Accounts Receivable (Schedule Of Accounts Receivable Under Long-Term Contracts) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Unbilled Receivables, Not Billable, Fiscal Year Maturity [Abstract]
Unbillable, current	$ 1,919	$ 2,024
Unbillable, expected to be collected after one year	2,011	2,001
Total Unbillable	3,930	4,025
Contracts Receivable, Claims and Uncertain Amounts, Fiscal Year Maturity [Abstract]
Claims, current	38
Claims, expected to be collected after one year	91	70
Total Claims	$ 129	$ 70