Segment Information - Assets by Segment (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting, Other Significant Reconciling Item [Line Items]
Cash and cash equivalents	$ 28	$ 15
Assets	36,662	40,430
L&S | Operating Segments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Assets	21,144	20,810
G&P | Operating Segments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Assets	$ 15,490	$ 19,605