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	$ 154	$ 154
Operating lease liability	$ 164	$ 164
Weighted average discount rate, operating lease	3.40%	3.40%
Weighted average remaining operating lease term	6 years	6 years
Operating lease expense	$ 12	$ 23
Sale-leaseback transactions, net	159	159
Total accumulated amortization related to sales leaseback transaction	$ 318	$ 318
Weighted average discount rate, finance lease	2.70%	2.70%
Weighted average remaining finance lease term	3 years	3 years
Additional office space leases		$ 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