Other Financial Data (Accrued Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities [Abstract]
Deferred revenue	$ 390	$ 355
Compensation	241	190
Billings in excess of costs and earnings	337	358
Tax liabilities	48	91
Dividend payable	71	75
Trade liabilities	135	131
Other	449	506
Accrued liabilities	$ 1,671	$ 1,706