Contingencies And Commitments (Narrative) (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Loss Contingencies [Line Items]
Operating lease ROU asset	$ 189	$ 189
Operating lease liability	$ 198	$ 198
Weighted average discount rate, operating lease	3.30%	3.30%
Weighted average remaining operating lease term	6 years	6 years
Operating lease expense	$ 13	$ 27
Sale-leaseback, net book value	159	159
Sale-leaseback, accumulated amortization	$ 318	$ 318
Weighted average discount rate, finance lease	2.70%	2.70%
Weighted average remaining finance lease term	3 years	3 years
Additional office lease		$ 40
Pending Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate	$ 50	$ 50
Maximum [Member]
Loss Contingencies [Line Items]
Lease term	11 years	11 years
Minimum [Member]
Loss Contingencies [Line Items]
Lease term	7 years	7 years