Goodwill And Other Intangible Assets (Narrative) (Details) - Customer Relationships [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Weighted average amortization period, customer relationships	15 years
Amortization expense of intangible assets	$ 127	$ 117	$ 56
Amortization expense, for each of the next five years	$ 123