Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Loss Contingencies [Line Items] | |||
| Rent expense | $ 232 | $ 229 | $ 239 |
| Notional value of offset agreement with certain customers in foreign countries | 9,700 | ||
| Thales- Raytheon Systems Air and Missile Defense Command and Control S.A.S. (TRS AMDC2) [Member] | |||
| Loss Contingencies [Line Items] | |||
| Estimated liability related to guarantees and letters of credit | $ 3 | $ 2 | |