Contingent Liabilities (Details) - USD ($) $ in Millions	May 20, 2016	Sep. 30, 2019
Loss Contingencies [Line Items]
Customer Refund Liability, Current		$ 131
Accrued environmental loss liabilities		33
Energy Transfer Merger [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 1,480
Gas Pipeline [Member]
Loss Contingencies [Line Items]
Accrued environmental loss liabilities		5
Natural Gas Under Ground Storage Facilities [Member]
Loss Contingencies [Line Items]
Accrued environmental loss liabilities		8
Former Operations [Member]
Loss Contingencies [Line Items]
Accrued environmental loss liabilities		20
Maximum [Member] | Former Alaska Refinery [Member]
Loss Contingencies [Line Items]
Loss contingency, range of possible loss		$ 32