Contingencies And Commitments (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Operating lease ROU asset	$ 197
Operating lease liability	$ 204
Weighted average discount rate, operating lease	3.40%
Weighted average remaining operating lease term	7 years
Operating lease expense	$ 13
Sale-leaseback, net book value	177
Sale-leaseback, accumulated amortization	$ 300
Weighted average discount rate, finance lease	2.50%
Weighted average remaining finance lease term	3 years
Additional office lease	$ 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