Other Financial Data (Accrued Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities [Abstract]
Deferred revenue	$ 439	$ 390
Compensation	250	241
Billings in excess of costs and earnings	434	337
Tax liabilities	111	48
Dividend payable	77	71
Trade liabilities	180	135
Other	620	449
Accrued liabilities	$ 2,111	$ 1,671