Commitments and Contingencies (Environmental) (Details) $ in Millions |
Dec. 31, 2018
USD ($)
Superfund_Sites
|
Dec. 31, 2017
USD ($)
|
|---|---|---|
| Accrual for Environmental Loss Contingencies Disclosure [Abstract] | ||
| Accrued liabilities for environmental matters | $ 42 | $ 48 |
| Superfund Sites [Member] | ||
| Accrual for Environmental Loss Contingencies Disclosure [Abstract] | ||
| Number of superfund sites | Superfund_Sites | 8 | |
| Accrual for site contingency | $ 9 |