Commitments and Contingencies (Environmental) (Details) $ in Millions |
Sep. 30, 2017
USD ($)
Superfund_Sites
|
Dec. 31, 2016
USD ($)
|
|---|---|---|
| Accrual for Environmental Loss Contingencies Disclosure [Abstract] | ||
| Accrual for Environmental Loss Contingencies | $ 44 | $ 50 |
| Superfund Sites [Member] | ||
| Accrual for Environmental Loss Contingencies Disclosure [Abstract] | ||
| Number of superfund sites | Superfund_Sites | 7 | |
| Accrual for site contingency | $ 3 |