Asset Retirement Obligations and Accrued Environmental Costs (Narrative) (Details) - USD ($) $ in Millions |
1 Months Ended | |
|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Site Contingency [Line Items] | ||
| Accrued environmental costs | $ 187 | $ 180 |
| Accrued environmental costs discounted | 153 | |
| Total environmental accrual included in balance sheet | $ 109 | |
| Maximum Number of Years Accrued Environmental Liabilities will be Paid Over | 30 years | |
| Expected expenditures for acquired environmental obligations, weighted-average discount factor rate | 5.00% | |
| Cleanup Remediation Activities [Member] | ||
| Site Contingency [Line Items] | ||
| Accrued environmental costs | $ 135 | 116 |
| Corporate and Other Environmental Liabilities [Member] | ||
| Site Contingency [Line Items] | ||
| Accrued environmental costs | 36 | 48 |
| Federal Comprehensive Environmental Response Compensation and Liability Act or Similar State Laws [Member] | ||
| Site Contingency [Line Items] | ||
| Accrued environmental costs | $ 16 | $ 16 |