Commitments and Contingent Liabilities Contingent Debt (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Indirect Guarantee of Indebtedness [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 330	$ 714
Number of equity investees subject to contingent obligation	3	4
Cortez Pipeline Company
Guarantor Obligations [Line Items]
Percentage of Debt Guaranteed	100.00%	100.00%
Long-term Debt | Cortez Pipeline Company
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 128	$ 147