Contingencies And Commitments (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Loss Contingencies [Line Items]
Operating lease ROU asset	$ 174	$ 174
Operating lease liability	$ 179	$ 179
Weighted average discount rate, operating lease	3.20%	3.20%
Weighted average remaining operating lease term	6 years	6 years
Operating lease expense	$ 11	$ 34
Sale-leaseback transactions, net	143	143
Total accumulated amortization related to sales leaseback transaction	$ 330	$ 330
Weighted average discount rate, finance lease	2.50%	2.50%
Weighted average remaining finance lease term	3 years	3 years
Additional office space leases		$ 37
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