Contingencies And Commitments (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Operating lease ROU asset	$ 161
Operating lease liability	$ 168
Weighted average discount rate, operating lease	3.40%
Weighted average remaining operating lease term	7 years
Operating lease expense	$ 12
Sale-leaseback transactions, net	177
Total accumulated amortization related to sales leaseback transaction	$ 300
Weighted average discount rate, finance lease	2.50%
Weighted average remaining finance lease term	3 years
Additional office space leases	$ 37
Pending Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate	$ 50
Maximum [Member]
Loss Contingencies [Line Items]
Lease term	11 years
Minimum [Member]
Loss Contingencies [Line Items]
Lease term	4 years