Leasing (Investments In Operating Leases) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease, weighted-average remaining lease term	6 years		7 years
Lessee, operating lease, noncancellable lease term	367 days
Lessee, operating lease, lease extension, maximum	48 months
Operating lease, right-of-use assets	$ 142		$ 168
Finance lease, right-of-use asset	48		0
Lease right-of-use asset	190		168
Operating lease, liabilities	170		196
Finance lease, liability	49		0
Lease liabilities	219		$ 196
Cash paid for amounts included in the measurement of lease liabilities	13	$ 12
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 35	$ 27
Operating lease, weighted average discount rate	2.75%		2.85%
Minimum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	2 months
Lessee, operating lease, option to terminate	P2Y
Maximum
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	9 years
Lessee, operating lease, option to terminate	P6Y
Land and Building | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend	P3Y
Land and Building | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend	P15Y