Leasing (Investments In Operating Leases) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lessee, operating lease, noncancellable lease term		367 days
Lessee, operating lease, lease extension, maximum		48 months
Operating lease, right-of-use assets	$ 140	$ 140		$ 168
Operating lease, liabilities	166	166		$ 196
Cash paid for amounts included in the measurement of lease liabilities	$ 12	37
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		$ 58	$ 41
Operating lease, weighted-average remaining lease term	6 years	6 years	7 years
Operating lease, weighted average discount rate	2.46%	2.46%	2.93%
Minimum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term		4 months
Lessee, operating lease, option to terminate		2
Maximum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term		8 years
Lessee, operating lease, option to terminate		6
Land and Building | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend		3
Land and Building | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend		15