Contingencies And Commitments (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) contract	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Operating lease ROU asset	$ 233
Operating lease liability	$ 240
Weighted average discount rate, operating lease	3.20%
Weighted average remaining operating lease term	6 years
Operating lease expense	$ 54	$ 50	$ 43
Sale-leaseback, net book value	128
Sale-leaseback, accumulated amortization	$ 345
Weighted average discount rate, finance lease	2.20%
Weighted average remaining finance lease term	2 years
Number of leases not yet commenced | contract	0
Loss contingency accrual, insurance-related assessment, premium tax offset	$ (12)	$ (17)
Maximum [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate	$ 90