount rate	2.19%		2.21%
Minimum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	3 months
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