Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive LossAs a result of the transactions contemplated by the June 2019 Acquisition, we recorded an accumulated other comprehensive loss related to pension and other post-retirement benefits provided by Explorer and Colonial to their employees. We are not a sponsor of these benefits plans. The June 2019 Acquisition is accounted for as a transaction between entities under common control on a prospective basis, and we have recorded the acquisition on our consolidated balance sheet at SPLC’s historical basis, which included accumulated other comprehensive loss. In 2020 and 2019, we recorded $1 million and $2 million, respectively, in other comprehensive loss related to remeasurements related to these pension and other post-retirement benefits.